The document summarizes research into using an amorphous silicon electronic portal imaging device (EPID) for intensity modulated radiation therapy (IMRT) quality assurance. It describes calibrating the EPID to correctly relate pixel values to dose. Measurements were made with the EPID and with film in a phantom to verify that the EPID provides accurate dose distributions for an IMRT plan compared to the treatment planning system and film measurements. The study shows the EPID can accurately verify IMRT field doses in a homogeneous phantom and replace film for pretreatment dose verification when used with the appropriate calibration and correction procedures.
Development and Implementation of VLSI Reconfigurable Architecture for Gabor ...Dr. Amarjeet Singh
This document presents a development of a VLSI reconfigurable architecture for a Gabor filter to be used in medical image applications, specifically for tonsillitis detection. It first provides background on Gabor filtering and its use in applications like texture analysis, object recognition, and medical image processing. It then reviews related works that have implemented Gabor filters. The document goes on to describe the proposed tonsillitis detection system, which includes modules for preprocessing, CORDIC filtering, filter generation, and convolution. It discusses simulating and synthesizing the design in Verilog and FPGA implementation. The results showed the design could operate at 394.563 MHz on an Artix 7 board.
IRJET- A New Strategy to Detect Lung Cancer on CT ImagesIRJET Journal
This document presents a new strategy for detecting lung cancer on CT images using image processing techniques. It involves acquiring CT scan images, preprocessing the images through techniques like grayscale conversion and Gabor filtering, segmenting the images using adaptive thresholding, extracting regions of interest through feature extraction methods like GLCM, and classifying images as cancerous or normal using support vector machines (SVM) and backpropagation neural networks (BPNN). The methodology achieves 96.32% accuracy for SVM and 83.07% accuracy for BPNN in detecting lung cancer from CT images.
IRJET- DNA Fragmentation Pattern and its Application in DNA Sample Type Class...IRJET Journal
This document proposes a framework for classifying DNA sample types using DNA fragmentation patterns. It involves several steps: (1) applying Gaussian blurring and bilateral filtering to reduce noise from images of fragmentation patterns, (2) extracting the region of interest, (3) calculating gray-level co-occurrence matrix features such as contrast and correlation, (4) using a k-nearest neighbors classifier to classify samples, and (5) segmenting images based on the classification. The results showed near 100% accuracy in classifying hundreds of DNA samples as different types based on their fragmentation patterns.
Whitepaper: Image Quality Impact of SmartGrid Processing in Bedside Chest Ima...Carestream
Scattered radiation is known to degrade image quality in
diagnostic X-ray imaging. A new image processing tool, SmartGrid, has been developed that compensates for the effects of X-ray scatter in an image, and produces results comparable to those of a physical antiscatter grid. Read the white paper to learn more.
Image restoration model with wavelet based fusionAlexander Decker
1. The document discusses various techniques for image restoration, which aims to recover a sharp original image from a degraded one using mathematical models of degradation and restoration.
2. It analyzes techniques like deconvolution using Lucy Richardson algorithm, Wiener filter, regularized filter, and blind image deconvolution on different image formats based on metrics like PSNR, MSE, and RMSE.
3. Previous studies have applied techniques like Wiener filtering, wavelet-based fusion, and iterative blind deconvolution for motion blur restoration and compared their performance.
Instant fracture detection using ir-raysijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Image-guided management of uncertainties in scanned particle therapyGiovanni Fattori
The document summarizes Giovanni Fattori's PhD thesis defense presentation on image-guided management of uncertainties in particle therapy. The presentation covers optical tracking and X-ray imaging used at CNAO, development and clinical implementation of these systems, and their impact on geometrical accuracy and dosimetry. It also discusses using optical tracking to monitor real-time motion of moving targets and experimental 4D dosimetry studies. Simulation results are presented showing the dosimetric impact of setup errors can be quantified through dose-volume histograms and indices.
Real Time Implementation of Ede Detection Technique for Angiogram Images on FPGAIRJET Journal
This document presents a new edge detection algorithm for angiogram images and its implementation on an FPGA. It begins with an introduction to angiography and importance of edge detection in analyzing angiogram images. It then describes the proposed algorithm which includes histogram equalization for enhancement followed by a modified Canny edge detection approach. The key steps of the modified Canny approach are also outlined. Experimental results on angiogram images demonstrate that the proposed FPGA implementation takes only 0.562ms for execution while maintaining accuracy. In conclusion, the algorithm is able to efficiently detect blood vessel edges in angiogram images making it useful for analyzing vascular diseases.
Development and Implementation of VLSI Reconfigurable Architecture for Gabor ...Dr. Amarjeet Singh
This document presents a development of a VLSI reconfigurable architecture for a Gabor filter to be used in medical image applications, specifically for tonsillitis detection. It first provides background on Gabor filtering and its use in applications like texture analysis, object recognition, and medical image processing. It then reviews related works that have implemented Gabor filters. The document goes on to describe the proposed tonsillitis detection system, which includes modules for preprocessing, CORDIC filtering, filter generation, and convolution. It discusses simulating and synthesizing the design in Verilog and FPGA implementation. The results showed the design could operate at 394.563 MHz on an Artix 7 board.
IRJET- A New Strategy to Detect Lung Cancer on CT ImagesIRJET Journal
This document presents a new strategy for detecting lung cancer on CT images using image processing techniques. It involves acquiring CT scan images, preprocessing the images through techniques like grayscale conversion and Gabor filtering, segmenting the images using adaptive thresholding, extracting regions of interest through feature extraction methods like GLCM, and classifying images as cancerous or normal using support vector machines (SVM) and backpropagation neural networks (BPNN). The methodology achieves 96.32% accuracy for SVM and 83.07% accuracy for BPNN in detecting lung cancer from CT images.
IRJET- DNA Fragmentation Pattern and its Application in DNA Sample Type Class...IRJET Journal
This document proposes a framework for classifying DNA sample types using DNA fragmentation patterns. It involves several steps: (1) applying Gaussian blurring and bilateral filtering to reduce noise from images of fragmentation patterns, (2) extracting the region of interest, (3) calculating gray-level co-occurrence matrix features such as contrast and correlation, (4) using a k-nearest neighbors classifier to classify samples, and (5) segmenting images based on the classification. The results showed near 100% accuracy in classifying hundreds of DNA samples as different types based on their fragmentation patterns.
Whitepaper: Image Quality Impact of SmartGrid Processing in Bedside Chest Ima...Carestream
Scattered radiation is known to degrade image quality in
diagnostic X-ray imaging. A new image processing tool, SmartGrid, has been developed that compensates for the effects of X-ray scatter in an image, and produces results comparable to those of a physical antiscatter grid. Read the white paper to learn more.
Image restoration model with wavelet based fusionAlexander Decker
1. The document discusses various techniques for image restoration, which aims to recover a sharp original image from a degraded one using mathematical models of degradation and restoration.
2. It analyzes techniques like deconvolution using Lucy Richardson algorithm, Wiener filter, regularized filter, and blind image deconvolution on different image formats based on metrics like PSNR, MSE, and RMSE.
3. Previous studies have applied techniques like Wiener filtering, wavelet-based fusion, and iterative blind deconvolution for motion blur restoration and compared their performance.
Instant fracture detection using ir-raysijceronline
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Image-guided management of uncertainties in scanned particle therapyGiovanni Fattori
The document summarizes Giovanni Fattori's PhD thesis defense presentation on image-guided management of uncertainties in particle therapy. The presentation covers optical tracking and X-ray imaging used at CNAO, development and clinical implementation of these systems, and their impact on geometrical accuracy and dosimetry. It also discusses using optical tracking to monitor real-time motion of moving targets and experimental 4D dosimetry studies. Simulation results are presented showing the dosimetric impact of setup errors can be quantified through dose-volume histograms and indices.
Real Time Implementation of Ede Detection Technique for Angiogram Images on FPGAIRJET Journal
This document presents a new edge detection algorithm for angiogram images and its implementation on an FPGA. It begins with an introduction to angiography and importance of edge detection in analyzing angiogram images. It then describes the proposed algorithm which includes histogram equalization for enhancement followed by a modified Canny edge detection approach. The key steps of the modified Canny approach are also outlined. Experimental results on angiogram images demonstrate that the proposed FPGA implementation takes only 0.562ms for execution while maintaining accuracy. In conclusion, the algorithm is able to efficiently detect blood vessel edges in angiogram images making it useful for analyzing vascular diseases.
This document compares the performance of image restoration techniques in the time and frequency domains. It proposes a new algorithm to denoise images corrupted by salt and pepper noise. The algorithm replaces noisy pixel values within a 3x3 window with a weighted median based on neighboring pixels. It applies filters like CLAHE, average, Wiener and median filtering before the proposed algorithm to further remove noise. Experimental results on test images show the proposed method achieves better noise removal compared to other techniques, with around a 60% increase in PSNR and 90% reduction in MSE. In conclusion, the proposed algorithm is effective at restoring images with high density salt and pepper noise.
Performance of a Novel SUV Calculation Scheme for PET StudyPawitra Masa-ah
1. The study developed a novel scheme for calculating standardized uptake values (SUV) directly from DICOM files using MATLAB. This allows SUV calculation without proprietary software.
2. The scheme extracts data like pixel intensities and calibration factors from the DICOM image and metadata headers. It uses this information to calculate activity concentration and SUV for regions of interest drawn on the images.
3. The scheme was tested on DICOM files from 11 PET/CT patients and showed 85% accuracy when compared to calculations from a commercial workstation, demonstrating it can reliably replace proprietary software for SUV analysis.
Medical Images are regularly of low contrast and boisterous/Noisy (absence of clarity) because of
the circumstances they are being taken. De-noising these pictures is a troublesome undertaking as they
ought to exclude any antiquities or obscuring of edges in the pictures. The Bayesian shrinkage strategy has
been chosen for thresholding in light of its sub band reliance property. The spatial space and Wavelet
based de-noising systems utilizing delicate thresholding strategy are contrasted and the proposed technique
utilizing GA (Genetic Algorithm) is used. The GA procedure is proposed in view of PSNR and results are
contrasted and existing spatial space and wavelet based de-noising separating strategies. The proposed
calculation gives improved visual clarity to diagnosing the restorative pictures. The proposed strategy in
view of GA surveys the better execution on the premise of the quantitative metric i.e PSNR (Peak Signal
to Noise-Ratio) and visual impacts. Reenactment results demonstrate that the GA based proposed
technique beats the current de-noising separating strategies.
Smart Noise Cancellation Processing: New Level of Clarity in Digital RadiographyCarestream
Smart Noise Cancellation (SNC) is a deep learning technique developed by Carestream Health to reduce noise in medical images while preserving fine detail. It uses a U-Net convolutional neural network trained on pairs of low-noise and simulated high-noise images. SNC predicts and subtracts a noise field from input images. Objective tests found SNC reduced noise by 2-4x while maintaining high-contrast sharpness and improving low-contrast detail detection. Subjective reader tests with radiologists found images processed with SNC were slightly to strongly preferable over traditional processing and had higher diagnostic capability ratings. SNC allows lowering radiation dose levels while maintaining image quality.
