β核素球囊预防血管再狭窄的临床剂量估算  

Calculation of radioactivity disposition from beta nuclide filled balloon in in travascular brachytherapy

作　　者：陈英茂[1] 耿建华[2] 田嘉禾[1] 邵明哲[1] 姚树林[1] 陈盛祖[2] 

机构地区：[1]解放军总医院核医学科,北京100853 [2]中国医学科学院,中国协和医科大学肿瘤医院核医学科

出　　处：《中华核医学杂志》2003年第5期308-309,共2页Chinese Journal of Nuclear Medicine

基　　金：国家自然科学基金资助项目( 30 2 70 4 0 8)

摘　　要：目的　探讨核素球囊内照射血管内的吸收剂量分布规律。方法　①依据吸收剂量点核函数模拟计算90 Y、188Re、3 2 P灌注球囊时血管组织中的吸收剂量率分布 ;②用非线性最小二乘法对吸收剂量率随球囊外径及组织深度的变化进行曲线拟合 ,并由此导出便于临床使用的经验公式。结果　球囊中吸收剂量率峰值出现在血管腔内球囊中 ,血管表面位于吸收剂量率曲线的拐点处 ,血管壁及周围组织中的吸收剂量率以近双指数方式下降。吸收剂量、持续照射时间、初始放射性浓度、组织深度及球囊外半径间的关系可用一经验公式表达。结论　血管组织中的 β核素吸收剂量分布呈快速下降。Objective To calculate the radioactivity disposition in endovascular irradiation for preve nting restenosis after angioplasty and to give an empirical formula easy to use . Methods ①The process of intravascular brachytherapy with 90 Y, 188 Re or 32 P filled balloon was simulat ed with the computer program based on beta particle dose point kernel; and the a bsorbed dose distribution was calculated. ②The curve of absorbed dose rate vers us the outer radius of the balloon and the penetrating depth in the vessel wall were fitted to a function with non-linear least squares method and an empirical formula easy to use was built. Results The absorbed doses distribu ting along the radial direction of the standard balloon showed that the peak val ue was inside the balloon, and the inflexion of the dose curve was at the endoth elial surface of the vessel. The dose decreased sharply with the radial distance approximately in an exponential manner in the vessel wall. The relationship of absorbed dose to radiation time, initial radioactivity, tissue depth, balloon ou ter radius were all expressed with an empirical formula. Conclusions The dose decreases sharply within the vessel wall, and that is very advantageo us for focusing radiation energy on the vessel wall and preventing damaging dist ant normal tissue. Using the empirical formula, according to the required absorb ed dose, the required radiation time can be easily calculated for clinical purpo se.

关 键 词：β核素 球囊 预防 血管再狭窄 剂量估算 放射疗法 经皮冠状动脉腔内成形术 

分 类 号：R817[医药卫生—影像医学与核医学]