Development of intensity modulated radiation therapy (IMRT) based on radiobiology

基于放射生物学的调强放射治疗（IMRT）的发展

基本信息

批准号：
14570887
负责人：
NISHIMURA Yasumasa
金额：
$ 2.18万
依托单位：
Kinki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14570887/
关键词：
quality assurance intensity modulated radiotherapy radiation biology xerostomia malignant glioma head and neck cancer PTV margin dose-rate effect 高精度照射法ファントム治療計画

项目摘要

A method of quality assurance in IMRT at our hospital was established. The measured dose distribution in phantoms were consistent with the calculated dose distribution within a difference of 2-4%. We measured the intrafraction and interfraction organ motions and set-up errors for patients with head and neck cancer. Based on the measured systematic and random errors, a planning target volume (PTV) margin of 5 mm was appropriate for our IMRT system.It took 15-20 min for a single fraction of IMRT, which may cause a dose-rate effect or sublethal damage repair during a farction. Cell survival curves of SCCVII tumors and CHO cells irradiated with IMRT and conventional beams were compared. Below the range of 10 Gy, no significant difference in cell survival curves were detected.IMRT using the simultaneous integrated boost (SIB) method was designed for treating malignant gliomas. IMRT delivered 70 Gy/28 fractions/daily 2.5 Gy to the gross tumor volume (GTV) and 56 Gy/28 fractions/daily 2.0 Gy to the surrounding edema defined as the clinical target volume annulus (CTV-a). Although this treatment was feasible both physically and clinically, the local control was not improved.The patterns of local-regional recurrence in patients with head and neck cancer treated by parotid-sparing IMRT were analyzed. The mean doses to the contra- and ipsi-lateral parotid glands were 24.0 Gy and 30.3 Gy, respectively Among the 33 patients, 19 patients (58%) showed only grade-0,1 xerostomia. Thus, parotid-sparing IMRT could reduce the incidence of xerostomia. However, some recurrences were noted at the margin of PTV. PTV delineation in IMRT should be cautious enough.

在我们医院建立了IMRT的质量保证方法。幻象中测得的剂量分布与计算出的剂量分布在2-4％的差异之内。我们测量了头部和颈部癌患者的肢体内和互动器官运动和设置误差。基于测量的系统错误和随机错误，计划量（PTV）5 mm适合我们的IMRT系统。单个IMRT的一小部分花费了15-20分钟，这可能会导致剂量率或额外的效果造成的损坏维修。比较了IMRT和常规束辐射的SCCVII肿瘤和CHO细胞的细胞存活曲线。低于10 Gy的范围，未检测到细胞存活曲线的显着差异。IMRT使用同时集成增强（SIB）方法设计用于治疗恶性神经胶质瘤。 IMRT输送了70 GY/28分数/每天2.5 Gy至总肿瘤体积（GTV）和56 Gy/28级分/每天2.0 Gy至周围的水肿定义为临床目标体积环（CTV-A）。尽管这种治疗方法在身体和临床上都是可行的，但局部控制并未得到改善。分析了通过羊毛蛋白乳腺比例IMRT治疗的头颈癌患者的局部区域复发模式。在33例患者中，对相反的和IPSI的外侧腮腺的平均剂量分别为24.0 Gy和30.3 Gy，只有19例患者（58％）显示出-0,0,1级静脉炎。因此，呈腮腺的IMRT可以降低静态症的发生率。但是，在PTV的边缘记录了一些复发。 IMRT中的PTV描述应该足够谨慎。