A Review of Endogenous and Exogenous Contrast Agents Used in Photoacoustic Tomography with Different Sensing Configurations

• Published in: Sensors (Basel, Switzerland) Vol. 20; no. 19; p. 5595
• Main Authors: Tsang, Victor T C, Li, Xiufeng, Wong, Terence T W
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 29.09.2020; MDPI
• Subjects: all-optical detection; Atoms & subatomic particles; Biomedical materials; Cancer; Configurations; Contrast agents; Contrast Media; Deoxyribonucleic acid; DNA; exogenous contrast agents; Hemoglobin; Histology; Humans; label-free imaging; Lasers; Longitudinal studies; Magnetic resonance imaging; Medical electronics; Medical imaging; Medical prognosis; Microscopy; multispectral imaging; Optical Imaging; Optical microscopy; Photoacoustic effect; Photoacoustic Techniques; photoacoustic tomography; Photons; Review; Tissues; Tomography; label-free imaging; multispectral imaging; exogenous contrast agents; all-optical detection; photoacoustic tomography
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s20195595

Optical-based sensing approaches have long been an indispensable way to detect molecules in biological tissues for various biomedical research and applications. The advancement in optical microscopy is one of the main drivers for discoveries and innovations in both life science and biomedical imaging. However, the shallow imaging depth due to the use of ballistic photons fundamentally limits optical imaging approaches' translational potential to a clinical setting. Photoacoustic (PA) tomography (PAT) is a rapidly growing hybrid imaging modality that is capable of acoustically detecting optical contrast. PAT uniquely enjoys high-resolution deep-tissue imaging owing to the utilization of diffused photons. The exploration of endogenous contrast agents and the development of exogenous contrast agents further improve the molecular specificity for PAT. PAT's versatile design and non-invasive nature have proven its great potential as a biomedical imaging tool for a multitude of biomedical applications. In this review, representative endogenous and exogenous PA contrast agents will be introduced alongside common PAT system configurations, including the latest advances of all-optical acoustic sensing techniques.