Spectral analysis of remotely sensed images provide the required information accurately even for small
targets. Hence Hyperspectral imaging is being used which follows the technique of dividing images into
bands. These Hyperspectral images find their applications in agriculture, biomedical, marine analysis, oil
seeps detection etc. A Hyperspectral image contains many spectra, one for each individual point on the
sample’s surface and in this project the required target on the Hyperspectral image is going to be detected
and classified. Hyperspectral remote sensing image classification is a challenging problem because of its
high dimensional inputs, many class outputs and limited availability of reference data. Therefore some
powerful techniques to improve the accuracy of classification are required. The objective of our project is
to reduce the dimensionality of the Hyperspectral image using Principal Component Analysis followed by
classification using Neural Network. The project is to be implemented using MATLAB.
Under the certain circumstances of the low and unacceptable accuracy on image recognition, the feature
extraction method for optical images based on the wavelet space feature spectrum entropy is recently
studied. With this method, the principle that the energy is constant before and after the wavelet
transformation is employed to construct the wavelet energy pattern matrices, and the feature spectrum
entropy of singular value is extracted as the image features by singular value decomposition of the matrix.
At the same time, BP neural network is also applied in image recognition. The experimental results show
that high image recognition accuracy can be acquired by using the feature extraction method for optical
images proposed in this paper, which proves the validity of the method.
IRJET- Analysis of Plant Diseases using Image Processing MethodIRJET Journal
This document describes a method for detecting plant diseases using image processing techniques. The method involves capturing images of plant leaves using a digital camera, preprocessing the images by converting them to grayscale and removing noise. Edge detection algorithms like Canny and Sobel are then applied to detect edges. K-means clustering is used for image segmentation to segment unhealthy parts of leaves. The process results in an effective solution for segmenting diseased areas of leaves.
Morphological and wavelet transform techniques were applied to enhance mammographic phantom images containing microcalcifications, nodules, and fibrils. Four observers evaluated the original and enhanced images using receiver operating characteristic analysis and subjective rating scales. While some techniques improved detection of certain structures over original images based on ROC curve analysis, subjective ratings indicated original images had better contrast, sharpness, and quality. Overall, the enhancement methods did not consistently increase detection performance. Future work should focus on improving enhancement algorithms to more effectively enhance image quality and visualization without altering structure morphology.
This document discusses brain tumor segmentation from MRI images using fuzzy c-means clustering. It begins with an introduction to brain tumors and MRI imaging. Next, it reviews existing methods for brain tumor segmentation such as thresholding, region growing, and clustering. It then discusses preprocessing MRI images, including converting images to grayscale and filtering. Finally, it describes fuzzy c-means clustering, which is an unsupervised learning technique used to segment and classify pixels in MRI images to detect tumor regions. The goal is to develop an accurate and automated method for brain tumor segmentation to assist medical experts.
Multimodality medical image fusion using improved contourlet transformationIAEME Publication
1. The document presents a technique for medical image fusion using an improved contourlet transformation with log Gabor filters.
2. It proposes decomposing images using a contourlet transformation with modified directional filter banks that incorporate log Gabor filters. This aims to provide high quality fused images while localizing features accurately and minimizing noise.
3. Experimental results on fusing medical images show that the proposed technique achieves higher quality measurements like PSNR compared to a basic contourlet transformation fusion approach.
IRJET - Lung Cancer Detection using GLCM and Convolutional Neural NetworkIRJET Journal
This document summarizes a research paper that proposes a method for detecting lung cancer using CT scan images with convolutional neural networks. The method involves preprocessing images using median filtering to remove noise, segmenting images using k-means clustering, extracting features using gray-level co-occurrence matrix, and classifying images using convolutional neural networks. The researchers achieved 96% accuracy in classifying tumors as malignant or benign, which is more accurate than traditional neural network methods.
This report summarizes quality control testing performed on a Philips fluoroscopy machine used for angiography procedures at a hospital in Trieste, Italy. Monthly quality control tests were conducted to check consistency of radiation output and automatic exposure control. Key parameters such as kVp, mA and air kerma were measured and found to be consistent with reference values, indicating proper functioning of automatic exposure control. The results confirm the importance of regular quality control testing to ensure optimal image quality while minimizing unnecessary radiation dose to patients.
An Image Enhancement Approach to Achieve High Speed using Adaptive Modified B...TELKOMNIKA JOURNAL
For real time application scenarios of image processing, satellite imaginary has grown more interest by researches due to the informative nature of image. Satellite images are captured using high quality cameras. These images are captured from space using on-board cameras. Wrong ISO setting, camera vibrations or wrong sensory setting causes noise. The degraded image can cause less efficient results during visual perception which is a challenging issue for researchers. Another reason is that noise corrupts the image during acquisition, transmission, interference or dust particles on the scanner screen of image from satellite to the earth stations. If quality degraded images are used for further processing then it may result in wrong information extraction. In order to cater this issue, image filtering or denoising approach is required.
Since remote sensing images are captured from space using on-board camera which requires high speed operating device which can provide better reconstruction quality by utilizing lesser power consumption. Recently various approaches have been proposed for image filtering. Key challenges with these approaches are reconstruction quality, operating speed, image quality by preserving information at edges on image.
Proposed approach is named as modified bilateral filter. In this approach bilateral filter and kernel schemes are combined. In order to overcome the drawbacks, modified bilateral filtering by using FPGA to perform the parallelism process for denoising is implemented.
A Flexible Scheme for Transmission Line Fault Identification Using Image Proc...IJEEE
This paper describes a methodology that aims to find and diagnosing faults in transmission lines exploitation image process technique. The image processing techniques have been widely used to solve problem in process of all areas. In this paper, the methodology conjointly uses a digital image process Wavelet Shrinkage function to fault identification and diagnosis. In other words, the purpose is to extract the faulty image from the source with the separation and the co-ordinates of the transmission lines. The segmentation objective is the image division its set of parts and objects, which distinguishes it among others in the scene, are the key to have an improved result in identification of faults.The experimental results indicate that the proposed method provides promising results and is advantageous both in terms of PSNR and in visual quality.
Basic Medical Imaging Processing and AnalysisKyla De Chavez
This document discusses basic medical image processing and analysis techniques. It covers topics such as basic image processing to enhance raw medical data, basic image analysis to supplement qualitative assessment, quality evaluation to assess new hardware and software, statistical analysis and entropy to provide a theoretical framework, coding and decoding of medical images, stable and unstable signal processing, common image transforms, pre-processing to remove artifacts and enhance images, post-processing to derive additional data, and medical image display.
my poster presentation in the jcms2011 conferencePawitra Masa-ah
1) The study created a new scheme for calculating standardized uptake values (SUVs) from DICOM files using MATLAB and tested it by comparing results to a GE healthcare software.
2) The SUVs calculated from the MATLAB scheme showed a high correlation of 0.974 with the GE software. The accuracy was 85% on average based on a 95% confidence interval.
3) The results demonstrated the SUVs from the MATLAB scheme can be used interchangeably with the GE software, providing increased accessibility for physicians to interpret PET/CT scans without other applications.
This document presents a novel edge detection algorithm proposed for mammographic images. It begins with an abstract summarizing the paper's focus on edge detection in mammograms and comparison to other common edge detection methods. It then provides background on edge detection and medical image analysis, describing common gradient and derivative-based edge detection methods. The main body introduces a new two-phase edge detection process called Binary Homogeneity Enhancement Algorithm (BHEA) that homogenizes the mammogram and detects edges by traversing the image horizontally and vertically. Results from the new method are then compared to other common edge detection filters.
Image De-noising and Enhancement for Salt and Pepper Noise using Genetic Algo...IDES Editor
Image Enhancement through De-noising is one of
the most important applications of Digital Image Processing
and is still a challenging problem. Images are often received
in defective conditions due to usage of Poor image sensors,
poor data acquisition process and transmission errors etc.,
which creates problems for the subsequent process to
understand such images. The proposed Genetic filter is capable
of removing noise while preserving the fine details, as well as
structural image content. It can be divided into: (i) de-noising
filtering, and (ii) enhancement filtering. Image Denoising
and enhancement are essential part of any image processing
system, whether the processed information is utilized for visual
interpretation or for automatic analysis. The Experimental
results performed on a set of standard test images for a wide
range of noise corruption levels shows that the proposed filter
outperforms standard procedures for salt and pepper removal
both visually and in terms of performance measures such as
PSNR.Genetic algorithms will definitely helpful in solving
various complex image processing tasks in the future.
Authentication of Degraded Fingerprints Using Robust Enhancement and Matching...IDES Editor
Biometric system is an automated method of
identifying a person based on physiological, biology and
behavioural traits. The physiological traits in include face,
fingerprint, palm print and iris which remains permanent
throughout an individual life time. In the event that these
physiological traits have been degraded then the
authentication of an individual becomes very difficult. The
challenge of restoring a degraded physiological image to an
acceptable appearance in order to authenticate an individual
is very enormous. Fingerprint is one of the most extensively
used biometric systems for authentication in areas where
security is of high importance. This is due to their accuracy
and reliability. However, extracting features out of degraded
fingerprints is the most challenging in order to obtain high
fingerprint matching performance. This paper endeavors to
enhance the clarity of fingerprint minutiae, removing false
minutiae and improve the matching performance using a
robust Gabor Filtering Technique (GFT) and Back Propagation
Artificial Neural Network (BP-ANN). The experiments showed
a remarkable improvement in the performance of the system.
ROI BASED MEDICAL IMAGE COMPRESSION WITH AN ADVANCED APPROACH SPIHT CODING AL...Journal For Research
Medical image compression has received great attention attributable to its increasing need to decrease the image size while not compromising the diagnostically crucial medical data exhibited on the image. Since the size of the image is primary matter of concern, to fix these issues compression was introduced. Over the past few years popularity of medical imaging lossless compression schemes rises radically because there is no loss of information. The only small part is more useful out of the whole image. Region of Interest Based Coding techniques are more considerable in medical field for the sake of efficient compression and to increase transmission bandwidth. The current work begins with the pre-processing of medical image. By assuming small part called roi part or deceased part in an image, Advanced SPIHT (ASPIHT) is applied. This paper propose techniques Region growing and Advanced Set Partition In Hierarchical Tree (ASPIHT) will enhance the performance of lossless compression and also enhance the Peak Signal to Noise Ratio (PSNR) and Compression Ratio (CR) than the Conventional SPIHT coding method.
This document compares five traditional methods for short-term load forecasting: simple moving average, weighted moving average, exponential smoothing, auto regressive, and multiple linear regression. It applies these methods to hourly load data from Paschim Gujarat Vij Co. Ltd to generate 1-hour ahead forecasts. For each method, it shows figures comparing the actual and forecasted loads for a selected day. The document concludes that time series models can provide reasonably accurate hourly load forecasts for short-term operational planning.
This document presents research on edge detection filters for gray images and analyzing the performance of different edge detection operators. It introduces edge detection as an important image processing technique for object detection. Several traditional edge detection operators are described, including Sobel, Prewitt, Laplacian, Robert, and Canny. The document then outlines an approach to apply these operators to a gray test image in MATLAB and analyze the results. Statistical measurements like PSNR and MSE are calculated and compared for each operator, with the results showing that Canny edge detection performed best. The conclusion is that edge detection filters can help with image segmentation and Canny provides relatively better performance than other operators.
This document compares the performance of image restoration techniques in the time and frequency domains. It proposes a new algorithm to denoise images corrupted by salt and pepper noise. The algorithm replaces noisy pixel values within a 3x3 window with a weighted median based on neighboring pixels. It applies filters like CLAHE, average, Wiener and median filtering before the proposed algorithm to further remove noise. Experimental results on test images show the proposed method achieves better noise removal compared to other techniques, with around a 60% increase in PSNR and 90% reduction in MSE. In conclusion, the proposed algorithm is effective at restoring images with high density salt and pepper noise.
