2A-2 Investigations into the Potential Contribution of a Thermal Mechanism for Pulsed High Intensity Focused Ultrasound Mediated Delivery

The mechanism behind pulsed high intensity focused ultrasound (pHIFU) effects leading to increased drug delivery is currently poorly understood. In this work, the thermal dose and peak temperatures associated with a typical pHIFU treatment were measured in mouse muscle. A non-ultrasonic hyperthermia (HT) treatment was then applied, designed to mimic the thermal component of the pHIFU treatment. The delivery of 200 nm fluorescent nanoparticles was measured as a surrogate marker for drug delivery by pHIFU and HT treatments. Only the pHIFU treatment showed a significant increase in particle delivery.