This master's thesis evaluates the clinical performance of the DAVID system for in vivo verification of VMAT irradiation. The study assesses the stability, sensitivity, and accuracy of the DAVID system in detecting errors in VMAT plans delivered to both prostate and head and neck patients. Deconvolution methods are analyzed to improve the system's sensitivity. Results show the DAVID provides real-time verification of MLC positions within 2% for IMRT and 1% for VMAT, and can detect artificial MLC errors as small as 2mm after deconvolution. The DAVID QA software allows automated online analysis of VMAT and IMRT treatments.
Enhancement of clinical outcome using OBI and Cone Beam CT in Radiotherapydrsumandas
Improving the quality of radiation treatment by use of on board image Guidance (OBI) with KV Xray and CBCT. This decreases the variability in daily dose delivery and improves outcome.
The document discusses the benefits of Siemens' SOMATOM Definition Dual Source CT scanner, which uses two X-ray sources and detectors to acquire imaging data twice as fast as single source CT scanners. This allows motion-free cardiac imaging of all patients regardless of heart rate or condition without needing beta blockers. The Dual Source CT technology also enables a variety of new clinical applications like plaque characterization, in-stent imaging, and dual energy scanning.
This document discusses various techniques used for treatment verification in radiation therapy. It describes electronic portal imaging devices (EPID) which can be used for daily treatment localization and verification through portal images with little additional dose. Cone beam computed tomography (CBCT) is also discussed, which provides volumetric CT images with submillimeter resolution, allowing verification of patient positioning before treatment. Both EPID and CBCT help ensure the correct radiation dose is delivered to the intended target volume.
A CT scan uses X-rays to create detailed images of the internal structures of the body. A CT scanner is composed of a rotating X-ray beam and detector that rotate around the patient, taking images from different angles. These images are processed by a computer to create 3D images of the body's internal structures. CT scans are usually outpatient procedures and provide detailed images to doctors, though the results are not immediate as images must be analyzed by a radiologist.
This document discusses quality assurance procedures for cone beam computed tomography (CBCT) imaging. It outlines the responsibilities of physicians, medical physicists, and radiation therapists in reviewing CBCT images and ensuring proper patient positioning. Daily quality assurance checks involve verifying safety interlocks and geometric accuracy using a positioning cube. Monthly quality assurance of image quality is performed by medical physicists using a Catphan phantom to check for uniformity, spatial resolution, low contrast visibility, and registration accuracy. Maintaining high image quality standards through a regular quality assurance program is important for correct patient localization.
The document discusses different types of computed tomography (CT) scanners and their components. It describes several CT scanning systems including axial CT scanners, helical CT scanners, multislice CT scanners, and dual-source CT scanners. It also discusses factors that affect image quality and resolution in CT scans like radiation dose, reconstruction filters, and spatial resolution. The document outlines some purchase considerations for CT scanners and notes that facilities should upgrade capabilities over time to get higher quality images and avoid more expensive upgrades later. It presents stages of ongoing CT development including reduced radiation dose, improved image quality, and dual-energy CT capabilities.
The document discusses the creation of a PET/CT center including a history of PET scans, the benefits of combined PET/CT scanners, tracer use, facility layout and design, and collaboration with Med Spectrum. Key points include the combined PET/CT scanner allowing detection of structure and function simultaneously with greater accuracy and convenience for patients. The facility plan shows high and low risk areas like preparation rooms and control rooms near scanners. Med Spectrum would provide full project support and coordination from personnel to financing to optimization of technologies.
Enhancement of clinical outcome using OBI and Cone Beam CT in Radiotherapydrsumandas
Improving the quality of radiation treatment by use of on board image Guidance (OBI) with KV Xray and CBCT. This decreases the variability in daily dose delivery and improves outcome.
The document discusses the benefits of Siemens' SOMATOM Definition Dual Source CT scanner, which uses two X-ray sources and detectors to acquire imaging data twice as fast as single source CT scanners. This allows motion-free cardiac imaging of all patients regardless of heart rate or condition without needing beta blockers. The Dual Source CT technology also enables a variety of new clinical applications like plaque characterization, in-stent imaging, and dual energy scanning.
This document discusses various techniques used for treatment verification in radiation therapy. It describes electronic portal imaging devices (EPID) which can be used for daily treatment localization and verification through portal images with little additional dose. Cone beam computed tomography (CBCT) is also discussed, which provides volumetric CT images with submillimeter resolution, allowing verification of patient positioning before treatment. Both EPID and CBCT help ensure the correct radiation dose is delivered to the intended target volume.
A CT scan uses X-rays to create detailed images of the internal structures of the body. A CT scanner is composed of a rotating X-ray beam and detector that rotate around the patient, taking images from different angles. These images are processed by a computer to create 3D images of the body's internal structures. CT scans are usually outpatient procedures and provide detailed images to doctors, though the results are not immediate as images must be analyzed by a radiologist.
This document discusses quality assurance procedures for cone beam computed tomography (CBCT) imaging. It outlines the responsibilities of physicians, medical physicists, and radiation therapists in reviewing CBCT images and ensuring proper patient positioning. Daily quality assurance checks involve verifying safety interlocks and geometric accuracy using a positioning cube. Monthly quality assurance of image quality is performed by medical physicists using a Catphan phantom to check for uniformity, spatial resolution, low contrast visibility, and registration accuracy. Maintaining high image quality standards through a regular quality assurance program is important for correct patient localization.
The document discusses different types of computed tomography (CT) scanners and their components. It describes several CT scanning systems including axial CT scanners, helical CT scanners, multislice CT scanners, and dual-source CT scanners. It also discusses factors that affect image quality and resolution in CT scans like radiation dose, reconstruction filters, and spatial resolution. The document outlines some purchase considerations for CT scanners and notes that facilities should upgrade capabilities over time to get higher quality images and avoid more expensive upgrades later. It presents stages of ongoing CT development including reduced radiation dose, improved image quality, and dual-energy CT capabilities.