Performance of a Novel SUV Calculation Scheme for PET StudyPawitra Masa-ah
1. The study developed a novel scheme for calculating standardized uptake values (SUV) directly from DICOM files using MATLAB. This allows SUV calculation without proprietary software.
2. The scheme extracts data like pixel intensities and calibration factors from the DICOM image and metadata headers. It uses this information to calculate activity concentration and SUV for regions of interest drawn on the images.
3. The scheme was tested on DICOM files from 11 PET/CT patients and showed 85% accuracy when compared to calculations from a commercial workstation, demonstrating it can reliably replace proprietary software for SUV analysis.
Medical Images are regularly of low contrast and boisterous/Noisy (absence of clarity) because of
the circumstances they are being taken. De-noising these pictures is a troublesome undertaking as they
ought to exclude any antiquities or obscuring of edges in the pictures. The Bayesian shrinkage strategy has
been chosen for thresholding in light of its sub band reliance property. The spatial space and Wavelet
based de-noising systems utilizing delicate thresholding strategy are contrasted and the proposed technique
utilizing GA (Genetic Algorithm) is used. The GA procedure is proposed in view of PSNR and results are
contrasted and existing spatial space and wavelet based de-noising separating strategies. The proposed
calculation gives improved visual clarity to diagnosing the restorative pictures. The proposed strategy in
view of GA surveys the better execution on the premise of the quantitative metric i.e PSNR (Peak Signal
to Noise-Ratio) and visual impacts. Reenactment results demonstrate that the GA based proposed
technique beats the current de-noising separating strategies.
Smart Noise Cancellation Processing: New Level of Clarity in Digital RadiographyCarestream
Smart Noise Cancellation (SNC) is a deep learning technique developed by Carestream Health to reduce noise in medical images while preserving fine detail. It uses a U-Net convolutional neural network trained on pairs of low-noise and simulated high-noise images. SNC predicts and subtracts a noise field from input images. Objective tests found SNC reduced noise by 2-4x while maintaining high-contrast sharpness and improving low-contrast detail detection. Subjective reader tests with radiologists found images processed with SNC were slightly to strongly preferable over traditional processing and had higher diagnostic capability ratings. SNC allows lowering radiation dose levels while maintaining image quality.
Spectral analysis of remotely sensed images provide the required information accurately even for small
targets. Hence Hyperspectral imaging is being used which follows the technique of dividing images into
bands. These Hyperspectral images find their applications in agriculture, biomedical, marine analysis, oil
seeps detection etc. A Hyperspectral image contains many spectra, one for each individual point on the
sample’s surface and in this project the required target on the Hyperspectral image is going to be detected
and classified. Hyperspectral remote sensing image classification is a challenging problem because of its
high dimensional inputs, many class outputs and limited availability of reference data. Therefore some
powerful techniques to improve the accuracy of classification are required. The objective of our project is
to reduce the dimensionality of the Hyperspectral image using Principal Component Analysis followed by
classification using Neural Network. The project is to be implemented using MATLAB.
Under the certain circumstances of the low and unacceptable accuracy on image recognition, the feature
extraction method for optical images based on the wavelet space feature spectrum entropy is recently
studied. With this method, the principle that the energy is constant before and after the wavelet
transformation is employed to construct the wavelet energy pattern matrices, and the feature spectrum
entropy of singular value is extracted as the image features by singular value decomposition of the matrix.
At the same time, BP neural network is also applied in image recognition. The experimental results show
that high image recognition accuracy can be acquired by using the feature extraction method for optical
images proposed in this paper, which proves the validity of the method.
IRJET- Analysis of Plant Diseases using Image Processing MethodIRJET Journal
This document describes a method for detecting plant diseases using image processing techniques. The method involves capturing images of plant leaves using a digital camera, preprocessing the images by converting them to grayscale and removing noise. Edge detection algorithms like Canny and Sobel are then applied to detect edges. K-means clustering is used for image segmentation to segment unhealthy parts of leaves. The process results in an effective solution for segmenting diseased areas of leaves.
Morphological and wavelet transform techniques were applied to enhance mammographic phantom images containing microcalcifications, nodules, and fibrils. Four observers evaluated the original and enhanced images using receiver operating characteristic analysis and subjective rating scales. While some techniques improved detection of certain structures over original images based on ROC curve analysis, subjective ratings indicated original images had better contrast, sharpness, and quality. Overall, the enhancement methods did not consistently increase detection performance. Future work should focus on improving enhancement algorithms to more effectively enhance image quality and visualization without altering structure morphology.
This document discusses brain tumor segmentation from MRI images using fuzzy c-means clustering. It begins with an introduction to brain tumors and MRI imaging. Next, it reviews existing methods for brain tumor segmentation such as thresholding, region growing, and clustering. It then discusses preprocessing MRI images, including converting images to grayscale and filtering. Finally, it describes fuzzy c-means clustering, which is an unsupervised learning technique used to segment and classify pixels in MRI images to detect tumor regions. The goal is to develop an accurate and automated method for brain tumor segmentation to assist medical experts.
Multimodality medical image fusion using improved contourlet transformationIAEME Publication
1. The document presents a technique for medical image fusion using an improved contourlet transformation with log Gabor filters.
2. It proposes decomposing images using a contourlet transformation with modified directional filter banks that incorporate log Gabor filters. This aims to provide high quality fused images while localizing features accurately and minimizing noise.
3. Experimental results on fusing medical images show that the proposed technique achieves higher quality measurements like PSNR compared to a basic contourlet transformation fusion approach.
IRJET - Lung Cancer Detection using GLCM and Convolutional Neural NetworkIRJET Journal
This document summarizes a research paper that proposes a method for detecting lung cancer using CT scan images with convolutional neural networks. The method involves preprocessing images using median filtering to remove noise, segmenting images using k-means clustering, extracting features using gray-level co-occurrence matrix, and classifying images using convolutional neural networks. The researchers achieved 96% accuracy in classifying tumors as malignant or benign, which is more accurate than traditional neural network methods.
This report summarizes quality control testing performed on a Philips fluoroscopy machine used for angiography procedures at a hospital in Trieste, Italy. Monthly quality control tests were conducted to check consistency of radiation output and automatic exposure control. Key parameters such as kVp, mA and air kerma were measured and found to be consistent with reference values, indicating proper functioning of automatic exposure control. The results confirm the importance of regular quality control testing to ensure optimal image quality while minimizing unnecessary radiation dose to patients.
An Image Enhancement Approach to Achieve High Speed using Adaptive Modified B...TELKOMNIKA JOURNAL
For real time application scenarios of image processing, satellite imaginary has grown more interest by researches due to the informative nature of image. Satellite images are captured using high quality cameras. These images are captured from space using on-board cameras. Wrong ISO setting, camera vibrations or wrong sensory setting causes noise. The degraded image can cause less efficient results during visual perception which is a challenging issue for researchers. Another reason is that noise corrupts the image during acquisition, transmission, interference or dust particles on the scanner screen of image from satellite to the earth stations. If quality degraded images are used for further processing then it may result in wrong information extraction. In order to cater this issue, image filtering or denoising approach is required.
Since remote sensing images are captured from space using on-board camera which requires high speed operating device which can provide better reconstruction quality by utilizing lesser power consumption. Recently various approaches have been proposed for image filtering. Key challenges with these approaches are reconstruction quality, operating speed, image quality by preserving information at edges on image.
Proposed approach is named as modified bilateral filter. In this approach bilateral filter and kernel schemes are combined. In order to overcome the drawbacks, modified bilateral filtering by using FPGA to perform the parallelism process for denoising is implemented.
A Flexible Scheme for Transmission Line Fault Identification Using Image Proc...IJEEE
This paper describes a methodology that aims to find and diagnosing faults in transmission lines exploitation image process technique. The image processing techniques have been widely used to solve problem in process of all areas. In this paper, the methodology conjointly uses a digital image process Wavelet Shrinkage function to fault identification and diagnosis. In other words, the purpose is to extract the faulty image from the source with the separation and the co-ordinates of the transmission lines. The segmentation objective is the image division its set of parts and objects, which distinguishes it among others in the scene, are the key to have an improved result in identification of faults.The experimental results indicate that the proposed method provides promising results and is advantageous both in terms of PSNR and in visual quality.
Basic Medical Imaging Processing and AnalysisKyla De Chavez
This document discusses basic medical image processing and analysis techniques. It covers topics such as basic image processing to enhance raw medical data, basic image analysis to supplement qualitative assessment, quality evaluation to assess new hardware and software, statistical analysis and entropy to provide a theoretical framework, coding and decoding of medical images, stable and unstable signal processing, common image transforms, pre-processing to remove artifacts and enhance images, post-processing to derive additional data, and medical image display.
my poster presentation in the jcms2011 conferencePawitra Masa-ah
1) The study created a new scheme for calculating standardized uptake values (SUVs) from DICOM files using MATLAB and tested it by comparing results to a GE healthcare software.
2) The SUVs calculated from the MATLAB scheme showed a high correlation of 0.974 with the GE software. The accuracy was 85% on average based on a 95% confidence interval.
3) The results demonstrated the SUVs from the MATLAB scheme can be used interchangeably with the GE software, providing increased accessibility for physicians to interpret PET/CT scans without other applications.
This document presents a novel edge detection algorithm proposed for mammographic images. It begins with an abstract summarizing the paper's focus on edge detection in mammograms and comparison to other common edge detection methods. It then provides background on edge detection and medical image analysis, describing common gradient and derivative-based edge detection methods. The main body introduces a new two-phase edge detection process called Binary Homogeneity Enhancement Algorithm (BHEA) that homogenizes the mammogram and detects edges by traversing the image horizontally and vertically. Results from the new method are then compared to other common edge detection filters.
Image De-noising and Enhancement for Salt and Pepper Noise using Genetic Algo...IDES Editor
Image Enhancement through De-noising is one of
the most important applications of Digital Image Processing
and is still a challenging problem. Images are often received
in defective conditions due to usage of Poor image sensors,
poor data acquisition process and transmission errors etc.,
which creates problems for the subsequent process to
understand such images. The proposed Genetic filter is capable
of removing noise while preserving the fine details, as well as
structural image content. It can be divided into: (i) de-noising
filtering, and (ii) enhancement filtering. Image Denoising
and enhancement are essential part of any image processing
system, whether the processed information is utilized for visual
interpretation or for automatic analysis. The Experimental
results performed on a set of standard test images for a wide
range of noise corruption levels shows that the proposed filter
outperforms standard procedures for salt and pepper removal
both visually and in terms of performance measures such as
PSNR.Genetic algorithms will definitely helpful in solving
various complex image processing tasks in the future.
Authentication of Degraded Fingerprints Using Robust Enhancement and Matching...IDES Editor
Biometric system is an automated method of
identifying a person based on physiological, biology and
behavioural traits. The physiological traits in include face,
fingerprint, palm print and iris which remains permanent
throughout an individual life time. In the event that these
physiological traits have been degraded then the
authentication of an individual becomes very difficult. The
challenge of restoring a degraded physiological image to an
acceptable appearance in order to authenticate an individual
is very enormous. Fingerprint is one of the most extensively
used biometric systems for authentication in areas where
security is of high importance. This is due to their accuracy
and reliability. However, extracting features out of degraded
fingerprints is the most challenging in order to obtain high
fingerprint matching performance. This paper endeavors to
enhance the clarity of fingerprint minutiae, removing false
minutiae and improve the matching performance using a
robust Gabor Filtering Technique (GFT) and Back Propagation
Artificial Neural Network (BP-ANN). The experiments showed
a remarkable improvement in the performance of the system.
