“减时增量”放疗技术原理及临床应用  

Principle and Clinical Application of Time-shortening and Dose-escalating in the Radiotherapy Technique

作　　者：王静[1] 周志孝[2] 

机构地区：[1]江苏省肿瘤医院放疗科物理室,南京210009 [2]上海新华医院放疗科物理室,上海200030

出　　处：《中国医学物理学杂志》2008年第2期555-559,共5页Chinese Journal of Medical Physics

基　　金：江苏省135医学重点学科资助项目(No.H200540)

摘　　要：目的:探讨采用非常规剂量分次模式和改变总治疗时间等生物优化的干预手段即"减时增量技术",以获得最大的放射治疗增益。方法:该技术在临床上可以用超分割(HF)、同期加量调强放疗(SMART)和适形大分次量放疗(HypoF-CRT)等技术来实现。结果:大多数肿瘤在总治疗时间T天内的Tk天就开始快速增长,每天将多损耗剂量为k(Gy/days),总损失的生物效应剂量为k(T-Tk),只有减少总治疗时间才能提高治疗增益;而肿瘤控制率(TCP)曲线基本上是S型的,70Gy对应的TCP值约仅为80%,必须对其20%未被控制住的肿瘤细胞加量。结论:现有的研究表明利用减时增量这一生物优化技术可以提高肿瘤病人的生存率和生存质量。Objective： To explore biological optimization based on the cellular biological characteristics, in order to achieve the therapeutic benefit with ＂Time-shortening and Dose-escalating＂ in the radiotherapy technique. Methods： ＂Time-shortening and Dose-escalating＂ were implemented in the form ofhyperfractionated radiotherapy, simultaneous modulated accelerated radiotherapy, or hypofractionation conformal. Results： During treatment period, most tumor cells growth began to accelerate after certaindays （DayTk）. Andthisgrowthaccelerationcansedtheloss of radiobiological effects （k）. Inthis view, Time- shorteningelevated the treatment ratio. The TCP （TumorControlProbability）curve,inmostcases,is a‘S＇type. A prescribed dose of70Gy contributes a TCP value of about 80%. That means we have to give extra-dose to the remaining 20% uncontrolled tumor cells. Conclusions： There are evidences that biological optimization, the＂ Time-shortening and Dose-escalating＂ could elevate survival rate and improve survival quality.

关 键 词：放射治疗 减时增量 生物优化 

分 类 号：R730.55[医药卫生—肿瘤]