SUBJECT: Ph.D. Proposal Presentation
BY: Serdar Charyyev
TIME: Wednesday, March 28, 2018, 12:30 p.m.
PLACE: Boggs Building, 3-47
TITLE: Development of proton minibeams as a new form of GRID radiotherapy
COMMITTEE: Dr. Chris K Wang, Chair (NRE)
Dr. Nolan Hertel (NRE)
Dr. Anna Erickson (NRE)
Dr. Mark McDonald (Emory)
Dr. Mark Artz (Provision)


This study aims to investigate, computationally and experimentally, the feasibility of proton GRID therapy based on an array of proton minibeams each of which has a diameter of 2-3 mm. The goal is to maximize the benefit of the dose-volume effect in radiobiology via GRID therapy. The optimal design of the proton minibeam array is based on the figures-of-merit parameters including peak-to-valley dose ratio (PVDR), dose rate and secondary neutron dose. Using MCNP Monte Carlo code, proton pencil-beams that mimic proton pencil-beams from cyclotron-based clinical facility will be simulated. Parallel beams of 2-3 mm diameter will be achieved using physical collimator made of brass. In the second part of the study, EBT3 film measurements will be performed to verify simulation results.

We will consider different combinations of parameters like beam size, center-to-center distance (c-t-c), air gap between the collimator and the phantom, and collimator thickness (t) to optimize the design.

Objectives are:
1. To ensure PVDR is maximized at shallower depths of the phantom and nearly homogeneous dose is delivered at tumor depth
2. To achieve comparable dose rate to other treatment modalities
3. To minimize secondary neutron dose