Figure 1.

Schematic diagram of the developed dual-modality US/PA imaging system. Using the photoacoustic effect, US waves were generated by delivering light generated by a laser to the imaging target with a pulse repetition rate of 20 Hz using fiber bundles. The US waves were then detected by a 17.5-MHz transducer and processed through a Verasonics ultrasound system. The developed PA probe includes a removable fiber bundle-based illumination system (FB), a single US transducer (TR), and a customized jacket. Two rectangular parts constituted the output end of the fiber bundle, and the input end was circular in shape. ROI, region of interest; PA, photoacoustic; US, ultrasound; TR, ultrasound transducer; FB, fiber bundle; PT, pancreatic tumor; and UG, ultrasound gel.