MEASUREMENTS FOR TUMOR BLOOD FLOW BY PET USING H2O IN LUNG CANCER

肿瘤血流量低和由此产生的肿瘤缺氧被认为是抵抗放疗或化疗等抗癌治疗的重要机制。因此，可以几乎完全减少新血管形成从而限制血流的药物正受到治疗学的相当大的兴趣。因此，需要一种非侵入性的定量方法来研究肿瘤血流的治疗前后状态。然而，目前还没有完善的临床测量方法来达到这一目的。正电子发射断层扫描(PET)是一种无创性的研究活体组织生理和代谢的方法。用PET测量静脉注射的[O-15]-水(O-15-水)，在分析脑或心肌局部血流方面显示出准确性。结果表明，用正电子发射计算机断层扫描(PET)测量肿瘤组织中O-15-水的扩散是测量肿瘤血流量的可行方法。虽然O-15-水方法已经在动物模型的微球研究中得到验证，但它在人体肿瘤体内的精确度尚未得到评估。目前，人们对使用可通过减少血管生成来减少肿瘤血流量的药物治疗癌症很感兴趣。此外，肿瘤血流的异质性被认为与恶性肿瘤的治疗反应差有关。尽管肿瘤血流量很重要，但在未经治疗的癌症患者中，使用正电子发射断层扫描(PET)进行微创肿瘤血流量测量研究的重复性研究很少。本研究的目的是：评价O-15水法定量测量肿瘤血流量在未经治疗的肺癌和其他大型肿瘤中的重复性。

Low tumor blood flow and resultant tumor hypoxia are recognized as important mechanisms of resistance to anticancer treatment such as radiotherapy or chemotherapy. Therefore, drugs that can nearly totally reduce new blood vessel formation and thus limit blood flow are receiving considerable interest of therapeutics. Thus a non-invasive and quantitative method is needed in order to investigate the pretreatment and post-treatment status of tumor blood flow. However, there is no well-established clinical measurement for this purpose. Positron emission tomography (PET) is a noninvasive method to study tissue physiology and metabolism in vivo. The measurement of [oxygen-15]-water (O-15-water) intravenous-injection with PET has shown accuracy in analyzing regional blood flow of brain or myocardium. It has been shown that measurement of O-15-water diffusion with PET in tumors is feasible in a measurement of tumor blood flow. While the O-15-water method has been validated in microsphere studies in animal models, it has not been assessed for precision in human tumor in vivo. Much current interest exists in treating cancer with agents that may reduce tumor blood flow through reducing angiogenesis. In addition, tumor blood flow heterogeneity is known to be related to poor treatment response in malignant tumors. Despite the importance of tumor blood flow, there has been little systematic study of the reproducibility of minimally invasive tumor blood flow measurement studies using positron emission tomography (PET) in untreated cancer patients. The aim of the present study is: To evaluate the reproducibility of quantitative tumor blood flow measurement using O-15 water method in untreated lung cancers and other large tumors.