Metal oxide semiconductor field effect transistor (MOSFET) detectors have recently been introduced to radiation therapy.
However, the response of these detectors is known to vary with dose rate. Therefore, it is important to evaluate how much variation between the treatment prescribed dose and the dose that is actually delivered to the
patient using high-energy photon or electron beams under conditions of different dose rates can be attributed to the detector.
The aim of this study was to investigate MOSFET dependence on different dose-rate levels. The measurements were done by exposing the mobile MOSFET detectors to a dose of 100 cGy using a linear accelerator
with energy of 6 MV and different dose rates from 100 cGy/MUs to 600 cGy/MUs.
The results showed that the dose rate dependence of a MOSFET dosimeter was within ±1.0%. MOSFET detectors are suitable for dosimetry of photon
beams, since they showed excellent linearity with dose rate variation.
Nearly 8,000 people are diagnosed with neuroendocrine tumors (NETs) annually in the US, with around 50% having metastases at diagnosis due to delays. Research shows that 68Ga-DOTA compounds provide better imaging resolution than 111In-pentetreotide, while 177Lu-DOTATATE demonstrates better survival and symptom reduction compared to 90Y-DOTATATE for treatment. Future research on combinations of therapeutic agents and a retrospective study assessing various radiopharmaceuticals' effectiveness is still needed.
2010 medical applications of optically stimulated luminescence dosimeters (os...Gerardo Rivera Barrera
This document discusses the use of optically stimulated luminescence dosimeters (OSLDs) for medical dosimetry applications in radiation therapy and diagnostic radiology. Specifically, it summarizes research conducted by a collaboration between Oklahoma State University and other institutions on: 1) Using OSLDs for high-precision dosimetry in radiation therapy with photons and electrons; 2) Determining dose profiles inside phantoms using OSLD strips in X-ray computed tomography; and 3) Investigating the performance of OSLDs for dosimetry of therapeutic proton beams, including measurements in air and along proton ranges. The results demonstrate the capability of OSLDs for medical dosimetry and their potential for one-dimensional dose
1) A study explored using an electrode array and signal characteristics to select an optimal electrode pair for surface electromyography (sEMG), aiming to improve on existing electrode placement methods.
2) A 3x4 electrode array was placed over seven muscles on subjects. Nine bipolar electrode pairs were formed from each array.
3) sEMG parameters were calculated for each pair and evaluated based on repeatability across trials and comparison to a traditionally placed electrode pair, to determine if signal characteristics could help select a high quality electrode pair.
This document summarizes the use of mass spectrometry techniques for analyzing new chemical entities in pharmaceutical discovery. It discusses how high-throughput synthesis has increased the need for high-throughput analytical methods to characterize large numbers of compounds efficiently. Mass spectrometry has emerged as a key technique due to its sensitivity, ease of automation, and ability to provide structural information. The document reviews various ionization techniques for mass spectrometry like MUX sources, combination sources, and MALDI that have helped increase analysis speed and throughput to keep pace with high-throughput synthesis.
This document discusses electrochemical sensors for detecting antibiotic residues in food. It begins with an introduction on the increasing global use of antibiotics and development of antibiotic resistance. It then discusses the working principles of electrochemical sensors and how they can be used to detect antibiotics. Specifically, it describes how electrochemical sensors use recognition elements like enzymes, antibodies, aptamers, and molecularly imprinted polymers to detect antibiotics. It also discusses using different electrode systems and materials like carbon nanotubes, nanoparticles, and graphene to improve detection. The document aims to provide an overview of developing electrochemical sensor techniques for antibiotic residue detection in food.
Molecular imaging has revolutionized our perceptions of imaging. This high impact field is finding transformative applications in the understanding, detection, and treatment of nearly all diseases.
The field of molecular imaging is a an exciting fusion and integration of many different disciplines including molecular biology, chemistry and probe design, imaging technologies, visualization, and image analysis, that are focused on understanding, detecting, and treating oncological, neurological, cardiovascular, inflammatory, metabolic, and infectious diseases. Based on their strengths, different imaging modalities provide different but equally valuable information that can be integrated in advancing our understanding of these diseases.
As the era of ‘omics’ progresses towards personalized medicine, the field of molecular imaging is finding multiple uses in noninvasive characterization of the molecular features of diseases and their impact on function. In complex diseases such as cancer, with its tremendous genetic diversity, it is becoming increasingly important to develop molecularly-targeted treatment strategies that combine detection with treatment.
Molecular imaging uses radiotracers and imaging modalities like PET and SPECT to non-invasively image biological processes at the molecular and cellular level. It has applications in both diagnostic imaging to locate targeted molecules involved in disease, as well as therapy to treat disease targets. PET provides higher resolution images while SPECT requires less equipment but has lower resolution. Both modalities detect emissions from radiotracers to construct 2D or 3D images showing the distribution of chemicals in the body.
Nearly 8,000 people are diagnosed with neuroendocrine tumors (NETs) annually in the US, with around 50% having metastases at diagnosis due to delays. Research shows that 68Ga-DOTA compounds provide better imaging resolution than 111In-pentetreotide, while 177Lu-DOTATATE demonstrates better survival and symptom reduction compared to 90Y-DOTATATE for treatment. Future research on combinations of therapeutic agents and a retrospective study assessing various radiopharmaceuticals' effectiveness is still needed.
