07/13/2021
By Joshua Wancura

The Kennedy College of Science, Department of Physics & Applied Physics invites you to attend an M.S. thesis defense by Joshua Wancura entitled “Modelling the Radiation Chemistry of Radiotherapy Machines to Assess Potential Radical-Induced T1 Relaxation Changes.”

Candidate: Joshua Wancura
Date: Tuesday, July 27, 2021
Time: 2 p.m.
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Joshua_Wancura@student.uml.edu to request access.

Committee:

  • Atchar Sudhyadhom, Ph.D., DABR, Assistant Professor of Radiation Oncology, Harvard Medical School
  • Erno Sajo, Ph.D., Professor, Department of Physics & Applied Physics, University of Massachusetts Lowell
  • James Egan, Ph.D., Professor, Department of Physics & Applied Physics, University of Massachusetts Lowell

Abstract:
The recent integration of magnetic resonance imaging (MRI) and radiotherapy machines into a single commercial device has greatly expanded the opportunities for simultaneous imaging and irradiating. It has recently been shown that steady-state concentrations of radicals as low as 10 pM are detectable using MRI. As ionizing radiation beams produce radical species when interacting with matter, it is hypothesized that it may be possible to image radiation-induced radicals in real-time using MRI. The radiation chemistry resulting from a proton beam is modelled, with a focus on the time-evolution of radical species concentration. An estimate of T1 changes resulting from these radical species is made using available relaxivity data. These T1 changes are then used to calculate the expected contrast ratio for several MRI sequences. Results of this model are compared with the experimental results of an existing MRI-proton system.