Marcelin Béatrice, Kjäll Per, Johansson Jonas, Lundin Anders, Nordström Håkan, Eriksson Markus, Bernard Christophe, Régis Jean
INSERM U751, Université de la Méditerranée, Hôpital La Timone, Marseille, France.
Stereotact Funct Neurosurg. 2010;88(4):208-15. doi: 10.1159/000314355. Epub 2010 May 12.
Gamma knife surgery (GKS) is used at subnecrotic doses for temporal lobe epilepsy (TLE) treatment. Rat models of TLE have been used to probe the mechanisms underlying GKS. Previous GKS studies on rats have used the Leksell GammaPlan (LGP) treatment planning system to determine the irradiation time to achieve the dose to deliver. Since LGP is not designed for such small structures, it is important to calibrate the system for the rat brain.
We have used a Monte Carlo simulation (MCS) radiation transport scheme, with CT data as anatomical and tissue-specific information, to simulate the dose distribution in a rat brain when using a Leksell Gamma Knife.
We show how dose distributions obtained by MCS quantitatively compare to those predicted by LGP, and discuss whether LGP should be used for studies involving rats. The energy deposited when using the 4-mm collimators was calculated for targets on both sides of the rat brain in the dorsal hippocampus, which allowed us to determine the exact time to irradiate rats with a given dose.
The MCS method used in this study can easily be used for future GKS studies on small animals when accurate dose distributions are required.
伽玛刀手术（GKS）以亚坏死剂量用于治疗颞叶癫痫（TLE）。TLE大鼠模型已被用于探究GKS的潜在机制。以往对大鼠进行的GKS研究使用Leksell GammaPlan（LGP）治疗计划系统来确定达到所需剂量的照射时间。由于LGP并非为如此小的结构设计，因此对大鼠脑进行系统校准很重要。
我们采用蒙特卡罗模拟（MCS）辐射传输方案，将CT数据作为解剖学和组织特异性信息，来模拟使用Leksell伽玛刀时大鼠脑内的剂量分布。
我们展示了MCS获得的剂量分布与LGP预测的剂量分布如何进行定量比较，并讨论了LGP是否应用于涉及大鼠的研究。计算了使用4毫米准直器时大鼠脑背侧海马两侧靶点的能量沉积，这使我们能够确定以给定剂量照射大鼠的确切时间。
当需要精确剂量分布时，本研究中使用的MCS方法可轻松用于未来对小动物的GKS研究。
