Intracranial Nonthermal Ablation Mediated by Transcranial Focused Ultrasound and Phase-Shift Nanoemulsions
* Presenting author
One of the major challenges of using transcranial focused ultrasound for ablating brain tumors is that the pressure and time-averaged power required to generate lesions is relatively high and could induce skull heating and pain. In this study, we investigate the utility of phase-shift nanoemulsions (PSNE), lipid-coated nanodroplets composed of perfluorobutane, to serve as cavitation nuclei and enable focal ultrasound-mediated nonthermal ablation in the brain using transcranial focused ultrasound. A transcranial focused ultrasound transducer operating at 740 kHz and 12 CD-1 mice were used to test the vaporization of PFB PSNE and the corresponding damage. The PNP was increased stepwise up to 1.8 MPa and the broadband emission from the inertial cavitation nucleated by vaporized PFB-based PSNE were recorded to quantify the inertial cavitation level. A significant elevation of broadband emission was noticed first at PNP = 1.25 MPa and increased dramatically, indicating strong inertial cavitation. The corresponding biological damage was analyzed with H&E staining and exhibited confined ischemic and hemorrhagic lesions. The damage was found to correlate with the acoustic pressure and depended upon the administered PFB PSNE concentration.