Paper |
Title |
Page |
MOPB51 |
Beam Monitors of NIRS Fast Scanning System for Particle Therapy |
182 |
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- T. Furukawa, Y. Hara, T. Inaniwa, K. Katagiri, K. Mizushima, K. Noda, S. Sato, T. Shirai, E. Takeshita
NIRS, Chiba-shi, Japan
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At National Institute of Radiological Sciences, more than 6500 patients have been successfully treated by carbon beams since 1994. The successful results of treatments have led us to construct a new treatment facility equipped with three-dimensional pencil beam scanning irradiation system. The commissioning of NIRS fast scanning system installed into the new facility was started in September 2010, and the treatment with scanned ion beam was started in May 2011. In the scanning delivery system, beam monitors are some of the most important components. In order to measure and control the dose of each spot, the main and the sub ionization chambers are placed separately as flux monitors. For monitoring of the scanned beam position, a beam position monitor, which is multi-wire proportional chamber, is installed just downstream from the flux monitors. This monitor can output not only the beam position but also the 2D fluence distribution using dynamic fast convolution algorithm. In this paper, the design and the commissioning of these monitors are described.
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MOPB76 |
Evaluation of a Fluorescent Screen with a CCD System for Quality Assurance in Heavy-Ion Beam Scanning Irradiation System |
249 |
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- Y. Hara, T. Furukawa, T. Inaniwa, K. Mizushima, K. Noda, S. Sato, T. Shirai, E. Takeshita
NIRS, Chiba-shi, Japan
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The precise heavy-ion therapy such as the scanning irradiation system necessitates the precise quality assurance (QA) procedures to verify the performance of therapeutic scanned ion beams. To evaluate the uniformity of the 2D field, radiographic film is used due to its high spatial resolution and suit for the measurements of the integral dose. However, this technique is time consuming. Thus, we developed the QA tool with high spatial resolution to verify accuracy of the lateral size, position and uniformity of scanned ion beams in clinical application at the HIMAC, which we called the QA-SCN. The QA-SCN consists of a fluorescent screen, a CCD camera, a mirror, camera controllers and a dark box to protect against surrounding light. In this paper, to evaluate the performance of the QA-SCN, we compared the results obtained by using it with the measurements by radiographic film performed in the same experimental conditions. Also, we verified several types of corrections about errors, e.g. background, vignetting, to distort the measurement results. As a result, we confirmed that the QA-SCN can be used as the system for QA procedures of therapeutic scanned ion beams.
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