One of the key challenges in linear array transducer‐based photoacoustic computed tomography is to image structures embedded deep within the biological tissue with limited optical energy. Here, we utilized a manually controlled multi‐angle illumination technique to allow the incident photons to interact with the imaging targets for longer periods of time and diffuse further in all directions. We have developed and optimized a compact probe that enables manual changes to the angle of illumination while acquiring photoacoustic signals. The performance has been demonstrated and evaluated by imaging complex blood vessel mimicking phantoms in‐vitro and sheep brain samples ex‐vivo. For effective image reconstruction from the data acquired by multi‐angle illumination method, we have utilized a method based on the extraction of maximum intensity. In both cases, multi‐angle illumination has out‐performed the conventional fixed angle illumination technique to improve the overall image quality. Specifically, extraction of the imaging targets located at greater axial depths was possible using this multi‐angle illumination technique.

This study aims to make the implementation of the attenuation and backscattering study to be apply for skin tissue. Attenuation and backscatter coefficients were defined in the range 22 to 48 MHz based on the L38 transducer which has a central frequency of 30 MHz and a 60% bandwidth. The attenuation coefficient was computed using local attenuation estimation algorithms (i.e., spectral difference and spectral log difference methods). Using a reference phantom technique, we compensated the recorded backscatter spectra for system-independent measurements. This study shows the experimental and theoretical steps needed to implement a quantitative study of ultrasounds images in the skin.