| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2015: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2014: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Outline of Final Research Achievements |
A dental alloy (DA) in the radiation field can cause severe oral mucositis and uncertain dose distribution due to the scattering and absorption of radiation. A spacer is thought to increase the accuracy and safety of radiotherapy. But, the effects of them on dose distribution have not been clarified. This study was conducted to identify the change of dose distribution caused by backscatter radiation from DAs and the optimal material and thicknesses of a spacer. This study showed that the dose enhancement caused by back and lateral scatter radiation from DA disappears at distances >= 6 mm and >= 3 mm, respectively. These dose enhancements strongly depended on both an atomic number and a physical density of DA, and the estimated equation was 0.077√atomic number + 0.79. Additionally, the optimal material and thickness of spacer should have a lower atomic number and physical density and the thickness of >= 6 mm each to prevent severe mucositis caused by backscatter radiation from DAs.
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