Mark D'Souza

Clinical translation of water calorimetry for absolute clinical dosimetry

• Summary: Currently water calorimeters are restricted to primary standard laboratories due to their size, extensive insulation requirements, and expertise to operate. We are designing and developing a water calorimeter that is suitablefor use in the clinical environment. Unlike existing clinical detectors, this water calorimeter will be able to measure absolute dose to water directly with minimal correction factors resulting in more accurate dose measurements.

Absolute dose measurements in volumetric delivery methods

• Summary: To date, absolute dose measurements using water calorimetry in volumetric delivery methods (e.g Gamma Knife Icon/VMAT) have not been performed. Here, the beam is delivered from multiple angles around the patient to achieve highly conformal treatment plans. Our main goal is to optimize and design a water calorimeter that can be used in volumetric delivery methods in order to measure dose absolutely.

Absolute determination of k_Q^mag for an ionization chamber in an MR-integrated linac

• Summary: An ionization chambers response changes in MR‑integrated linacs due to the presence of a magnetic field. As such, additional corrections are required for dose measurements. We have designed a portable MR‑compatible water calorimeter that can measure dose absolutely in MR‑integrated linacs and be used to calibrate ionization chambers directly in these machines.

Synthetic CT Generation

• Summary: Synthetic CTs (SCTs) are artificial CT images created from MR images that display the required electron density information for radiation therapy treatment plans. In this project a SCT algorithm was created that automatically converted T1 weighted MR images into SCTs using a combination of atlas, intensity based methods, and non-supervised machine learning.

Graduate Teaching Assistant

• Provided support for Physics Department courses through instruction, grading, and overseeing labs and tutorials: Physics I, Physics II, Physics: Mechanics, Nuclear Physics, Radiation Therapy for Undergraduate Students, Radiation Therapy for Graduate Students, Radiatioon Physics for Graduate Students (PCS 120, PCS 130, PCS 211, PCS 352, PCS 407, BP 8104, BP 8103)

Research Assistant

• Developed protocols for 3D-printing of patient boluses from radiation treatment planning system
• Deployed central quality control database (QA Track +) to store QA results
• Created program to compile QA data from different sources, check for errors, and submit to central database to ensure all data was accurately reported

Harold E Johns Summer Student

• Developed program to automatically generate Synthetic CTs (SCTs) from MR images using unsupervised machine learning
• Used Pinnacle to evaluate the fidelity of produced SCTs

Tutoring and Learning Centre Coordinator

• Created program in Python to gather and report key statistics on centre usage
• Developed sign-in program to track hours worked by employees and automatically submit file to payroll biweekly
• Lead peer review sessions on different mathematical topics

Physics Technician

• Performed daily, weekly, and monthly quality assurance tests on Varian Clinac 21EX and TrueBeam linear accelerators as well as a Gulmay Superficial X-ray unit
• Prepared written and verbal reports on progress made in projects
• Used Python to develop program to QA patient data submitted to CCO and check for errors.

Health Physics Research Assistant

• Modelled ionizing radiation in humans using Monte Carlo methods
• Modelled different types of radiation and detectors using MCNP to determine their efficiencies
• Used CT Scans to create voxel phantoms for simulations
• Operated and mantained 3D Printer to create lung set for LLNL Phantom

Canadian Association of Medical Physics

Medical Physics for World Benefit

American Association of Physicists in Medicine

Canadian Organization of Medical Physicists