Speaker
Description
Due to highly conformal treatment, reduced late and acute side and minimized risk of damaging healthy tissue, proton therapy has become a preferred form of radiation treatment over traditional photon and electron therapies. However, there are no means to directly verify proton depth range within the patient during treatment. One possible solution is the use of Prompt Gamma imaging (PGI), which utilises characteristic gamma rays, referred to as prompt gammas (PG), that are produced at the location of proton-tissue interactions. These PGs can be recorded via a Compton camera (CC) and subsequently used to infer the proton depth locations via PGI.
The UCT PGI system is comprised of four M400 CCs, manufactured by H3D Inc. (Ann Arbor, MI, USA), that operates at room temperature. Each M400 detector contains four 20×20×10 mm3 cadmium zinc telluride crystals. Each crystal is arranged in a 2×2 array, pixelated in a 11×11 x- and y- direction and a z- direction depth of interaction, allowing for three-dimensional gamma-ray detection.
Measurements using the M400 detectors were conducted at the Maryland Proton Therapy Centre in Baltimore, USA, using a 150 MeV single energy and spread-out Bragg peak (132-173 MeV) proton beam at gantry angles of 90° and 270°. The clinical beams were incident on an anthropomorphic phantom, delivering doses of 2.0 Gy and 7.5 Gy respectively. Across the aforementioned beam types, the M400 detectors were positioned on the patient couch perpendicular to the proton beam direction. These measurements were taken in conjunction with four nozzle-mounted M400 detectors. Using a kernel-weighted back projection image reconstruction technique, the work successfully demonstrates the ability of the UCT M400 detector system to produce images for proton beam range verification.
| Apply for student award at which level: | MSc |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |