Ultrasound has long since become more than a diagnostic and imaging tool only – in focused form, it allows deep treatment of tissues in a non-invasive way and with a high degree of accuracy. Researcher Noa Guzner reviews some advanced uses of this technology, which is in a constant process of development and innovation.
Focused Ultrasound (or FU for short) is an emerging technology that allows reaching and treating various tissues in the body without the use of incisions or radiation. Much like the heating effect obtained when focusing the rays of the sun through the lenses of glasses, ultrasound beams can be focused to a highly precise point deep in the body. This focus permits very accurate treatment without causing damage to nearby tissues. Sometimes, treatment is MRI-guided, which aids in pinpointing the operation accurately.
In 2022, a report was published detailing the various fields of medicine where studies that use this technology are being conducted. These fields are very diverse, and clinical research is already being conducted among participants with various medical conditions. From non-alcoholic steatohepatitis, anxiety disorders, and schizophrenia, to urinary incontinence. Studies in pre-clinical stages are also conducted in these fields at an ever-increasing pace.
Thanks to the heating effect, one of the earliest studied uses is the ablation of tumors and tissues in various depths within the body. Currently, one of the most common uses for focused ultrasound is the ablation of uterine myomas. Myomas are benign growths that develop on the uterine wall and cause various symptoms such as heavy menstrual bleeding, and symptoms originating in the growths pressing against various abdominal organs. The prevalence of myomas is relatively high and stands at 20-50% in women over the age of 30. By using focused ultrasound, the uterus and adjacent tissues remain unharmed. The treatment is considered safe, does not usually necessitate hospitalization, and has minimal side effects. A highly substantial matter in treating myomas is maintaining female fertility. This is because the current proposed treatments may jeopardize the ability to carry out future pregnancies. While no randomized clinical studies on this matter have been published, evidence has been mounting for this treatment not being damaging to ovarian function, and permits carrying a pregnancy to term without any increase in the rates of miscarriage and obstetric complications.
One condition for which this treatment has been approved for use, and even been included in the healthcare basket since 2018, is essential tremor. During this treatment, under MRI guidance, ultrasound beams are focused on a highly particular area of the brain in order to stop the transmission of uncontrollable movement signals. With the help of this treatment, many patients experience a substantial decrease in tremors and significant quality-of-life improvements.
Another use that was approved in Israel as far back as 2017 is the use of MRI-guided focused ultrasound to treat bone metastases. This treatment is palliative, intended to reduce pain by destroying nerve cells and reducing the size of metastases, and is not proposed as a treatment for the actual disease. Treatment is performed under general anesthesia and is intended for metastases in the bones of the extremities, the pelvis, the ribs, and the lower-back part of the spinal column. It has been reported that the treatment is effective in 60-100% of patients, who experience near-immediate pain relief, which may last for a period of up to 3 months. There are very few contra-indications for this treatment, and it does not disrupt, nor is it affected by, other treatment types such as chemotherapy or radiotherapy. However, one should remember that complications exist, with a frequency of about 3% – most of them minor and resolve after several days, such as burns and bone structure damage. This treatment, of course, also has complications associated with anesthesia.
In summary, it appears that focused ultrasound treatments have been on the upswing in recent years. We only showed a small number of examples for its use, but the scope of research being conducted draws attention, and following developments in this field may be worthwhile.
