HIFU

HIFU (High Intensity Focused Ultrasound)

History

Although medical applications of the HIFU treatment have only come in recent years the first work to consider the potential applications of HIFU was completed in 1942. This work was built upon in the 1950’s by William and Frank Fry. Frank Fry was able to treat patients with Parkinson’s disease and other neurological conditions with HIFU treatment. Research into the use of HIFU continued throughout the 1950’s and 60’s but practical and technological limitations hampered their progress.

In 1956 it was suggested that high intensity ultrasound could be used to treat cancer and several studies were undertaken looking at the effects of ultrasound on tissue. Throughout the 1970’s and 80’s the study of high intensity ultrasound was orientated toward focused ultrasound and studies using HIFU to eradicate experimental tumors followed.

In 1989, Dr. Wang Zhibiao started the research of biological effects of ultrasound with Prof Ruo Feng and a team. Following this Dr. Wang and his team began to use HIFU on treating malignant tumors since 1996 and in that year the first noninvasive treatment of bone tumor in a human patient was undertaken in the Institute of Ultrasound Engineering in Medicine of Chongqing University of Medical Sciences. Since then, HIFU had been widely used in clinical application for the treatment of human malignant and benign tumors in Italy, Spain, Russia, UK, Korea, Japan, Hongkong and mainland China. Over 10000 patients have been treated.

Gradually, HIFU in combination with MRI was also used in clinical trials and till now a number of patients with benign uterine fibroids were treated with reluctantly satisfactory effects.

In Chongqing China since 1999, new applications of focused ultrasound have been discovered to treat gynecological diseases and allergic rhinitis respectively. Through massive clinical experience gained from over 300 hospitals in China, it was disclosed that focused ultrasound treatment of both diseases were effective and more acceptable than conventional therapies.

Recent medical application

Current clinical trials led by David Cunningtham and Gail ter Haar at Royal Marsden Hospital in London, in which 68 patients have been treated to date. Wu Feng and Wang Zhibiao at Chongqing University of Medical Sciences have reported encouraging results in the treatment 164 patients with a range of malignancies. A number of groups, including those of Ian Rivens at the Institute of Cancer Research, Larry Crum at the University of Washington’s Applied Physics Laboratory, and Kullervo Hynynen at Brigham and Women’s Hospital in Boston, have shown that HIFU beams can be used both to seal blood vessels and to occlude or block them. Pierre Mourad (at the University of Washington) and Hynynen are actively studying the possibility of altering the blood-brain barrier to increase the permeability from the bloodstream into the brain of a variety of therapeutic agents, with transskull ultrasound. (These two paragraphs are adapted from Acoustic Surgery by Dr. Gail ter Haar. Physics Today, Dec 2001: 29-34.)

The most significant body of clinical experience with therapeutic ultrasound has been in treating benign prostate prostatic hyperplasia. Another application in benign disease lies in the treatment of uterine fibroids. The search continues for therapies that treat the tumor without having significant effect on normal tissues. Therapeutic ultrasound may provide such a therapy.

When conventional surgery is undertaken to treat patients surgical complications often occur. These adverse effects can make patients lives very difficult. These side effects are more common in major surgical operations, such as the removal of cancerous tumours. The most radical development in modern surgery is the reorientation of emphasis from conventional surgery to minimally or non-invasive techniques. These new methods for surgery will reduce significantly the side effects associated with surgery. Some minimal and non-invasive methods, such as endoscopy and stereotactic technology have been applied clinically with great success. Furthermore, new emerging technologies further push back the boundaries of progress and make new forms of treatment possible. High-intensity focused ultrasound (HIFU) is one of the developments in non-invasive surgery.

HIFU technology integrates modern engineering technology and medical sciences. Using the biological effects of ultrasound, extracorporeal ultrasound beams are focused at the treatment area. Due to the significant energy deposition at the focus of the beam instantly the cancerous cells in the target area are destroyed. The HIFU technology can achieve precise “ablation” of the diseased area, because the treatment also destroys the diseased tissue non-invasively, it is also known as “Non-invasive HIFU surgery”. Unlike conventional methods, using HIFU healthy tissue is not affected by the treatment.