ROI BASED MEDICAL IMAGE COMPRESSION WITH AN ADVANCED APPROACH SPIHT CODING AL...Journal For Research
Medical image compression has received great attention attributable to its increasing need to decrease the image size while not compromising the diagnostically crucial medical data exhibited on the image. Since the size of the image is primary matter of concern, to fix these issues compression was introduced. Over the past few years popularity of medical imaging lossless compression schemes rises radically because there is no loss of information. The only small part is more useful out of the whole image. Region of Interest Based Coding techniques are more considerable in medical field for the sake of efficient compression and to increase transmission bandwidth. The current work begins with the pre-processing of medical image. By assuming small part called roi part or deceased part in an image, Advanced SPIHT (ASPIHT) is applied. This paper propose techniques Region growing and Advanced Set Partition In Hierarchical Tree (ASPIHT) will enhance the performance of lossless compression and also enhance the Peak Signal to Noise Ratio (PSNR) and Compression Ratio (CR) than the Conventional SPIHT coding method.
This document compares five traditional methods for short-term load forecasting: simple moving average, weighted moving average, exponential smoothing, auto regressive, and multiple linear regression. It applies these methods to hourly load data from Paschim Gujarat Vij Co. Ltd to generate 1-hour ahead forecasts. For each method, it shows figures comparing the actual and forecasted loads for a selected day. The document concludes that time series models can provide reasonably accurate hourly load forecasts for short-term operational planning.
This document presents research on edge detection filters for gray images and analyzing the performance of different edge detection operators. It introduces edge detection as an important image processing technique for object detection. Several traditional edge detection operators are described, including Sobel, Prewitt, Laplacian, Robert, and Canny. The document then outlines an approach to apply these operators to a gray test image in MATLAB and analyze the results. Statistical measurements like PSNR and MSE are calculated and compared for each operator, with the results showing that Canny edge detection performed best. The conclusion is that edge detection filters can help with image segmentation and Canny provides relatively better performance than other operators.
Auxin induced germination and plantlet regeneration via Rhizome section cultu...IOSR Journals
1) The study developed a protocol for propagating the vulnerable medicinal orchid Spiranthes sinensis using rhizome section culture.
2) Rhizome sections were cultured on different concentrations of growth hormones including IBA, IAA, NAA, GA3, and cytokinin.
3) IBA at 100 ppm and GA3 at 500 ppm favored good germination and bud formation from the rhizome sections, with 100% and 90% survival rates respectively. The plantlets grew to 0.6 cm and 1.0 cm in length respectively.
Modeling and Analysis for Cutting Temperature in Turning of Aluminium 6063 Us...IOSR Journals
Deviation in machining process due to the temperature influence, cutting force, tool wear leads to
highly inferior quality of finished product, especially in high speed machining operations where product quality
and physical dimensions seems to be meticulous. Moreover, temperature is a significant noise parameter which
directly affects the cutting tool and work piece. Hence the aim of this project work is to study the machining
effect on 6063 Aluminium alloy at varies combinations of process parameters such as speed, feed rate and depth
of cut; and also to determine the effect of those parameters over the quality of finished product. A L27
Orthogonal Array (OA) based Design of Experiments (DOE) approach and Response Surface Methodology
(RSM) was used to analyse the machining effect on work material in this study. Using the practical data
obtained, a mathematical model was developed to predict the temperature influence and surface quality of
finished product. The ultimate goal of the study is to optimize the machining parameters for temperature
minimization in machining zone and improvement in surface finish.
A Study on the Relationship between Nutrition Status and Physical Fitness of ...IOSR Journals
Abstract: Nutritional status during school age is a major determinant of nutritional and health status in adult
life. Many studies showed that under nutrition and anaemia had an adverse impact on performance and
consequently led to reduction in wages for persons employed in manual labour.
The past three decades have witnessed the emergence of over nutrition as a problem in school-age children in
developed countries and in affluent urban segments in developing countries. The main determinants of
performance are physical fitness and skill. Longitudinal studies have shown that the lifestyle and physical
fitness during childhood and adolescence were major determinants of lifestyle, physical fitness and freedom
from non-communicable diseases in adult life.
This document discusses quality assurance in technical vocational education (TVE) for sustainable national development in the 21st century. It defines TVE and outlines its importance for providing skilled workers and empowering youth. The status of TVE in Nigeria is examined, noting issues like inadequate funding, resources, and the perception of TVE. Quality assurance is defined as measures to ensure TVE achieves its goals. Sustainable development and the role of TVE in enabling it are also discussed. The document concludes with recommendations like increasing government funding for TVE to improve its quality and contribution to Nigeria's sustainable development.
The Performance Analysis of a Fettling Shop Using SimulationIOSR Journals
Fettling shop is the product finishing shop of casting products.After the knockout, the casting is taken
to the fettling shop for doing the fettling work. The fettling process includes cutting, shot blasting, grinding and
painting. In all these process the sand and extra metal on the castings are removed. The project titled „The
performance analysis of a fettling shop using simulation‟ is based on a fettling shop of a casting industry. The
main aim of the project is the performance analysis of the fettling shop. This project is a simulation based
project and is done using a simulation tool called arena. The main concepts related with the performance
analysis are Bottleneck analysis, Productivity analysis and System improvement analysis.
Network Lifetime Analysis of Routing Protocols of Short Network in QualnetIOSR Journals
Abstract: A Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes that communicates with each other without using any existing infrastructure, access point or centralized administration. Mobile ad-hoc network have the attributes such as wireless connection, continuously changing topology, distributed operation and ease of deployment. In this paper we have compared the energy consumption of reactive, proactive & hybrid routing protocol AODV,DSR,RIP & ZRP by using different mobility model. We have analyzed the Network lifetime of protocols by varying pay load, mobility, pause time and type of traffic (CBR). A detailed simulation has been carried out in qualnet. The metrics used for performance analysis are energy consumed & battery consumption. It has been observed that RIP has better network lifetime than other.
This document provides an overview of hydrogen powered vehicles, including their types and benefits as well as challenges. It discusses how hydrogen can be used as an alternative fuel source for vehicles, produced through various methods like methane steam reforming and from coal. The key challenges of hydrogen storage are also outlined, such as liquid hydrogen, metal hydrides, compressed hydrogen gas. The working of hydrogen fuel cells is explained, noting they generate electricity through an electrochemical process without combustion. Advantages are zero emissions and high efficiency, while disadvantages include high production and storage costs.
Comparative Study of End Moments Regarding Application of Rotation Contributi...IOSR Journals
Abstract: Analysis of portal frames involves lot of complications and tedious calculations by conventional
methods. To carry out such analysis is a time consuming task. The rotation contribution method i.e. Kani’s
Method & Moment Distribution Method for analysis of portal frames can be handy in approximate and quick
analysis so as to get the detailed estimates ready. In this work, these two methods have been applied only for
vertical loading conditions. This paper presents the analysis of portal frame, considering mainly the case of
single bay portal frame, which is the most common in practice. The Kani’s method is self correcting, that is, the
error, if any, in a cycle is corrected automatically in the subsequent cycles. The checking is easier as only the
last cycle is required to be checked. The convergence is generally fast. It leads to the solutions in just a few
cycles of iterations.
Congestion Control in Manets Using Hybrid Routing ProtocolIOSR Journals
1. The document proposes a hybrid routing protocol that combines DSDV and IAODV to reduce packet loss due to congestion in MANETs.
2. Under the proposed scheme, DSDV is used initially for path selection. If congestion occurs, nodes switch to using IAODV to find an alternate path to avoid congested areas.
3. Simulation results show that the hybrid protocol improves end-to-end delay, packet delivery fraction, and throughput compared to using only DSDV or IAODV. The hybrid approach balances the advantages of proactive and reactive routing to better handle congestion in mobile ad hoc networks.
This document presents a comparative study of major telecom service providers in India based on secondary data analysis and a customer satisfaction survey. It analyzes the providers over the last five years on business metrics like net sales, profit after tax, total income, total expenditures, and market capitalization. It also evaluates customer satisfaction levels for the providers based on factors like network coverage, tariffs, plans, billing, and customer service. The study found that Bharti Airtel led in all business metrics over the period analyzed and had the highest overall customer satisfaction levels among the major Indian telecom providers.
This document discusses methods for detecting and preventing power theft. It begins by outlining the problem of electricity theft in India, costing $17 billion annually. It then describes some common methods of theft, such as attaching magnets to meters or bypassing meters. The document presents a proposed circuit to detect two types of theft: phase bypassing and overloading. It includes block diagrams of the circuit and simulations of overload and phase bypass conditions. It concludes that the circuit can detect and instantly stop the supply in these theft situations, helping to reduce losses for electricity boards.
Pollution Due To Noise from Selected PlacesIOSR Journals
Noise pollution degrades environment and also causes health hazard to human beings. In urban areas major sources of noise pollution are traffic and construction activities. Available guide lines for noise pollution have been reviewed in the paper. Measurement of noise levels at selected locations reported in the paper, for example, railway stations, use of machinery at construction sites, etc., was made and compared with the guide line values. It has been observed that the noise level at all locations exceeds the value prescribed by the competent authorities. At the pedestrian locations the noise level is 60 dB to 110 dB. At the railway crossing the noise level is 45 dB to 110 dB. The above inference shows that the noise pollution is paramount at all sources. Due to the various adverse impacts of noise on humans and environment, noise should be controlled. The conclusion drawn from this study is that the technique or the combination of techniques to be employed for noise control depends upon the extent of the noise reduction required, nature of the equipment used and the economy aspects of the available techniques
LC-MS/MS method for the quantification of carbinoxamine in human plasmaIOSR Journals
A simple, reverse-phase high performance liquid chromatographic method with mass spectrometric detection (HPLC-MS/MS) was developed for determination of carbinoxamine in human plasma using pargeverine HCl as an internal standard. The procedure involves a simple protein precipitation technique using BDS HYPERSIL C8 (100 x 4.6mm) column. The mobile phase used was acetonitrile: buffer (25mm ammonium formate solution) (80:20). Precipitation was done using acetonitrile and detection was done in MRM mode, using an Electro Spray positive ionization. The ion transition monitored was (m/z) carbinoxamine (Q1 Mass: 291.2; Q3 Mass: 167.1), Internal standard (Q1 Mass: 338.1; Q3 Mass; 167.0). The retention time of carbinoxamine and internal Standard were 1.61 and 1.75 respectively. Method was evaluated in terms of linearity, accuracy, precision, recovery, sensitivity. The simple extraction procedure and short chromatographic runtime make the method suitable for therapeutic drug monitoring studies.
