Effects of vessel geometry and catheter position on dose delivery in intracoronary brachytherapy.
Effects of vessel geometry and catheter position on dose delivery in intracoronary brachytherapy.
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血管几何形状和导管位置对冠状动脉近距离放射治疗中剂量输送的影响。
DOI：
10.1109/tbme.2003.818474
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Sonka,Milan
中科院分区：
文献类型：
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作者：
Wahle,Andreas;Lopez,JohnJ;Pennington,EdwardC;Meeks,SanfordL;Braddy,KathleenC;Fox,JamesM;Brennan,TheresaMH;Buatti,JohnM;Rossen,JamesD;Sonka,Milan
支架内再狭窄是冠状动脉介入治疗后常见的并发症。已发现血管内近距离放射治疗可有效减少支架植入后再狭窄的复发。用于具有β（/spl β/）辐射的近距离放射治疗的常规剂量模型忽略血管几何形状以及递送导管的位置。本文表明，在计算机模拟的幻影和体内患者的数据，估计的剂量分布变化很大，在弯曲的血管。在长度为50 mm的模拟体模中，形状对应于60/spl deg/-180/spl deg/段的相应尺寸的环面，与直体模相比，2 mm深度的平均剂量在外曲率处降低2.70%-7.48%，在内曲率处增加2.95%-9.70%。在体内数据表示在一个几何正确的三维模型，是由血管内超声（IVUS）和双平面血管造影融合。这些数据进行了比较，一个简化的管状模型，反映了传统的给药方案的共同假设。与几何校正模型相比，简化模型产生的递送辐射和剂量变异性的估计值显著较低（p < 0.001）。8名患者的10个血管节段的估计剂量在管腔/斑块处平均低8.76%，在中膜/外膜界面处平均低6.52%（简化管状模型相对于几何形状正确的模型）。与左冠状动脉相比，两种模型之间的剂量估计差异在右冠状动脉中显著更高（p < 0.001）。
In-stent restenosis is commonly observed in coronary arteries after intervention. Intravascular brachytherapy has been found effective in reducing the recurrence of restenosis after stent placement. Conventional dosing models for brachytherapy with beta (/spl beta/) radiation neglect vessel geometry as well as the position of the delivery catheter. This paper demonstrates in computer simulations on phantoms and on in vivo patient data that the estimated dose distribution varies substantially in curved vessels. In simulated phantoms of 50-mm length with a shape corresponding to a 60/spl deg/-180/spl deg/ segment of a respectively sized torus, the average dose in 2-mm depth was decreased by 2.70%-7.48% at the outer curvature and increased by 2.95%-9.70% at the inner curvature as compared with a straight phantom. In vivo data were represented in a geometrically correct three-dimensional model that was derived by fusion of intravascular ultrasound (IVUS) and biplane angiography. These data were compared with a simplified tubular model reflecting common assumptions of conventional dosing schemes. The simplified model yielded significantly lower estimates of the delivered radiation and the dose variability as compared with a geometrically correct model (p < 0.001). The estimated dose in ten vessel segments of eight patients was on average 8.76% lower at the lumen/plaque and 6.52% lower at the media/adventitia interfaces (simplified tubular model relative to geometrically correct model). The differences in dose estimates between the two models were significantly higher in the right coronary artery as compared with the left coronary artery (p < 0.001).