Figure 2.

Operation sequence of the programmable dual-modality US/PA imaging system. The laser was pulsed with a pulse repetition rate of 20 Hz and coupled by a laser energy coupling system to a removable fiber bundle-based illumination system to illuminate the targets. PA waves were detected by an 18.5-MHz transducer and then processed through a Verasonics US system to the PC for further data analysis and display. US, ultrasound; PA, photoacoustic; HARP: handheld dual-modality real-time ultrasound/photoacoustic imaging system; TR, ultrasound transducer; FB, fiber bundle; OPO, optical parametric oscillator; Tx, transmitter; Rx, receiver.