TOOL TO ADJUST FOR SOURCE DECAY IN VACULAR IRRADIATION

在美国，每年有近40万患者接受球囊血管成形术 来改善动脉血流量 大约40%的手术 由于再狭窄而不成功，据估计， 美国的医疗保健系统每年约为8 - 20亿美元。 血管内照射是一种新的创新方法， 有效预防再狭窄的潜力。 几乎所有使用/建议的放射性核素都具有短放射性半衰期， 寿命，因此，在源的使用寿命期间，曝光时间必须 由于放射源活动的减少而不断延长。 由于暴露时间与亚致死剂量的半衰期相当， 损伤修复（T1/2），给定剂量的生物效应将有所不同 在源的实际寿命上显著地增加。 我们的目标是生产一个可靠的用户友好的软件工具， 医生找到最佳的方式来调整给定的减少 在放射源的放射性（因此也是剂量率）中， 生物学效应保持不变。所需的基本信息 是靶细胞的T1/2，以及其他相关的 放射生物学响应参数（α/β）。 在第一阶段， 对一种人冠状动脉平滑肌细胞系进行测定 起源，并将编写和评估试点计算机程序，以 调整暴露时间以获得恒定的生物有效剂量 因为放射源衰变和治疗时间不同。 建议的商业应用 美国医疗保健系统的费用约为8 - 20亿美元 美元/年 血管放射治疗是一种具有潜在应用价值的新技术 提供有效的再狭窄预防， 广泛应用。 因为放射源的衰变 它们的使用寿命，一个灵活的工具， 将根据剂量率的变化调整剂量处方， 具有本质意义

In the US, almost 400,000 patients annually receive balloon angioplasty to improve arterial blood flow. About 40 percent of these procedures are unsuccessful because of restenosis, which is estimated to cost the US health care system approximately 0.8-2 billion dollars annually. Endo-vascular irradiation is a new and innovative approach offering the potential of effective restenosis prevention. Almost all the used/proposed radionuclides have short radioactive half- lives so that, during the useful life of the source, exposure times must be continuously extended because of the decreasing source activity. Since the exposure times are comparable to the half-time of sublethal damage repair (T1/2), the biological effect of a given dose will vary significantly over the practical lifetime of the source. The goal is to produce a reliable user-friendly software tool allowing the physician to find the optimal way to adjust for a given reduction in the activity (and therefore the dose rate) of the source, so that the biological effect will remain unchanged. The basic information required is the T1/2 of the target cells, together with the other relevant radiobiological response parameter (alpha/beta). In Phase I, these will be determined for one coronary artery smooth muscle cell line of human origin, and a pilot computer program will be written and assessed, to adjust exposure times to obtain a constant biologically effective dose as the radioactive source decays and treatment times vary. PROPOSED COMMERCIAL APPLICATION Restenosis costs the US health care system approximately 0.8-2 billion dollars/yr. Vascular irradiation is a new technique potentially offering effective restenosis prevention, and is likely to have widespread application. Because the radioactive sources used decay over their useful lifetime, a flexible tool giving biologically-based adjustments in the dose prescription for changes in dose rate will be essential.