This document describes a simulation of a space vector PWM controller for a five-level voltage-fed inverter motor drive. It begins by introducing multilevel inverters and some of the challenges in controlling them, specifically the increased complexity with more levels. It then presents a new approach to implementing space vector PWM for a five-level inverter by treating it as a conventional two-level system, making the calculations simpler. The methodology and implementation are described, including estimating switching times. Simulation results are presented showing the current, voltage and THD waveforms both with and without an LC filter. It is concluded that the proposed 2D system approach allows for simple implementation of SVPWM for a five-level inverter using common D
Monitoring Of Macronutrients Uptake by Soil and Potato Plants – A Comparative...IOSR Journals
Soil test1, 2 is necessary to identify optimal concentrations of essential elements required for plant growth. The fertility of soil is affected by the presence of some essential elements as Macronutrients like N, P& K. This study including the status of Macronutrients in the soil and potato plans. The percentage of nitrogen (N) in soil of potato plant was obtained 5.6% and 1.89% where as nitrogen percentage in plant ash was 17.45% and 16.4% respectively. But the phosphorus and potassium are present in adequate amount in soil. As it was found that the concentration of phosphorus (P) and potassium (K) in part per million in soil of potato was 62ppm and 148.3ppm and in potato plant ash the concentration was 64.23ppm and 103.3ppm respectively.
Impact of Frequency Offset on Interference between Zigbee and Wifi for Smart ...IOSR Journals
Abstract: The Zigbee is a low cost communication technology used for low data rate communication system such as industrial automation etc. Because of its low complexity it is widely adopted for many applications. But the utilization of the same spectrum band by the WLAN system causes interference between both the systems. The proposed approach presents an analysis of this interference effect on Zigbee system when operated with WLAN sources at different distances and different power. It also analyzes the effect when a frequency offset is established between both systems. The simulation results shows that a small offset can provide sufficient improvement in the performance. Keywords: Smart Grids, Zigbee Network, Mesh Network, Wireless LAN (WLAN), BER
Thermal spray coatings can enhance the wear resistance of materials. High-velocity oxy-fuel (HVOF) spraying is particularly effective due to producing very dense coatings with low porosity and high hardness. HVOF spraying involves melting or softening powder using a high-velocity oxy-fuel flame and projecting it onto a substrate. HVOF coatings have exceptional wear resistance, high bond strength, and are more cost-effective than other coating methods. Studies have shown that HVOF sprayed ceramic oxide and carbide coatings can significantly reduce wear in applications, performing better than uncoated materials. HVOF sprayed chromium carbide and tungsten carbide coatings are commonly used for their high wear resistance and ability to
Prediction of electronic and magnetic properties of Full Heusler Alloy – Ir2CrAlIOSR Journals
This document summarizes a study that used density functional theory calculations to predict the structural, electronic, and magnetic properties of the full Heusler alloy Ir2CrAl. The calculations found that Ir2CrAl has:
1) A lattice constant of 5.9648 Å after structural optimization, with a bulk modulus of 270.9 GPa.
2) Half-metallic behavior with 100% spin polarization at the Fermi level, due to an indirect band gap of 0.3 eV in the minority spin channel.
3) Ferromagnetic ordering with a total magnetic moment of 3 μB per formula unit, in agreement with Slater-Pauling rules for Heusler alloys.
PROFILE DOSE ANALYSIS OF 6MV LINEAR ACCELERATOR WITH CCD ELECTRONIC PORTAL IM...AM Publications
Profile dose analysis of 6 MV linear accelerator use CCD Electronic portal imaging device has been ivestigated. The aim of that research is analysis the profile dose curve of CCD EPID. The analysis include calculate the linierity. Symetrisity and penumbra value. Linier accelerator electa compac and CCD EPID are the material of that research. CCD EPID beamed with 10 x 10 cm field with 5 kind of MU. The MU values are 20 MU until 100 MU. The image of CCD EPID converted to grey-scale. Than we calculated the grey scale value become profile dose curve in cross-line and inline position. The result are we get simetrisity and penumbra less than 2%, but linierity value more 0,2% more than 3%. It means that the symetrisity and penumbra agree with AAPM TG no. 47. But the linerity must has more investigated to decrease he value until 3%.
This study compared the Varian portal dosimetry system and ImatriXX 2D array system for patient-specific quality assurance of IMRT and RapidArc plans. Fifteen IMRT and fifteen RapidArc plans were evaluated using both systems. For portal dosimetry, area gamma, average gamma, and maximum gamma were analyzed. For ImatriXX, the percentage of pixels passing a 3%-3mm gamma criteria was used. Portal dosimetry results were more consistent than ImatriXX. Both systems can be used for patient-specific QA, but portal dosimetry is less time-consuming and easier to perform, especially for individual IMRT field verification. Significant differences were seen between IMRT and RapidArc
IRJET- Fabric Defect Detection using Discrete Wavelet TransformIRJET Journal
This document describes a system for detecting defects in fabric images using discrete wavelet transform and a K-nearest neighbor classifier. The system takes an image using a camera, converts it to grayscale, applies discrete wavelet transform to decompose the image, and then uses a KNN classifier to classify the image as defective or defect-free based on extracted features. The system is able to detect common fabric defects like vertical yarn missing, horizontal yarn missing, and stains. It is implemented using MATLAB software and uses a basic hardware setup of a camera, motor, and lighting. Test results showed the system could accurately detect different types of synthetic fabric defects in real-time images.
This document presents Jeevn-Net, a new neural network architecture for brain tumor segmentation and overall survival prediction. Jeevn-Net uses a cascaded U-Net structure with two U-Nets and applies auto-encoder regularization. It takes in MRI scans and outputs a segmented tumor image with extracted features. Random forest regression is then used to predict survival based on these features. The network achieves state-of-the-art performance for brain tumor segmentation and survival prediction.
IRJET-Retina Image Decomposition using Variational Mode DecompositionIRJET Journal
This document describes research applying the variational mode decomposition (VMD) algorithm to decompose retina images. VMD is presented as an improvement over existing empirical mode decomposition methods as it is less sensitive to noise and frequencies. The researchers apply VMD to decompose a retina image into intrinsic mode functions (IMFs) representing different frequency bands. Texture features are extracted from the IMFs and used to classify retina images as healthy or unhealthy, achieving perfect detection. Hardware implementation of the VMD algorithm on an FPGA is also discussed to improve computational speed for potential medical applications in disease diagnosis.
Lung Cancer Detection using Image Processing TechniquesIRJET Journal
This document presents a technique for detecting lung cancer in x-ray images using image processing. It involves enhancing images using Gabor filtering, segmenting images using marker-controlled watershed segmentation, and extracting features using binarization and masking. The key steps are collecting lung x-ray images, enhancing quality using Gabor filtering, segmenting regions of interest using watershed segmentation, extracting pixel counts and mask features, and classifying images as normal or abnormal based on these features. The goal is to enable early detection of lung cancer through automated analysis of medical images.
IRJET - Automated 3-D Segmentation of Lung with Lung Cancer in CT Data using ...IRJET Journal
This document presents a novel robust active shape model (RASM) approach for automated 3D segmentation of lungs with lung cancer in CT data. The method consists of two main steps: 1) RASM matching is used to roughly segment the lung outline, with initial position found via skeletal structure detection. 2) Optimal surface finding further adapts the segmentation to the lung shape. Experiments on 30 datasets showed the proposed method achieved statistically better segmentation results than two commercial lung segmentation approaches, and is applicable to large shape models.
This document describes a study applying intensity modulated radiation therapy (IMRT) using independent jaws rather than a multi-leaf collimator for cancer patients in Dongnai General Hospital in Vietnam. IMRT plans were generated for a nasopharynx patient case using both conventional 3D conformal radiation therapy and jaw-only IMRT (JO-IMRT) techniques. The JO-IMRT plan provided better sparing of critical structures like the parotid glands and spinal cord compared to 3D-CRT. Measurement of the JO-IMRT plan delivery showed differences from calculated doses of less than 2.5%. The study aims to introduce JO-IMRT as a more economical and practical IMRT option for facilities
Supervised Blood Vessel Segmentation in Retinal Images Using Gray level and M...IJTET Journal
The segmentation of membranel blood vessels within the retina may be a essential step in designation of diabetic retinopathy during this paper, gift a replacement methodology for mechanically segmenting blood vessels in retinal pictures. 2 techniques for segmenting retinal blood vessels, supported totally different image process techniques, square measure represented and their strengths and weaknesses square measure compared. This methodology uses a neural network (NN) theme for element classification and gray-level and moment invariants-based options for element illustration. The performance of every algorithmic program was tested on the STARE and DRIVE dataset. wide used for this purpose, since they contain retinal pictures and also the
vascular structures. Performance on each sets of check pictures is healthier than different existing pictures. The methodology
proves particularly correct for vessel detection in STARE pictures. This effectiveness and lustiness with totally different image conditions, is employed for simplicity and quick implementation. This methodology used for early detection of Diabetic Retinopathy (DR)
1. Electronic Portal Imaging Devices (EPIDs) are imaging devices mounted on linear accelerators opposite the MV x-ray source.
2. EPIDs have a wide variety of applications including real-time patient setup verification during treatment and determining beam blocking shapes and leaf positions.
3. Commercially available EPIDs include scanning liquid-filled ion chamber devices, camera-based devices, and active matrix flat panel detectors. They provide localization quality images with doses less than 3 cGy.
A DEEP LEARNING APPROACH FOR DEFECT DETECTION AND SEGMENTATION IN X-RAY COMPU...gerogepatton
Additive manufacturing is an emerging and crucial technology that can overcome the limitations of
traditional manufacturing techniques to accurately manufacture highly complex parts. X-ray Computed
Tomography (XCT) is a widely used method for non-destructive testing of AM parts. However, detection
and segmentation of defects in XCT images of AM have many challenges due to contrast, size, and
appearance of defects. This study developed deep learning techniques for detecting and segmenting defects
in XCT images of AM. Due to a large number of required defect annotations, this paper applied image
processing techniques to automate the defect labeling process. A single-stage object detection algorithm
(YOLOv5) was applied to the problem of defect detection in image data. Three different variants of
YOLOv5 were implemented and their performances were compared. U-Net was applied for defect
segmentation in XCT slices. Finally, this research demonstrates that deep learning techniques can improve
the automatic defect detection and segmentation in XCT data of AM
Image Denoising of various images Using Wavelet Transform and Thresholding Te...IRJET Journal
The document discusses image denoising using wavelet transforms and thresholding techniques. It first provides background on image denoising and wavelet transforms. It then reviews several existing studies that used wavelet transforms like Haar, db4, and sym4 along with thresholding to denoise images corrupted with Gaussian and salt-and-pepper noise. Next, it describes the proposed denoising algorithm which involves adding noise to test images, decomposing the noisy images using different wavelet transforms, applying thresholding, and calculating metrics like PSNR to evaluate performance. The algorithm aims to eliminate noise in the wavelet domain using soft and hard thresholding followed by reconstruction.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IRJET - Change Detection in Satellite Images using Convolutional Neural N...IRJET Journal
The document describes a method for detecting changes in satellite images using convolutional neural networks. It discusses how existing methods have limitations in terms of accuracy and speed. The proposed method uses preprocessing techniques like median filtering and non-local means filtering. It then applies convolutional neural networks to extracted compressed image features and classify detected changes. The method forms a difference image without explicitly training on change images, making it unsupervised. Testing achieved 91.63% accuracy in change detection, showing the effectiveness of the proposed convolutional neural network approach.
This document discusses a digital image processing (DIP) based system for identifying defects in industrial materials like steel rods. Images of reference and test samples are taken and compared using techniques like thresholding, histograms, and cell segmentation in MATLAB. Defects are identified by variations between the images. The system is implemented on an FPGA for hardware acceleration. Images of steel rods with and without defects are compared to demonstrate the system's ability to detect cracks. The DIP based approach can replace manual inspection and provides faster quality evaluation of industrial materials compared to software-only methods.
