In vivo imaging and treatment of solid tumor using integrated photoacoustic imaging and high intensity focused ultrasound system

Purpose: The purpose of this study is to show the feasibility of combined contrast imaging and treatment of solid tumor in vivo by an integrated photoacoustic imaging and high intensity focused ultrasound (HIFU) system. Methods: During this study, photoacoustic imaging was performed to identify the location of a CT26 tumor, which was subcutaneously inoculated on the hip of a BALB/c mouse. Then the CT26 tumor was ablated by HIFU with the guidance of photoacoustic images. To enhance the contrast and specificity of photoacoustic imaging, gold nanorods were used as the contrast agents during the experiment. After being injected into the blood stream, gold nanorods passively accumulated around the tumor region, and therefore outlined the location and shape of the tumor in the photoacoustic images, which were used to guide the subsequent HIFU therapy. Results: The experiment results showed that the tumor was clearly visible on photoacoustic images after the injection of gold nanorods and HIFU was able to ablate the tumor under the guidance of photoacoustic imaging. Conclusions: The authors demonstrated that their integrated photoacoustic imaging and HIFU system has the potential for contrast imaging with gold nanorods with possible diagnosis and treatment of solid tumors.