2010 medical applications of optically stimulated luminescence dosimeters (os...Gerardo Rivera Barrera
This document discusses the use of optically stimulated luminescence dosimeters (OSLDs) for medical dosimetry applications in radiation therapy and diagnostic radiology. Specifically, it summarizes research conducted by a collaboration between Oklahoma State University and other institutions on: 1) Using OSLDs for high-precision dosimetry in radiation therapy with photons and electrons; 2) Determining dose profiles inside phantoms using OSLD strips in X-ray computed tomography; and 3) Investigating the performance of OSLDs for dosimetry of therapeutic proton beams, including measurements in air and along proton ranges. The results demonstrate the capability of OSLDs for medical dosimetry and their potential for one-dimensional dose
1) A study explored using an electrode array and signal characteristics to select an optimal electrode pair for surface electromyography (sEMG), aiming to improve on existing electrode placement methods.
2) A 3x4 electrode array was placed over seven muscles on subjects. Nine bipolar electrode pairs were formed from each array.
3) sEMG parameters were calculated for each pair and evaluated based on repeatability across trials and comparison to a traditionally placed electrode pair, to determine if signal characteristics could help select a high quality electrode pair.
This document summarizes the use of mass spectrometry techniques for analyzing new chemical entities in pharmaceutical discovery. It discusses how high-throughput synthesis has increased the need for high-throughput analytical methods to characterize large numbers of compounds efficiently. Mass spectrometry has emerged as a key technique due to its sensitivity, ease of automation, and ability to provide structural information. The document reviews various ionization techniques for mass spectrometry like MUX sources, combination sources, and MALDI that have helped increase analysis speed and throughput to keep pace with high-throughput synthesis.
This document discusses electrochemical sensors for detecting antibiotic residues in food. It begins with an introduction on the increasing global use of antibiotics and development of antibiotic resistance. It then discusses the working principles of electrochemical sensors and how they can be used to detect antibiotics. Specifically, it describes how electrochemical sensors use recognition elements like enzymes, antibodies, aptamers, and molecularly imprinted polymers to detect antibiotics. It also discusses using different electrode systems and materials like carbon nanotubes, nanoparticles, and graphene to improve detection. The document aims to provide an overview of developing electrochemical sensor techniques for antibiotic residue detection in food.
Molecular imaging has revolutionized our perceptions of imaging. This high impact field is finding transformative applications in the understanding, detection, and treatment of nearly all diseases.
The field of molecular imaging is a an exciting fusion and integration of many different disciplines including molecular biology, chemistry and probe design, imaging technologies, visualization, and image analysis, that are focused on understanding, detecting, and treating oncological, neurological, cardiovascular, inflammatory, metabolic, and infectious diseases. Based on their strengths, different imaging modalities provide different but equally valuable information that can be integrated in advancing our understanding of these diseases.
As the era of ‘omics’ progresses towards personalized medicine, the field of molecular imaging is finding multiple uses in noninvasive characterization of the molecular features of diseases and their impact on function. In complex diseases such as cancer, with its tremendous genetic diversity, it is becoming increasingly important to develop molecularly-targeted treatment strategies that combine detection with treatment.
Molecular imaging uses radiotracers and imaging modalities like PET and SPECT to non-invasively image biological processes at the molecular and cellular level. It has applications in both diagnostic imaging to locate targeted molecules involved in disease, as well as therapy to treat disease targets. PET provides higher resolution images while SPECT requires less equipment but has lower resolution. Both modalities detect emissions from radiotracers to construct 2D or 3D images showing the distribution of chemicals in the body.
This study aimed to develop a non-destructive method of measuring lactate concentration in atherosclerotic plaques using near-infrared spectroscopy. Human carotid plaques were maintained ex vivo under physiologic conditions for extended measurements. Measurements of pH, temperature, PO2 and PCO2 over time validated plaque viability. Near-infrared spectroscopy measurements of lactate correlated well with destructive assays, suggesting feasibility of non-destructively assessing plaque activity and vulnerability.
This study aimed to develop a non-destructive method of measuring lactate concentration in atherosclerotic plaques using near-infrared spectroscopy. Human carotid plaques were maintained ex vivo under physiologic conditions for extended measurements. Measurements of pH, temperature, PO2 and PCO2 over time validated plaque viability. Near-infrared spectroscopy measurements of lactate correlated well with destructive assays, suggesting feasibility of non-destructively assessing plaque activity and vulnerability.
The document describes progress made in calibrating a 3 French near infrared spectroscopy fiber optic catheter to non-invasively measure pH and lactate levels in atherosclerotic plaque. Researchers were able to maintain excised human carotid plaques under near physiological conditions for extended periods to collect measurements. Preliminary results show the near infrared measurement of tissue lactate in living plaques correlates well with destructive standard measurements, and this approach may allow direct translation of calibration equations to future in vivo validation studies.
Multimodality Molecular Imaging – An Overview With Special Focus on PET/CTApollo Hospitals
Multimodality molecular imaging combines multiple imaging modalities to provide enhanced visualization of biological processes. Positron emission tomography (PET) is particularly useful for molecular imaging as it can radiolabel biological molecules to image specific targets or pathways. PET combined with computed tomography (CT) or magnetic resonance imaging (MRI) provides highly accurate anatomical and functional information by precisely aligning PET and anatomical images. These hybrid PET/CT and PET/MRI systems utilize the strengths of each modality and offer opportunities to study molecular biology and disease in novel ways.
The document discusses various biomolecular interaction analysis (BIA) techniques for studying interactions between biomolecules and small molecules. It begins with an introduction to BIA and its importance for understanding biology, drug discovery, and diagnostics. The document then outlines and describes several BIA techniques categorized as biochemistry and biophysics methods, molecular methods, computer-aided techniques, and novel creative approaches. Specific techniques discussed in detail include fluorescence spectroscopy, circular dichroism spectroscopy, nuclear magnetic resonance spectroscopy, mass spectrometry, and isothermal titration calorimetry. The document provides information on the principles, applications, advantages, and limitations of each technique.
This document discusses various applications of radionuclide imaging. It begins with an overview of types of ionizing radiation and how different radionuclides are used in nuclear medicine. Examples are given of specific radiotracers used in cardiac, cerebral, and oncologic imaging. The document then focuses on applications of nuclear medicine in evaluating the gastrointestinal system and hepatobiliary system, including imaging of the liver, spleen, and detection of Meckel's diverticulum and gastrointestinal bleeding. Safety considerations of radiotracer administration are also reviewed.
The Molecular Imaging Laboratory at Howard University provides state-of-the-art imaging equipment including high resolution MRI systems for small animal and clinical research. The lab aims to train students and foster multidisciplinary research using imaging to study disease processes and investigate new treatments. Areas of research include in vivo MRI and optical imaging of disease models in small animals, as well as molecular imaging of biological processes and developing new imaging probes and nanoparticles.
Parameters affecting the selectivity of an electrical insecticideIJECEIAES
Using an electrical approach in the field of agriculture can be considered as one of the solutions in order to control harmful flying insects. This technique is based on the use of a bio and selective electrical insecticide whose principle consists in attracting insects by the light then get them electrocuted by an electrical discharge. Moreover, There are several parameters that affect the selectivity of electrical insecticide such as: the light, the most efficient, the inter electrode distance, where the insect is exterminated, and the electric current that passes through the insect’s body. In this paper, a simulation study was carried out concerning the distribution of the electric field between two electrodes in presence of particle conductor while focusing on the different body sizes. On the other hand, an experimental study was conducted on live locusts to determine the effect of electrical current on insect’s body taking into account the voltage and frequency. Finally, the results are discussed and analyzed in this paper.
PET and SPECT Scanning: Functional Brain ImagingBrendan Quinn
PET and SPECT are functional brain imaging techniques. PET has higher resolution but is more expensive, while SPECT has lower resolution but is less expensive. Both techniques involve injecting radioactive tracers and detecting their location in the brain to map blood flow and metabolic activity. fMRI is another functional imaging technique that detects changes in blood oxygenation to map brain activity.
This study compares image quality between a Nikon light microscope and a Zeiss scanning microscope using histology slides stained with H&E. 14 images from renal carcinoma tissue slides were acquired with each microscope and analyzed based on pixel value distributions, resolution, and quantitative image quality metrics. While both microscopes produced diagnostically adequate images, the Zeiss microscope had higher resolution and better control over metadata, which is important as computational analysis of histology images increases. Further analysis is needed to more precisely quantify differences in image quality between microscopes.
The document discusses building multi-target bioactivity models in Pipeline Pilot using both ligand and target descriptors. It describes combining ligand fingerprints with target descriptors derived from protein binding site properties, such as principal components describing amino acid physicochemical properties. Example applications to HIV and other drug targets are mentioned. Key steps included generating ligand and target representations, building proteochemometric models, and analyzing feature importance to understand determinants of bioactivity and resistance.
The document discusses the application of nanotechnology in biosensors. It begins by defining nanotechnology and biosensors. Nanoparticles are gaining interest in biosensing applications due to their size-dependent properties. Standard procedures for detection are time-consuming, non-specific, costly, and require trained personnel. Nanoparticles can be used to develop micro/nanobiosensors that are fast, inexpensive, simple to use, efficient, and portable. Various types of nanoparticles and detection techniques using nanoparticles like fluorescence, inductively coupled plasma mass spectrometry, and potentiometric analysis are then described.
PET RADIOTRACERS
PET images are based on the detection of a tracer
that is typically injected into the body. By comparing
the distribution of the tracer in a patient to
normal templates, a physician is able to evaluate
how well different organs and systems in the body
are functioning. The tracer consists of two components:
a pharmaceutical and a radioactive label.
This document summarizes research using a radio frequency sensor to detect and distinguish particle concentration. The RF sensor uses changes in dielectric permittivity to detect particles without labelling. Test results showed the sensor could detect 4 μm polystyrene particles at different concentrations and frequencies, and distinguish between 1% and 10% concentrations. Future work will further test the sensor's ability to detect different particles and concentrations at more frequencies to support its use in applications like medicine, biology and environmental monitoring.
Variation of dose distribution with depth and incident energy using EGSnrc Mo...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document describes an experiment using a radio frequency (RF) sensor to detect particles of different sizes and concentrations in solution. The RF sensor detects changes in dielectric permittivity to identify particles. The experiment tested a 1% concentration of 4 μm silica particles, distinguished between 1% and 10% concentrations of 4 μm particles, and observed single 10 μm polystyrene particles. The results showed the RF sensor could detect particles in solution and changes for single particles, but distinction between concentrations was less clear. Further research is needed to improve concentration distinction and support the sensor's ability to detect single particles.