The document discusses the creation of a PET/CT center including a history of PET scans, the benefits of combined PET/CT scanners, tracer use, facility layout and design, and collaboration with Med Spectrum. Key points include the combined PET/CT scanner allowing detection of structure and function simultaneously with greater accuracy and convenience for patients. The facility plan shows high and low risk areas like preparation rooms and control rooms near scanners. Med Spectrum would provide full project support and coordination from personnel to financing to optimization of technologies.
The document describes the new Siemens SOMATOM Definition Flash CT scanner. It has the fastest scan speeds on the market at up to 458 mm/s, allowing full body scans in less than 5 seconds. This speed means patients no longer need to hold their breath during scans. The scanner also uses new FAST CARE technologies to simplify workflows and make dose reduction easier. Its high speeds and productivity improvements allow clinicians to get better clinical outcomes with fewer resources spent on the CT system.
The document discusses the CT scan, a diagnostic tool that uses x-rays to create images of the body. It describes how a patient lies on a narrow bed that slides into a large circular machine, where an x-ray tube and detector array spin around the patient to take cross-sectional images called slices. Modern CT scanners can perform a full scan within 10 seconds and prepare images just as quickly, allowing for early detection and treatment of disorders.
This document summarizes the work completed during a medical physics rotation focused on imaging for treatment planning and verification. Key tasks included:
- Performing quality assurance tests on the electronic portal imaging device (EPID) including measurements of image uniformity, signal-to-noise ratio, and modulation transfer function at varying imaging parameters.
- Analyzing contrast-to-noise ratio, signal-to-noise ratio, and dose dependence using phantoms imaged with the EPID.
- Validating calculations of the EPID's modulation transfer function.
- Ensuring proper alignment of the EPID with the radiation isocenter using reticule alignment tests at different gantry angles.
- Observing clinical treatments for sites
1. The first generation of CT used a single narrow x-ray beam and detector that rotated around the patient in a translate-rotate motion. It took 5-6 minutes to complete a scan.
2. The second generation used multiple narrow beams and detectors, reducing scan time by a factor equal to the number of detectors by collecting multiple views simultaneously. Scan times were reduced to 20 seconds.
3. The third generation eliminated translation motion by using a fan-beam of x-rays and multiple stationary detectors arranged in a ring. Only rotational motion was needed, simplifying the mechanics. This further reduced scan times.
Computed tomography (CT) uses X-rays and digital image processing to generate cross-sectional images of the body. It has undergone several generations of technological advancement, increasing scanning speed and image quality. Modern multi-detector CT can acquire multiple slices simultaneously in a few seconds, and its 3D imaging capabilities are useful for medical diagnosis and guiding procedures. However, the increased use of CT has also led to higher population radiation exposure from medical imaging.
This document provides radiation shielding calculations for a small clinic or hospital using a WHIS-RAD X-ray unit. It estimates a typical workload of 3,000 examinations per year and distributions the exams across common exam types and kV settings. Shielding requirements are calculated for a sample clinic layout with a 16 square meter exam room, operator console, and film storage, using international dose limits. The calculations show that with proper safety procedures and typical building materials 4cm thick, radiation exposure is below limits for all areas.
Comparison of film sensitivity with epid for different doses.Jyoti Bisht
This document describes a study comparing the sensitivity of GAFCHROMIC EBT film to measurements from an electronic portal imaging device (EPID) for different radiation doses. Four head and neck patient plans were selected and delivered doses of 200 cGy and 800 cGy. Film calibration curves were generated by exposing films to known doses from 0-1000 cGy. Films and EPID images from patient plans were analyzed using gamma evaluation with 3%/3mm and 4%/4mm criteria. Results showed over 95% of points passed for both lower and higher dose deliveries. The document provides details on the facilities, equipment, and procedures used in the study.
MRI uses magnetic fields and radio waves to generate images of organs and tissues without exposing the body to radiation. It provides different information than CT scans, which use X-rays to produce cross-sectional images, and was developed based on work with computer-assisted tomography. Both MRI and CT are widely used in medical diagnosis and research to examine the inside of the body in detailed spatial images.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Austin Journal of Clinical Case Reports is an open access scholarly journal. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine. Case Reports is an open access journals. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine.
The aim of this open access journal is to offer service for scientists and academicians to promote, share, and discuss various new issues and developments by publishing clinical case reports in all aspects.
Austin Journal of case repots are a reflective analysis of one, two, or three clinical cases. All clinical case reports submitted must have been approved by an ethics committee or institutional review board.
Austin Journal of Clinical Case Reports is an open access scholarly journal. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine. Case Reports is an open access journals. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine.
The document provides an overview of liver anatomy, blood supply, and imaging techniques. It discusses the lobes and ligaments of the liver, as well as the blood supply from the hepatic artery, portal vein, and hepatic vein. Porto-systemic anastomoses are described as connections between the portal and systemic circulations that can occur due to conditions like cirrhosis. Both computed tomography (CT) scans and plain film radiography are examined, with CT scans providing cross-sectional slices and plain films producing 2D images using X-rays. CT scans are useful for assessing conditions of the liver like tumors or bleeding and can aid in surgical planning. Examples of normal and abnormal liver images from CT scans are also presented.
A single slice CT scanner uses a single x-ray source and detector that rotate around the patient to acquire a series of transmission measurements from different angles. A multi-slice CT scanner uses multiple detectors arranged in a row, allowing it to acquire multiple slices of data simultaneously with each rotation. This provides advantages like faster scanning, reduced motion artifacts, and the ability to perform 3D imaging. Common hospitals in the area have CT scanners ranging from single slice to 128 slice models.
1) The CyberKnife system uses a robotic arm to precisely deliver high doses of radiation from many angles to tumors while tracking their movement with cameras.
2) It offers two main advantages over other radiosurgery methods: the radiation source is mounted on a robot for increased accuracy, and continuous image guidance tracks tumor movement in real time.
3) Studies show CyberKnife radiosurgery provides effective tumor control for indications like early stage lung cancer, oligometastases, and spinal metastases with minimal side effects.
