The purpose of this study was to optimize the light delivery method in a prostate photoacoustic imaging system. A three dimensional (3D) optical model of the human prostate was developed, and the optical energy distribution in the prostate was estimated via three-dimensional Monte Carlo simulation. Then, the feasibility of prostate photoacoustic imaging (PAI) using two endoscopic light delivery methods was studied. Photoacoustic pressure generation and the corresponding photoacoustic images had been obtained and the comparisons were made between each other. Also, the results of cylinder diffusing light source with different lengths were compared. After that, phantom experiment was carried out to validate the simulation results. Our results would be significant in the optimizing photoacoustic imaging system for an accurate diagnosis of prostate cancer.

Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber (CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.

Determination of light absorption distribution in the prostate tissue irradiated by diffusing light source is important for the treatment planning. In this paper, a three-dimensional (3D) optical model of human prostate is developed, and the light absorption distribution in the prostate tissue is estimated by Monte Carlo simulation method. Light distribution patterns including 3D distributions in the tissue model irradiated by two diffusing light sources are obtained and compared. Also, the impacts of length and energy of cylinder diffusing light source on the irradiance volume are demonstrated. Those results will be significant for the nondestructive qualitative assessments of photodosimetry in biomedical phototherapy.