Ortho-positronium lifetime for soft-tissue classification

• Published in: Scientific reports Vol. 14; no. 1; pp. 21155 - 9
• Main Authors: Avachat, Ashish V., Mahmoud, Kholod H., Leja, Anthony G., Xu, Jiajie J., Anastasio, Mark A., Sivaguru, Mayandi, Di Fulvio, Angela
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10-09-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/985; 639/301/930/12; Adipose tissue; Adipose Tissue - diagnostic imaging; Animals; Data acquisition; Electrons; Humanities and Social Sciences; Lifetime; Liver; Liver - diagnostic imaging; Liver - metabolism; multidisciplinary; Muscles - diagnostic imaging; PALS; Porous materials; Positron emission tomography; Positron-Emission Tomography - methods; Positronium annihilation lifetime spectroscopy; Science; Science (multidisciplinary); Soft tissue analysis; Soft tissues; Spectroscopy; Spectrum analysis; Swine; Tissue analysis; Tomography; X-ray phase-contrast imaging; PALS; Soft tissue analysis; X-ray phase-contrast imaging; Positronium annihilation lifetime spectroscopy
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-71695-7

The objective of this work is to showcase the ortho-positronium lifetime as a probe for soft-tissue characterization. We employed positron annihilation lifetime spectroscopy to experimentally measure the three components of the positron annihilation lifetime—para-positronium (p-Ps), positron, and ortho-positronium (o-Ps)—for three types of porcine, non-fixated soft tissues ex vivo: adipose, hepatic, and muscle. Then, we benchmarked our measurements with X-ray phase-contrast imaging, which is the current state-of-the-art for soft-tissue analysis. We found that the o-Ps lifetime in adipose tissues (2.54 ± 0.12 ns) was approximately 20% longer than in hepatic (2.04 ± 0.09 ns) and muscle (2.03 ± 0.12 ns) tissues. In addition, the separation between the measurements for adipose tissue and the other tissues was better from o-Ps lifetime measurement than from X-ray phase-contrast imaging. This experimental study proved that the o-Ps lifetime is a viable non-invasive probe for characterizing and classifying the different soft tissues. Specifically, o-Ps lifetime as a soft-tissue characterization probe had a strong sensitivity to the lipid content that can be potentially implemented in commercial positron emission tomography scanners that feature list-mode data acquisition.