Dose Evaluation in the Movement Couch of the Total Body Irradiation Technique...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This study aimed to develop a non-destructive method of measuring lactate concentration in atherosclerotic plaques using near-infrared spectroscopy. Human carotid plaques were maintained ex vivo under physiologic conditions for extended measurements. Measurements of pH, temperature, PO2 and PCO2 over time validated plaque viability. Near-infrared spectroscopy measurements of lactate correlated well with destructive assays, suggesting feasibility of non-destructively assessing plaque activity and vulnerability.
This study aimed to develop a non-destructive method of measuring lactate concentration in atherosclerotic plaques using near-infrared spectroscopy. Human carotid plaques were maintained ex vivo under physiologic conditions for extended measurements. Measurements of pH, temperature, PO2 and PCO2 over time validated plaque viability. Near-infrared spectroscopy measurements of lactate correlated well with destructive assays, suggesting feasibility of non-destructively assessing plaque activity and vulnerability.
The document describes progress made in calibrating a 3 French near infrared spectroscopy fiber optic catheter to non-invasively measure pH and lactate levels in atherosclerotic plaque. Researchers were able to maintain excised human carotid plaques under near physiological conditions for extended periods to collect measurements. Preliminary results show the near infrared measurement of tissue lactate in living plaques correlates well with destructive standard measurements, and this approach may allow direct translation of calibration equations to future in vivo validation studies.
Multimodality Molecular Imaging – An Overview With Special Focus on PET/CTApollo Hospitals
Multimodality molecular imaging combines multiple imaging modalities to provide enhanced visualization of biological processes. Positron emission tomography (PET) is particularly useful for molecular imaging as it can radiolabel biological molecules to image specific targets or pathways. PET combined with computed tomography (CT) or magnetic resonance imaging (MRI) provides highly accurate anatomical and functional information by precisely aligning PET and anatomical images. These hybrid PET/CT and PET/MRI systems utilize the strengths of each modality and offer opportunities to study molecular biology and disease in novel ways.
The document discusses various biomolecular interaction analysis (BIA) techniques for studying interactions between biomolecules and small molecules. It begins with an introduction to BIA and its importance for understanding biology, drug discovery, and diagnostics. The document then outlines and describes several BIA techniques categorized as biochemistry and biophysics methods, molecular methods, computer-aided techniques, and novel creative approaches. Specific techniques discussed in detail include fluorescence spectroscopy, circular dichroism spectroscopy, nuclear magnetic resonance spectroscopy, mass spectrometry, and isothermal titration calorimetry. The document provides information on the principles, applications, advantages, and limitations of each technique.
This document discusses various applications of radionuclide imaging. It begins with an overview of types of ionizing radiation and how different radionuclides are used in nuclear medicine. Examples are given of specific radiotracers used in cardiac, cerebral, and oncologic imaging. The document then focuses on applications of nuclear medicine in evaluating the gastrointestinal system and hepatobiliary system, including imaging of the liver, spleen, and detection of Meckel's diverticulum and gastrointestinal bleeding. Safety considerations of radiotracer administration are also reviewed.
The Molecular Imaging Laboratory at Howard University provides state-of-the-art imaging equipment including high resolution MRI systems for small animal and clinical research. The lab aims to train students and foster multidisciplinary research using imaging to study disease processes and investigate new treatments. Areas of research include in vivo MRI and optical imaging of disease models in small animals, as well as molecular imaging of biological processes and developing new imaging probes and nanoparticles.
Parameters affecting the selectivity of an electrical insecticideIJECEIAES
Using an electrical approach in the field of agriculture can be considered as one of the solutions in order to control harmful flying insects. This technique is based on the use of a bio and selective electrical insecticide whose principle consists in attracting insects by the light then get them electrocuted by an electrical discharge. Moreover, There are several parameters that affect the selectivity of electrical insecticide such as: the light, the most efficient, the inter electrode distance, where the insect is exterminated, and the electric current that passes through the insect’s body. In this paper, a simulation study was carried out concerning the distribution of the electric field between two electrodes in presence of particle conductor while focusing on the different body sizes. On the other hand, an experimental study was conducted on live locusts to determine the effect of electrical current on insect’s body taking into account the voltage and frequency. Finally, the results are discussed and analyzed in this paper.
PET and SPECT Scanning: Functional Brain ImagingBrendan Quinn
PET and SPECT are functional brain imaging techniques. PET has higher resolution but is more expensive, while SPECT has lower resolution but is less expensive. Both techniques involve injecting radioactive tracers and detecting their location in the brain to map blood flow and metabolic activity. fMRI is another functional imaging technique that detects changes in blood oxygenation to map brain activity.
This study compares image quality between a Nikon light microscope and a Zeiss scanning microscope using histology slides stained with H&E. 14 images from renal carcinoma tissue slides were acquired with each microscope and analyzed based on pixel value distributions, resolution, and quantitative image quality metrics. While both microscopes produced diagnostically adequate images, the Zeiss microscope had higher resolution and better control over metadata, which is important as computational analysis of histology images increases. Further analysis is needed to more precisely quantify differences in image quality between microscopes.
The document discusses building multi-target bioactivity models in Pipeline Pilot using both ligand and target descriptors. It describes combining ligand fingerprints with target descriptors derived from protein binding site properties, such as principal components describing amino acid physicochemical properties. Example applications to HIV and other drug targets are mentioned. Key steps included generating ligand and target representations, building proteochemometric models, and analyzing feature importance to understand determinants of bioactivity and resistance.
