Characterization of Tumor Vasculature to Specify Cancer Therapy

该项目的目的是建立肿瘤血管结构异常对动态血流/体积关系和随后的代谢状态的影响。为此，我们进行了以下四个方面的研究：1)对恶性肿瘤患者进行了血管造影、动态增强CT和核素显像等临床检查。这些检查的数据显示，随着肿瘤的增大和放射性示踪剂对肿瘤的隔离，肿瘤内的流量/体积关系呈下降趋势。2)由于肿瘤内由于流量/体积比降低而产生的热量积累可能是可能的，在使用射频电容加热的热疗中，我们使用模拟动态体模研究验证了这一假设。3)为了建立合理的肿瘤控制方案，如热疗，似乎有必要对这种灌注状态进行高精度的成像。4)31P-MR波谱证实，随着肿瘤大小的增加，肿瘤的血流状态呈下降趋势，从而引起无氧能量的产生。5)总之，肿瘤血管的解剖紊乱通过降低血流/体积关系的效率而引起代谢变化。因此，足够的灌注成像手段，如扩散成像，可能对建立适当的肿瘤控制策略起到关键作用。

The aim of this project is to establish the effect of abnormal constitution of tumor vascularure on dynamic flow/volume relation and subsequent metabolic state. In this connection, we have investigated following four themes.1) A battery of clinical examination such as angiography, dynamic contrast enhanced CT and radionuclide estudies using flow tracer as well as tumorseeking agents were done, in patients with malignant tumor. Data of these examinations revealed decreased tendeney of flow/volume relation in the tumor with increasing its size and with tumor sequestration of the radiotracer.2) Since heat accumulation within tumor due to the decreased flow/volume ratio might be plausible, in the hyperthermia therapy using RF capacitive heating, we validated this assumption using simulated dynamic phantom study.3) In order to establish the rational scheme for cancer control such as thermotherapy, imaging of this perfusion status with highly precision seems to be necessary. So, an attempt to image diffusion or microcirculation were successfuly accomplished using MR imaging modality.4) The lowered tendeney of perfusion status in the malignant tumor with increasing size was proved to cause anerobic energy production as evidence by the 31-P-MR Spectroscopy.5) In conclusion, anatomical derangement of the tumor vasculature causes metabolic change through decreased efficiency of the perfusion status (flow/volume relation). Thus adequate means for perfusion imaging such as diffusion imaging may play a key role to establish an adequate strategy for the cancer control.