| 赵楠,杨瑞杰*,王俊杰.125I放射性粒子植入计划定制研究[J].中华放射医学与防护杂志,2014,34(1):54-58 |
| 125I放射性粒子植入计划定制研究 |
| Customized planning for radioactive 125I seed implantation |
| 投稿时间：2013-03-16 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.01.015 |
| 中文关键词: 125I 放射性粒子 粒子植入 治疗计划 计划定制 |
| 英文关键词:125I Radioactive seeds Seeds implant Treatment planning Customized planning |
| 基金项目:国家自然科学基金（81372420，81071834）；首都医学发展科研基金（2009-2024） |
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| 中文摘要: |
| 目的 定制125I 放射性粒子植入计划的优选方案。方法 将125I 粒子等间距植入直径为1、2和3 cm的3种球形模体和三径分别为1 cm×1 cm×2 cm、1 cm×1 cm×3 cm、1 cm×2 cm×2 cm、1 cm×2 cm×3 cm、1 cm×3 cm×3 cm、2 cm×2 cm×3 cm和2 cm×3 cm×3 cm的7种椭球形模体，粒子分布均匀对称，调整粒子活度和间距，使靶区剂量满足处方剂量D90 145 Gy，并实现尽可能适形均匀的剂量分布。初始粒子间距是1 cm，为改善靶区剂量分布适形度和均匀性，将粒子间距调整为0.75 cm。通过评价均匀性指数（HI）、靶区外体积指数（EI）和适形指数（CI）定制粒子植入优选方案。同时记录植入粒子活度和数目。结果 对直径1 cm的球形靶区，粒子间距1和0.75 cm 时HI分别为40.0%和55.9%，EI分别为98.3%和95.1%，CI均为0.44；对直径3 cm的球形靶区和1 cm×2 cm×2 cm的椭球形靶区，粒子间距1 cm植入方式的HI、EI和CI优于粒子间距0.75 cm 的植入方式。对其余靶区粒子间距0.75 cm植入方式的EI和CI均优于间距1 cm的植入方式，HI略小于间距1 cm的植入方式。粒子间距0.75和1 cm植入单颗粒子活度分别为17.0~27.8 MBq 和30.0~58.8 MBq，间距0.75 cm比间距1 cm多植入粒子2~10颗。结论 对于10种靶区，除直径为1 cm、3 cm的球形靶区和1 cm×2 cm×2 cm 的椭球形靶区以外，其余7种靶区0.75 cm 植入方式的剂量分布适形度更好，靶区外接受处方剂量体积更小，为粒子均匀植入的优选方案。 |
| 英文摘要: |
| Objective To customize the optimal plans for radioactive 125I seeds volumetric implants in selected regular target volumes. Methods 125I seeds were symmetrically and uniformly implanted into 3 spherical targets with the diameters of 1, 2 and 3 cm and 7 ellipsoidal targets with the 3 dimensions of 1 cm×1 cm×2 cm, 1 cm×1 cm×3 cm, 1 cm×2 cm×2 cm, 1 cm×2 cm×3 cm, 1 cm×3 cm×3 cm, 2 cm×2 cm×3 cm and 2 cm×3 cm×3 cm. The activity and inter-space of seeds were adjusted to obtain the conformal and uniform dose distribution, with the prescribed D90 (the dose delivered to 90% of the targets) greater than 145 Gy. The inter-space of seeds was changed from 1 cm to 0.75 cm, to improve the conformity and uniformity of dose distribution. Plan quality was assessed using homogeneity index (HI), external index (EI) and conformal index (CI). The activity and number of seeds implanted were also recorded and compared. Results For the spherical target with the diameter of 1 cm, when seeds were implanted with the inter-space of 1 cm and 0.75 cm, the HI were 40.0% and 55.9%, the EI were 98.3% and 95.1%, the CI were 0.44 and 0.44, respectively. For the spherical target with the diameter of 3 cm and the target with the 3 dimensions of 1 cm × 2 cm× 2 cm, the implant with the inter-space of 1 cm provided better indices of HI, EI and CI than those with the inter-space of 0.75 cm. For the other targets, the implants with the inter-space of 0.75 cm provided better indices of EI and CI than those with the inter-space of 1 cm, although they displayed a little worse homogeneity in terms of HI. The activity per seed was 17.0-27.8 MBq and 30.0-58.8 MBq in the implants with the inter-spaces of 0.75 cm and 1 cm, respectively. 2-10 more seeds were needed in the implants with the inter-space of 0.75 cm. Conclusions For the studied targets except the spherical targets with the diameter of 1 cm and 3 cm and the ellipsoidal target with the dimension of 1 cm×2 cm×2 cm, 125I seeds implanted with the inter-space of 0.75 cm could provide more conformal dose distribution. It could be the better customized plans for uniformly spaced seed implantation. |
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