Wang Yihan, Li Jiao, Lu Tong, Zhang Limin, Zhou Zhongxing, Zhao Huijuan, Gao Feng
Appl Opt. 2017 Jan 10;56(2):303-311. doi: 10.1364/AO.56.000303.
Hybrid imaging methods combining diffuse optical tomography (DOT) and other anatomical or nonoptical functional modalities have been widely investigated to improve imaging performance degraded by the strong optical scattering of biological tissues, through constraining the reconstruction process by prior structures. However, these modalities with different contrast mechanisms may be ineffective in revealing early-staged lesions with high optical contrast but no morphological changes. Photoacoustic tomography (PAT) is particularly useful for visualizing light-absorbing structures embedded in soft tissues with high spatial resolution. Although it is still challenging for PAT to quantitatively disclose the absorption distribution, the modality does provide reliable and specific a priori information differentiating light-absorbing structures of soft tissues and might be more appropriate to guide DOT in lesion diagnosis, as compared with other anatomical or nonoptical functional modalities. In this study, a PAT-guided DOT approach is introduced with both soft- and hard-prior regularizations. The methodology is experimentally validated on small-animal-sized phantoms using a computed-tomography-analogous (CT-analogous) PAT/DOT dual-modality system, focusing on future whole-body applications. The results show that the proposed scheme is capable of effectively improving the quantitative accuracy and spatial resolution of DOT reconstruction.
结合扩散光学断层扫描（DOT）与其他解剖学或非光学功能模态的混合成像方法已得到广泛研究，旨在通过利用先验结构约束重建过程，改善因生物组织强烈光学散射而退化的成像性能。然而，这些具有不同对比机制的模态在揭示具有高光学对比度但无形态变化的早期病变方面可能无效。光声断层扫描（PAT）对于可视化嵌入软组织中的光吸收结构特别有用，具有高空间分辨率。尽管PAT在定量揭示吸收分布方面仍然具有挑战性，但与其他解剖学或非光学功能模态相比，该模态确实提供了区分软组织光吸收结构的可靠且特定的先验信息，可能更适合在病变诊断中指导DOT。在本研究中，引入了一种具有软先验和硬先验正则化的PAT引导DOT方法。该方法在使用计算机断层扫描类似（CT类似）PAT/DOT双模态系统的小动物尺寸模型上进行了实验验证，重点关注未来的全身应用。结果表明，所提出的方案能够有效提高DOT重建的定量准确性和空间分辨率。
