恶性肿瘤已成为威胁人类健康和生命的头号"杀手"，肿瘤的早期诊断和早期治疗是提高患者生存质量和治愈率的关键。分子显像是从分子水平揭示疾病早期阶段的分子变化程度，以达到对疾病的早期诊断。但单模态分子影像不是完美的，不足以充分地获取肿瘤的信息，难免会有漏诊、误诊，从而延误病人最佳治疗时机，因此多模态分子影像已成为医学影像学的发展趋势。多模态分子影像的核心和基础是设计和制备高特异性的多功能分子探针。基于这一迫切需求，本课题针对新生血管和多种肿瘤高表达的integrin αvβ3，设计基于卟啉的，以高特异性RGD二聚体为靶向分子的多功能分子探针，进行核医学/光学双模态显像研究和有效性评价，并探讨其用于肿瘤光动力治疗的潜力，为设计新型集诊断与治疗于一体的多功能分子探针提供研究思路和参考依据。

Malignant tumors have become the number one "killer" to human health. Early detection and treatment is one of the most effective approaches to reduce cancer mortality. Molecular imaging, which can characterize and measure the biologic processes on the molecular level, provides a powerful tool for the early diagnosis of diseases. Since single modality molecular imaging can not provide all necessary information for cancer diagnosis, multi-modality molecular imaging, which harnesses the strengths of different imaging methods, is attracting an increasing interest for both clinicians and scientists. Central to multimodality molecular imaging is the development of high specific multifunctional molecular probes. In this proposal, the multifunctional porphyrin-based RGD dimeric probes will be designed and prepared for dual nuclear/optical imaging of tumor neovasculature integrin αvβ3 expression. The potential of this probe for tumor photodynamic therapy (PDT) will also be investigated. This study would provide important information for the design and development of other multifunctional theranostic agents for tumor targeting.