The document discusses the application of nanotechnology in biosensors. It begins by defining nanotechnology and biosensors. Nanoparticles are gaining interest in biosensing applications due to their size-dependent properties. Standard procedures for detection are time-consuming, non-specific, costly, and require trained personnel. Nanoparticles can be used to develop micro/nanobiosensors that are fast, inexpensive, simple to use, efficient, and portable. Various types of nanoparticles and detection techniques using nanoparticles like fluorescence, inductively coupled plasma mass spectrometry, and potentiometric analysis are then described.
PET RADIOTRACERS
PET images are based on the detection of a tracer
that is typically injected into the body. By comparing
the distribution of the tracer in a patient to
normal templates, a physician is able to evaluate
how well different organs and systems in the body
are functioning. The tracer consists of two components:
a pharmaceutical and a radioactive label.
This document summarizes research using a radio frequency sensor to detect and distinguish particle concentration. The RF sensor uses changes in dielectric permittivity to detect particles without labelling. Test results showed the sensor could detect 4 μm polystyrene particles at different concentrations and frequencies, and distinguish between 1% and 10% concentrations. Future work will further test the sensor's ability to detect different particles and concentrations at more frequencies to support its use in applications like medicine, biology and environmental monitoring.
Variation of dose distribution with depth and incident energy using EGSnrc Mo...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document describes an experiment using a radio frequency (RF) sensor to detect particles of different sizes and concentrations in solution. The RF sensor detects changes in dielectric permittivity to identify particles. The experiment tested a 1% concentration of 4 μm silica particles, distinguished between 1% and 10% concentrations of 4 μm particles, and observed single 10 μm polystyrene particles. The results showed the RF sensor could detect particles in solution and changes for single particles, but distinction between concentrations was less clear. Further research is needed to improve concentration distinction and support the sensor's ability to detect single particles.
Dose Evaluation in the Movement Couch of the Total Body Irradiation Technique...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
CT Dose Issues.pptx on the factors to be considered on radiation protectionsanyengere
summary, mobile radiography allows for the diagnostic imaging of patients who are unable to be seen in the X-ray examination room. Therefore, mobile X-ray equipment is useful for patients who have difficulty with movement. However, staff are exposed to scattered radiation from the patient, and can receive potentially harmful radiation doses during radiography. The protection of staff is of utmost importance; therefore, we investigated the occupational radiation doses received by RTs, particularly eye doses, using phantom measurements. RTs can be located close to a patient (i.e., the source of scattered radiation) during mobile radiography. As eye doses can be significant, protective measures are essential for RTs. Protective aprons are important for protecting RTs, as is increasing the distance from the radiation source (i.e., the patient). Lead glasses may also be necessary for protecting the eyes of RTs. To reduce RT radiation exposure, RTs should remain distant from the patient if possible. However, because this distance may hinder verification of the patient’s condition, RTs sometimes work in close proximity to patients. This is a patient phantom study. In future, the data may need validation by comparison with personal RT dosimeter records. It is important to evaluate the radiation doses delivered to RTs during mobile radiography, as well as the scattered radiation distribution, to ensure adequate protection. Further comparison studies may be needed using the Monte Carlo method.
radiographers and nurses have a responsibility to ensure that no one is within the radiation field during the X-ray exposure of the patient. This is achieved by informing all persons in the immediate area that an X-ray exposure is about to be made and asking them to stand a safe distance from the radiation field area.
Shielding
Placing a barrier of lead or concrete between the radiation source and an individual provides protection from X-radiation (Jones and Taylor, 2006; Ehrlich and Coakes, 2017). During mobile radiography, anyone assisting in an examination and staying in the radiation field should wear a lead-rubber apron or stand behind a mobile lead screen. Generally, walls in special care units where ionising radiation is used are designed to contain the radiation produced by the mobile X-ray tube within a set of criteria and limits determined by relevant legislation (Hart et al, 2002).
Radiation protection during mobile radiography
Nurses' understanding and adherence to radiation protection control measures during mobile radiography is of paramount importance in protecting patients, themselves and members of the public visiting the ward/unit. However, some research studies have found limited awareness and non-adherence to radiation protection control measures among nurses during mobile radiography (Anim-Sampong et al, 2015; Luntsi et al, 2016; Azimi et al, 2018). This can be attributed to a lack of radiation protection awareness programmes for nurses working
Interferometric Evanescent Wave Biosensor Principles and Parametersiosrjce
This review tries to present an overview of the most important parameters to be taken in
consideration in the evaluation of interferometer biosensors. Waveguide interferometers have particular
importance, because by utilizing the combination of two very sensitive methods, the waveguiding and the
interferometry techniques, they offer very good reliability and possibility for miniaturization and integration in
optical chips. By using the evanescent wave technology they measure the interaction between receptors and
biomolecules in real time without using labels. Receptors are immobilized onto a sensor surface and the
interaction with the biomolecules near it cause a refractive index change. A large number of applications in life
sciences, including binding kinetics of receptor-biomolecule pairs and virus-protein interactions, are using
evanescent wave-based biosensors for their studies. This article describes the technology behind their sensing
techniques, and a range of applications where they are used.
This document describes a new device designed to measure dental implant stability using resonance frequency analysis. The device uses an electromagnetic actuator to deliver an impact force to the implant, triggering vibrations that are detected to determine the resonance frequency. In vitro and in vivo tests show the device provides measurements that highly correlate with a commercially available device. A clinical study using the new device found initial resonance frequency values above 10 kHz indicated implants were ready for immediate loading, while values from 4-10 kHz required more osseointegration time. The new device allows for minimum contact measurement of implant stability without additional attachment or disassembly steps.
This document discusses biosensors, which combine biological components with physiochemical detectors. It provides examples of common sensors and their characteristics. Biosensors can detect analytes and convert biochemical signals to measurable electrical outputs. They have various applications in pharmaceutical, medical, food, and other industries. Examples of detection principles for biosensors include photometric, electrochemical, and ion channel methods. Overall, biosensors provide selective, sensitive detection of substances with minimal sample preparation.
This document summarizes a study that tested the effects of varying width and length on the behavior of a soft, stretchable sensor. The sensor consists of a stretchable fabric substrate and a composite of multiwall carbon nanotubes in a polymer matrix. Samples of the sensor were fabricated with three different lengths (30, 60, and 90 mm) and four different widths (5, 10, 15, and 20 mm). The samples underwent static and dynamic testing using a custom extensometer and load cell. Preliminary results showed that sensors with larger dimensions had lower resistivity, as there were more opportunities for carbon nanotube cross-paths to allow electron flow. Future work will analyze dynamic test results and sensor performance in practical applications
Biomedical Application of Magnetic NanomaterialsMahmudun Nabi
This document discusses a project to characterize magnetic nanoparticles for use in biomedical applications. The objectives are to:
1. Characterize the magnetic nanoparticles and study their AC susceptibility, size distribution, magnetic properties, and relaxation to determine parameters like magnetic moment and blocking temperature.
2. Develop a system to detect biological targets using magnetic nanoparticles and improve the system's sensitivity.
3. Validate the magnetic immunoassay technique by comparing results to conventional methods and analyzing outcomes for biological targets.
1504ACS-UCSD Murphy-Brown-Pradel Abstract 150304 mm wtMegan Murphy
Nonlinear multi-photon laser wave-mixing detection coupled with capillary electrophoresis provides an ultrasensitive method for analyzing malachite green, crystal violet, and their metabolites. This method offers zepto-mole detection sensitivity, excellent chemical selectivity and specificity, and high spatial resolution suitable for single-cell analysis. A 266 nm UV laser probes analytes in their native form while a visible laser probes labeled analytes. Coupling with capillary electrophoresis further enhances chemical selectivity. This portable, battery-powered method is suitable for a wide range of biomedical and environmental applications.
Plasmonic wave assessment via optomechatronics system for biosensor applicationIJECEIAES
Transduction biosensor (mass-based, optical and electrochemical) involves analysis, recognition and amplification in the acquired sample. In this work, the plasmonic-based biosensor was employed without using tags. It is crucial to determine angles of Brewster (Ɵb) and critical (Ɵc) for generating plasmonic resonance (Ɵr). The objective is to verify a cost-effective plasmonic biosensor through Fresnel simulation and experimentation of a developed optomechatronics system. The borosilicate glass, Au and Air layers were simulated with the Winspall 3.02 simulator. The optomechatronics system consists of: 1-optics (650 nm laser, slit, polarizer, photodiode), 2-mechanical (bipolar stepper motors, gears, stages) and 3-electronics (PIC18F4550, liquid crystal display (LCD) and drivers). Later, the software performs angular interrogation by reading the reflected beam from a rotating prism at 0.1125. Experimentation to simulation accuracy indicates that percentage differences for Ɵr and Ɵc are 1% and 0.2%, respectively. In conclusion, excellence verification was successfully achieved between experimentation and simulation. It proved that the lowcost optomechatronics system is capable and reliable to be deployed for the biosensor application.
This document summarizes applications of nanotechnology in biomedical systems for diagnostics and therapy. It discusses how nanoparticles can be used for targeted drug delivery and theranostics (combining therapy and diagnosis). Examples discussed include using microcantilevers and atomic force microscopy to detect small mass differences for applications like screening enzyme inhibitors, and using noble metal nanoparticles for label-free detection of biomarkers. The significance of understanding nanomaterials to develop safe and effective clinical tools is also noted.
SP-ICP-MS Analysis of Size and Number Concentration in Mixtures of Monometall...PerkinElmer, Inc.
It is challenging to separate and measure the physical and chemical properties of monometallic and bimetallic engineered nanoparticles (NPs), especially when mixtures of NPs consist of particles of similar size, composition, and especially when present at low concentrations.
CBCT is rapidly becoming the standard in 3D dental imaging. First generation CBCT was first used in 1982 (Mayo Clinic Biodynamics Research Laboratory) to perform angiography.
Hence, CBCT system was extended to other medical section, finding its best application in dentistry and maxilla-facial region study.
Although the CBCT principle has been in use for almost 2 decades, only recently—with the development of inexpensive x-ray tubes, high-quality detector systems and powerful personal computers—have affordable systems become commercially available.
CBCT is a compact, faster and safer version of conventional CT.
Using a coneshaped X-ray beam, the size of the scanner, radiation dosage and time needed for scanning are all dramatically reduced. CBCT scanners are systems that are able to provide 3D reconstructions that are based on the reformat of 2D images.
