Withers H R
Cancer. 1985 May 1;55(9 Suppl):2086-95. doi: 10.1002/1097-0142(19850501)55:9+<2086::aid-cncr2820551409>3.0.co;2-1.
Conventional is commonly not universally correct, and so with dose fractionation in radiotherapy. Fractionation spares slowly responding tissues more than tissues and tumors that show an early response, suggesting that therapeutic gains may be further increased by reducing fractional doses below 1.8 to 2 Gy. The overall duration of a course of radiotherapy should not be the same for all tumors in all sites because the time of onset of regeneration after the start of radiotherapy varies from tissue to tissue and among tumors. Although growth kinetics and dose-response characteristics are known to vary, inability to identify and quantify them prospectively frustrates rational selection of patients for individualized fractionation regimens. In general, curative radiotherapy should be delivered in as short an overall time as possible using the smallest practical dose per fraction. Although 2 Gy, 5 times per week may be a reasonable "average" treatment, greater individualization should be a research goal.
传统观念通常并非普遍正确，放射治疗中的剂量分割也是如此。与早期反应的组织和肿瘤相比，分割放疗对反应缓慢的组织的保护作用更大，这表明将分次剂量降低至1.8至2 Gy以下可能会进一步提高治疗效果。放疗疗程的总时长对于所有部位的所有肿瘤而言不应相同，因为放疗开始后组织再生开始的时间因组织和肿瘤而异。尽管已知生长动力学和剂量反应特征会有所不同，但无法前瞻性地识别和量化它们会阻碍为个体化分割方案合理选择患者。一般来说，根治性放疗应在尽可能短的总时间内进行，每次分割使用尽可能小的实际剂量。虽然每周5次、每次2 Gy可能是一种合理的“平均”治疗方式，但更大程度的个体化应成为一个研究目标。
