%0 Journal Article %T Optimized light delivery probe using ball lenses for co-registered photoacoustic and ultrasound endo-cavity subsurface imaging %A Atahar Mostafa %A Eghbal Amidi %A Guang Yang %A Quing Zhu %A Sreyankar Nandy %J Archive of "Photoacoustics". %D 2019 %R 10.1016/j.pacs.2018.12.001 %X An optimized hand-held photoacoustic and ultrasound probe suitable for endo-cavity tumor subsurface imaging was designed and evaluated. Compared to previous designs, the prototype probe, consisting of four 1£żmm multi-mode optical fibers attached with 1.5£żmm diameter ball-shaped fiber tips sandwiched between a transvaginal ultrasound transducer and a custom-made sheath, demonstrated a higher light output and better beam homogeneity on tissue subsurface. The output power and fluence profile were simulated for different design parameters. A camera recorded fluence profiles through calibrated intralipid solution at various imaging depths. The light delivery efficiency was experimentally compared with and without the ball lenses, based on ex-vivo imaging of human colorectal cancer and in-vivo imaging of a palmar vein proximal to the human wrist. The simulations and experiments demonstrated that ball-shaped fiber tip design can achieve homogeneous fluence distribution on tissue subsurface with acceptable light output efficiency, suggesting its clinical potential for in-vivo endo-cavity imaging %K Photoacoustic imaging %K Optimized light delivery probe %K Ball-shaped fiber tip %K Adenocarcinoma %U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6304457/