Pulsed-Focused Ultrasound Enhances Boron Drug Accumulation in a Human Head and Neck Cancer Xenograft-Bearing Mouse Model

This study aims to demonstrate that pulsed high-intensity focused ultrasound (pulsed-HIFU) may enhance the fructose-conjugated 4-borono-L-phenylalanine (BPA-Fr) accumulation in tumor lesion using F-18-FBPA-Fr microPET scans. To the mice bearing orthotopic SASC03 human tongue squamous carcinoma xenograft, a 2-min pulsed-HIFU was applied to tumor. Immediately after pulsed-HIFU treatment, F-18-FBPA-Fr was intravenously injected, and biological characterizations including microPET imaging and biodistribution were conducted. Both biodistribution studies and microPET imaging performed after intravenous injection of F-18-FBPA-Fr revealed higher tumor uptake in HIFU-treated mice than that of the control. CD31 and Ki-67 histochemical staining of tumor sections and H&E staining of nearby normal tissues revealed no significant difference between the pulsed-HIFU-treated mice and the control. This study demonstrated that pulsed-HIFU was beneficial to the accumulation of boron drug in the head and neck tumor lesion and may enhance the therapeutic efficacy of clinical BNCT.