서강대학교

초록/요약

Photoacoustic imaging (PAI) is capable of providing real-time anatomical and functional information when tracking pathological changes. In PAI, the frame averaging (FA) technique is commonly used for enhancing signal-to-noise ratio (SNR) instead of increasing the power of a pulsed laser to avoid unwanted adverse effects. However, the FA technique suffers from motion artifacts due to the limited pulse repetition frequencies (PRFs) (e.g., 10-20 Hz) of a commonly-used Nd:Yag laser. In this paper, to improve the image quality of PAI, a new FA technique combined with selective inter-frame motion compensation (i.e., FA-SIFMC) is proposed. The RF data acquisition was conducted with a commercial ultrasound imaging system (Ultrasonix Inc., Vancouver, BC, CANADA) for both 1.5-cm diameter diluted melanin injected agar phantom and small animal. For the laser excitation, a Surelite Nd:YAG OPO system (Continuum Inc., Santa Clara, CA, USA) was used at the rate of 10 Hz and at the wavelength of 700nm with a bifurcated fiber bundle. From the in-vivo experiment, peak signal-to-noise ratio (PSNR) and the axial resolution were improved by 5.29 dB and 0.161 mm compared to the FA method, respectively. These results indicate that the suggested FA-SIFMC method can improve image quality of PAI by enhancing PSNR and axial resolution. This is due to the lowered blurring artifacts from motions not only from the phantom experiment, but also for the in-vivo experiment.