Development of Compact Dose Verification System Using a Fluorescent Screen for Carbon-ion Therapy

For quality assurance (QA) of therapeutic ion beams, QA tool having high spatial resolution and quick verification is required. The imaging system with a fluorescent screen is suitable for QA procedure. We developed a quick verification system (NQA-SCN) using a fluorescent screen with a charge-coupled device (CCD) camera for the sake of two dimensional dosimetry. The NQA-SCN is compact size to attach to irradiation port and water column. Several types of corrections were applied to the raw image obtained by the NQA-SCN. Our goal is to use the NQA-SCN for three-dimensional dose verification. In carbon-ion therapy, the fluorescent light is decreased by suffering from quenching effect due to the increased linear energy transfer (LET) in the Bragg peak. For the use of three-dimensional dose verification, as a first approach, we investigated the quenching effect of carbon-ion beam in water. Also, to evaluate the performance of NQA-SCN, we carried out experiments concerning QA procedures.19th International conference on accelerators and beam utilizations (ICABU2015