This document provides background information on computed tomography (CT) scans. It discusses how CT scans work, the process a patient goes through during a scan, and how images are produced and analyzed. Key advantages of CT scans are its ability to show soft tissue and structural changes. However, risks include exposure to radiation, which can potentially increase cancer risks. The document serves to inform readers on the technical aspects and clinical applications of CT scans.
X-rays were discovered in 1895 by the German physicist Wilhelm Conrad Röntgen,
who earned the Nobel Prize in Physics in 1901. Although their potential applications
in medical imaging diagnosis were clear from the beginning, the implementation of
the first X-ray computed tomography system was made in 1972 by Godfrey Newbold
Hounsfield (Nobel prize winner in 1979 for Physiology and Medicine), who constructed
the prototype of the first medical CT scanner and is considered the father of computed
tomography. CT was introduced into clinical practice into 1971 with a scan of a cystic
frontal lobe tumor on a patient at Atkinson Morley Hospital in Wimbledon (United
Kingdom). After this, CT was immediately welcomed by the medical community and
has often been referred to as the most important invention in radiological diagnosis, since
the discovery of X-rays [1].
The first applications of CT in an industrial context is traced back to the first 1980´s, in the
field of non destructive testing, where small number of slices of the object were visually
inspected. 3D quantitative industrial CT applications appeared in the later 1990s, with
simple volume and distance analysis [2]. Today, thanks to relevant improvements in both
hardware and software, CT has become a powerful and widely used tool among non
destructive techniques, capable of inspecting external and internal structures (without
destroying them) in many industrial applications. Development of more and more stable
X-ray sources and better detectors led to design of more complex CT system, providing
accurate geometrical information with micrometer accuracy. CT is widely used for
geometrical characterization of test objects, material composition determination, density
variation inspection etc. In a relative short time, CT is capable to produce a complete
three-dimensional model and tolerances of the scanned machined parts can be verified.
Because of the growing interest on precision in production engineering and an increasing
demand for quality control and assurance, CT is leading the field of manufacturing
and coordinate metrology. With respect to traditional techniques, CT systems have indisputable advantages: internal and external geometry can be acquired without
destroying the part, with a density of information much higher than common tactile and
optical coordinate measuring. A key parameter for reliability of the measurement process
is the establishment of measuring uncertainty. Since there are many influence parameters
in CT, uncertainty contributors in CT and standards dealing with quantification of CT
have not been completely established yet. The assessment of the uncertainty budget
becomes a challenge for all researchers
CT-SCAN provides concise summaries of medical documents. This document discusses the history and evolution of computed tomography (CT) scanning technology. It begins with definitions of CT scanning and diagrams of early CT scanner designs. It then summarizes the key developments, including the invention of CT scanning by Godfrey Hounsfield in 1971, the installation of the first CT prototype, and improvements in processing time. The document outlines the generations of CT scanners from first to fifth generation and describes advances in multi-slice and multi-detector array technologies. It concludes with examples of clinical applications and cases imaged with various CT techniques.
This document provides an overview of fundamental physics concepts relevant to radiation. It defines key physical constants, units, and relationships including Einstein's mass-energy equivalence. It also classifies the four fundamental forces and different types of particles and radiation. Atomic structure is discussed, defining atomic number, mass, and other properties. Rutherford's nuclear model of the atom is briefly introduced.
The document discusses the parts and functioning of an x-ray machine. It is comprised of an x-ray tube, transformer, tube stand, and control panel. The x-ray tube produces electromagnetic radiation when electric current is supplied by the transformer. The images are recorded digitally on a computer after the radiation passes through the body. The document also provides a brief history of x-rays from their discovery in 1895 to the introduction of digital x-ray technology in 1997.
X-rays are a form of electromagnetic radiation with wavelengths between 0.01 to 10 nanometers that can penetrate some materials like soft tissue. The three main components of an x-ray machine are the vacuum tube, high voltage power source, and operating console. X-rays are produced when electrons are accelerated toward a metal target in the vacuum tube. They are used medically for diagnostic imaging like radiography and mammograms due to their non-invasive nature, though overexposure can increase cancer risk.
The document provides an overview of radiation physics, beginning with the composition of matter and basic atomic structure. It describes the Bohr-Rutherford model of the atom and the development of the quantum mechanical model. Key concepts covered include atomic number, mass number, ionization, electrostatic and centrifugal forces, electron binding energy, and the nature of radiation.
The document then focuses on the history and properties of x-rays, the components and functioning of an x-ray machine, including the x-ray tube, cathode, anode, target, transformers, and power supply. Factors that control the x-ray beam such as exposure time, current and voltage are also summarized.
The document describes the new Siemens SOMATOM Definition Flash CT scanner. It has the fastest scan speeds on the market at up to 458 mm/s, allowing full body scans in less than 5 seconds. This speed means patients no longer need to hold their breath during scans. The scanner also uses new FAST CARE technologies to simplify workflows and make dose reduction easier. Its high speeds and productivity improvements allow clinicians to get better clinical outcomes with fewer resources spent on the CT system.
The document discusses the CT scan, a diagnostic tool that uses x-rays to create images of the body. It describes how a patient lies on a narrow bed that slides into a large circular machine, where an x-ray tube and detector array spin around the patient to take cross-sectional images called slices. Modern CT scanners can perform a full scan within 10 seconds and prepare images just as quickly, allowing for early detection and treatment of disorders.
This document summarizes the work completed during a medical physics rotation focused on imaging for treatment planning and verification. Key tasks included:
- Performing quality assurance tests on the electronic portal imaging device (EPID) including measurements of image uniformity, signal-to-noise ratio, and modulation transfer function at varying imaging parameters.
- Analyzing contrast-to-noise ratio, signal-to-noise ratio, and dose dependence using phantoms imaged with the EPID.
- Validating calculations of the EPID's modulation transfer function.
- Ensuring proper alignment of the EPID with the radiation isocenter using reticule alignment tests at different gantry angles.
- Observing clinical treatments for sites
1. The first generation of CT used a single narrow x-ray beam and detector that rotated around the patient in a translate-rotate motion. It took 5-6 minutes to complete a scan.
