Evaluation of tumor progression and magnetic hyperthermia therapy efficacy with ultrasound localization microscopy

Tumor progression and ablation are accompanied by changes in the microvascular network. Ultrasound localization microscopy (ULM) is a promising tool for observing such changes. This study aims to use this method to evaluate the microvasculature in tumor regions and its changes under magnetic hyperthermia treatment. By establishing a mouse tumor animal model and setting up an experimental platform for ultrasound experiments, imaging of the intratumoral microvasculature is achieved. Magnetic hyperthermia treatment combines an external magnetic field and injected magnetic nanoparticles, which causes heat effect on the tumor tissue. Experiment results show that the changes of intratumoral microvasculature during tumor evolution can be observed by the ULM, which was consistent with the results of immunohistochemistry. Furthermore, comparing the microvascular images of the tumor area before and after magnetic hyperthermia treatment, a significant reduction in blood vessels is found, which is also consistent with the pathological slice results. The results verified the feasibility of magnetic hyperthermia treatment.