前列腺癌的α/β比值有多低？
How low is the alpha/beta ratio for prostate cancer?
作者信息
Kal Henk B, Van Gellekom Marion P R
机构信息
Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands.
出版信息
Int J Radiat Oncol Biol Phys. 2003 Nov 15;57(4):1116-21. doi: 10.1016/s0360-3016(03)01455-x.
PURPOSE
Recently, low alpha/beta values of 1.2 and 1.5 Gy for prostate tumors have been derived from clinical results of external beam radiotherapy and of permanent implants of (125)I and (103)Pd. In the analyses the contributions of tumor repopulation, and edema as a result of inserting radioactive seeds in the prostate, have been ignored. In this paper we reanalyzed the clinical data and introduced the contribution of repopulation and edema.
METHODS AND MATERIALS
The linear quadratic-biologically effective dose model was used for reanalysis. In this model, the influence of repopulation and edema has been taken into account. The biologically effective dose was calculated as a function of alpha/beta for 2 brachytherapy regimens with (125)I and (103)Pd and 2 fractionated treatments, and for different half-times for repair of sublethal damage for the brachytherapy regimens.
RESULTS
We have found a plausible alpha/beta value of 3.1 to 3.9 Gy, an alpha value of 0.1 to 0.15 Gy(-1), and a half-time of repair of about 0.5 h.
CONCLUSIONS
It seems now that the alpha/beta value is low, 3.1-3.9 Gy, but not as low as the 1.2 and 1.5 Gy reported earlier.
目的
最近，前列腺肿瘤的低α/β值分别为1.2和1.5 Gy，这是根据外照射放疗以及¹²⁵I和¹⁰³Pd永久性植入的临床结果得出的。在分析中，肿瘤再增殖以及因在前列腺中插入放射性粒子导致的水肿的影响被忽略了。在本文中，我们重新分析了临床数据，并引入了再增殖和水肿的影响。
方法和材料
使用线性二次生物等效剂量模型进行重新分析。在该模型中，已考虑再增殖和水肿的影响。针对采用¹²⁵I和¹⁰³Pd的2种近距离治疗方案以及2种分次治疗方案，计算生物等效剂量作为α/β的函数，并针对近距离治疗方案中不同的亚致死损伤修复半衰期进行计算。
结果
我们发现合理的α/β值为3.1至3.9 Gy，α值为0.1至0.15 Gy⁻¹，修复半衰期约为0.5小时。
结论
现在看来，α/β值较低，为3.1 - 3.9 Gy，但不像之前报道的1.2和1.5 Gy那么低。
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