Cao Yue, Platt Joel F, Francis Isaac R, Balter James M, Pan Charlie, Normolle Daniel, Ben-Josef Edgar, Haken Randall K Ten, Lawrence Theodore S
Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109-0010, USA.
Med Phys. 2007 Feb;34(2):604-12. doi: 10.1118/1.2431081.
We have shown that high dose conformal radiation combined with chemotherapy appears to prolong the survival of patients with unresectable intrahepatic cancers. The ability to safely deliver higher doses is primarily limited by the development of radiation-induced liver disease, characterized by venous occlusion. In this study, we investigated whether portal venous perfusion measured prior to the end of radiation therapy (RT) together with dose could predict liver venous perfusion dysfunction after treatment. Ten patients with unresectable intrahepatic cancer participated in an IRB-approved computer tomography (CT) perfusion study. Hepatic arterial and portal vein perfusion distributions were estimated by using dynamic contrast enhanced CT and the single compartmental model. Scans were obtained at four time points: prior to treatment, after 15 and 30 fractions of 1.5 Gy treatments, and one month following the completion of RT. Multivariant linear regression was used to determine covariances among the first three time point measurements plus dose for prediction of the post RT measurement. The reduction in the regional venous perfusion one month following RT was predicted by the local accumulated dose and the change in the regional venous perfusion after -30 fractions (F=90.6,p <0.000 01). Each Gy produced an approximately 1.2% of reduction in the venous perfusion. This local dose and venous perfusion model has the potential to predict individual sensitivity to radiation. This is the first step toward developing a method to deliver higher and potentially more curative radiation doses to the patients who can safely receive these higher doses.
我们已经表明，高剂量适形放疗联合化疗似乎能延长无法切除的肝内癌症患者的生存期。安全给予更高剂量的能力主要受到以静脉闭塞为特征的放射性肝病发展的限制。在本研究中，我们调查了放疗（RT）结束前测量的门静脉灌注与剂量是否能预测治疗后肝静脉灌注功能障碍。10例无法切除的肝内癌症患者参与了一项经机构审查委员会（IRB）批准的计算机断层扫描（CT）灌注研究。通过动态对比增强CT和单室模型估计肝动脉和门静脉灌注分布。在四个时间点进行扫描：治疗前、1.5 Gy治疗15次和30次后以及RT完成后1个月。使用多变量线性回归来确定前三个时间点测量值与剂量之间的协方差，以预测RT后测量值。RT后1个月局部静脉灌注的减少可通过局部累积剂量和-30次分割后局部静脉灌注的变化来预测（F = 90.6，p < 0.000 01）。每Gy使静脉灌注减少约1.2%。这种局部剂量和静脉灌注模型有可能预测个体对放疗的敏感性。这是朝着开发一种方法迈出的第一步，该方法可为能够安全接受这些更高剂量的患者提供更高且可能更具治愈性的放疗剂量。
