Photoacoustic imaging (PAI)

Photoacoustic imaging is a **biomedical imaging modality** that utilizes the photoacoustic effect, where pulsed laser light is absorbed by biological tissues causing localized heating and resulting in acoustic (ultrasound) waves used to generate images[1][3][7]. This imaging method combines optical imaging contrast (sensitive to the presence of chromophores such as hemoglobin, melanin, or administered contrast agents) with the spatial resolution and depth penetration of ultrasound, offering non-invasive, non-ionizing deep tissue visualization with both structural and functional information[4][3][1][7]. Its applications include vascular imaging, tumor angiogenesis monitoring, blood oxygenation mapping, and numerous preclinical/clinical diagnostic procedures, but *photoacoustic imaging itself is not a molecular target, receptor, or molecule*—it is a **technology modality**[1][3][7].

Other names

Optoacoustic imagingPA imagingPAIPhotoacoustic tomography (PAT)Photoacoustic microscopy (PAM)