Proton Dose Distribution and its Biological Effect Distribution

质子剂量分布及其生物效应分布

• 批准号: 10670822
• 负责人: MARUHASHI Akira
• 金额: $ 1.79万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10670822/
• 关键词: proton therapy; dose distribution; screen; CCD camera; imaging plat; Let dependency; faculty of proliferation; 発光LET依存性; 細胞の増殖能分布; Proton; Dose Distrebution; Biological Desimetry; CCD camera; Photoluminescence Microscope

For an application to the dose-distribution measurement, response of an imaging plate (IP) has been studied with proton beams, which are routinely utilized for the radiation therapy. The upper limit of measurable proton dose by an IP system is almost controlled by the readout range of scanner used. Within this limit, reasonable linear response of an IP to proton dose to water is maintained. Fading curves are neither so sensitive to a small change of room temperature nor to a certain variation of proton dose (0.0108-0.132 Gy). Reproducibility of the PSL intensity is fairly good if both the fading characteristics and the lot-dependence of the sensitivity of each IP are taken into account carefully. Stopping power dependence of IP response has been measured at different positions in a Bragg curve. Tolerance of IP to radiation damage by proton irradiation has been examined.In PMRC, dose distributions on the axis of proton beam and on the lines perpendicular to that in the water phantom hav … More e been measured by scanning Si semiconductor detector, under the same condition of a beam delivery system including bolus and patient collimator as that of patient treatment.The purpose of this measurement is to verify that the width of high dose region (90%-95% to maximum on beam axis in the target volume in general) given by SOBP beam is coincident to that of planned target region as a result of the treatment planning. Now, we test the two dimensional dose distribution detector usable in water in place of the present detection system. For this purpose, a system composed of intensifying screen used for X-ray radiography and CCD camera was used. The screen stood vertically in water phantom was set to the axis of proton beam as 1) at small angle to mainly measure intensity distributions of its scintillation light on depth and 2) perpendicularly to measure 2-D light intensity distribution at given depth. In latter case, a miller set at 45 degrees to the proton beam direction was attached to the distal edge of the water phantom. Characteristics of the screen about efficiency converting the absorbed dose to light intensity were investigated on the basis of dose measured by Si semiconductor detector. We show LET dependency of light intensity generated from the screen and relationships between dose distributions by silicon dosimeter and light intensity distributions by the screen as experimental and analytical results on a poster. Less

对于剂量分布测量的应用，已经用质子束研究了成像板（IP）的响应，质子束通常用于放射治疗。IP系统可测量的质子剂量的上限几乎由质子束控制。在此限制内，IP 对水的质子剂量的合理线性响应不会对室温的微小变化或质子剂量的某些变化那么敏感。 (0.0108-0.132 Gy) 如果仔细考虑每个 IP 的衰落特性和灵敏度的批次依赖性，则在不同位置测量 IP 响应的停止功率依赖性。已经检查了 IP 对质子辐照辐射损伤的耐受性。在 PMRC 中，质子束轴上和垂直于质子束轴的线上的剂量分布。水体模通过扫描硅半导体探测器进行测量，在与患者治疗相同的光束传输系统（包括团注和患者准直器）条件下进行测量。该测量的目的是验证高剂量区域的宽度（作为治疗计划的结果，SOBP 束给出的目标体积中射束轴上的最大值（90%-95%）与计划目标区域一致。现在，我们测试可在水中使用的二维剂量分布检测器。代替目前的检测为此，使用了由用于X射线照相的增感屏和CCD相机组成的系统，将屏幕垂直放置在水体模中，以小角度设置为1)，以主要测量强度分布。 2) 垂直测量给定深度处的闪烁光强度分布。在后一种情况下，将与质子束方向成 45 度的米勒固定在其远端边缘。根据硅半导体探测器测量的剂量，研究了屏幕将吸收剂量转换为光强度的效率特性，并显示了屏幕产生的光强度的 LET 依赖性以及硅剂量计和剂量分布之间的关系。屏幕上的光强度分布作为海报上的实验和分析结果。