High-Intensity Focused Ultrasound (HIFU) is quickly gaining momentum as an upcoming tool for incision-free noninvasive surgery. The Hospital for Sick Children (SickKids, Toronto, Canada) and Sunnybrook Hospital (Toronto, Canada) have treated the first pediatric patient in North America for a bone tumor using MR-guided HIFU, destroying it from his leg without piercing any skin. The technology uses ultrasonic waves that are focused to interfere constructively at a single point. By doing so, the sound waves generate high-intensity, rapid vibrations at that point to create frictional heat that eventually ablates the tissue target from the inside out. The health care team monitored the progress using an MRI scanner, which was used both for positioning and assessing the temperature of the target and surrounding areas.
The therapy is less risky than traditional surgery, and has advantages over radiation-based treatments by eliminating radiation exposure, reducing damage to surrounding tissues, and reducing risk of bone fracture from holes caused by radiation treatments. The targeted focus in HIFU is roughly the size and shape of a grain of rice.
The patient, a 16 year-old hockey player, snowboarder, and wakeboarder, had a benign bone tumor called osteoid osteoma that releases prostaglandin, a signalling molecule involved with inflammation and pain. The pain in his leg disrupted his sleep and forced him to take 700 painkillers a year. After the procedure, the recovery was remarkable – by bedtime that same night, he was completely pain-free and has required no more painkillers since.
“With high-intensity focused ultrasound, we are moving from minimally-invasive to non-invasive therapy, significantly reducing risk to the patient and fast-tracking recovery,” said SickKids interventional radiologist Dr. Michael Temple, who led the team that performed the surgery.
HIFU Lab Demonstration: