中国物理B ›› 2023, Vol. 32 ›› Issue (11): 118702-118702.doi: 10.1088/1674-1056/acef05
所属专题: SPECIAL TOPIC — Celebrating the 100th Anniversary of Physics Discipline of Northwest University
Yun-He Zhang(张云鹤)1, Huan-Zheng Zhu(朱桓正)2, Yong-Jiang Dong(董泳江)2, Jia Zeng(曾佳)2,†, Xin-Peng Han(韩新鹏)3, Ivan A. Bratchenko4, Fu-Rong Zhang(张富荣)1, Si-Yuan Xu(许思源)1, and Shuang Wang(王爽)1,‡
Yun-He Zhang(张云鹤)1, Huan-Zheng Zhu(朱桓正)2, Yong-Jiang Dong(董泳江)2, Jia Zeng(曾佳)2,†, Xin-Peng Han(韩新鹏)3, Ivan A. Bratchenko4, Fu-Rong Zhang(张富荣)1, Si-Yuan Xu(许思源)1, and Shuang Wang(王爽)1,‡
摘要: As one type of spatially offset Raman spectroscopy (SORS), inverse SORS is particularly suited to in vivo biomedical measurements due to its ring-shaped illumination scheme. To explain inhomogeneous Raman scattering during in vivo inverse SORS measurements, the light-tissue interactions when excitation and regenerated Raman photons propagate in skin tissue were studied using Monte Carlo simulation. An eight-layered skin model was first built based on the latest transmission parameters. Then, an open-source platform, Monte Carlo eXtreme (MCX), was adapted to study the distribution of 785 nm excitation photons inside the model with an inverse spatially shifted annular beam. The excitation photons were converted to emission photons by an inverse distribution method based on excitation flux with spatial offsets Δs of 1 mm, 2 mm, 3 mm and 5 mm. The intrinsic Raman spectra from separated skin layers were measured by continuous linear scanning to improve the simulation accuracy. The obtained results explain why the spectral detection depth gradually increases with increasing spatial offset, and address how the intrinsic Raman spectrum from deep skin layers is distorted by the reabsorption and scattering of the superficial tissue constituents. Meanwhile, it is demonstrated that the spectral contribution from subcutaneous fat will be improved when the offset increases to 5 mm, and the highest detection efficiency for dermal layer spectral detection could be achieved when Δs = 2 mm. Reasonably good matching between the calculated spectrum and the measured in vivo inverse SORS was achieved, thus demonstrating great utility of our modeling method and an approach to help understand the clinical measurements.
中图分类号: (Monte Carlo simulations)