A5010583378- Radiation Therapy and Dosimetry
- Advanced Radiotherapy Techniques
- Radiation Detection and Scintillator Technologies
- thermodynamics and calorimetric analyses
- Radiation Effects and Dosimetry
- Radiation Dose and Imaging
- Radiation Effects in Electronics
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Medical Imaging Techniques and Applications
- Boron Compounds in Chemistry
- Particle physics theoretical and experimental studies
- Graphite, nuclear technology, radiation studies
- Photonic and Optical Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Diamond and Carbon-based Materials Research
- Carcinogens and Genotoxicity Assessment
- Plant Genetic and Mutation Studies
- Radioactivity and Radon Measurements
- Diagnosis and treatment of tuberculosis
- Materials Engineering and Processing
- Solar and Space Plasma Dynamics
- Virology and Viral Diseases
- Catalytic Processes in Materials Science
- Advances in Oncology and Radiotherapy
National Research Council Canada
2012-2025
National Metrology Centre
2024
McGill University
2012-2021
University of Toronto
2016
Toronto Metropolitan University
2015
University of Waterloo
2015
Sunnybrook Hospital
2015
UCLouvain
2014
Cliniques Universitaires Saint-Luc
2014
London Health Sciences Centre
2008-2011
Abstract Background Ultra‐high dose rate radiotherapy (UHDR) delivers therapeutic doses at rates >40 Gy/s in a fraction of second, aiming to enhance the ratio through FLASH effect. The substantial increase UHDR beam current poses serious challenges for conventional active dosimeters. Integrating transformers (ICT) offer nondestructive solution accurate monitoring, enabling type fast transient readout that will be crucial treatment verification. Purpose aim this study is build and...
Practical guidelines that are not explicit in the TG-51 protocol and its Addendum for photon beam dosimetry presented implementation of reference external high-energy electron beams. These pertain to: (i) measurement depth-ionization curves required to obtain quality specifiers selection conversion factors, (ii) considerations system specifications a reference-class ionization chamber, (iii) commissioning frequency measurements, (iv) positioning/aligning water tank chamber depth dose (v)...
Purpose In this work, the design, operation, initial experimental evaluation, and characterization of a small‐scale graphite calorimeter probe — herein referred to as Aerrow developed for routine use in clinical environment, are described. Similar size shape Farmer type cylindrical ionization chamber, represents first translation calorimetry intended direct by physicists radiotherapy clinic. Methods Based on numerically optimized design obtained previous functioning prototype capable two...
Purpose: In this work, the authors describe an electron sealed water calorimeter (ESWcal) designed to directly measure absorbed dose in clinical beams and its use derive beam quality conversion factors for two ionization chamber types. Methods: A functioning prototype was constructed in‐house used obtain reproducible measurements accelerator‐based 6, 9, 12, 16, 20 MeV beams. Corrections radiation field perturbation due presence of glass vessel were calculated using Monte Carlo (MC)...
The purpose of this investigation is to evaluate the use a probe-format graphite calorimeter, Aerrow, as an absolute and relative dosimeter high-energy pulse dose rate (UHPDR) electron beams for in-water reference depth-dose-type measurements, respectively.In paper, calorimeter system used investigate potential influence per pulses delivered up 5.6 Gy, number measurement, its measurement (depth-dose curve measurement). directly compared against Advanced Markus ion chamber. finite element...
The aim of this work is to present the numerical design optimization, construction, and experimental proof concept a graphite probe calorimeter (GPC) conceived for dose measurement in clinical environment (U.S. provisional patent 61/652,540). A finite element method (FEM) based heat transfer study was conducted using commercial software package explore feasibility GPC optimize shape, dimensions, materials used its design. functioning prototype constructed inhouse perform water measurements...
Purpose To use a portable 4°C cooled MR‐compatible water calorimeter to measure absorbed dose in magnetic resonance‐guided radiation therapy (MRgRT) system. Furthermore, the calorimetric results and direct cross‐calibration experimentally combined beam quality field correction factor ( ) of clinically used reference‐class ionization chamber placed under same field. Methods An Elekta Unity MR‐linac (7 MV FFF, B = 1.5 T) was this study. Measurements were taken using in‐house designed built...
Beam current transformers (BCT) are promising detectors for real-time beam monitoring in ultra-high dose rate (UHDR) electron radiotherapy. However, previous studies have reported a significant sensitivity of the BCT signal to changes source-to-surface distance (SSD), field size, and phantom material which until now been attributed fluctuating levels electrons backscattered within BCT. The purpose this study is evaluate hypothesis, with goal understanding mitigating variations due...
