125Ⅰ粒子源近距离治疗前列腺癌模型的剂量学研究

目的 研究放射性125Ⅰ粒子源在治疗前列腺癌中的剂量分布,探寻治疗计划系统(TPS)优化效果的有效方法.方法 选定1个治疗计划系统,应用热释光剂量计,基于前列腺癌等效模体,模拟测量前列腺癌中的剂量分布.模拟植入共89颗125Ⅰ粒子,每个粒子的活度为1.37×107Bq(±5%).结果 各层的最大剂量为151～241 Gy,与处方剂量145 Gy的偏差在4.1%～66.0%.各层的最小剂量在101～128 Gy,与处方剂量的偏差在12%～30%.离模体边缘10 mm处正常组织的最大剂量为46～91 Gy,偏差为44%～63%.结论 该系统对实际的粒子植入治疗,评估TPS提供了实用的方法.

Abstract：

Objective To study the dose distribution of the radioactive 125Ⅰ seeds sources in the treatment of prostate cancer and also to explore the more effective method for improving treatment planning system (TPS).Methods Choose the designated TPS and use TLDs dosimeter based on a prostate cancer model.Finally stimulated measurement was focused on dose distribution in prostate cancer.The number of 125Ⅰ seed sources implanted was 89, each with 1.37 × 107 ( ± 5% ) Bq.Results Maximum dose of every layer ranged from 151 to 241 Gy, by 4.1% to 66.0% higher than the prescribed dose (145 Gy).The Minimum dose of every layer ranged from 101 to 128 Gy, by 12% to 30% higher than the prescribed dose.The maximum dose of normal tissue at 10 mm from the edge of model ranged from 46 to 91 Gy.The deviation was 44% -63% compared with the prescribed dose.Conclusions The designated TPS shows that it could be used as a practical guide for treatment of prostate cancer with the radioactive 125Ⅰ seed sources.The research methods offered by the study can provide evaluation of the TPS.