Characterization of Tumor Vasculature to Specify Cancer Therapy

本项目旨在探讨肿瘤血管结构异常对动态流量/体积关系及后续代谢状态的影响。在这方面，我们研究了以下四个主题。1)对恶性肿瘤患者进行了一系列临床检查，如血管造影、动态增强CT和使用血流示踪剂的放射性核素研究以及肿瘤寻找剂。这些检查的数据显示，随着肿瘤体积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)由于流量/体积比降低可能导致肿瘤内热量积累，因此在采用射频电容加热的热疗治疗中，我们通过模拟动态幻影研究验证了这一假设。3)为了建立合理的癌症控制方案，如热疗，这种灌注状态的高精度成像似乎是必要的。因此，尝试成像扩散或微循环使用磁共振成像模式成功完成。4) 31-P-MR谱证实了恶性肿瘤灌注状态随体积增大而降低的趋势导致无氧能量的产生。5)总之，肿瘤血管的解剖紊乱通过灌注状态效率（流量/容积关系）的降低引起代谢变化。因此，适当的灌注成像手段，如扩散成像，可能在建立适当的癌症控制策略中发挥关键作用。

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.