The scan is performed with a single 360 scan in which the x-ray source and a reciprocating area detector synchronously move around the patient’s head, which is stabilized by a head holder
Analysis of Phase Error and Cross Talk for the Young Interferometer Immunosensoriosrjce
This document analyzes factors that influence measurement errors in a four-channel Young interferometer immunosensor. Through simulations in Matlab, it is shown that increasing the CCD camera resolution to 2048 pixels and applying a Hanning window to the interference pattern can significantly reduce phase error and cross-talk. Noise averaging through overlapping 16 or more signals also leads to a notable reduction in errors by a factor of around 7.58. The document explores these techniques to minimize errors in the immunosensor measurements.
Similar to Vol 1,issue 7 Radiation therapy treatment unit dose-rate effects on metal–oxide–semiconductor field-effect transistor (MOSFET) detectors (20)
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Vol 1,issue 7 Radiation therapy treatment unit dose-rate effects on metal–oxide–semiconductor field-effect transistor (MOSFET) detectors
1.
2. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-701)
http://www.ijmshc.com Page 1
Radiation therapy treatment unit dose-rate effects on metal–oxide–semiconductor field-effect
transistor (MOSFET) detectors
Tamader Y. AL-Rammah1
, H. I. Al-Mohammed2
, F. H. Mahyoub3
1
Division of Radiological Sciences, College of Applied Medical Sciences, King Saud University,Riyadh,
Saudi Arabia
2
Correspondence to: Dr. H. I. Al-Mohammed, King Faisal Specialist Hospital &Research Centre Dept of
Biomedical PhysicsMBC # 03, POB 3354 Riyadh 11211, Saudi Arabia.
Abstract
Metal oxide semiconductor field effect transistor (MOSFET) detectors have recently been introduced to radiation
therapy. However, the response of these detectors is known to vary with dose rate. Therefore, it is important to
evaluate how much variation between the treatment prescribed dose and the dose that is actually delivered to the
patient using high-energy photon or electron beams under conditions of different dose rates can be attributed to the
detector. The aim of this study was to investigate MOSFET dependence on different dose-rate levels. The
measurements were done by exposing the mobile MOSFET detectors to a dose of 100 cGy using a linear accelerator
with energy of 6 MV and different dose rates from 100 cGy/MUs to 600 cGy/MUs.The results showed that the dose
rate dependence of a MOSFET dosimeter was within ±1.0%. MOSFET detectors are suitable for dosimetry of photon
beams, since they showed excellent linearity with dose rate variation.
Key Words: MOSFET, dose rate response, megavoltage photon beam (MV), monitor unit (MU)
Introduction
Monitoring the radiation dose delivered to a
patient during a radiation therapy session has been
accomplished recently by the use of metal oxide
semiconductor field effect transistor (MOSFET)
detectors. The system may be used to measure
doses at specific patient sites such as skin dose,
and for exit and entrance doses during a treatment
with total body irradiation (TBI) (1). The detectors
show good reproducibility and stability for
measuring the skin dose during radiation therapy
treatment (2). The MOSFET system allows
immediate dose readout and is small and easy to
use. The detection system is based on the
measurement of threshold voltage shift(3,4).
MOSFET detectors have dosimetric dependence
characteristics of temperature, dose and dose rate,
source-to-skin distance (SSD), angular
dependence and energy dependence (5).The
energy dependence varies not only with the silicon
oxide layers but also depends on the detector
construction as well as the materials used in the
construction of the substrate and the detector
housing (6 ,7). The system consisted of five high-
sensitivity dosimeters attached to a reader. The
five supporting MOSFET probes permit
measurements of five different locations (8 ,9).
The attached reader records a voltage difference in
each of the dosimeters if exposed to radiation.
MOSFET calibrations are performed under full
buildup conditions, which then produce a very
small sensing volume and less than 2% isotropy
under full buildup through 360 degrees rotation.
All five probes of the mobile MOSFET are made
for multiple uses and can accumulate doses up to
7000 cGy before needing to be replaced (2). The
system is controlled by remote dose-verification
software running on a personal laptop computer.
The aim of this study was to investigate the
reproducibility of mobile MOSFET detectors with
variable dose rates.
Materials and Methods
All mobile MOSFET detectors (TN-RD-16,
Thomson-Nielson, Ottawa, Ontario, Canada) were
calibrated in full buildup conditions prior to use.
The calibration was performed to obtain
maximum accuracy and repeatability of the
system. The calibration was carried out using a
Varian Clinac 2300 EX linear accelerator (Varian
3. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-701)
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Oncology Systems, Palo Alto, CA, USA) using 6
MV beams and a field size of 10 × 10 cm2
at 100
cm SSD and 100 cGy. All measurements were
performed by placing the mobile MOSFET
detectors at a depth of 1.5 cm using a tissue-
equivalent bolus to represent the Dmax of 6 MV.
Five sequential measurements at each dose rate
setting were recorded using the five detectors
(Figure 1). The overall physical size of the sensors
is 1.0 x 1.0 x 3.5 mm3
(Figure 2), and the actual
sensitive volume is 0.2 mm x 0.2 mm x 0.5 µm.
Statistical analysis
Data from each sample were run in duplicate and
expressed as means ± standard deviation (SD) (n
= 5 sequential reading for each channel). The
results were compared using one-way ANOVA
analysis followed by Tukey’s test for multiple
comparisons. Means were considered significant if
P<.05.