2. The second generation used multiple narrow beams and detectors, reducing scan time by a factor equal to the number of detectors by collecting multiple views simultaneously. Scan times were reduced to 20 seconds.
3. The third generation eliminated translation motion by using a fan-beam of x-rays and multiple stationary detectors arranged in a ring. Only rotational motion was needed, simplifying the mechanics. This further reduced scan times.
Computed tomography (CT) uses X-rays and digital image processing to generate cross-sectional images of the body. It has undergone several generations of technological advancement, increasing scanning speed and image quality. Modern multi-detector CT can acquire multiple slices simultaneously in a few seconds, and its 3D imaging capabilities are useful for medical diagnosis and guiding procedures. However, the increased use of CT has also led to higher population radiation exposure from medical imaging.
This document provides radiation shielding calculations for a small clinic or hospital using a WHIS-RAD X-ray unit. It estimates a typical workload of 3,000 examinations per year and distributions the exams across common exam types and kV settings. Shielding requirements are calculated for a sample clinic layout with a 16 square meter exam room, operator console, and film storage, using international dose limits. The calculations show that with proper safety procedures and typical building materials 4cm thick, radiation exposure is below limits for all areas.
Comparison of film sensitivity with epid for different doses.Jyoti Bisht
This document describes a study comparing the sensitivity of GAFCHROMIC EBT film to measurements from an electronic portal imaging device (EPID) for different radiation doses. Four head and neck patient plans were selected and delivered doses of 200 cGy and 800 cGy. Film calibration curves were generated by exposing films to known doses from 0-1000 cGy. Films and EPID images from patient plans were analyzed using gamma evaluation with 3%/3mm and 4%/4mm criteria. Results showed over 95% of points passed for both lower and higher dose deliveries. The document provides details on the facilities, equipment, and procedures used in the study.
MRI uses magnetic fields and radio waves to generate images of organs and tissues without exposing the body to radiation. It provides different information than CT scans, which use X-rays to produce cross-sectional images, and was developed based on work with computer-assisted tomography. Both MRI and CT are widely used in medical diagnosis and research to examine the inside of the body in detailed spatial images.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
Austin Journal of Clinical Case Reports is an open access scholarly journal. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine. Case Reports is an open access journals. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine.
The aim of this open access journal is to offer service for scientists and academicians to promote, share, and discuss various new issues and developments by publishing clinical case reports in all aspects.
Austin Journal of case repots are a reflective analysis of one, two, or three clinical cases. All clinical case reports submitted must have been approved by an ethics committee or institutional review board.
Austin Journal of Clinical Case Reports is an open access scholarly journal. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine. Case Reports is an open access journals. The goal of this journal is to provide a platform for scientists and academicians all over the world to promote, share, and discuss various new issues and developments by publishing case reports in all aspects of Clinical Medicine.
The document provides an overview of liver anatomy, blood supply, and imaging techniques. It discusses the lobes and ligaments of the liver, as well as the blood supply from the hepatic artery, portal vein, and hepatic vein. Porto-systemic anastomoses are described as connections between the portal and systemic circulations that can occur due to conditions like cirrhosis. Both computed tomography (CT) scans and plain film radiography are examined, with CT scans providing cross-sectional slices and plain films producing 2D images using X-rays. CT scans are useful for assessing conditions of the liver like tumors or bleeding and can aid in surgical planning. Examples of normal and abnormal liver images from CT scans are also presented.
A single slice CT scanner uses a single x-ray source and detector that rotate around the patient to acquire a series of transmission measurements from different angles. A multi-slice CT scanner uses multiple detectors arranged in a row, allowing it to acquire multiple slices of data simultaneously with each rotation. This provides advantages like faster scanning, reduced motion artifacts, and the ability to perform 3D imaging. Common hospitals in the area have CT scanners ranging from single slice to 128 slice models.
1) The CyberKnife system uses a robotic arm to precisely deliver high doses of radiation from many angles to tumors while tracking their movement with cameras.
2) It offers two main advantages over other radiosurgery methods: the radiation source is mounted on a robot for increased accuracy, and continuous image guidance tracks tumor movement in real time.
3) Studies show CyberKnife radiosurgery provides effective tumor control for indications like early stage lung cancer, oligometastases, and spinal metastases with minimal side effects.
This document provides background information on computed tomography (CT) scans. It discusses how CT scans work, the process a patient goes through during a scan, and how images are produced and analyzed. Key advantages of CT scans are its ability to show soft tissue and structural changes. However, risks include exposure to radiation, which can potentially increase cancer risks. The document serves to inform readers on the technical aspects and clinical applications of CT scans.
X-rays were discovered in 1895 by the German physicist Wilhelm Conrad Röntgen,
who earned the Nobel Prize in Physics in 1901. Although their potential applications
in medical imaging diagnosis were clear from the beginning, the implementation of
the first X-ray computed tomography system was made in 1972 by Godfrey Newbold
Hounsfield (Nobel prize winner in 1979 for Physiology and Medicine), who constructed
the prototype of the first medical CT scanner and is considered the father of computed
tomography. CT was introduced into clinical practice into 1971 with a scan of a cystic
frontal lobe tumor on a patient at Atkinson Morley Hospital in Wimbledon (United
Kingdom). After this, CT was immediately welcomed by the medical community and
has often been referred to as the most important invention in radiological diagnosis, since
the discovery of X-rays [1].
The first applications of CT in an industrial context is traced back to the first 1980´s, in the
field of non destructive testing, where small number of slices of the object were visually
inspected. 3D quantitative industrial CT applications appeared in the later 1990s, with
simple volume and distance analysis [2]. Today, thanks to relevant improvements in both
hardware and software, CT has become a powerful and widely used tool among non
destructive techniques, capable of inspecting external and internal structures (without
destroying them) in many industrial applications. Development of more and more stable
X-ray sources and better detectors led to design of more complex CT system, providing
accurate geometrical information with micrometer accuracy. CT is widely used for
geometrical characterization of test objects, material composition determination, density
variation inspection etc. In a relative short time, CT is capable to produce a complete
three-dimensional model and tolerances of the scanned machined parts can be verified.
Because of the growing interest on precision in production engineering and an increasing
demand for quality control and assurance, CT is leading the field of manufacturing
and coordinate metrology. With respect to traditional techniques, CT systems have indisputable advantages: internal and external geometry can be acquired without
destroying the part, with a density of information much higher than common tactile and
optical coordinate measuring. A key parameter for reliability of the measurement process
is the establishment of measuring uncertainty. Since there are many influence parameters
in CT, uncertainty contributors in CT and standards dealing with quantification of CT
have not been completely established yet. The assessment of the uncertainty budget
becomes a challenge for all researchers
CT-SCAN provides concise summaries of medical documents. This document discusses the history and evolution of computed tomography (CT) scanning technology. It begins with definitions of CT scanning and diagrams of early CT scanner designs. It then summarizes the key developments, including the invention of CT scanning by Godfrey Hounsfield in 1971, the installation of the first CT prototype, and improvements in processing time. The document outlines the generations of CT scanners from first to fifth generation and describes advances in multi-slice and multi-detector array technologies. It concludes with examples of clinical applications and cases imaged with various CT techniques.
This document provides an overview of fundamental physics concepts relevant to radiation. It defines key physical constants, units, and relationships including Einstein's mass-energy equivalence. It also classifies the four fundamental forces and different types of particles and radiation. Atomic structure is discussed, defining atomic number, mass, and other properties. Rutherford's nuclear model of the atom is briefly introduced.
The document discusses the parts and functioning of an x-ray machine. It is comprised of an x-ray tube, transformer, tube stand, and control panel. The x-ray tube produces electromagnetic radiation when electric current is supplied by the transformer. The images are recorded digitally on a computer after the radiation passes through the body. The document also provides a brief history of x-rays from their discovery in 1895 to the introduction of digital x-ray technology in 1997.
X-rays are a form of electromagnetic radiation with wavelengths between 0.01 to 10 nanometers that can penetrate some materials like soft tissue. The three main components of an x-ray machine are the vacuum tube, high voltage power source, and operating console. X-rays are produced when electrons are accelerated toward a metal target in the vacuum tube. They are used medically for diagnostic imaging like radiography and mammograms due to their non-invasive nature, though overexposure can increase cancer risk.
The document provides an overview of radiation physics, beginning with the composition of matter and basic atomic structure. It describes the Bohr-Rutherford model of the atom and the development of the quantum mechanical model. Key concepts covered include atomic number, mass number, ionization, electrostatic and centrifugal forces, electron binding energy, and the nature of radiation.
The document then focuses on the history and properties of x-rays, the components and functioning of an x-ray machine, including the x-ray tube, cathode, anode, target, transformers, and power supply. Factors that control the x-ray beam such as exposure time, current and voltage are also summarized.
Introduction to the parts of x ray machineHuzaifa Oxford
The document describes the key components of an X-ray machine:
1. The X-ray tube which produces X-rays and contains a cathode and anode in a vacuum tube housed in a protective casing.
2. The operating console which controls the voltage, current, and exposure time of the X-ray tube.
3. Additional components include a high voltage transformer, collimator to control the beam, patient table, grid to reduce scattering, and Bucky device which holds the X-ray film.
The document discusses the components and functioning of an X-ray tube. The key components are the glass envelope, cathode, and anode. Electrons are emitted from the cathode filament and accelerated toward the anode, where their impact produces X-rays. The rotating anode allows for greater heat dissipation to enable higher exposures. Factors like focal spot size and the anode heel effect determine the quality and characteristics of the emitted X-rays. Proper cooling and protective housing are also important for safe tube operation.
RT-GRID: Grid Computing for RadiotherapyBarakaFundo1
The document discusses using grid computing resources to perform Monte Carlo dose calculations for radiotherapy treatment planning, as Monte Carlo simulations can provide more accurate dose calculations but are computationally expensive; grid computing allows simulations to be run simultaneously across many computers to reduce calculation time from weeks to hours or days, making Monte Carlo planning clinically feasible on a national scale.
The document provides a brief history of radiation therapy and x-rays, including their discovery in the late 19th century, and developments in equipment over time. It discusses early radiation therapy methods like orthovoltage and kilovoltage treatments. It also summarizes linear accelerators and how they improved upon older cobalt-60 and betatron technology to allow higher energy photon beams for treating deeper tumors. Simulation equipment is covered, comparing conventional versus CT-based simulation and how various imaging modalities can aid treatment planning.
This document summarizes recent advances in electrophysiology technologies:
1. New devices include dual chamber leadless pacemakers and a multi-electrode balloon catheter for radiofrequency ablation.
2. Subcutaneous ICDs eliminate transvenous leads, and a leadless CRT system is in development.
3. Improved ablation technologies include laser and radiofrequency balloon catheters.
4. Wearable and implantable devices are replacing Holter monitors for arrhythmia detection.
5. New electroanatomical mapping systems provide higher resolution maps.
6. MRI and ultrasound guidance are being used to visualize ablation effects.
7. Smartwatches can detect atrial fibrillation with E
43.Merlyn Elizabeth Monsy et al. ROLE OF CBCT IN ORAL AND MAXILLOFACIAL SURGERY – A REVIEW. International Journal of Psychosocial Rehabilitation, Vol. 24, Issue 04, 2020: 10302-10310
The document discusses helical tomotherapy, a form of radiation therapy that uses a rotating x-ray beam. It summarizes a study of 150 patients treated with tomotherapy between 2006-2007 for reasons such as complex tumor geometry or need for image guidance. Setup corrections were often needed based on pretreatment MV CT scans. Treatment times were typically under 25 minutes with minimal increases over time. Tomotherapy allows conformal dose distributions and image-guided radiation for difficult cases near critical organs.
Parsons and Robar, An investigation of kV CBCT image quality and dose reducti...David Parsons
- An investigation was conducted of kV CBCT image quality and dose reduction for volume-of-interest (VOI) imaging using dynamic collimation.