A Novel Framework For Preprocessing Of Breast Ultra Sound Images By Combining...IRJET Journal
The document presents a novel framework for preprocessing breast ultrasound images that combines non-local means filtering and morphological operations. Non-local means filtering is used to reduce speckle noise, which is a significant issue for ultrasound images. Then morphological techniques are applied to enhance the noise-reduced images. The framework achieves peak signal-to-noise ratios of 60-80 decibels when tested on real breast ultrasound images. It provides an effective method for preprocessing ultrasound images to reduce noise and improve image quality.
Retinal Vessel Segmentation using Infinite Perimeter Active Contour with Hybr...IRJET Journal
This document proposes a retinal vessel segmentation method using an infinite perimeter active contour model with hybrid region information. It first enhances retinal images using three filters: an eigen value based filter, isotropic undecimated wavelet filter, and local phase based filter. It then segments the vessels from the enhanced images using the proposed infinite active contour model. When tested on two public datasets, the local phase based enhancement achieved the best segmentation accuracy compared to the other filters, with a sensitivity of 9.056% and accuracy of 96.52% on the DRIVE dataset. The proposed segmentation method outperforms most existing approaches in terms of segmentation performance.
A Survey on Ultrasound Beamforming StrategiesIRJET Journal
This document summarizes different strategies for ultrasound beamforming. Beamforming is the crucial step in ultrasound imaging where sound waves are focused on a specific point or area. The strategies are different in aspects like the type of signals used, imaging region size, time and computational costs. Several strategies are discussed including plane wave beamforming using the Fourier transform, software-based beamforming using data compression techniques, and FPGA-based modular digital beamforming. Beamforming strategies also differ in image resolution, information loss, and ability to reduce clutter from unwanted signals. Strict timing architectures can guarantee timing coherence for applications like ultrasound beamforming.
MULTI WAVELET BASED IMAGE COMPRESSION FOR TELE MEDICAL APPLICATIONprj_publication
Analysis and compression of medical image is an important area of biomedical
engineering. Analysis of medical image and data compression are rapidly evolving field with
growing applications in the teleradiology, Bio-medical, tele-medicine and medical data
analysis. Wavelet based techniques are latest development in the field of medical image
compression. The ROI must be compressed by a Lossless or a near lossless compression
algorithm. Wavelet based techniques are most recent growth in the area of medical image
compression.
Wavelet multi-resolution decomposition of images has shown its efficiency in many
image processing areas and specifically in compression. Transformed coefficients are
obtained by expanding a signal on a wavelet basis. The transformed signal is a different
representation of the same underlying data. Such representation is efficient if a relevant part
of the original information is found in a relative small number of coefficients. In this sense,
wavelets are near optimal bases for a wide class of signals with some smoothness, which is
the reason for compression.
Keywords: Image compression, Integer Multiwavelet Transform.
1. INTRODUCTION
Image Compression is used to reduce the number of bits required to represent an
image or a video sequence. A Compression algorithm takes an input X and generates
compressed information that requires fewer bits. The Decompression algorithm reconstructs
the compressed information and gives the original.
A compression of medical image is an important area of biomedical and telemedici
Wavelet based Image Coding Schemes: A Recent Survey ijsc
A variety of new and powerful algorithms have been developed for image compression over the years. Among them the wavelet-based image compression schemes have gained much popularity due to their overlapping nature which reduces the blocking artifacts that are common phenomena in JPEG compression and multiresolution character which leads to superior energy compaction with high quality reconstructed images. This paper provides a detailed survey on some of the popular wavelet coding techniques such as the Embedded Zerotree Wavelet (EZW) coding, Set Partitioning in Hierarchical Tree (SPIHT) coding, the Set Partitioned Embedded Block (SPECK) Coder, and the Embedded Block Coding with Optimized Truncation (EBCOT) algorithm. Other wavelet-based coding techniques like the Wavelet Difference Reduction (WDR) and the Adaptive Scanned Wavelet Difference Reduction (ASWDR) algorithms, the Space Frequency Quantization (SFQ) algorithm, the Embedded Predictive Wavelet Image Coder (EPWIC), Compression with Reversible Embedded Wavelet (CREW), the Stack-Run (SR) coding and the recent Geometric Wavelet (GW) coding are also discussed. Based on the review, recommendations and discussions are presented for algorithm development and implementation.
Similar to Efficacy of Use of A-Si EPID as Imaging Device in IMRT QA (20)
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
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This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
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The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
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Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
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Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Efficacy of Use of A-Si EPID as Imaging Device in IMRT QA
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861.Volume 7, Issue 1 Ver. III (Jan.-Feb. 2015), PP 27-43
www.iosrjournals.org
DOI: 10.9790/4861-07132743 www.iosrjournals.org 27 | Page
Efficacy of Use of A-Si EPID as Imaging Device in IMRT QA
Dina Abdelaziz, Wafaa Khalifa and Nader El Sherbini
Abstract: When IMRT treatment is considered to be a routine work, one should seek for an accurate, time
saving, fast and simple QA procedure. Electronic portal imaging device (EPID), especially amorphous silicon
type, is a promising tool for IMRT dosimetry. In this work a calibration of an amorphous silicon flat panel-type
imager (Elekta iViewGT, release 3.2) is done, which was incorrect (figure 3.1.) due to the EPID
renormalization to the target value (Elekta instructions). The calibration of the amorphous silicon flat panel-
type imager (Elekta iViewGT) was repeated after considering the Pixel Scaling Factor (PSF), which gave the
correct response (figure 3.2.). By using Omni Pro software the EPID images are converted into doses and a
correction for the dose reading from these images is done to obtain the same results as that measured at the
isocenter in 20 cm PMMA slab phantom. A correction for the EPID profiles for different field sizes is done to be
like those measured in the full scatter water phantom. A pre-treatment verification for a clinical step & shoot
IMRT plan is done for a prostate cancer case generated by Xio (version 4.2.2) treatment planning system (TPS).
The pre-treatment verification is done by EPID and a comparison in dose distribution against TPS and Films
are performed. This study show that the combination between iViewGT and Omni Pro software with the
corrections provided in the present study gave an accurate method to verify the dose of IMRT fields in two
dimensions inside a homogenous slab phantom. The results indicated also that the EPID (Elekta iViewGT) is an
accurate and can replace film for field-by field pretreatment verification of IMRT inside a phantom.
I. Introduction
The challenge of external beam radiotherapy for cancer treatment is to irradiate the tumor with a
desired dose, while the surrounding healthy tissue suffers as little as possible radiation damage.
Due to increase of complexity in modern radiotherapy techniques the needs for checking accuracy of
the delivered dose to patient has been also increased, either pretreatment or in vivo. This reflects the importance
of quality assurance (QA) as a step in radiation therapy treatment.
Quality assurance procedures of a patient treatment can be divided into two main parts:
Quality control of the technical aspects of the linear accelerator (Linac) itself includes verification of:
Dose output, the transferred parameter between treatment planning system (TPS) to linac (collimator settings,
the direction of wedges and multileaf collimator (MLC) shape) and Isodose check.
Verification of the actual patient treatment, including verification of both patient setup and delivery of
correct dose.
Ionization chamber is the predominant tool used to check the dose accuracy at certain points, while the
dose distribution of certain plan could be measured using different tools, e. g. Films, 2D diode array. The
increasing of using IMRT to deliver conformal radiation treatment has prompted the search for a faster and more
cost effective quality assurance (QA) system. The standard technique relies on the use of film for two-
dimensional dose distribution verification. Although film is considered the standard and most widely used for
this purpose, the procedures involved are relatively lengthy, labor intensive and costly for multiple field IMRT
verification. (Lim S. 2008).
QA of intensity modulated radiation therapy (IMRT) is a sophisticated and time consuming task,
where one should check not only the delivered dose and dose distribution but also need to check the field
segments shape, number and machine capability to deliver IMRT plan. When IMRT treatment is considered to
be a routine work, one should seek for an accurate, time saving, fast and simple QA procedure. Electronic portal
imaging device (EPID), especially amorphous silicon type, is a promising tool for IMRT dosimetry. A
commercial a-Si EPID has been studied by Talamonti C., et al, (2006) to investigate its potential in the field of
pretreatment verifications of step and shoot, IMRT for 6 MV photon beams.
An a-Si EPID has been investigated by Budgell G., et al, (2005) to determine its usefulness and
efficiency for performing linear accelerator quality control checks specific to step and shoot IMRT. Several
dosimetric parameters were measured using the EPID: dose linearity and segment to segment reproducibility of
low dose segments, and delivery accuracy of fractions of monitor units. Xu C., et al, (2002) have developed an
automated image based method for MLC positioning verification using images acquired from an EPID. Yeo I.
(2007) developed a method based on dose-response function, which verifies the beamlet intensity in IMRT from
dose image in EPID and reconstructs dose in a patient. Greer P., et al, (2007) determined the difference in
response between an a-Si EPID to the open and MLC transmitted beam components of IMRT beams. Ansbacher
2. Efficacy of use of a-Si EPID as imaging device in IMRT QA
DOI: 10.9790/4861-07132743 www.iosrjournals.org 28 | Page
W. (2006) developed a method for rapid evaluation of IMRT plans, using portal images for reconstruction of the
dose delivered to a virtual 3D phantom.
II. Materials And Methods
Elekta Precise (Crawley, UK) linear accelerator, which support IMRT deliver, was used in this study
(figure 2.1a). This linear accelerator (LINAC) produces photon energies of 6 and 15MV, also it produces
electrons with energies of 6, 8, 10, 12 and 15 Mev. Only 6 MV photon beam is used in this study. The LINAC is
equipped with MLC. The MLC consists of 40 leaf pairs with 1 cm leaf width at the isocenter.The type of EPID
used throughout this study is an amorphous silicon flat panel-type imager (Elekta iViewGT, release 3.2).The
detector panel is a PerkinElmer Amorphous Silicon (a-Si) detector, and provides a resolution of 1024 × 1024
16-bit pixel images, with a detector panel size of 41 × 41 cm2
(approximately 26 × 26 cm2
at isocenter).Display
pixel factor information;When images are acquired by iViewGTTM
, the pixel values are re-normalized or
averaged before the image data is saved to the database. At the time of acquisition, the pixel scaling factor is
saved with the images in the database. This feature allows us to determine the original accumulated pixel value
by dividing the pixel value by the pixel scaling factor.Polymethyl methacrylate (PMMA), also known as
acrylic. Trade names are Lucite, Plexiglas or Perspex. It consists of 1 cm for each sheet of density 1.19 g/cm3
and area 30 х 30 cm2
.GAFCHROMIC® EBT2 Dosimetry Film (8x10 in size) was used. The film spatial
resolution >5,000 dpi (dots per inch) with dose range 1cGy – 10Gy (in red color channel).Omni ProTM
IMRT is
software used for complete dosimetric verification and QA of IMRT treatment cycle. This software function is
to import and compare calculated doses fromTPS planned data with measured dose distributions from films that
were exposed in the IMRT phantom. It includes 1D profile, 2D isodose profiles as well as fully automated
comparisons using analysis tools such as Gamma index method.A computerized welhÖfer WP 700 water
phantom version 3.5 was used in the present study for acquiring the beam data.XiO treatment planning system
(TPS) (from CMS Inc., USA) version 4.2.2 implemented superposition algorithm is used in this study.
