A Review of High-Intensity Focused Ultrasound

Abstract

For 80 years, high-intensity focused ultrasound (HIFU) has been the subject of interest in medical research. It is a non-invasive procedure that causes the death of cells in a very select area through one of two mechanisms, either heat or cavitation. While diagnostic ultrasound is well known in the medical profession and ultrasound is also used in physiotherapy, high-intensity focused ultrasound is less known but is becoming increasingly important as a non-invasive tool that can be used in many ways, including in the treatment of several cancers as well as benign uterine fibroids. Other interesting developments are underway, including its use in the treatment through an intact skull of essential tremors and the tremor associated with Parkinson’s disease, and in a modified form, it is used to target drug delivery to the brain due to its potential opening of the blood–brain barrier. The depth of penetration of HIFU is variable depending on the type of transducer used and the distance from it. Clinical trials of abdominal malignancies and benign uterine fibroids are reviewed in this article along with potential side effects of the procedure. Over the past two decades, the technology has improved considerably, and the clinical indications have broadened. The current limitations of the technology are also discussed, along with the potential advances in the field that may be made over the next decade.