Morris G M, Coderre J A, Hopewell J W, Micca P L, Fisher C
CRC Normal Tissue Radiobiological Research Group, University of Oxford, Churchill Hospital, UK.
Radiother Oncol. 1996 Jun;39(3):253-9. doi: 10.1016/0167-8140(95)01693-7.
The Fischer 344 rat spinal cord model has been used to evaluate the response of the central nervous system to boron neutron capture irradiation with variable doses of the neutron capture agent, borocaptate sodium (BSH). Three doses of BSH, 190, 140 and 80 mg/kg body weight, administered by i.p. injection, were used to establish the time course of 10B accumulation in and removal from the blood. After administration of the two lower doses of BSH, blood 10B levels peaked at 0.5 h after injection, with no significant (P > 0.1) change at 1 h after injection. Beyond this time point, levels of 10B in the blood began to decrease after a dose of 80 mg/kg BSH, but remained constant until 3 h after administration after the two higher doses of BSH. Myelopathy developed after latent intervals of 20.4 +/- 0.1, 20.8 +/- 1.4, 15.0 +/- 0.8, 15.4 +/- 0.4 and 15.6 +/- 0.4 weeks, following irradiation with thermal neutrons in combination with BSH at doses of 20, 40, 80, 140 and 190 mg/kg body weight, respectively. The radiation-induced lesion in the spinal cord was white matter necrosis. ED50 values for myelopathy were calculated from probit-fitted dose-effect curves. Expressed as total physical absorbed doses, these values were 20.7 +/- 1.9, 24.9 +/- 1.2, 27.2 +/- 0.9, 28.4 +/- 0.6 and 32.4 +/- 1.9 Gy after irradiation with thermal neutrons in the presence of 20, 40, 80, 140 and 190 mg/kg body weight of BSH, respectively. The compound biological effectiveness (CBE) factor values, estimated from this data, were in the range 0.49-0.55. There was no significant (P > 0.1) variation in the CBE factor for BSH as a function of increasing 10B concentration in the blood. It was concluded that there was no significant synergistic interaction between the low and high linear energy transfer (LET) components of the boron neutron capture (BNC) radiation field.
费希尔344大鼠脊髓模型已被用于评估中枢神经系统对不同剂量的中子俘获剂硼酸钠（BSH）进行硼中子俘获辐照的反应。通过腹腔注射给予三种剂量的BSH，分别为190、140和80mg/kg体重，以确定10B在血液中积累和清除的时间进程。给予两种较低剂量的BSH后，血液中10B水平在注射后0.5小时达到峰值，注射后1小时无显著（P>0.1）变化。超过这个时间点，80mg/kg BSH剂量后血液中10B水平开始下降，但在给予两种较高剂量的BSH后，直到给药后3小时仍保持恒定。在用热中子与分别为20、40、80、140和190mg/kg体重的BSH联合辐照后，分别在20.4±0.1、20.8±1.4、15.0±0.8、15.4±0.4和15.6±0.4周的潜伏间隔后出现脊髓病。脊髓中的辐射诱导损伤为白质坏死。从概率拟合剂量效应曲线计算脊髓病的ED50值。以总物理吸收剂量表示，在用分别为20、40、80、140和190mg/kg体重的BSH存在下用热中子辐照后，这些值分别为20.7±1.9、24.9±1.2、27.2±0.9、28.4±0.6和32.4±1.9Gy。根据这些数据估计的复合生物有效性（CBE）因子值在0.49-0.55范围内。随着血液中10B浓度的增加，BSH的CBE因子没有显著（P>0.1）变化。得出的结论是，硼中子俘获（BNC）辐射场的低和高线性能量转移（LET）成分之间没有显著的协同相互作用。
