Browsing by Author "Li, Lei S."

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    Challenges and advances in two-dimensional photoacoustic computed tomography: a review
    (SPIE, 2024) Zhang, Shunyao; Miao, Jingyi; Li, Lei S.
    SignificancePhotoacoustic computed tomography (PACT), a hybrid imaging modality combining optical excitation with acoustic detection, has rapidly emerged as a prominent biomedical imaging technique.AimWe review the challenges and advances of PACT, including (1) limited view, (2) anisotropy resolution, (3) spatial aliasing, (4) acoustic heterogeneity (speed of sound mismatch), and (5) fluence correction of spectral unmixing.ApproachWe performed a comprehensive literature review to summarize the key challenges in PACT toward practical applications and discuss various solutions.ResultsThere is a wide range of contributions from both industry and academic spaces. Various approaches, including emerging deep learning methods, are proposed to improve the performance of PACT further.ConclusionsWe outline contemporary technologies aimed at tackling the challenges in PACT applications.
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    Sharp-peaked lanthanide nanocrystals for near-infrared photoacoustic multiplexed differential imaging
    (Springer Nature, 2024) Loh, Kang Yong; Li, Lei S.; Fan, Jingyue; Goh, Yi Yiing; Liew, Weng Heng; Davis, Samuel; Zhang, Yide; Li, Kai; Liu, Jie; Liang, Liangliang; Feng, Minjun; Yang, Ming; Zhang, Hang; Ma, Ping’an; Feng, Guangxue; Mu, Zhao; Gao, Weibo; Sum, Tze Chien; Liu, Bin; Lin, Jun; Yao, Kui; Wang, Lihong V.; Liu, Xiaogang
    Photoacoustic tomography offers a powerful tool to visualize biologically relevant molecules and understand processes within living systems at high resolution in deep tissue, facilitated by the conversion of incident photons into low-scattering acoustic waves through non-radiative relaxation. Although current endogenous and exogenous photoacoustic contrast agents effectively enable molecular imaging within deep tissues, their broad absorption spectra in the visible to near-infrared (NIR) range limit photoacoustic multiplexed imaging. Here, we exploit the distinct ultrasharp NIR absorption peaks of lanthanides to engineer a series of NIR photoacoustic nanocrystals. This engineering involves precise host and dopant material composition, yielding nanocrystals with sharply peaked photoacoustic absorption spectra (~3.2 nm width) and a ~10-fold enhancement in NIR optical absorption for efficient deep tissue imaging. By combining photoacoustic tomography with these engineered nanocrystals, we demonstrate photoacoustic multiplexed differential imaging with substantially decreased background signals and enhanced precision and contrast.