Results
The dependence of mobile MOSFET detectors to
variation of dose rate was determined. Figure 3
shows the average dose rate dependence of the
MOSFET detectors at different dose rates ranging
from 100 cGy/MUs to 600 cGy/MUs. The system
shows acceptable reproducibility and stability at
the delivered dose rates. The highest level of
fluctuation was seen with dose rate of 100
cGy/MUs, within ± 0.72 %, with a standard
deviation of 2.16. However, less fluctuation was
observed with other dose rates, and no significant
difference was seen between dose rates (P<
0.001). The MOSFET response was within ± 1.1
% and remained uniform with variable dose rates.
Discussion
Although the device shows sensitivity dependence
to integrated dose, this sensitivity dependence and
other MOSFET dosimetric dependences were
outside the scope of this study, which examined
the reproducibility of mobile MOSFET detectors
with variable dose rates. A commercially available
mobile MOSFET detector (TN-RD-16, Thomson-
Nielson, Ottawa, Ontario, Canada) verification
system was used for this study, which showed a
linear response with the dose and no dependency
with the dose rate was found. MOSFET
calibration was performed in order to convert the
radiation-induced dosimeter voltage shift to cGy.
The calibration coefficient was defined as the ratio
of the measured voltage shift of the dosimeter and
the actual dose measured with the 0.6 cc Farmer-
type ionization chamber (Model -2571) at the
depth of maximum dose (Dmax). The MOSFET
system has ports for five probes which can be
used simultaneously. The MOSFET probes were
placed at a source-to-dosimeter distance of 100
cm. The system included a wireless (Bluetooth)
MOSFET reader (TN-RD-16, Thomson-Nielson)
connection controlled with remote dose
verification software running on a laptop
computer. Although the system has two bias
supply settings (high and standard), for this study
and for the calibration of the MOSFET detectors
we used the standard setting giving a normal
sensitivity of ~1mV/cGy.
All dose measurements were carried out with the
flat side of the MOSFET detectors placed to face
the beam. The detectors were inserted in grooves
in the surface of a 1-cm thick polymethyl
methacrylate (PMMA) slab of dimensions 30 × 30
× 1.0 cm3
(Figure 2). In addition, a bolus sheet of
1.5 cm was placed on the top of the MOSFET to
minimize air gaps.
The MOSFET detectors were then irradiated with
100 MUs using a 10 x 10 cm2
field size, and
calibration factors in cGy/mV were obtained.
Calibration factors for each MOSFET were
determined by recording detector response in
millivolts (mV) and normalizing by absorbed dose
(cGy). In this study the calibration factor for the
detectors was 1.12. MOSFET probes were
connected to the bias for one hour prior to
measurement as recommended by the
manufacturer.
Six dose rates were used in this investigation (100,
200, 300, 400, 500, and 600 cGy/MUs. The
recording results were normalized to the MOSFET
response at 300 cGy/MUs. The responses from
each channel were recorded at the end of each
exposure. The mean MOSFET responses were
calculated and standard deviation was obtained to
evaluate the variation of MOSFET with different
dose rates.
4. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-701)
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The overall uncertainty with different dose rates
using calibrated MOSFET detectors in this study
was about 1.1 %. The percentage dose difference
was calculated for every channel in MOSFET
after taking the mean and the standard deviation at
different dose rates at a fixed delivered dose of
100 cGy. Mobile MOSEFT detectors are easy to
use and give immediate dose readouts. This study
demonstrated that mobile MOSFET are reliable
detectors that have limited fluctuation with
variations of dose rate.
Conclusion
MOSFET detectors, with their properties of small
size, accuracy, reproducibility and immediate
readout make good detectors for radiation therapy
treatment. MOSFET detectors showed good
responses at all dose rates in comparison to the
delivered dose. These detectors were fast, reliable,
small, and user-friendly. MOSFET detectors offer
outstanding potential as a dose monitor for
treatment and quality assurance in medical
radiation therapy departments.
Acknowledgements
The authors would like to express their gratitude
to the Biomedical Physics Department and the
Radiation Therapy Department at King Faisal
Specialist Hospital and Research Center, Riyadh,
Saudi Arabia, and to Radiological Sciences
Department; King Saud University, Riyadh, Saudi
Arabia for continuous support. The authors would
like to acknowledge the professional editing
assistance of Dr. Belinda Peace.
References
1. Al-Mohammed HI, Mahyoub FH, Moftah
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measurement using MOSFET and TLD for
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Al-Mohammed.Measurement and
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Fig 1 The experimental setup for metal oxide semiconductor field effect transistor ( MOSFET). The
setup consists of the reader, the bias box, and the MOSFET dosimeter with phantom. In addition, it
shows the setup for the measurement where is the detectors are placed in the top of water slab phantom
and covered with 1.5 cm bolus.
6. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-701)
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Fig 2 MOSFETs probes dosimeters placed with the flat side facing the photon beam.
7. International Journal of Medical Sciences and Health Care Vol-1 Issue-7 (Ijmshc-701)
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Dose Rate (cGy/MU)
Dose(100cGy)
92
96
100
104
100
200
300
400
500
600
.
Fig 3 Dose-rate dependence of the MOSFET dosimeter for different dose rates from 100 to 600 cGy/MUs.