Flickinger J C, Schell M C, Larson D A
Department of Radiation Oncology, University of Pittsburgh School of Medicine, PA 15213.
Int J Radiat Oncol Biol Phys. 1990 Jul;19(1):143-8. doi: 10.1016/0360-3016(90)90146-b.
Radiosurgery techniques permit high doses of single fraction irradiation to be administered to small volumes of tumor with relative sparing of surrounding brain tissue. The tolerance of surrounding normal brain tissue to dose distributions from linear accelerator radiosurgery with different collimator sizes is an important factor that must be estimated by anyone using these treatment techniques. The exponential and linear quadratic versions of the integrated logistic formula were used to estimate the probability of brain necrosis at different doses for radiosurgical dose distributions administered by a 6 MV linear accelerator with a 5 arc technique for collimator sizes from 12.5 to 30 mm in diameter. Dose-volume isoeffect curves for a 3% risk of brain necrosis from linear accelerator radiosurgery were then calculated. These curves approximate those calculated for gamma knife radiosurgery and a published 1% dose-volume isoeffect line predicted for proton beam irradiation. Similar dose-volume isoeffect curves were calculated for single fraction radiosurgery boosts administered after 30 Gy of whole brain irradiation in 12 fractions. The integrated logistic formula appears to be a useful tool for estimating tolerance and providing guidelines for prescribing radiation doses for linear accelerator radiosurgery.
放射外科技术允许对小体积肿瘤给予高剂量的单次分割照射，同时相对 sparing 周围脑组织。周围正常脑组织对不同准直器尺寸的直线加速器放射外科剂量分布的耐受性是任何使用这些治疗技术的人都必须估计的重要因素。使用积分逻辑公式的指数和线性二次版本来估计由 6 MV 直线加速器采用 5 弧技术、准直器尺寸直径从 12.5 到 30 毫米进行放射外科剂量分布时，不同剂量下脑坏死的概率。然后计算直线加速器放射外科导致 3%脑坏死风险的剂量 - 体积等效应曲线。这些曲线近似于为伽玛刀放射外科计算的曲线以及为质子束照射预测的已发表的 1%剂量 - 体积等效应线。对于在 12 次分割的全脑照射 30 Gy 后给予的单次分割放射外科增强，计算了类似的剂量 - 体积等效应曲线。积分逻辑公式似乎是估计耐受性以及为直线加速器放射外科规定放射剂量提供指导方针的有用工具。