Calibration of the EPID Several steps are necessary to reconstruct the dose in the phantom or patient from the
pixel values of the EPID. All measurements of this study were performed at gantry and collimator angle 0°.
A- Calibration of EPID response to different doses:EPID images of reference field size (typically 10x10
cm2
) were recorded for different MU (2, 5, 10, 15, 25, 50, 100, 150 and 200 MU).The acquired images by
iViewGTTM
are re-normalized (automatically by the iViewGTTM
) before saving process; which means that
all images will appear with the same optical density (OD) for all different doses images. Sofor each image
the pixel scaling factor (PSF) is recorded to determine the original accumulated pixel value by dividing the
pixel value by this factor
Originalaccumulatedpixelvalue=
Pixelvalue
PixelScalingFactor (PSF )
(1)
To convert these images into doses, all images were exported to Omni Pro system.The Omni Pro
software can read the Optical Density OD of the image.Each EPID image imported to Omni Pro will be
corrected for its own PSF.even after dividing each image by its corresponding PSF it will still incorrect because
of several reasons:The scattered radiation from EPID;The scatter within the phantom;The scatter from the
phantom to the EPID;The attenuation of the beam by the phantom; andThe distance from the radiation source to
the EPID plane and to the dose reconstruction plane. (Wendling M., et al, 2006).Record the Omni Pro reading
value for each EPID dose, and get the Dose correction factor (DF), which is the Omni Pro reading value for a
specific dose divided by the Actual irradiated dose at isocenter
DF =
OmniProreadingvalueforaspecificdose
Actualirradiateddose
(2)
B- Calibration of the EPID profile
In order to determine the necessary parameters for correcting the dose profile reconstruction, i.e.,
relating pixel values in the EPID images with absolute dose values in the phantom, the EPID images at different
square field sizes are recorded with PMMA slab phantom of thickness 20 cm(an average thickness to encompass
the phantom (or patients) thickness at 6 MV photon beam). For all phantom measurements an isocentric setup
[SAD (source –axis distance) setup] was used. Dose profiles for the same field sizeswere obtained using
semiflex 0.147 ion chamber in the full-scatter water phantom [Source-Skin Distance (SSD) = 88.6cm] were
measured with ion chamber at 11.4cm depth.Where 11.4 cm water is equivalent to 10 cm of Perspex. These dose
profiles will be the reference for EPID dose profile correction. The EPID images were taken and corrected by
PSF & DF. After the conversion of EPID pixel values into dose values according to the dose response relation,
the resulting image is called dose image DEPID
. The corrected portal pixel dose according to its position
3. Efficacy of use of a-Si EPID as imaging device in IMRT QA
DOI: 10.9790/4861-07132743 www.iosrjournals.org 29 | Page
regarding to central axis (CAX) is PDEPID
, which is the image after profile correction, is obtained by the
predicted equation based on the previous work by Wendling, et al, 2006 and Renner, et al, 2005.
PDij
EPID
= Dij
EPID
× e−ar
3
Where r is the distance of a pixel ij from the central axis, a is the exponential fitting constant.This constant is
fitted properly for all field sizes.
Pre-treatment verification: EPID versus filmA clinical step & shoot IMRT plan is used for a prostate cancer
treatment generated by Xio (version 4.2.2) TPS. This plan consists of seven fields, and each field had between
8-14 segments.With EPID, one image was acquired for each segment using single exposure option in the image
acquisition mode for IMRT (Pre- segment image acquisition and storage also allows verification of MLC leaf
position), where the dose construction was also done separately for each segment. All of these images were sent
to the Omni Pro and corrected according to the previous corrections.The film irradiated simultaneously with the
corresponding EPID image acquisition for each field using PMMA phantom. A film is placed at 10 cm depth in
the PMMA phantom on the Linac table and 10 cm of PMMA slabs are placed under the film to achieve the
backscatter. This simultaneous irradiationto avoid any fluctuation in doses between film and EPID irradiation
like dose, dose rate fluctuation and MLC reposition. These images are compared with the simultaneously
irradiated films and a γ evaluation was done in two dimensions.
III. Results &Discussion
3.1 EPID Response
Wendling, et al, (2006) stated that the resulting response of the a-Si EPID has been shown to be linear with
dose, although a small ghosting effect remains, which is mainly a function of the number of exposed frames and
no correction for ghosting effect was made in their study. So, in the present study the original accumulated pixel
values of the raw images data which are obtained from iViewGTTM
software, by using equation (2-1) as
described in section (2) were used.
Figure (3.1.) central axis original accumulated pixel values versus monitor units for a 10x10 cm2
field.
3.2 Pixel Scaling Factor
Table (3-1) shows the signal reading in Omni Pro software of the doses calculated at the isocenter at
10cm depth in a 20cm thick PMMA slab phantom at SSD = 90cm.
Table (3-1)the signal reading in Omni Pro software of the doses calculated at the isocenter at 10cm depth in a
20cm thick PMMA slab phantom at SSD = 90cm.
Dose mGy at the isocenter of the PMMA phantom Signal reading 100%
20 479
50 513
100 520
150 521.5
200 521.5
250 521.7
500 521.6
1000 521.6
2000 521.6
4. Efficacy of use of a-Si EPID as imaging device in IMRT QA
DOI: 10.9790/4861-07132743 www.iosrjournals.org 30 | Page
These signals readings were obtained without any correction where one can found that there is
incorrect response,so all of these images numerical values will be divided by the PSF values listed in table (3-2).
These PSF are obtained from EPID row image data.
Table (3-2) The PSF for different doses at the isocenter at 10cm depth in a 20cm thick PMMA slab
phantom at SSD = 90cm for reference field size 10x10 cm2
Dose (mGy) PSF
20 4.61207
50 1.98999
100 0.93866
150 0.67392
200 0.51005
250 0.41549
500 0.20685
1000 0.10175
2000 0.05091
The resulting signal reading (100%) that irradiated to different doses 2,5,10, 50,100 and 200 cGy at the
isocenter at 10cm depth in a 20cm thick PMMA slab phantom at SSD = 90cm for reference field size 10x10
cm2
after dividing all images values by the corresponding PSF using the equation (2-1), that are obtained by
Omni Pro show different response for the different doses, as indicated in table (3-3).
Table (3-3)the signal reading in Omni Pro software after dividing each image numerical values by its
own PSF using equation (2-1).
Dose mGy at the isocenter of the PMMA phantom Signal reading 100%
20 103.4
50 257.5
100 554
150 773
200 1021
250 1254
500 2519
1000 5120
2000 10230
3.3 Dose Correction Factor
Although the Omni Pro gave a linear relationship between the dose and the signal reading for the EPID
images after dividing by PSF, the Omni Pro signal reading is not the same as the incident dose values. These
results agree with those obtained by Wendling,et al, (2006).
Wendling,et al, (2006) attributes these incorrect results to that the scatter within the EPID, the scatter within the
phantom, the scatter from the phantom to the EPID and the attenuation of the beam by the phantom are not
considered. Also the distance from the radiation source to the EPID plane and to the dose reconstruction plane is
not considered.
From our results the discrepancies may also be attributed to the introduction of a proposed
sensitometric curve which is the relation that consolidates Omni Pro to read the EPID images.
Figure (3.2.) The relation between Omni Pro reading and doses.
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It is clear from figure (3.2.) that the relation between Omni Pro reading and the delivered doses is a
linear relationship, and its slope = 51.26. By using equation (2-2) then the Omni Pro signal reading is the dose at
the isocenter at 10cm depth in a 20cm thick PMMA slab phantom at SSD = 90cm.
Table (3-4) Dose correction factor (DF) factor for different doses that obtained using equation (2-2).
Dose mGy at the isocenter of the Perspex phantom DF
20 51.70
50 51.50
100 55.00
150 51.53
200 51.05
250 50.16
500 50.38
1000 51.20
2000 51.15
Average value of DF 51.51
It is obvious from table (3-4) that the average DF factor is nearly the same as the slope of linear
relationship of figure (3.2.), this slope = 51.26.
So the slope value of the linear relationship between the dose and the signal reading for the EPID
images is used as DF value for different doses.
In this case the signal reading in Omni Pro is the same as that irradiated at the isocenter at 10cm depth
in a 20cm thick PMMA slab phantom at SSD = 90cm.
Figure (3.3.) shows the two dimensional dose distributions for the EPID images after PSF and DF correction.
(a) 2CGy (b) 5CGy
(c) 10CGy (d) 50CGy
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(e)100CGy (f) 200CGy
Figure (3.3.) Two dimensional dose distributions for the EPID images for 10x10 cm2
of 6MV photon beam
after PSF & DF correction
3.4 Dose correction for different field size
Table (3-5) shows the PSF for different field sizes with the same delivered doses (500 mGy).
Although all the field sizes were irradiated to the same dose at the isocenter at 10cm depth in a 20cm thick
PMMA slab phantom and at SSD = 90cm, there was difference in the PSF values, which is due to the different
contribution of scatter by changing the field size.
Table (3-5): PSF for different field sizes using 500 MGY.
Field size PSF
3×3 0.1688
5×5 0.20515
10×10 0.20683
15×15 0.20022
These differences in PSF values for the different field sizes receiving the same dose at the isocenter at
10cm depth in a 20cm thick PMMA slab phantom and at SSD = 90cm may be due to the dose calculation for
each field size is in full scatter conditions, that takes into consideration the collimator scatter factor and the
phantom scatter factor (calculated under full scatter situation), on the other hand EPID is not a full scatter
phantom (Varian Portal Vision instructions).
Also the EPID is known to have a lateral scatter (Wendling,et al, 2005) which is not considered in the
full scatter phantom calculation.
By trial it was found that the PSF for the reference field 10x10 cm2
gave approximately the same dose
value for different field sizes, as tabulated in table (3-6).
Table (3-6): OmniPro maximum signal reading for different field size images obtained by EPID after
dividing by the PSF of the reference field (10×10 cm2
).
Field size Signal reading 100%
3×3 2563
5×5 2562.9
10×10 2562.9
15×15 2562.9
Then after dividing the signal reading for each image of the different field sizes by the DF (51.26) the correct
dose at the isocenter, at 10cm depth in a 20cm thick PMMA slab phantom and SSD = 90cm is obtained with
maximum difference ± 0.2 % as shown by the red arrow in figure (3.4.).
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(a) 3×3 cm2
(b) 5×5 cm2
Figure (3.4.)
Generally after DF correction either for different doses of the reference field size 10×10cm2
or for the
same dose at different field size the average dose values agreed with the ionization chamber measurements at
the isocenter at 10cm depth in a 20cm thick PMMA slab phantom at SSD = 90cm with ± 0.2 % (which agree
with work done by Wendling,et al, 2006 and Renner,et al, 2005).
3.2 Profile Correction:
Profiles of square fields from EPID images were compared with those measured using an ionization
chamber that was located in a full-scatter water phantom. Figure (3.5.) shows the actual dose profiles of square
fields of different sizes obtained by EPID against the water phantom and TPS. The measurements are performed
in water phantom at 11.4 cm water (which is equivalent to 10 cm of PMMA), and source skin distance (SSD) =
88.6 cm.
(a) Field size 3×3 cm2
(b) Field size 5×5 cm2
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(c) Field size 10×10 cm2
Figure (3.5.) dose profile as measured by water phantom and from TPS against the reconstructed dose
profile from the EPID images without profile correction (a) 3×3 cm2 field size. (b) 5×5 cm2field size. (c)
10×10 cm2 field size. All profiles are normalized to 100% of the measured dose.
