光声层析成像技术(PAT)结合了光学成像的功能性和超声成像的高空间分辨率等优点，是肿瘤早期诊断和生物学研究的有效影像手段，但面向深层组织成像时，传统PAT方法由于未充分考虑光能分布特征，造成了光学吸收定量精度上的局限性。定量PAT技术则在其基础上结合了基于光子输运理论的光学反演策略，能够实现组织吸收系数图像的定量重建，其性能取决于光能吸收数理模型的精确性，图像反演理论的适定性和测量方法信息完备性等基本要素。本课题以实现肿瘤早期诊断和生物学研究中活体小动物功能成像和定量检测为目标，围绕上述要素探讨的科学问题主要包括：建立基于数字鼠模型扩散光学层析成像（DOT）先验信息的光能吸收数理模型、发展高空间分辨率和高鲁棒性的定量PAT图像反演算法和研究高空间采样率和高频宽DOT/PAT联合测量方法，最终建立基于DOT支持的小动物定量PAT先进成像方法，开展其在肿瘤早期诊断和恶性生物学方向上的应用研究。

Photoacoustic tomography (PAT) features a combination of the high optical contrast and the high ultrasonic resolution, and provides an effective imaging modality for early diagnosis of tumors and in vivo exploration of its biological mechanism. However, without sufficiently taking account of the absorbed energy density distribution, the traditional PAT methods have limited quantitative accuracy of the optical absorption, especially for deep-tissue imaging. Quantitative PAT, by further introducing the photon-migration-based inversion strategy, enables quantitative reconstruction of the optical coefficient distribution in tissues. Its performances mainly rely on several fundamental factors: accuracy of the absorbed energy modeling, satisfiability of the optical inversion scheme for absorption recovery and completeness of the measured information. In order to develop a small-animal imaging tool with high spatial resolution, high functional contrast and improved quantitative accuracy, the proposal focuses on three essential scientific problems with the above relevant factors of quantitative PAT: 1) in vivo extraction of the a priori optical structure using mouse-atlas-based diffuse optical tomography (DOT) methodology for the absorbed energy modeling; 2) a robust and high spatial resolution inversion framework for quantitative PAT image reconstruction; 3) a dual-modality measurement scheme of DOT/PAT and the prototype system with high spatial sampling and wideband frequency properties. The ultimate goal of the research is to establish a beneficial guide to the advanced methodology of DOT-supported quantitative PAT of small-animals, for disclosure of early-phase tumors and their biological mechanism.