Nasrollah Jabbari, Mikaeil Molazadeh, Omid Esnaashari, Mojtaba Seyed Siahi, Ahad Zeinali
Department of Medical Physics and Imaging, University of Medical Sciences, Urmia, Iran.
J Cancer Res Ther. 2014 Jan-Mar;10(1):147-52. doi: 10.4103/0973-1482.131465.
The impact of intravenous (IV) contrast media (CM) on radiation dose calculations must be taken into account in treatment planning.
The aim of this study is to evaluate the effect of an intravenous contrast media on dose calculations in three-dimensional conformal radiation therapy (3D-CRT) for lower esophageal and rectal cancers.
Seventeen patients with lower esophageal tumors and 12 patients with rectal cancers were analyzed. At the outset, all patients were planned for 3D-CRT based on the computed tomography (CT) scans with IV contrast media. Subsequently, all the plans were copied and replaced on the scans without intravenous CM. The radiation doses calculated from the two sets of CTs were compared.
The dose differences between the planning image set using intravenous contrast and the image set without contrast showed an average increase in Monitor Units (MUs) in the lower esophageal region that was 1.28 and 0.75% for 6 and 15 MV photon beams, respectively.
There was no statistical significant difference in the rectal region between the two sets of scans in the 3D-CRT plans. The results showed that the dose differences between the plans for the CT scans with and without CM were small and clinically tolerable. However, the differences in the lower esophageal region were significant in the statistical analysis.
在治疗计划中必须考虑静脉内（IV）造影剂（CM）对辐射剂量计算的影响。
本研究的目的是评估静脉造影剂对下食管癌和直肠癌三维适形放疗（3D-CRT）中剂量计算的影响。
分析了17例下食管肿瘤患者和12例直肠癌患者。一开始，所有患者均根据静脉造影剂增强的计算机断层扫描（CT）进行3D-CRT计划。随后，将所有计划复制并替换为无静脉造影剂的扫描图像。比较两组CT计算出的辐射剂量。
使用静脉造影剂的计划图像集与无造影剂的图像集之间的剂量差异显示，在下食管区域，6和15 MV光子束的监测单位（MUs）平均分别增加了1.28%和0.75%。
在3D-CRT计划中，两组扫描在直肠区域无统计学显著差异。结果表明，有和无造影剂的CT扫描计划之间的剂量差异较小且临床可耐受。然而，在统计分析中，下食管区域的差异具有显著性。
