| Budget Amount *help |
¥14,690,000 (Direct Cost: ¥11,300,000、Indirect Cost: ¥3,390,000)
Fiscal Year 2015: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2014: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2013: ¥7,150,000 (Direct Cost: ¥5,500,000、Indirect Cost: ¥1,650,000)
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| Outline of Final Research Achievements |
We have measured the secondary particles generated by the nuclear interactions with matters in the therapeutic radiation such as X-ray, proton and carbon beams. Especially, we have established the angular correction method for evaluating the dose of secondary particles quantitatively. For example, we found that the proton-induced secondary particles contribute to 20% in dose equivalent for primary protons. The production cross section depends on the nuclear charge of primary ions. The cross section for carbon beam is about 25 times higher than proton beam. On the other hand, the particle fluence giving 1 Gy dose for carbon beam is about 1/25 lower than proton beam. Therefore, in the viewpoint of dosimetry, we confirmed that the dose contribution of secondary particles for carbon beam is about 1/5 - 1/6 lower than proton beam.
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