Figure (3.5.) shows a difference between water phantom measurements and the reconstructed profiles from the
EPID images for the studied field sizes.
Table (3-7) show the maximum percent of error between profiles measured and t
he EPID at different field sizes.
Table (3-7) (% error) between EPID and the water phantom dose profiles.
Field size(cm2
) Error (%)
3×3 3%
5×5 3.5%
10×10 3%
It is clear from figure (3.5.) and table (3-7); that the profile behaviour along the central axis region by
the three methods is good, and became worse in the penumbra region and the tails. This is because within the
EPID mainly lateral X-ray scatters and optical photon scatter occurs, resulting in more flattened at the shoulders
more than in water phantom &TPS. These findings are in agreement with the results of Wendling, et al, 2006.
The fit parameter [a] in equation (2-3) correct for these behaviour where it is obtained from the water phantom
measurements.
Figure (3.6.) shows the dose profiles of square fields for different sizes obtained by EPID after correction using
equation (2-3) and water phantom and TPS.
(a) Field size 3×3 cm2
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(b) Field size 5×5 cm2
(c) Field size 10×10 cm2
Figure (3.6.) dose profiles for different square field sizes as measured by water phantom at the isocenter at 11.4
cm depth which is equivalent to 10 cm Perspex, TPS and profiles reconstructed by the EPID using the Omni Pro
software at 6MV photon beam.
The fitting constant (a) in equation (2-3) was got by iteration to minimize the variation between the
measured dose by the water phantom and the reconstructed dose from the EPID, and it was found to be 0.03 for
all field sizes studied.
Figure (3.6.) shows that the agreement has improved and become in agreement with the other methods
(water phantom and TPS).
Among all field sizes the error does not exceed 0.2% between the EPID profiles and the profiles
measured by the water phantom and calculated by the TPS except for field size 10×10 cm2
where the agreement
is down to the 30 % dose on the central axis. These findings were found to be in qualitative agreement with
Wendling M., et al, 2006 who stated that the agreement was very good with the central axis, but remain worse
in the penumbra and in the tail of the profiles due to blurring of the measurements by the ionization chamber)
but in this study the most importance is for the small field sizes in order that the small segments in the IMRT
verification and the entire profiles for small field sizes agree with the measured ones.
Figure (3.7.) shows the difference between the EPID after dose and profile correction against the TPS
for different field size with the gamma evaluation (with criteria 3mm and 3%) using the Omni Pro software
and after implementing the dose and profile correction factor.
The plane dose profile comparison between the corrected EPID images and TPS is taken arbitrary on
the periphery of the field, to be sure that it correct through out the field.
10. Efficacy of use of a-Si EPID as imaging device in IMRT QA
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(a) (b)
(c)
Figure (3.7) Workspace – Omni Pro IMRT QA program reveal the dose profile of the EPID against that of
TPS (upper) and the γ index (upper) figure (a) for 3×3 field size, (b) for 5×5 field size and (c) for 10×10 field
size. Be sure that there is no red area (γ index > 1) within the field.
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3.3 Pre-treatment IMRT Verification
a) Segment by segment:
Now, instead of using ordinary open fields, an IMRT plan distribution is displayed by EPID & films in
comparison with the TPS.
The plan is done using superposition algorithm. For an IMRT case, 7 fields were used. The number of
segments in each field is illustrated in the plan report, (table 3-8).
Plan Report:
Table (3-8): number of segments for a prostate IMRT plan using Xio TPS version (4.2.2).
An IMRT plan has 7 fields
Beam number Number of segments
1 14
2 9
3 9
4 12
5 13
6 8
7 8
The correction factors (PSF, DF & profile correction equation) will be applied to each segment for every field.
EPID in comparison with Films versus TPS
Figures from (3.8.) to (3.10.) show some of the seventh field segments as an examples with their dose
distribution comparisons in terms of dose profile and theγ evaluation for EPID,as compared with film versus
TPS. The γ evaluation issued to judge about the comparison on the basis of the standard deviations in the γ
index between EPID & films using the Omni Pro software after all correction factors.
Since the dose for each segment was within 5-10 MUs which are under the response of Gafchromic films, the
doses were normalized to 50 cGy within the isocenter.
Figure (3.8, a) Workspace – Omni Pro IMRT QA program for segment 2 reveal the dose profile of the EPID
against that of TPS (upper) and the γ index (down).
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Figure (3.8, b) Workspace – Omni Pro IMRT QA program for segment 2 reveal the dose profile of the film
against that of TPS (upper) and the γ index (down).
Figure (3.9, a) Workspace – Omni Pro IMRT QA program for segment 3 reveal the dose profile of the EPID
against that of TPS (upper) and the γ index (down).
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Figure (3.9,b) Workspace – Omni Pro IMRT QA program for segment 3 reveal the dose profile of the film
against that of TPS (upper) and the γ index (down).
Figure (3.10, a) Workspace – Omni Pro IMRT QA program for segment 7 reveal the dose profile of the EPID
against that of TPS (upper) and the γ index (down).
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Figure (3.10,b) Workspace – Omni Pro IMRT QA program for segment 7 reveal the dose profile of the film
against that of TPS (upper) and the γ index (down).
Table (3-11) show the gamma evaluation for segments as comparison between EPID & films of the
present study.
Table (3-11): the standard deviation (SD) for both EPID and films in comparison to TPS using Omni Pro
software for the segments of field number 7
Segment number EPID SD % Film SD %
1 0.24 0.31
2 0.14 0.23
3 0.15 0.29
4 0.19 0.30
5 0.23 0.28
6 0.36 0.38
7 0.23 0.24
8 0.27 0.29
Average 0.22 0.29
As seen from table (3-11); the values of the SD and the average among the 8 segments for EPID are
less than that for Gafchromic films. This may be due to that the scanning of the film is not reproducible as the
EPID, and even by using the protocol in the method of film scanning (taken from Estro booklet 9 (2008)) there
is still a deviation, where scanning is done for the film more than 5 times which is an evidence on the instability
and turning the scanner off between scanning this may be contributed to the total error because the condition
will not be the same for all films, especially that the results will be affected if the orientation of the film is
inversed. Also Alber M., et al, (2008) stated that if there is any defect in the film manufacturing it will strongly
affect the results.
If the values of standard deviation for EPID and films in table (3-11) are analyzed separately, it will be
clear that as the shaping of the segment increase with the MLC the SD relatively increases. Renner,et al, 2005
stated that the superposition algorithm is generally known to be more accurate at tissue interfaces but it does not
model either multileaf collimator leaf-end leakage or inter-leaf leakage. So increasing the number of segments
in a plan will demonstrate any inaccuracy of the planning system.
On the other hand the difference between Films and EPID can also be compared by the percentage of
pixels passing the gamma test in the region of interest for each segment of the field as demonstrated by the
histogram in figure (3.19.).
Khan F., et al, (2008) also used the percentage of pixels passing the digital gamma test to compare between
EPID and the Matrixx (in this study films used instead of MatriXX, IMRT MatriXX is a two dimensional ion
chamber array (IBA Dosimetry, Schwarzenburck,Germany))
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Figure (3.11.) shows the percent of pixel passing the gamma test for EPID against films.
From figure (3.11.) it is clear that for all segments the percent of pixels passing the gamma test for
EPID is better than that for films. Also the minimum number of pixels passing the gamma test for EPID and
film were 99% and 98% respectively for segment 8. For segments 2 and 3, all pixels pass the gamma test for
both EPID and films.
Figures (3.8.) to (3.10.) show the comparison between EPID and films for samples of the segments in the
seventh field. These results prove that the EPID can replace films in IMRT QA.
b) Segment combination: Finally, it important to show the difference between reconstructed dose distribution
from EPID after correction and the calculated dose by TPS in the fields as a total with the same prescribed doses
for the planed prostate case plan. The two-dimensional midplan (isocentric-plan) dose distributions for all
segments of each field were then summed to obtain the total midplan dose of that specific field. Figure (3.12, a)
show Workspace – Omni Pro IMRT QA program for the a field from IMRT plan for the prostate case with its
prescribed doses that calculated by the TPS in the PMMA slab phantom( at 10 cm depth and SSD=90) at gantry
zero. The difference in dose distribution between the calculated dose by TPS and the reconstructed dose
distribution by EPID is also presented in the figures. Figure (3.12, b) show the histograms of the γ index,
indicating the maximum, minimum signal, the average signal and the standard deviation for each field using
EPID.
Figure (3.12, a) Workspace – Omni Pro IMRT QA program for field 7, reveal the dose distribution of the
EPID(down-left),the TPS dose distribution (upper-left),the dose profile of the EPID against that of TPS (upper-
right) and the γ index (down-right).
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Figure (3.12, b) Gamma index histogram for field 7.
Table (3-12) shows the difference in dose distribution between the measured films and the
reconstructed ones from EPID in comparison with the TPS in terms of SD.
Table (3-12) gamma evaluation comparison for the fields as a total between EPID and films.
Field number EPID SD % Film SD % Number of segments
1 0.30 0.33 14
2 0.25 0.26 9
3 0.28 0.27 9
4 0.16 0.31 12
5 0.20 0.32 13
6 0.18 0.30 8
7 0.15 0.28 8
Average 0.21 0.29
From table (3-12) if the data is analyzed separately either for EPID or for films it will be clear that
increasing the number of segments in the plan, increase the value of the SD for both EPID and films that
indicate that the deviation is due to the TPS calculation accuracy for either multileaf collimator leaf-end leakage
or inter-leaf leakage.
For films and EPID the percentage of pixels passing the gamma test in the region of interest for each field as are
shown in figure (3.13.).
Figure (3.13.) shows the percent of pixel passing the gamma test for EPID against films for each field.
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From figure (3.13.) it is clear that all the fields reconstructed from EPID are above 99% (for the criteria 3% dose
or 3mm distance to agreement).
Khan,et al, (2008) used 9 beam step-and-shoot IMRT plan for head phantom irradiated with 6MV X-ray and
the gamma evaluation histograms calculated for all9 beams indicates that 95% of all points pass the preset
criteria 3% dose or 3mm distance to agreement for each field.
IV. Conclusion
From this study one may conclude the following:
The time required to perform dose reconstruction with the EPID (iViewGT, release 3.2) is probably the
same as the established method using film. Yet, EPID as QA device has advantages over film QA in that it
is linear, more reproducible, and eliminates film problems, with scanners.
The total annual cost of imaging with film is higher than thatusing EPID concerning IMRT QA.
EPID (iViewGT, release 3.2) can replace the ionization chamber for measuring dose for the studied field
sizes at the isocenter at 10cm depth in a 20cm thick PMMA slab phantom at SSD = 90cm after correction
for PSF and DF.
From the study the combination between iViewGTand Omni Pro software with the used corrections can be
applied and provides an accurate method to verify the dose of IMRT fields in two dimensions inside a
homogenous slab phantom.
The EPID is an accurate and fast alternative to film for field-by field pretreatment verification of IMRT
inside a phantom.
Generally, Michael G. Herman – AAPM Task Group 58 – Electronic Portal Imaging – 2001 shows that
the annual cost of imaging with EPID as a function of increasing use of portal imaging is cheaper than that with
films. When IMRT QA by films taken into consideration especially that the cost of QA films for IMRT is more
expensive than that for portal imaging, sure this cost will be more effective.