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High-precision compton imaging of 4.4 MeV prompt gamma-ray toward an on-line monitor for proton therapy

Authors :
Koki Sueoka
Taku Inaniwa
Kazuya Fujieda
A. Koide
Takuya Maruhashi
Masaki Yoneyama
Jun Kataoka
Saku Mochizuki
T. Kurihara
Leo Tagawa
Source :
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 936:43-45
Publication Year :
2019
Publisher :
Elsevier BV, 2019.

Abstract

Proton therapy is a widely used and effective treatment for cancer. A high-dose concentration of proton beam reduces damage to normal tissues. However, it also requires a high accuracy of irradiation. PET is generally used to verify the proton range after irradiation, but, the distributions of positrons and the energy deposited by protons are not similar to each other. Recently, prompt gamma-ray imaging has attracted attention as a new, online imaging technique. In particular, 4.4 MeV gamma rays emitted from 12 C* is one of the best probes to monitor the proton dose, however imaging techniques are far from established. We have developed a novel, 3-D position sensitive Compton camera based on Ce:GAGG scintillators coupled with multi-pixel photon counter (MPPC) arrays, thus making it optimized for imaging in the 1–10 MeV range. The angular resolution is 5 degrees (FWHM) at 4.4 MeV. We have established various methods to discriminate multiple-Compton and escape events, both of which can be critical backgrounds for precise imaging of prompt gamma rays. By irradiating a 70 MeV proton beam on the PMMA phantom, we demonstrated that 4.4 MeV gamma ray image is sharply concentrated on the Bragg peak, as was expected from the PHITS simulation.

Details

ISSN :
01689002
Volume :
936
Database :
OpenAIRE
Journal :
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Accession number :
edsair.doi...........25060a2b71a19c3124b32ba71c56510d
Full Text :
https://doi.org/10.1016/j.nima.2018.11.032