- A prototype iris aperture was used to dynamically collimate the radiation field as a function of gantry angle to track a predefined VOI, reducing scatter and improving image quality while lowering dose outside the VOI.
- Preliminary results found that VOI imaging reduced scatter ratios by up to a factor of 8.4 compared to full-field imaging, lowered dose outside the VOI by up to 90%, and improved contrast-to-noise ratio by a factor of 2, demonstrating the potential for improved image guidance with reduced patient dose.
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
This document summarizes intensity modulated radiotherapy (IMRT) and its advantages over conventional radiotherapy. IMRT allows for superior dose distribution and better sparing of normal tissues by modulating the radiation beam intensity inside each treatment field. It provides more conformal dose coverage of irregularly shaped tumor targets while further reducing dose to nearby healthy tissues and critical organs. IMRT planning requires defining treatment goals and optimizing dose constraints using computer algorithms to determine the optimal intensity patterns delivered via multileaf collimators.
This document discusses key considerations for designing radiation shielding in diagnostic radiology facilities. It outlines parameters to calculate shielding needs such as workload, occupancy, equipment used, and dose constraints. Common materials for shielding like lead, concrete, and gypsum are mentioned. The importance of continuity of shielding and reducing penetrations is emphasized. Record keeping of shielding design is recommended.
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This document summarizes experiences using dual energy CT (DECT) from experts in Germany, the Netherlands, and Japan. DECT provides additional clinical information compared to conventional CT. Experts in Munich are researching using single source DECT to quantify iodine uptake in lesions. Experts in Rotterdam are using dual source DECT in pediatric patients to assess heart and lung abnormalities without sedation. Experts in Japan find DECT useful for distinguishing thyroid cartilage from head and neck tumors to avoid overtreatment. DECT is becoming more widely used in clinical practice and research due to improved diagnostic capabilities.
The document discusses proton beam radiotherapy and its advantages over traditional x-ray radiotherapy. It describes the equipment used for proton beam therapy including cyclotrons, treatment rooms with rotating gantries, patient immobilization devices, and beam shaping tools. It also provides examples of treatment plans comparing proton and x-ray intensity modulated radiotherapy for tumors in brain and spine.
The document discusses proton beam radiotherapy and its advantages over traditional x-ray radiotherapy. It describes the equipment used for proton beam therapy including cyclotrons, treatment rooms with rotating gantries, patient immobilization devices, and beam shaping components. It also compares treatment plans using proton therapy to those using intensity-modulated x-ray therapy, showing that protons can lower doses to surrounding healthy tissues. The case for developing a proton therapy facility at University College Hospital in London is made due to its location in a center of medical expertise and research.
Medtronic international the future of cardiac resynchronisation therapydrucsamal
The document discusses the future of cardiac resynchronization therapy (CRT). It notes that while CRT has been successful, current technology still has unmet needs like suboptimal response rates, relatively high complication rates, and long unpredictable procedure times. The document outlines Medtronic's work to address these issues through innovations like AdaptivCRT technology, which aims to produce more synchronized left ventricular pacing for improved outcomes. It also discusses the development of leadless pacing technologies and percutaneous approaches that could simplify CRT and reduce risks in the future. The overall message is that CRT technology will continue to advance towards making the procedure quicker, safer, simpler and more predictable with higher response rates and lower complication risks.
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Thomas Osborne, MD presented on advances in health technology from the past, present, and future perspectives of radiology. He discussed major developments in radiology technology over time like the discovery of X-rays and development of CT, MRI, and teleradiology. In the present, he emphasized trends of convergence and interoperability between systems. Examples of leading practices at vRad were described, including protocols for stroke, trauma, and critical findings. The future will see more connected and integrated systems, a shift to paying for quality outcomes, and growing roles for analytics and AI.
1. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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Master Thesis :
The clinical performance of the DAVID-system for the
in vivo verification of VMAT irradiation
Presented by Mustafa Saibu Danpullo
1st supervisor
Prof. Dr.B.Poppe
2nd supervisor
Dr. HK. Looe,
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Layout
I Introduction
II Theory
VMAT and IMRT
MLC Design and Agility
MWPC and DAVID system
III Materials & Methods
Equipment, alignment, patient data, stability of DAVID chamber
Beam property, Error detection
Deconvolution
DAVID QA software
IV Results / Discussion
V Conclusion
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I Introduction
IMRT (Intensity-modulated radiation therapy)
VMAT (Volumetric Modulated Arc Therapy):
Why In vivo verification ?
ICRU report 24 (1976) recommended that certain types of tumors
requires improve accuracy from 5% to 3.5%.
To detect Equipment-related errors and deviations from the initial plan
Complexity of planning and delivery techniques increases risk for
treatment-related error incidents.
In 1992 to 2007, more than 4,000 near misses without adverse
outcome to patient’s case were reported, more than 50% were related
to the planning or treatment delivery stage.
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In vivo dosimetry methods:
in vivo intracavitary dosimetry with TLD
Diodes
DAVID (Device for Advanced Verification of IMRT deliveries
In-vivo verification during treatment
Online measurement of differences in dose to reference
Error detection of the Multi Leaf Collimator (MLC)
I Introduction
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II Theory
Mostly Siemens, Elekta and Varian have introduced new LINAC
control systems that will be able to change the MLC leaf positions
IMRT uses many small fields to generated by beam-shaping
devices (MLC) to deliver a single dose of radiation
IMRT: Intensity-modulated Radiation Therapie
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II Theory
VMAT : Volumetric Modulated Arc Therapy
VMAT is a rotational IMRT that can be delivered using
conventional LINAC with MLC
Elekta and Varian have introduced new LINAC control systems
that will be able to change the MLC leaf positions and dose rate
while the gantry is rotating.
