Department of Radiation Oncology, Tygerberg Hospital, Tygerberg, South Africa.
Int J Radiat Biol. 2010 Jun;86(6):486-98. doi: 10.3109/09553001003667982.
To determine alpha/beta (alpha/beta) values of arteriovenous malformations (AVM), meningiomas, acoustic neuromas (AN), and the optic chiasma using clinical data.
Data of dose/fractionation schedules form the literature, iso-effective for a specific clinical outcome, were analysed using the Fraction Equivalent plot (FE) method and the Tucker method. Established safe dose/fractionation schedules for the optic chiasma were used to determine its alpha/beta value.
With the FE plot method, an alpha/beta value of 3.76 Gray (Gy) (95% confidence level [CL]: 2.8-4.6 Gy) for meningiomas, 2.4 Gy (95% CL: 0.8-3.9 Gy) for acoustic neuroma, and 14.7 Gy (95% CL: 3.8-25.7 Gy) for arteriovenous malformations were determined. The respective alpha/beta values using the Tucker method were 3.3 Gy (95%CL: 2.2-6.8 Gy), 1.77 Gy (95%CL: 1.3-3.0 Gy) and -57 Gy (95%CL: -79.6 to -35.2 Gy). No meaningful alpha/beta values could be determined for the optic chiasma.
Acoustic neuromas with a low alpha/beta value would show no lesion intrinsic benefit from fractionation. Meningiomas probably benefit from a hypofractionated schedule. The high alpha/beta value for AVM can be explained but needs further research. Fractionation versus radiosurgery can be considered when the primary objective is to avoid normal tissue damage.
利用临床数据确定动静脉畸形（AVM）、脑膜瘤、听神经瘤（AN）和视交叉的α/β值。
使用 Fraction Equivalent plot（FE）方法和 Tucker 方法分析了文献中剂量/分割方案的数据，这些数据对于特定的临床结果具有等效性。使用视交叉的既定安全剂量/分割方案来确定其α/β值。
通过 FE 图方法，确定脑膜瘤的α/β值为 3.76 戈瑞（Gy）（95%置信区间[CL]：2.8-4.6 Gy），听神经瘤为 2.4 Gy（95%CL：0.8-3.9 Gy），动静脉畸形为 14.7 Gy（95%CL：3.8-25.7 Gy）。使用 Tucker 方法分别确定的α/β值为 3.3 Gy（95%CL：2.2-6.8 Gy）、1.77 Gy（95%CL：1.3-3.0 Gy）和-57 Gy（95%CL：-79.6 至-35.2 Gy）。对视交叉无法确定有意义的α/β值。
具有低α/β值的听神经瘤不会从分割中获得病灶内在获益。脑膜瘤可能受益于低分割方案。AVM 的高α/β值可以解释，但需要进一步研究。当主要目标是避免正常组织损伤时，可以考虑分割与放射外科治疗。
