Duggan D M, Coffey C W, Levit S
Center for Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN 37232-5671, USA.
Int J Radiat Oncol Biol Phys. 1998 Feb 1;40(3):713-20. doi: 10.1016/s0360-3016(97)00812-2.
Restenosis, caused by proliferation of smooth-muscle cells, limits the efficacy of catheter-based revascularization of coronary arteries. Irradiation has been shown to inhibit growth of smooth-muscle cells in vitro and to prevent restenosis in animal models following stent placement. An intraarterial source of 32P, a pure beta emitter with a half-life of 14.28 days and a 90% range in water of 3.6 mm, is almost ideal for irradiating just arterial wall without exposing any other part of the patient's heart or any other organs, while posing minimal hazards to medical personnel. Two types of previously developed coronary stent impregnated with 32P were investigated. This study aimed to calculate and measure the dose outside of two types of 32P-impregnated beta-emitting coronary stents under conditions closely simulating clinical use.
The dose distributions in water surrounding these stents were calculated using a convolution method and measured by exposing radiochromic film in a solid-water phantom.
Experimental results were in excellent agreement with theoretical calculations.
Radiochromic dosimetry can be used to measure the dose distribution around a beta-emitting intraarterial stent at distances as small as 0.1 mm from the stent surface. A simple cylindrical shell model is adequate for calculating the dose at points farther than 0.5 mm from the stent surface.
由平滑肌细胞增殖引起的再狭窄限制了基于导管的冠状动脉血运重建的疗效。已表明辐射在体外可抑制平滑肌细胞生长，并能在动物模型中防止支架置入后再狭窄的发生。32P是一种纯β发射体，半衰期为14.28天，在水中的射程90%为3.6毫米，其动脉内放射源几乎是理想的，可仅对动脉壁进行照射，而不暴露患者心脏的任何其他部分或任何其他器官，同时对医务人员造成的危害最小。研究了两种先前研制的含32P的冠状动脉支架。本研究旨在在紧密模拟临床使用的条件下，计算并测量两种含32P的β发射冠状动脉支架外部的剂量。
使用卷积法计算这些支架周围水中的剂量分布，并通过在固体水模体中曝光放射变色胶片进行测量。
实验结果与理论计算结果高度吻合。
放射变色剂量测定法可用于测量距β发射动脉内支架表面小至0.1毫米处的剂量分布。一个简单的圆柱壳模型足以计算距支架表面超过0.5毫米处的剂量。
