In Silico Demonstrations of the Impact of Wavelength and Skin Tone on Photoacoustic Breast Imaging

Breast photoacoustic imaging is an emerging clinical application that requires non-invasive illumination through skin. However, the melanin content of skin can introduce unwanted acoustic clutter, thereby compromising target visibility and overall image quality, which presents a significant challenge when considering the wide range of skin tones that are expected to benefit from access to the technology. To quantify the impact of this challenge, we conducted a series of multidomain photoacoustic simulations using five optical wavelengths, 18 skin constitutive pigmentations, and a previously validated 3D breast model. Three scenarios were considered: (i) the baseline scenario, in which a photoacoustic target was surrounded by breast tissue and covered by a layer of skin; (ii) the baseline scenario with the skin layer removed; and (iii) the baseline scenario with the photoacoustic target removed. Clutter levels ranged -11 dB to 11 dB with the baseline scenario. When skin was removed, this clutter was reduced by up to 39 dB and the associated target contrast improved by up to 39 dB relative to the baseline scenario, confirming skin as the primary source of clutter. When the target was removed, clutter decreased by less than 2.7 dB relative to the baseline scenario, indicating minimal to nonexistent clutter contributions from scattering due to the presence of the photoacoustic target. Future work will investigate novel system designs and protocols for patient-specific photoacoustic imaging system customizations.