Pre-clinical validation of transrectal diffuse optical tomography for monitoring photocoagulation progression during photothermal therapy of prostate cancer

Diffuse optical tomography in a transrectal configuration (TR-DOT) has been developed to monitor progression of the photocoagulation front during interstitial photothermal therapy (PTT) of focal prostate cancer. Building on simulations and feasibility studies in coagulating phantoms, ex vivo porcine muscle and ex vivo canine prostate, the technique was tested here in preclinical canine prostate models in vivo to assess the signal stability and device sensitivity for clinical translation. Co-registration of DOT measurements with magnetic resonance imaging (MRI)-based thermometry in photocoagulating phantoms provide temperature profiles for correlation with DOT signals changes. DOT measurements were performed near the treatment fiber tip during PTT with near-infrared light delivery in healthy canine prostate and kidney in vivo. The results were compared with numerical simulations, given the tissue optical absorption and scattering properties. In parallel studies, TR-DOT is being investigated to localize prostate tumor and to enhance PTT using porphyrin-lipid nanoparticles (porphysomes, pPS). The DOT system is being further optimized for real-time monitoring of focal prostate PTT.