| 田源,张良安,戴光复.α核素非均匀微观分布对细胞微剂量的影响[J].中华放射医学与防护杂志,2007,27(3):271-273 |
| α核素非均匀微观分布对细胞微剂量的影响 |
| The influence of nonuniform micro-distribution of alpha emitter on microdosimetry in cells |
| 投稿时间：2006-05-22 |
| DOI： |
| 中文关键词: α核素 非均匀 微观分布 微剂量 |
| 英文关键词:Alpha radionuclide Nonuniform Micro-distribution Microdosimetry |
| 基金项目:国家自然科学基金资助项目(10375091) |
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| 摘要点击次数: 2835 |
| 全文下载次数: 1916 |
| 中文摘要: |
| 目的 探讨放射免疫治疗中α核素在细胞水平上非均匀微观分布对细胞S因子的影响。方法 利用蒙特卡罗方法随机模拟α粒子的发射;基于连续慢化近似模型,根据α粒子剩余射程_能量的关系,采用插值法计算α粒子入射动能和出射动能,得到其在靶区内的能量沉积。以 213Po 为例,计算了不同细胞大小及核素不同微观分布(均匀分布、中心分布、随核素距细胞中心的距离线性递增、线性递减、指数递增、指数递减)下细胞对细胞的S因子。结果 213Po 均匀分布下的S(C←C)与Hamacher给出的结果符合得很好;不同微分布下的S(C←C)有显著差别。分析表明,核素不同微观分布所造成的α粒子在靶区内运动的平均弦长的显著变化,以及由此产生的α粒子平均碰撞阻止本领的变化,是造成细胞S因子有显著差别的主要原因。结论 放射性核素非均匀微分布类型显著影响细胞S因子的大小,在估算细胞吸收剂量时应予以重视。 |
| 英文摘要: |
| Objective To study the influence of nonuniform micro-distribution of alpha emitter on cellular S values(in the radiommunotherapy). Methods Emission of alpha particles is randomly simulated by Monte Carlo method; the incident energy and exit energy are calculated with interpolation technique based on the relationship between range and energy of alpha particle and the analytical Continuous Slowing Down Approximation (CSDA) model. So energy deposited in the target area can be obtained. To take 213Po as an example, cellular S values with various cell dimensions and possible micro-distributions of radioactivity are calculated, such as linear increase, linear decrease, exponential increase and exponential decrease.Results S values from cell to cell of uniform distribution showed no difference with the Hamacher's results. S values of different micro-distributions are distinguishing with each other. It is indicated that different micro-distributions of radioactivity will result in significant change of average chord length of alpha particles traveling in the target area, as well as the change of average stopping power over the chord,which is primary reason for differences of S values.Conclusions The nonuniform micro-distributions show remarkable influence on cellular S values and hence should be taken consideration in cellular absorbed dose estimation, especially in microdosimetry. |
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