SPINAL CORD TOLERANCE TO SINGLE-FRACTION PARTIAL-VOLUME IRRADIATION: A SWINE MODEL
SPINAL CORD TOLERANCE TO SINGLE-FRACTION PARTIAL-VOLUME IRRADIATION: A SWINE MODEL
复制标题
DOI：
10.1016/j.ijrobp.2010.07.1979
复制
发表时间：
2011-01-01
影响因子：
7
通讯作者：
Solberg, Timothy D.
中科院分区：
文献类型：
--
作者：
Medin, Paul M.;Foster, Ryan D.;Solberg, Timothy D.
目的：为了确定脊髓耐受性的单分数，部分体积照射在swines.Methods和材料：一个5厘米长的颈部段照射在38-47周龄的尤卡坦小型猪使用专用的，图像引导放射外科直线加速器。将辐射输送到位于颈脊髓外侧的约5 cm长、2 cm直径的圆柱体中，导致剂量分布为90%、50%和10%等剂量线分别穿过同侧、中央和对侧脊髓。处方剂量为90%等剂量线。共26头猪被分为8个剂量组，剂量为12-47戈伊。16、18、20、22和24戈伊剂量组的平均最大脊髓剂量分别为16.9 +/-0.1、18.9 +/-0.1、21.0 +/- 0.1、23.0 +/- 0.2和25.3 +/- 0.3戈伊。同一组接受≥ 10戈伊照射的脊髓体积的平均百分比分别为43% +/-3%、48% +/-4%、51% +/-2%、57% +/-2%和59% +/-4%。研究的终点是运动神经功能缺损的步态变化确定在1年的随访period.Results：一个陡峭的剂量反应曲线观察到的中位有效剂量为20.0戈伊的最大剂量点（95%置信区间，18.3-21.7）。观察到神经系统变化的发生与组织学变化的存在之间具有极好的一致性。所有运动缺陷的小型猪在照射侧均表现出一定程度的脱髓鞘和局灶性白色坏死，灰质相对较少。组织学检查结果是不显着的minipigs与正常neurologic status.Conclusions：我们的研究结果表明，一个陡峭的横向梯度的剂量分布，猪有一个较低的中位有效剂量的瘫痪比已经观察到的大鼠和更密切类似的大鼠，小鼠和豚鼠接受统一的脊髓照射。(C)2011 Elsevier Inc.
Purpose: To determine the spinal cord tolerance to single-fraction, partial-volume irradiation in swine.Methods and Materials: A 5-cm-long cervical segment was irradiated in 38-47-week-old Yucatan minipigs using a dedicated, image-guided radiosurgery linear accelerator. The radiation was delivered to a cylindrical volume approximately 5 cm in length and 2 cm in diameter that was positioned lateral to the cervical spinal cord, resulting in a dose distribution with the 90%, 50%, and 10% isodose lines traversing the ipsilateral, central, and contralateral spinal cord, respectively. The dose was prescribed to the 90% isodose line. A total of 26 pigs were stratified into eight dose groups of 12-47 Gy. The mean maximum spinal cord dose was 16.9 +/- 0.1, 18.9 +/- 0.1, 21.0 +/- 0.1, 23.0 +/- 0.2, and 25.3 +/- 0.3 Gy in the 16-, 18-, 20-, 22-, and 24-Gy dose groups, respectively. The mean percentage of spinal cord volumes receiving >= 10 Gy for the same groups were 43% +/- 3%, 48% +/- 4%, 51% +/- 2%, 57% +/- 2%, and 59% +/- 4%. The study endpoint was motor neurologic deficit determined by a change in gait during a 1-year follow-up period.Results: A steep dose-response curve was observed with a median effective dose for the maximum dose point of 20.0 Gy (95% confidence interval, 18.3-21.7). Excellent agreement was observed between the occurrence of neurologic change and the presence of histologic change. All the minipigs with motor deficits showed some degree of demyelination and focal white matter necrosis on the irradiated side, with relative sparing of the gray matter. The histologic findings were unremarkable in the minipigs with normal neurologic status.Conclusions: Our results have indicated that for a dose distribution with a steep lateral gradient, the pigs had a lower median effective dose for paralysis than has been observed in rats and more closely resembles that for rats, mice, and guinea pigs receiving uniform spinal cord irradiation. (C) 2011 Elsevier Inc.