质子点扫描技术与光子Tomotherapy在前列腺癌应用中的剂量学比较

Dosimetric comparison between single spot scanning of proton therapy and tomotherapy for prostate cancer

目的:比较前列腺癌质子点扫描技术(SSS-PT)与光子螺旋断层放射治疗(HT)两者之间的剂量学特点,其数据将为临床提供一定的参考。方法:选取12例既往前列腺癌患者作为研究对象,定位后,将CT图像分别传至Raystation和HT计划系统进行放疗计划设计。处方剂量为69Gy/25F。比较分析两种放疗计划的靶区适形度指数(CI)、均匀性指数(HI)、靶区和危及器官剂量学参数。结果:靶区的均匀性方面,SSS-PT优于HT(P=0.001);直肠平均剂量SSS-PT[(21.92±4.00)Gy]低于HT[(31.97±2.60)Gy](P=0.000);膀胱平均剂量SSS-PT[(17.62±3.15)Gy]低于HT[(30.52±3.94)Gy](P=0.000);对于直肠和膀胱的保护,SSS-PT在低、中剂量区总是优于HT。结论:SSS-PT和HT两种治疗方式在靶区剂量分布均可满足临床需求,在同样靶区覆盖条件下,SSS-PT相较于HT能够更好地保护直肠和膀胱,尤其是在低、中剂量区。

Objective To compare the dosimetric characteristics between single spot scanning of proton therapy (SSS-PT) and helical tomotherapy (HT) for prostate cancer, so as to provide some reference for clinical practice. Methods Twelve patients with the previous history of prostate cancer were enrolled as subjects. After positioning, CT images were transferred into Raystation and HT planning systems for radiotherapy planning. The prescription dose was 69 Gy/25 F. The conformity index and homogeneity index of target areas and the dosimetric parameters of target areas and organs-at-risk in two radiotherapy schemes were compared. Results SSS-PT was superior to HT in the homogeneity index of target areas (P=0.001). Compared with HT, SSS-PT had lower mean doses to rectum[(21.92±4.00) Gy vs (31.97±2.60) Gy, P=0.000]and bladder[(17.62±3.15) Gy vs (30.52±3.94) Gy, P=0.000]. For the sparing of rectum and bladder, SSS-PT was always better than HT in the low- and medium-dose regions. Conclusion Both SSS-PT and HT can satisfy the clinical requirement of target coverage. For the same target coverage, SSS-PT is superior to HT in the sparing of rectum and bladder, especially in the low- and medium-dose regions.