Gamma knife model C with the automatic positioning system and its impact on the treatment of vestibular schwannomas.
Gamma knife model C with the automatic positioning system and its impact on the treatment of vestibular schwannomas.
复制标题
具有自动定位系统的C型伽玛刀及其对治疗前庭神经鞘瘤的影响。
DOI：
10.3171/jns.2002.97.supplement_5.0450
复制
发表时间：
2002
影响因子：
4.1
通讯作者：
A. V. van Eck
中科院分区：
文献类型：
--
作者：
G. Horstmann;A. V. van Eck
对象
本研究旨在评估伽玛刀自动定位系统（APS）对患者治疗的影响，特别是该系统对前庭神经鞘瘤（VS）患者治疗的影响，以减少听力损失。
方法
使用GAFChromic Film检查不同注射次数（1 - 129）的注射次数增加的剂量输送。记录了前549例患者的结果。此外，一系列的59例患者与VS治疗13戈伊的65%的等剂量。作者称之为“13对65”概念。胶片剂量测定表明，大量小剂量照射对伽玛刀治疗产生的剂量和剂量分布没有实质性影响。APS单独用于72%的动静脉畸形、71%的脑膜瘤、94%的VS和84%的垂体腺瘤。在所有病例中，59%的转移性肿瘤在纯APS模式下可接近，58%的胶质瘤和10%的葡萄膜黑色素瘤。因此，三分之二的患者可以单独使用APS治疗。对于复杂或非常偏心放置的目标，可以同时使用APS和手动系统。APS导致使用了更多的等中心点。平均随访15个月后，65%等剂量13戈伊的VS患者的结果与更传统的50%边缘等剂量治疗的患者相似。研究期间听力损失的发生率没有变化，治疗后三叉神经和面神经病变的发生率也保持不变。
结论
APS鼓励设计更适形的剂量计划。更多地使用较小的准直器导致剂量梯度更陡，靶体积外的辐射量更少。由于APS能够在可接受的时间内应用大量较小的等中心点，因此使用的等中心点数量增加。增加等中心的数量也可以用于减少最大辐射剂量并增加给定剂量计划中的均匀性。
OBJECT
The aim of this study was to assess the effects of the gamma knife automatic positioning system (APS) on the treatment of patients, particularly effects of this system on the treatment of patients with vestibular schwannomas (VSs), with a view to reducing loss of hearing.
METHODS
The dose delivery with an increased number of shots was checked with GAFChromic Film for various numbers of shots (one to 129). The results in the first 549 patients were recorded. In addition a series of 59 patients with VSs treated with 13 Gy to the 65% isodose is presented. The authors have termed this the "13 on 65" concept. The film dosimetry showed that a large number of small shots did not materially affect the dose and dose distribution produced by gamma knife treatment. The APS was used alone in 72% of arteriovenous malformations, 71% of meningiomas, 94% of VSs, and 84% of pituitary adenomas. Metastatic tumors were accessible in a pure APS mode in 59% of all cases, glioma in 58%, and uveal melanoma in 10% of the cases. Thus two thirds of patients could be treated using APS alone. It was possible to use the APS and manual systems together for complex or very eccentrically placed targets. The APS resulted in the use of a larger number of isocenters. After a mean follow-up period of 15 months, the results in patients with the VSs in whom 13 Gy was delivered to the 65% isodose were similar to those in patients treated with the more conventional 50% margin isodose. There was no change in the incidence of hearing loss within the study period, and the incidence of trigeminal and facial neuropathies remained unchanged after treatment as well.
CONCLUSIONS
The APS encourages the design of more conformal dose plans. The greater use of smaller collimators results in a steeper dose gradient with a smaller amount of radiation outside the target volume. Because the APS is able to apply a large number of smaller isocenters in an acceptable time, the number of isocenters used is increased. An increased number of isocenters can also be used to reduce the maximum radiation dose and increase the homogeneity in a given dose plan.