Real-time, contrast enhanced photoacoustic imaging of cancer in a mouse window chamber.

A clinical ultrasound scanner and 14 MHz linear array collected real-time photoacoustic images (PAI) during an injection of gold nanorods (GNRs) near the region of a mature PC-3 prostate tumor in mice implanted with a skin flap window chamber. Three dimensional spectroscopic PAI (690-900 nm) was also performed to investigate absorption changes near the tumor and enhance specific detection of GNRs. Whereas GNRs improved PAI contrast (+18 dB), the photoacoustic spectrum was consistent with the elevated near infrared absorption of GNRs. The versatile imaging platform potentially accelerates development of photoacoustic contrast agents and drug delivery for cancer imaging and therapy.