Precise Beam infinity and Rapid Arc
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A schematic drawing of the Siemens type A, Elekta type B and Varian type C MLC [18]
Stepped leafs for different manufacturers [34]
II Theory
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II Theory: Agility MLC design
• 160 tungsten leafs,
• rounded arc edge,
• 5 mm width,
• High speed(2x normal MLC) of up to
3cm/sec,
• large field MLC enable clinicians to
shape radiation,
• extremely low transmission of about
<0.5%
• 45 cm isocenter clearance from
accessory holder.
MLC Motor
9. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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Inventor:
Prof. Georges Charpak,
France,1968
Nobel Prize in Physics (1992)
II Theory: Multi wire proportional chamber (MWPC)
The DAVID chamber is a multi-wire
ionization chamber designed by PTW
Freiburg based on Charpark's multi wire
proportional chamber.
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Compton scattering Electric field causes electrons move to the
anode(wire) and ionizied atoms/molecules to the
cathode(plate)
Each detection wire accumulates charge which
loads a C.
After the voltage at the capacitor is read out, it is set
to zero and charged again
The voltage achieved is read out by the associated
amplifier at a rate of 1 Hz.
Performed by multi-channel electrometer
(MULTIDOS) + additional Software
.
II Theory: DAVID system functioning principle
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Signal interpretation:
Ri: reading of a single channel (ion charge collected)
C: cross section of the lengthy collection volume along the wire
Ii: ionization density (x1 start of wire, x2 end of wire)
li1-li2: aperture of the associated leave pair
II Theory
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Front Plate
Back Plate
Air Volume
II Theory: DAVID system signal recording
3 groups of secondary electrons contributing to the signal:
a)“primary signal”
b)scattered signal
c)leakage radiation
(background signal)
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VMAT Planning:
Treatment Planning System: ONCENTRA Masterplan Version 4.3
ELEKTA Synergy accelerator with an Agility 80 leaf-pair MLC
• Desktop Pro TM 7.011 is Elekta's third generation fully integrated
digital control system. MOSAIQ, DAVID software version 2.0
DAVID T34065
III Materials and Methods
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Patient data configuration chart
III Materials & Methods
Reference
1st session
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DAVID Analysis
• PTW: DAVID 2.0 software
III Materials & Methods
Warning level: 3%
Alarm level: 5%
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III Materials & Methods:
•VMAT: 4 (1 H&N, 3 Prostates)
•180° to -180° Clockwise and anti clockwise
Stability of the DAVID system
•IMRT : 1 (Prostate)
•0°
•90°
•270°
(Prostate and Head and Neck) 14 days
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III Materials & Methods:
The beam property of the DAVID chamber
•Percentage depth dose (PDD)
•Roos chamber 34001
•MP3 water phantom
•Transmission factor for 6 and 15 MV
•Semifex T31010 (Diff Field sizes)
Setup conditions
• With and without DAVID
• SSD 100 and 80 cm
• Photon energy 6 and 15
MV
• Different field sizes
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1. Successive opening of 1 leaf on 1
side
III Materials & Methods:
VMAT Plan Editing for error detection
• MATLAB script to change the MLC-positions
3. Field shift of a leaf gap (size of leave
gap remains)
2. Successive shift of a leaf gap (size of
leave gap remains)
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1. Successive opening of 1 leaf on 1
side
VMAT Plan Editing for error detection
• MATLAB script to change the MLC-positions
3. Field shift of a leaf gap (size of leave
gap remains)
2. Successive shift of a leaf gap (size of
leave gap remains)
III Materials & Methods:
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Deconvolution
III Materials & Methods:
S(x) measured signal as convolution of
P(x) True „dose“ profile with
LRF fɛ(x).
S(x) = P(x) * f(x)
„van Cittert“ iterative deconvolution
algorithm
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opened MLC at every 10th interval from 1st to 80th
pairs.
Nine MLC slit through the entire DAVID chamber
IV Results and Discussion: Alignment
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IV Results and Discussion: Stability of DAVID System
• IMRT: prostate
• Deviation of ±2% (+2%)
• VMAT: prostate
• Deviation of ±1% (-1%)
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IV Results/Discussion: Stability of DAVID System
• IMRT: prostate
• Deviation of ±2% (+2%)
• VMAT: H&N
• Deviation of <0.5%
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IV Results/Discussion: Transmission factor
The average KDAVID
• 0.939 ±0.003 for 6 MV
and
• 0.953 ± 0.004 for 15 MV
Reduction of dose at isocenter
due to 8mm of PMMA
By measuring the attenuation
factor the output value can be
corrected.
Attenuation of the beam by the DAVID chamber
25. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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100 cm SSD,
Increased about
0.32% with DAVID
No change of
Dmax
1.4 cm with
and without DAVID
80 cm SSD,
An increased about
4.26% with DAVID
slight change of
Dmax
1.3 cm with DAVID
1.4 cm without DAVID
IV Results/Discussion: Changes in PDD
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100 cm SSD,
An increased about
0.67% with DAVID
Dmax
2.6 cm No change
80 cm SSD,
An increased about
18% with DAVID
slight change of
Dmax
1.8 cm with DAVID
2.4 cm without DAVID
IV Results/Discussion
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Surface dose
Increase with increase in field size
Increase with increase in energy
Increase with decrease in SSD
IV Results/Discussion
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Pronounce with
decrease in SSD and,
increase in photon energy and
increase in field size.
Increase in surface dose is
due to scattered secondary
electrons from the DAVID
chamber reaching the
water phantom surface
(electron contamination).
6 cm
45 cm
100 cm
IV Results/Discussion
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Deconvolution test
by iteration method
IV Results/Discussion: Deconvolution
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Deconvolution
•does not depend on the length of the slit.
•40 cm slit results showed a small decrease in the tail signals.
10 x 10 cm
10 cm slit
40 cm slit
20 cm slit
30 cm slit
IV Results/Discussion
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IV Results/Discussion:
Deconvoluted slit signal at 40th and 65th wire
Deconvolution test
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10x10cm fields before and after deconvolution
Single arc prostate plan before and after deconvolution (3 mm )
IV Results/Discussion: Deconvolution with DAVID software.
33. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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before deconvolution 6.1 mm
Gradients of the linear fit
before deconvolution : 0.47 and
after deconvolution 2.9 mm
Gradients of the linear fit
after deconvolution : 0.94
.
IV Results/Discussion:
Enhance sensitivity after deconvolution
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before deconvolution after deconvolution
H&N 6mm error.
.
IV Results/Discussion
False alarm/warning effect before deconvolution.
The effect is eliminated after deconvolution
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Undeconvoluted
deconvoluted
Measuring the deconvolution matrix with
the DAVID software as manual. LSF of single middle slit is measured and
used to generate the 80x80 LRF matrix with
MAT LAB and installed in the DAVID software
for deconvolution.
IV Results/Discussion: Limitations of DAVID-160 system
36. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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2mm MLC error, single bank shift
2mm MLC error, single leaf
Analyzing both the maximum deviation
and total deviation in two different plots
at the same time
IV Results/Discussion
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Max Dose 75.99GyMax Dose 57.27Gc
IV Results/Discussion: Artificial MLC bang shift Error 2
cm
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0
1
2
3
4
5
6
7
8
0 8 10 12 14 16 18 20
shift / mm
doseincrease/Gy
maximaldeviation/%
Undetectable error! Design of the chamber
DAVID: Gap-Shift (prostate with OAR: rectum back wall)
IV Results/Discussion
39. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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DAVID Quality Assurance software (DQA)
MAT LAB 2011b and 2012b
analyzes the daily session for all patient's data with 2 clicks online.
• NDD- Non deconvoluted data
• ˆDD-Deconvoluted data
• ED- Electrical data
IV Results/Discussion
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Analysis only specific data on
specific date, session and only print
out the deconvoluted data (DD)
IV Results/Discussion
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Patient text file from DQA software
Sample patient 2014-01-12
Display only data's with MLC error
indicating the data type (DD),Beam
number, Session, segment and
particular MLC with error.
IV Results/Discussion:
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The DQA software displays the warning and alarm errors
Warning and error dialogs at future date entry and invalid date entry respectively
year-month-day `yyyy-mm-dd'
IV Results/Discussion
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VMAT and IMRT plans sessions
IV Results/Discussion:
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DAVID chamber:
• Linear dependency on leaf opening
• Sensitivity dependent on leaf gap opening
• How much radiation pass through the opening
• Deconvolution double the sensitivity
DAVID is design for specifics LINACS
Independent from the LINAC
In-vivo verification of MLC malfunction during VMAT
• Undetectability field shifts due to chamber design
(Suggestion: perpendicular wires or gradient)
V Conclusions
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V Conclusion
Single MLC bank shift error
Maximum and total deviation to be analysed
Deconvolution matrix
To be generated for each linac
To be generated by single single slit
• In comparison to other techniques measurement of undisturbed
signals
-> no dependence on patient position(EPID)
-> measurement of the complete delivered dose(TLD, diode or MOSFET
detectors)
• Suggestions for future development: Standard design for software
• Deconvolution program to be integrated,
• DQA to be integrated
• Design two chambers perpendicular to each other
Co-operate directly with LINAC vendors for specifics designs
46. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
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Sources
1. [1] Ezzel GA, Galvin JM, Low D, Palta JR, Rosen I , Sharpe MB, Xia P, Xiao Y, Xing L and Yu CX. Guidance on delivery,
treatment planning, and clinical implementation of IMRT: report of the IMRT subcommittee of the AAPM radiation
therapy committee Med Phys 2003; 30:2089-115.
2. [2] ESTRO Booklet No. 9, 2008. Guidelines for the verification of IMRT, edited by Ben Mijnheer and Dietmar Georg.
ISBN 90-804532-9.
3. [3] Schneider F, Polednik M, Wol D, Steil V, Delana A, Wenz F, Menegotti L. Optimization of the gafchromic EBT
protocol for IMRT QA. Z Med Phys 2009; 19(1):29-37.
4. [4] Poppe B, Blechschmidt A, Djouguela A, Kollho R, Rubach A and Harder D. Two-dimensional ionisation-chamber
arrays for IMRT plan verication. Med Phys 2006; 33:1005-15
5. [5] Poppe B, Thieke C, Beyer D, Kollho R, Djouguela A, Rühmann A, Willborn KC and Harder D. DAVID-a translucent
multi-wire transmission ionization chamber for in vivo verication of IMRT and conformal irradiation techniques. Phys
Med Biol 2006; 51:1237-48.
6. [9] Poppe B, Looe H K, Chofor N, Rühmann A, Harder D and Willborn K. Clinical Performance of a Transmission
Detector Array for the Permanent Supervision of IMRT Deliveries. Radiother. Oncol. 2010; 95:158-65
7. [10] Looe H K, Harder D, Rühmann A, Willborn K and Poppe B. Enhanced accuracy of the permanent surveillance of
IMRT deliveries by iterative deconvolution of DAVID chamber signal proles Phys. Med. Biol. 2010; 55:3981-92
8. [11] Heukelom, S., el al.Wedge factor constituents of high-energy photon beams: Head and phantom scatter dose
components Radiother. Oncol. 32: (1994) 66-3
9. 12] Jursinic, P. A. Changes in incident photon uence of 6 and 18 MV x rays caused by blocks and block trays Med
Phys 26 (1999) 2092-8
10.[13] v. Klevens, H. Dependence of the tray transmission factor on collimator setting and sourcesurface distance Med.
Phys. 27 (2000) 2117-3
11.[14] Sharma, S.C., el al., Recommendations for measurement of tray and wedge factors for high energy photons Med
Phys 21 (1994) 573-5
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Thank you for your
attention
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Additional Slides
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50. WG Medical Radiation Physics, Pius-Hospital and Carl von Ossietzky University, Oldenburg
Description of the Elekta synergy DAVID160 system
50
David58
David160
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•Φ constant with depth
(small # interactions)
•Same # electrons set in
motion in each square
•i.e., interactions per
volume constant through
target
•dose reaches a
maximum at R (kerma
constant with depth,
equals absorbed dose
beyond )
Number of electron tracks set in motion by
photon interaction
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