Photoacoustic Cystography

Abstract

Conventional pediatric cystography, which is based on diagnostic X-ray using a radio-opaque dye, suffers from the use of harmful ionizing radiation. The risk of bladder cancers in children due to radiation exposure is more significant than many other cancers. Here we demonstrate the feasibility of nonionizing and noninvasive photoacoustic (PA) imaging of urinary bladders, referred to as photoacoustic cystography (PAC), using near-infrared (NIR) optical absorbents (i.e. methylene blue, plasmonic gold nanostructures, or single walled carbon nanotubes) as an optical-turbid tracer. We have successfully imaged a rat bladder filled with the optical absorbing agents using a dark-field confocal PAC system. After transurethral injection of the contrast agents, the rat's bladders were photoacoustically visualized by achieving significant PA signal enhancement. The accumulation was validated by spectroscopic PA imaging. Further, by using only a laser pulse energy of less than 1 mJ/cm 2 (1/20 of the safety limit), our current imaging system could map the methylene-blue-filled-rat-bladder at the depth of beyond 1 cm in biological tissues in vivo. Both in vivo and ex vivo PA imaging results validate that the contrast agents were naturally excreted via urination. Thus, there is no concern regarding long-term toxic agent accumulation, which will facilitate clinical translation. Video LinkThe video component of this article can be found at

Near-infrared fluorescent probes in cancer imaging and therapy: an emerging field

“…Jeon et al demonstrated the feasibility of photoacoustic cystography by NIR dyes with low toxicity. 101 Thus, appropriate multimodal molecular probes can exert synergistic advantages over any single modality alone.…”

Dual modality ultrasound - photoacoustic clinical imaging system and its applications

“…imaging, urinary bladder imaging, imaging of neoangiogenesis, GIT imaging, etc. [33][34][35][36][37][38][39][40][41][42].…”