Abstract An Addendum to the AAPM's TG‐51 protocol for determination of absorbed dose water is presented electron beams with energies between 4 MeV and 22 (). This updated formalism allows simplified calibration procedures, including use calibrated cylindrical ionization chambers in all without a gradient correction. New data are provided based on Monte Carlo simulations. Implementation guidance provided. Components uncertainty budget determining at reference depth discussed. Specifications...
In this work, we describe a new design of water calorimeter built to measure absorbed dose in non-standard radiation fields with reference depths the range 6-20 mm, and its initial testing clinical electron proton beams. A functioning prototype total equivalent thickness less than 30 mm was constructed in-house used obtain measurements accelerator-based 6 MeV 8 beams cyclotron-based 60 monoenergetic modulated Corrections for conductive heat transfer due gradients non-water materials also...
Purpose With the introduction of a novel graphite probe calorimeter, called Aerrow, various thermal insulating materials are being explored to further improve device. Silica‐based aerogels proving be an optimal material due their low densities, small conductivities, rigidity, and machinability. The aim this work is determine how silica aerogel densities affect Aerrow’s performance. Methods Performance concerns three areas: heat transfer from core, beam quality dependence, effects applied...
Purpose In this work, the fabrication, operation, and evaluation of a probe‐format graphite calorimeter — herein referred to as Aerrow an absolute clinical dosimeter high‐energy photon beams while in presence B = 1.5 T magnetic field is described. Comparable cylindrical ionization chamber (IC) terms utility usability, has been developed for purpose accurately measuring absorbed dose water clinic with minimum disruption existing workflow. To our knowledge, first reported application...
The aim of this study is to reduce the uncertainty associated with determining dose-to-water using an amorphous silicon electronic portal imaging detector (EPID) under reference conditions by identifying and accounting for operational environmental factors influencing long-term stability EPID response.Measurements relative response, corrected variations in linear accelerator (linac) output, were performed regularly over a period 12 months. For every acquired image set, measurements supply...
The aims of this study were to investigate the variability between physicians in delineation head and neck tumors on original tomotherapy megavoltage CT (MVCT) studies corresponding software enhanced MVCT images, establish an optimal approach for evaluation image improvement. Five contoured gross tumor volume (GTV) three cancer patients 34 studies. Variation was quantified by DICE coefficient variance. Based agreement physicians, higher correlation terms average coefficients observed GTV 1,...
Purpose: To reduce the uncertainty of beam quality correction factor k<sub>Q,Q0</sub>, for scattered proton beams (SPB). This is used in dosimetry protocols, to determine absorbed dose-to-water with ionization chambers. For Roos plane parallel chambers (RPPICs), IAEA TRS-398 protocol estimates k<sub>Q,Q0</sub>-factor be 1.004(for a Rres=2 g.cm2), an 2.1%. Methods: A graphite calorimeter (GCal), water (WCal) and RPPICs were exposed, single experiment, 60 MeV non-modulated SPB. calibrated...
Abstract Objective . While the accuracy of dose calculations in water with Acuros XB is well established, experimental validation bone limited. reports both dose-to-medium and dose-to-water, these values differ bone, but there are no measurements bone. This work compares to absolute aluminum (medium similar bone). The validity using selected relative dosimeters also investigated. Approach A calorimeter an core embedded phantom was as surrogate for measurement dose. Matching medium allowed...
The LHCb experiment at the Large Hadron Collider (LHC) CERN is aimed to study CP violation and measure rare decays of B-mesons with exceptionally high precision. A 4 Tm dipole magnet required for particle separation momentum measurements. 1600 ton warm sloping poles was installed fully commissioned by end 2004. It first detector four LHC experiments have been aligned in its final position. In this paper, installation underground cavern Point 8 alignment on beam line are shortly reviewed....
Abstract Purpose To characterize and build a cylindrically layered graphite calorimeter the size of thimble ionization chamber for absolute dosimetry small fields. This detector has been designed in familiar probe format to facilitate integration into clinical workflow. The feasibility operating this absorbed dose quasi‐adiabatic mode is assessed high‐energy accelerator‐based photon beams. Methods detector, herein referred as Aerrow MK7, miniaturized version previously validated...
The aim of this study is to reduce the uncertainty associated with determining dose-to-water using an amorphous silicon electronic portal imaging detector (EPID) under reference conditions by developing a direct calibration formalism based on radiochromic film measurements made within EPID panel and detailed Monte Carlo simulations. To our knowledge, first EPID-based dosimetry reporting uncertain budget METHODS: Pixel sensitivity relative off-axis response were mapped simultaneously...