影像引导下血管内近距离放射治疗剂量递增
Image-guided intravascular brachytherapy dose escalation.
作者信息
Lussier Luke, Wallner Kent, Kearney Kathleen E, Tiwana Jasleen, Kim Edward Y, Parvathaneni Upendra, Lombardi William L, Phillips Mark, Don Creighton, Kim Minsun
机构信息
Department of Physics, St. Mary's University, San Antonio, TX.
Department of Radiation Oncology, University of Washington, Seattle, WA.
出版信息
Brachytherapy. 2023 Jul-Aug;22(4):518-523. doi: 10.1016/j.brachy.2023.04.004. Epub 2023 May 20.
PURPOSE
Coronary stents reduce IVBT radiation dose with a single layer by 10-30%. However, the impact of multiple stent layers and stent expansion remains unexplored. Individualized dose adjustments considering variations in stent layers and expansion could improve radiation delivery effectiveness.
METHODS
EGSnrc was used to compute the delivered vessel wall dose in various IVBT scenarios. Stent effects were modeled for the stent density of 25%, 50%, and 75% with 1, 2, and 3 layers respectively. Doses were calculated at 1.75 to 5.00 mm away from the source center, normalized to 100% at 2 mm.
RESULTS
Dose fall-off increased with increasing stent density. With a single layer, the dose at 2 mm from source fell from 100% of prescription to 92%, 83% and 73% at 25%, 50% and 75% density, respectively. The computed dose to points with increasing radial distance from the source decreased progressively with increasing stent layers. With three layers, at 75% stent density, the dose at 2 mm from source center fell to 38%.
CONCLUSIONS
A schema for image-guided IVBT dose adjustment is described. While it would be an improvement over current standard of care, myriad factors remain to be addressed in a comprehensive effort to optimize IVBT.
目的
冠状动脉支架可使单层近距离放疗的辐射剂量降低10%-30%。然而，多层支架和支架扩张的影响仍未得到探索。考虑支架层数和扩张变化的个体化剂量调整可提高放疗效果。
方法
使用EGSnrc计算不同近距离放疗场景下传递到血管壁的剂量。分别对支架密度为25%、50%和75%的1层、2层和3层支架效果进行建模。在距离源中心1.75至5.00毫米处计算剂量，并在2毫米处归一化为100%。
结果
剂量衰减随支架密度增加而增加。对于单层支架，距离源2毫米处的剂量从处方剂量的100%分别降至密度为25%、50%和75%时的92%、83%和73%。计算得出，随着距源径向距离增加，各点的剂量随着支架层数增加而逐渐降低。对于三层支架，在支架密度为75%时，距离源中心2毫米处的剂量降至38%。
结论
描述了一种图像引导下近距离放疗剂量调整方案。虽然这将比当前的护理标准有所改进，但在全面优化近距离放疗的努力中仍有许多因素需要解决。
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