High Resolution Ultrasound and Photoacoustic Imaging of Orthotopic Lung Cancer in Mice: New Perspectives for Onco-Pharmacology.

OBJECTIVES:We have developed a relevant preclinical model associated with a specific imaging protocol dedicated to onco-pharmacology studies in mice. MATERIALS AND METHODS:We optimized both the animal model and an ultrasound imaging procedure to follow up longitudinally the lung tumor growth in mice. Moreover we proposed to measure by photoacoustic imaging the intratumoral hypoxia, which is a crucial parameter responsible for resistance to therapies. Finally, we compared ultrasound data to x-ray micro computed tomography and volumetric measurements to validate the relevance of this approach on the NCI-H460 human orthotopic lung tumor. RESULTS:This study demonstrates the ability of ultrasound imaging to detect and monitor the in vivo orthotopic lung tumor growth by high resolution ultrasound imaging. This approach enabled us to characterize key biological parameters such as oxygenation, perfusion status and vascularization of tumors. CONCLUSION:Such an experimental approach has never been reported previously and it would provide a nonradiative tool for assessment of anticancer therapeutic efficacy in mice. Considering the absence of ultrasound propagation through the lung parenchyma, this strategy requires the implantation of tumors strictly located in the superficial posterior part of the lung