Experimental investigation of effect of ultrasonic duty cycle on generation of reactive oxygen species for highly efficient sonodynamic treatment

Abstract

Sonodynamic treatment (SDT) is a non-invasive treatment of cancer, combining ultrasound, reactive oxygen species (ROS), and sonosensitizer. When cavitation bubbles generated by ultrasound oscillate and collapse, ROS are generated due to the high temperature and high pressure inside the bubble. By generating cavitation bubbles in a target tissue, it can be treated by the cytotoxicity of ROS, which can be further enhanced by a sonosensitizer. In SDT, the small treatment region by a single shot of HIFU results in a long treatment time, which needs to be reduced by improving the efficiency of ROS generation. ROS can be visualized by the sonochemiluminescence of luminol. In this study, a polyacrylamide gel soaked with luminol solution is used as a target of ultrasonic exposure. The effect of the duty cycle of HIFU exposure on ROS generation was investigated by capturing sonochemiluminescent light emission, and high-speed photography of cavitation bubbles.

Effect of focal spot scanning method in agarose gel and chicken breast on heating efficiency in cavitation-enhanced ultrasonic heating

“…A previous study suggested that the duration of intermission has an effect on the amount of bubbles. 34) Many bubbles in front of the focal In addition, the generated bubbles may interfere with the succeeding ultrasound focused at the neighboring foci. In Fig.…”

Intracranial Sonodynamic Therapy With 5-Aminolevulinic Acid and Sodium Fluorescein: Safety Study in a Porcine Model

“…In preclinical sonodynamic treatment studies performed to date, typically a 10% DC (where the transducer is on 10% of the time and off for 90%) has been used in order to provide a power sufficient to activate the sonosensitizer agent but avoid a thermal rise in the target and surrounding tissues (23)(24)(25). In our procedure, each sonication target was a series of 10 subsonications centered around the target chosen on the targeting software; by taking advantage of the fact that each sonication needed to be 10ms in length and a 10% DC, the 90% off time could be used to treat additional targets.…”

Development of efficient method of generating reactive oxygen species by expanding cavitation region using ultrasound focus scanning in the direction of ultrasound propagation

“…This can result in a long treatment time, and the spatial selectivity can be reduced by scanning the HIFU focus. Therefore, efficient ultrasound irradiation methods and preoperative monitoring of the ultrasound focal position [11][12][13] have been studied to shorten the treatment time and reduce the effect on normal tissues.…”