结直肠癌早期肝转移的诊断具有重要临床意义，但缺乏准确的检查手段是目前面临的严峻挑战，而肝转移的早期发现与其分子机制密切相关。前期研究证实，多种单一模态成像难以发现肝早期转移，而多模态分子影像可以发现转移相关生物学特性变化(增殖、血管生成、乏氧等），为肝转移分子机制研究带来新的契机。本课题将在体外结直肠癌细胞和体内肝转移结节进行实验，利用核素和Micro-CT的多模态分子成像技术对肝转移生物学特性指标(VEGF、nm23-H1、HIF-1α等）和转移潜能（运动、侵袭等）进行定量检测，获得肿瘤代谢（18F-FDG）、增殖（18F-FLT）和乏氧（18F-FMISO）的成像特征。基于多模态分子影像、生物学特性指标构建多元线性回归模型，获得反映肝转移生物学特性变化的分子影像特征，通过该特征与参考值间的欧氏距离来判定肝转移潜能，开发判定转移潜能的预测软件，建立多模态分子影像早期发现肝转移的新方法。

Early diagnosis of colorectal liver metastases has clinic significence.But, it is currently facing severe challenges lack of accurate means of detection. But,early detection of liver metastases has closely related to molecular mechanisms.Our previous studies had shown that various of single-mode imaging techniques were difficult to find early liver metastases.But, multi-modality molecular imaging techniques can early find the related changes of metastasis-relatedly biological characters (proliferation, angiogenesis, hypoxia, et al),which bring new opportunity to study the mechanism. We will test in colorectal cancer cells in vitro and liver metastatic nodules in vivo, using multi-modality molecular imaging（including radionuclide and micro-PET）to study the biological indicators (VEGF、nm23-H1、HIF-1α，et al）and metastatic potentials (proliferation, motility, invasion, et al) quantitatively ,further to obtain the imaging characters of tumor metabolism (18F-FDG molecular imaging probe),tumor proliferation (18F-FLT molecular imaging probes imaging) and tumor hypoxia (18F-FMISO molecular imaging probe).Multiple linear regression model was built on multi-modality molecular imaging and biological characters,in order to obtain the molecular imaging characteristics ,further to assess the metastatic abilities by euclidean distance between the model results and references values, and to develop the prediction software of metastatic potential,also build new methods of early detection of liver metastasis by multi-modal molecular imaging.