Program Information
Imaging of Secondary Electron Bremsstrahlung X-Ray Emitted During Proton Irradiation by the Use of a Low-Energy X-Ray Camera for Range Estimation
M Yamaguchi , S Yamamoto*, K Ando , T Toshito , N Kawachi , Nagoya University Graduate School of Medicine, Nagoya, Aichi Prefecture
Presentations
MO-RAM-GePD-J(B)-5 (Monday, July 31, 2017) 9:30 AM - 10:00 AM Room: Joint Imaging-Therapy ePoster Lounge - B
Purpose: Low energy X-ray imaging of the secondary electron bremsstrahlung X-ray emitted during proton irradiation is a possible method for beam distribution measurements. However it is not clear the method is used for range estimation of protons. For this purpose, we developed a low-energy X-ray camera and imaging was conducted for the bremsstrahlung X-ray during irradiation of proton beams of different energies.
Methods: We used a 20 mm x 20 mm x 1 mm thick finely grooved GAGG scintillator. The scintillator was optically coupled to a 1-inch square high quantum efficiency (HQE) type position sensitive photomultiplier tube (PSPMT) to form an imaging detector. The imaging detector was encased in a 2 cm thick tungsten container and a pinhole collimator was attached to its camera head. After performance of the camera was evaluated, secondary electron bremsstrahlung X-ray imaging was conducted during irradiation of the proton beams for three different proton energies and the results were compared with Monte Carlo simulation.
Results: The system spatial resolution and sensitivity of the developed X-ray camera with 1.5mm diameter pinhole collimator were estimated to be 32 mm FWHM and 5.2E-7 for ~35 keV X-ray photons at 100 cm from the collimator surface, respectively. We could image the beam tracks by measuring the secondary electron bremsstrahlung X-ray during irradiation of the proton beams and the ranges for different proton energies could be estimated from the images. The measured ranges from the images were well matched with the Monte Carlo simulation and calculated values.
Conclusion: We confirmed that the imaging by the secondary electron bremsstrahlung X-ray emitted during proton irradiation is promising for proton range estimations. Also the developed X-ray camera is promising for the imaging by the secondary electron bremsstrahlung X-ray and range estimations.
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