Rojas A, Joiner M C, Johns H
CRC Gray Laboratory, Mount Vernon Hospital, Northwood, Middlesex, U.K.
Radiother Oncol. 1989 Nov;16(3):211-20. doi: 10.1016/0167-8140(89)90021-2.
Recovery kinetics and recovery capacity were studied in a fast proliferating normal tissue, skin, and in an anaplastic mouse mammary carcinoma, CaNT. Three fractions per day of X-rays, repeated over 5 days, were given at varying interfraction intervals from 0 to 8 h. The rate of recovery in tumours (t1/2 = 0.31 +/- 0.15 h for local control) was significantly faster than in skin (t1/2 = 0.96 +/- 0.10 h). By contrast, the fractionation sensitivity of CaNT tumours was less than that of skin (alpha/beta = 43.3 +/- 8.5 Gy vs. alpha/beta = 7.9 +/- 0.2 Gy). Tissues with recovery half-times similar to or longer than that determined for skin would be at risk if interfraction intervals less than 6 h are used in regimes which involve the use of two or more fractions per day. This would be especially true for tissues that show a greater sensitivity to dose fractionation, and hence more sparing of radiation damage with hyperfractionation.
在快速增殖的正常组织皮肤以及间变性小鼠乳腺癌CaNT中研究了恢复动力学和恢复能力。每天分三次给予X射线，持续5天，分区间隔从0到8小时不等。肿瘤的恢复速率（局部控制的t1/2 = 0.31±0.15小时）明显快于皮肤（t1/2 = 0.96±0.10小时）。相比之下，CaNT肿瘤的分次敏感性低于皮肤（α/β = 43.3±8.5 Gy，而皮肤α/β = 7.9±0.2 Gy）。如果在每天使用两个或更多分次的方案中采用小于6小时的分区间隔，恢复半衰期与皮肤相似或更长的组织将面临风险。对于那些对剂量分次显示出更高敏感性、因此超分割时对辐射损伤更具保护作用的组织而言尤其如此。
