Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
Int J Radiat Oncol Biol Phys. 2012 Aug 1;83(5):1406-13. doi: 10.1016/j.ijrobp.2011.10.024. Epub 2011 Dec 29.
To investigate the relationship between the conformality index (CIn), heterogeneity index (HIn), and gradient index (GIn) and the development of toxicity in patients treated with Gamma Knife radiosurgery (GKRS) for intracranial meningiomas.
Treatment records of patients treated from 1997 to 2009 with at least 6 months of follow-up were reviewed. The following parameters were collected: CIn, HIn, GIn (ratio of the volume receiving half the prescription isodose to the volume receiving the full prescription isodose), brainstem (BS) maximum dose (MD), BS volume receiving ≥ 12 Gy (V12), optic apparatus (OA) MD, OA V8 Gy, OA V10, number of isocenters, number of isocenters outside target volume, and the occurrence of six toxicities. Univariate and multivariate logistic regression modeling were used for analysis.
This study included 145 patients (148 meningiomas) with a median follow-up time of 27 months (range, 6-113.9 months). The majority of meningiomas were located in the skull base (53%). The median prescription dose was 13 Gy (range, 10-24 Gy) to the 51.50% (range, 50-92%) isodose. A lower HIn was correlated with a higher GIn (p = 0.007). CIn was not associated with any toxicity. Higher HIn was associated with the development of dizziness (odds ratio [OR] 1.9; p = 0.02), whereas a lower GIn was associated with motor deficits (OR 0.38; p = 0.04) and auditory changes (OR 0.59; p = 0.04). The OA MD, V8, and V12 were not associated with visual changes, but visual changes were associated with a higher number of isocenters outside the target volume (OR 1.93; p = 0.07). BS V12 was correlated with the development of auditory changes (OR 1.05; p = 0.05), whereas patients with higher BS MD tended to have increased toxicity.
Close attention must be paid to all three indices (CIn, HIn, GIn) when optimal treatment plans are determined. We recommend that the target CIn should be ≤ 2.0, the HIn ≤ 2.0, and the GIn ≥ 3.0 for intracranial meningiomas.
探讨适形指数（CI n）、不均匀性指数（HIn）和梯度指数（GIn）与伽玛刀放射外科（GKRS）治疗颅内脑膜瘤患者毒性发展之间的关系。
回顾分析了 1997 年至 2009 年至少接受 6 个月随访的患者的治疗记录。收集了以下参数：CI n、HIn、GIn（接受处方等剂量一半的体积与接受全处方等剂量的体积之比）、脑干（BS）最大剂量（MD）、BS 接受 12 Gy 以上的体积（V12）、视器（OA）MD、OA 接受 8 Gy 的体积、OA 接受 10 Gy 的体积、等中心点数量、靶区外等中心点数量以及六种毒性的发生情况。采用单变量和多变量逻辑回归模型进行分析。
本研究纳入了 145 例（148 个脑膜瘤）患者，中位随访时间为 27 个月（范围为 6-113.9 个月）。大多数脑膜瘤位于颅底（53%）。中位处方剂量为 13 Gy（范围为 10-24 Gy），达到 51.50%（范围为 50-92%）等剂量。较低的 HIn 与较高的 GIn 相关（p=0.007）。CI n 与任何毒性均无关。较高的 HIn 与头晕的发生相关（比值比[OR]1.9；p=0.02），而较低的 GIn 与运动障碍（OR 0.38；p=0.04）和听觉变化（OR 0.59；p=0.04）相关。OA MD、V8 和 V12 与视力变化无关，但视力变化与靶区外更多的等中心点相关（OR 1.93；p=0.07）。BS V12 与听觉变化的发生相关（OR 1.05；p=0.05），而 BS MD 较高的患者毒性增加的趋势更为明显。
在制定最佳治疗方案时，必须密切关注所有三个指数（CI n、HIn、GIn）。我们建议颅内脑膜瘤的靶区 CI n 应≤2.0，HIn≤2.0，GIn≥3.0。
