Medial Physics Projects

Multiscale Monte Carlo Simulations for Radiation Therapy

Radiation transport simulations are broadly used to study many aspects of physics related to radiotherapy treatments for cancer on different length scales from patients to cells to subcellular components.

Different projects involving computational and theoretical studies of the interactions of radiation with matter are possible and may be tailored to the student's background and interests.  Some projects involve use of egs_brachy, a fast Monte Carlo dose calculation for brachytherapy (developed in the Carleton Laboratory for Radiotherapy Physics), to investigate questions in brachytherapy physics (brachytherapy is a type of radiation treatment in which radioactive sources are placed next to or inside a tumour) as well as coupling advanced dose calculations with models of biological effect.  Other projects involve simulation of radiation interactions at cellular or subcellular levels, including comparison of quantum and classical approaches for modelling electron transport at low energies.


Prof. Rowan Thomson:
rthomson atphysics [dot] carleton [dot] ca

Volume-of-interest cone beam CT imaging

Project description: In radiation therapy of cancer, cone beam CT images are used to position the patient immediately before each treatment session. Cone beam CT images are acquired by directing a cone of kilovoltage x rays at the patient from different angles during a full 360-degree rotation. At each angle, the x-rays transmitted through the patient are detected using a flat panel detector past the patient. The data from all angles are fed into image reconstruction software to reconstruct the 3D volume image of the patient. The "cone" nature in cone beam CT imaging makes the images suffer from a large scatter component and a higher patient imaging dose. This project aims to  develop a prototype that explores the relatively novel concept of "volume of interest" cone beam CT imaging where the x-ray beam is dynamically collimated to the patient areas of interest, and the image reconstruction is modified to handle missing information due to the collimation during acquisition. The project has a strong experimental component to develop the prototype and to interface it with the state-of-the-art radiation treatment facilities at The Ottawa Hospital Cancer, as well as programming component using Python.

Supervisor: Ali Elsayed, elali attoh [dot] ca 

Motion models for 4D Monte Carlo simulation of the impact of respiratory motion in radiation therapy

Radiotherapy treatments seek to deliver a tightly conformal dose of radiation to a tumour, while sparing nearby healthy organs. Tumour and organ motion due to respiration can cause a blurring of the delivered dose which decreases the dose to the tumour and increases dose to healthy tissues.

Our group has developed and experimentally validated a Monte Carlo simulation tool which models the transport of ionizing radiation in a dynamic patient geometry, thus enabling the calculation of dose to a breathing patient. The proposed summer project would work on extending the motion models in our 4D Monte Carlo simulation tool to improve the modelling of internal-external motion correlation as well as incorporating information from different image modalities (CT, cone-beam CT). Programming experience is required. 

Supervisor: Emily Heath, eheath atphysics [dot] carleton [dot] ca 

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