摘要
目的 计算90 Y、3 2 P、186Re三种核素在血管及周围组织中产生的吸收剂量分布情况 ,为实施放射性核素照射防止血管成形术后再狭窄的研究提供剂量学的参考。方法 依据剂量点核函数 ,由计算机程序对在标准球囊 (2 0mm长 ,内外直径分别为 1mm和 3mm)内均匀分布的90 Y、3 2 P和186 Re核素分别进行数值积分 ,计算其在周围空间产生的吸收剂量分布。结果 吸收剂量峰值出现在血管腔内球囊中 ,血管表面位于吸收剂量曲线的拐点处 ,血管壁及周围组织中的吸收剂量以近指数方式下降 ;核素的能量越低 ,吸收剂量下降速度越快 ,且沿管壁均匀分布区越长 ;在中点的血管表面处 ,1MBq/cm3 的90 Y、3 2 P和186Re持续 1min照射所产生的吸收剂量分别为 :74、71和 45mGy ,而在距表面仅 0 5mm的血管壁内的吸收剂量分别下降到 5 3%、48%和 2 8%。结论 β射线的吸收剂量在血管组织中以近指数方式的快速下降 ,有利于集中能量在靶区且对周围正常组织损伤较轻 ,低能量的186Re更具有这一优势。
Objective To give a dose reference to the researcher who study prevention of restenosis using endovascular brachytherapy Methods The dose distributions around a 3 mm diam by 20 mm long balloon filled with 90 Y , 32 P and 186 Re separately have been calculated by a computer program based on a dose point kernel Results The peak value of the absorbed dose is found inside the balloon, the inflexion of the dose curve at the endothelial surface of the vessel In the vessel tissue the dose decreases with distance in an approximately exponential manner The lower the nuclide energy is, the faster the dose falls with distance, and the longer the region of uniform dose distribution along vessel wall is The dose rate at the surface of the vessel wall is approximately 74, 71, and 45 mGy/min per mCi/ml, with the dose rate decreasing to 53%, 48% and 28% at 0 5 mm for 90 Y , 32 P and 186 Re separately Conclusion The fast falling of the dose in an approximately exponential manner in the vessel tissue makes for focusing β radionuclide energy to the vessel wall target and reducing the injury of the normal tissue around the vessel, and especially 186 Re with lower energy has a more obvious advantage in this aspect
出处
《中国介入心脏病学杂志》
2001年第3期146-149,共4页
Chinese Journal of Interventional Cardiology
基金
军队九五课题 (96Z0 5 2 )
