PhotoAcoustic imaging is an imaging modality that uses laser light and ultrasound detectors to image tissues. Photo = Light. Acoustic = Sound. The imaging uses the photoacoustic effect principle. The photoacoustic effect is not new in terms of discovery as it was reported by none other than Alexander Graham Bell (yes! Rings a bell doesn’t it?) as early as 1880. But, the unavailability of proper detectors and instruments at his time was an obstacle to expanding research in this field.