Compton Imaging Study for Dose Monitoring in Carbon Therapy

To achieve precise radiotherapy for carbon therapy, it is necessary to accurately monitor the dose distribution in the patient's body. We conducted a methodological study on the 3D dose monitoring of the double-layer Compton camera in carbon therapy by MC simulation. We built a prototype LYSO Compton imaging system in the laboratory to verify the feasibility of the method. This article evaluates the performance of the dual-layer Compton camera, including sensitivity, point-source imaging, and plane-source imaging. A PMMA phantom was bombarded with a carbon ion beam of 200 MeV/μ, and the reconstructed image showed a position deviation of 9.1% from the 3D dose distribution. We also analyzed the influence of the uncertainty of the depth of interaction (DOI) on the reconstructed image. Finally, the prototype of LYSO Compton imaging system was used to perform tomography experiment on a
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Na point source. The FWHM of the reconstructed image was 1.35 times of the diameter of the point source.