Liang Cheng-Loong, Ho Meng-Wei, Lu Kang, Tsai Yu-Duan, Liliang Po-Chou, Wang Kuo-Wei, Chen Han-Jung
Department of Neurosurgery, E-DA Hospital, I-SHOU University, Kaohsiung, Taiwan, Republic of China.
J Neurosurg. 2006 Dec;105 Suppl:112-6. doi: 10.3171/sup.2006.105.7.112.
The authors conducted a study to assess the eye lens dosimetry in trigeminal neuralgia (TN) treatment when using the Leksell Gamma Knife model C.
Phantom studies were used to measure the maximal dose reaching the eye lens with and without eye shielding. Six consecutive patients with TN were evaluated for Gamma Knife surgery (GKS). The maximum prescribed dose of 80 Gy was delivered with a single shot using the 4-mm collimator helmet. High-sensitivity thermoluminescence dosimeter chips (TLDCs) were used to measure the dosimetry. In vitro, the Leksell GammaPlan (LGP) system predicted the mean maximal doses of 1.08 +/- 0.08 and 0.15 +/- 0.01 Gy (mean +/- standard deviation) to the lens ipsilateral to the treated trigeminal nerve without and with eye shielding, respectively. The TLDCs-measured dosimetry indicated the mean maximal doses of 1.12 +/- 0.09 and 0.17 +/- 0.01 Gy without and with eye shielding, respectively. The maximal doses to the lens contralateral to the nerve were similar. In vivo, the LGP predicted the mean maximal doses to the lens ipsilateral to the treated nerve as 1.1 +/- 0.07 and 0.16 +/- 0.02 Gy, respectively, without and with eye shielding. The dosimetry measured by TLDCs indicated the mean maximal dose to the lens ipsilateral to the treated nerve as 0.17 +/- 0.02 Gy with eye shielding. The mean maximal doses to the lens contralateral to the nerve were similar. Using the 110 and 125 degrees gamma angles, the LGP predicted the mean maximal doses of 0.32 +/- 0.04 and 0.12 +/- 0.04 Gy to the lens without and with eye shielding, respectively.
Patients with TN undergoing GKS without eye shielding may develop cataracts due to the high radiation dose to the eye lenses. The authors suggest the routine use of bilateral eye shielding for the patients.
作者开展了一项研究，以评估使用Leksell伽玛刀C型治疗三叉神经痛（TN）时眼晶状体的剂量测定情况。
采用体模研究来测量有无眼部屏蔽时到达眼晶状体的最大剂量。对连续6例TN患者进行伽玛刀手术（GKS）评估。使用4毫米准直器头盔单次给予80 Gy的最大处方剂量。采用高灵敏度热释光剂量计芯片（TLDC）测量剂量。在体外，Leksell伽玛计划（LGP）系统预测，在无眼部屏蔽和有眼部屏蔽时，治疗侧三叉神经同侧晶状体的平均最大剂量分别为1.08±0.08 Gy和0.15±0.01 Gy（平均值±标准差）。TLDC测量的剂量显示，无眼部屏蔽和有眼部屏蔽时，平均最大剂量分别为1.12±0.09 Gy和0.17±0.01 Gy。神经对侧晶状体的最大剂量相似。在体内，LGP预测，无眼部屏蔽和有眼部屏蔽时，治疗侧神经同侧晶状体的平均最大剂量分别为1.1±0.07 Gy和0.16±0.02 Gy。TLDC测量的剂量显示，有眼部屏蔽时，治疗侧神经同侧晶状体的平均最大剂量为0.17±0.02 Gy。神经对侧晶状体的平均最大剂量相似。使用110度和125度的伽马角时，LGP预测，无眼部屏蔽和有眼部屏蔽时，晶状体的平均最大剂量分别为0.32±0.04 Gy和0.12±0.04 Gy。
接受GKS且未进行眼部屏蔽的TN患者，可能因眼晶状体接受高辐射剂量而发生白内障。作者建议对患者常规使用双侧眼部屏蔽。
