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The ExAblate® system is fully integrated into a magnetic resonance imaging scanner. The whole procedure is conducted inside the imaging scanner. During this procedure, the physician will use the MR imaging to plan your treatment and deliver treatment guidance and therapy feedback during the procedure.
Am I suitable for the ExAblate® treatment?
Locations of treatable tumors include the ribs, sternum, extremities, pelvis, shoulders, and posterior aspects of the lower lumbar spine, sacrum, and coccyx.
Tumors must be visible on MRI.
Tumors must be accessible to the focused ultrasound beam; for example, tumors blocked by extensive scarring or bowel cannot be treated.
The targeted bone must be at least 1 cm from the skin surface.
Benefits of MRgFUS to treat pain from bone metastasis
The pivotal study for this device was conducted under an investigational device exemption and the results are published in the Journal of the National Cancer Institute. This was a global study conducted at 17 centers located in the US, Canada, Israel, Rome, and Russia. The study design included randomization into a treatment arm and a placebo arm in a 3:1 ratio.
A total of 147 subjects completed the study. The post treatment follow up was through 3 months. The primary endpoint was clinically significant pain relief with stable or reduced pain medication usage; secondary endpoints were related to improved quality of life. After 3 months of follow-up, 65% of patients experienced substantial pain relief at the site of ExAblate® treatment. Pain relief was observed within 3-7 days after the procedure and coincided with improvement in quality of life. The procedure is non-invasive (i.e., no surgical scars) and is generally performed on an out-patient basis.
ExAblate® MRgFUS is not suitable for all patients. Patients who have any of the following should inform their doctor so that he or she can make good treatment choices with you.
If you cannot safely undergo MR imaging, you may not be a good candidate for the procedure. For example, any metallic implants must be non-magnetic to prevent injury to the patient from the MR's strong magnetic field.
If your physician has told you that you have a bone that is fragile and may break or needs surgery to be stabilized, or has already been stabilized with surgical implants, you may not be a good candidate. The cancer itself as well as cancer treatments may cause the bone to weaken and fracture.
If you have extensive skin scarring in the areas that would be treated, you may not be a good candidate for the procedure.
Please discuss all of these conditions with your physician so your doctor can properly evaluate your suitability for the ExAblate® therapy.
The most common potential risks associated with the ExAblate® procedure is pain and discomfort (mild, moderate and severe) related to the delivery of the ultrasound energy to the bone; this dissipates shortly after the sonication (approximately less than 1 minute) and can be managed with judicious use of anesthetic, analgesic and sedative medications administered by your physician. Occasionally, patients may experience post-procedure pain which usually resolves within a few days.
If a nerve was located close to the designated area for ablation or close to a bone in the far beam path, you may feel pain during sonications, or numbness, or pain immediately after the treatment or during the following few days. If you experience pain in a nearby area during the sonication, you should tell your physician so he or she can check for the presence of nearby nerves in the beam path.
Longer term risks include bone fractures, which may occur at any time as a result of the bone metastases weakening the bone, prior radiation therapy, or the ExAblate® procedure.