Photoacoustic-based sO(2) estimation through excised bovine prostate tissue with interstitial light delivery

Photoacoustic (PA) imaging is capable of probing blood oxygen saturation (sO(2)), which has been shown to correlate with tissue hypoxia, a promising cancer biomarker. However, wavelength-dependent local fluence changes can compromise sO(2) estimation accuracy in tissue. This work investigates using PA imaging with interstitial irradiation and local fluence correction to assess precision and accuracy of sO(2) estimation of blood samples through ex vivo bovine prostate tissue ranging from 14% to 100% sO(2). Study results for bovine blood samples at distances up to 20 mm from the irradiation source show that local fluence correction improved average sO(2) estimation error from 16.8% to 3.2% and maintained an average precision of 2.3% when compared to matched CO-oximeter sO(2) measurements. This work demonstrates the potential for future clinical translation of using fluence-corrected and interstitially driven PA imaging to accurately and precisely assess sO(2) at depth in tissue with high resolution.