Methods to improve dose uniformity for radioactive stents in endovascular brachytherapy
- 作者：Amols ; Howard I.
- 关键词：Brachytherapy ; Endovascular ; Dosimetry ; Gamma ; Beta ; Stents
- 刊名：Cardiovascular Radiation Medicine
- 出版年：1999
- 期刊代码：47_15221865
- 类别：med
- 出版时间：July - September, 1999
- 卷：1
- 期：3
- 页码：270-277
- 文件大小：320 K
摘要
Intravascular brachytherapy (IVBT) has rapidly gained acceptance as a new treatment modality for reducing restenosis and improving the success rate of percutaneous transluminal coronary angioplasty (PTCA). Recent clinical results on patients treated with beta-emitting 32P stents suggest that radiation reduces in-stent restenosis but may exacerbate neointimal growth at the edges of the stents. This has been referred to as the “candy wrapper effect.” It is well known that radioactive stents yield extremely inhomogeneous dose distributions, with low doses delivered to tissues in between stent struts, at the ends of the stent, and also at depth. Some animal model studies suggest that low doses of radiation may stimulate rather than inhibit neointimal growth in an injured vessel, and it is hypothesized that dose inhomogeneity at the ends of a stent may contribute to the candy wrapper effect. We present here a theoretical study comparing dose distributions for beta stents vs. gamma stents; “dumbbell” radioactive loaded stents vs. uniformly loaded stents; and stents with alternate strut design.