Laser-enhanced high-intensity focused ultrasound heating in an in vivo small animal model

• DOI: 10.1063/1.4968509
• Publication Date: 2016-11-22T18:00:50Z
• Authors: Janggun Jo; Xinmai Yang
• Keywords: 03 medical and health sciences; 0302 clinical medicine; 616; 0103 physical sciences; 01 natural sciences

The enhanced heating effect during the combination of high-intensity focused ultrasound (HIFU) and low-optical-fluence laser illumination was investigated by using an in vivo murine animal model. The thighs of murine animals were synergistically irradiated by HIFU and pulsed nano-second laser light. The temperature increases in the target region were measured by a thermocouple under different HIFU pressures, which were 6.2, 7.9, and 9.8 MPa, in combination with 20 mJ/cm2 laser exposures at 532 nm wavelength. In comparison with conventional laser therapies, the laser fluence used here is at least one order of magnitude lower. The results showed that laser illumination could enhance temperature during HIFU applications. Additionally, cavitation activity was enhanced when laser and HIFU irradiation were concurrently used. Further, a theoretical simulation showed that the inertial cavitation threshold was indeed decreased when laser and HIFU irradiation were utilized concurrently.