Skin vasculature imaging by acoustical resolution photoacoustic microscope with parabolic array transducer

Abstract

Photoacoustic (PA) signal is highly dependent on the structure of the target. In the present study, PA imaging system with parabolic array transducer for multi-angle detection is developed and the skin vasculature is observed. The transducer was consisted of 256 ch 1-3-composite elements with the center frequency of 10 MHz. The diameter was 42.4 mm and the opening angle was 90 degree. A hole was made in the center of the transducer for transmission of the laser. PA signal was acquired by a programmable ultrasound data acquisition system with the sampling frequency of 60 MHz. A diode laser with the wavelength of 532 nm, pulse width of 8 ns, pulse energy of 5 mJ, and repetition frequency of 10 Hz was equipped for generation of PA signal. Three dimensional image was reconstructed by delay-and-sum beamforming of PA signals received by all channels. The frame rate for displaying x-y, y-z, and x-z images was 10 Hz, and the full width at half maximum (FWHM) of the x-z image was 70 μm. 3D structure of the skin ca...