ExAblate® 2000 system uses MR guided focused ultrasound breakthrough technology which combines high intensity focused ultrasound beam that heats and destroys targeted tissue, non-invasively and Magnetic Resonance Imaging system (MRI) which visualizes patient anatomy, and controls the treatment by monitoring the tissue effect in real time.
Click here to see how MR guided focused ultrasound works.
How does MR guided Focused Ultrasound work
Ultrasound is a form of energy that passes through skin, muscle, fat and other soft tissue. When used for diagnostic imaging the low intensity ultrasound waves have little to no biologic effect on cells or tissues. High intensity focused ultrasound energy , focused on a small target volume, provides a therapeutic effect by raising the tissue temperature of the target high enough to destroy it. This is similar to how the sun's rays ignite a flame when focused under a magnifying glass.
The ultrasound waves are directed from a transducer (which converts electrical energy into ultrasound energy) into a small focal volume. The cone-shaped ultrasound beam penetrates through soft tissue and produces well defined regions of protein denaturation, irreversible cell damage, and coagulative necrosis, at specific target locations. Tight focusing is designed to limit the ablation to the targeted location. Treatments consist of multiple exposures of focused energy or sonications.
Beam of focused ultrasound energy emanating from the transducer through the skin and uterus to a specific focal poin on the uterine fibroid. Note that the energy in the far field is much lower than that in the near field.
Why is MR guidance and control important for a non-invasive procedure?
Magnetic Resonance imaging capabilities provide an ideal control system for safely directing the energy. These include excellent anatomic resolution, very high differentiation between treated and untreated tissue, and the ability to create real time temperature "maps" during the treatment.
High precision tumor localization
High precision anatomical MR images in 3 orientations, showing the tumor and surrounding organs, are used to position the patient and to plan the treatment to ensure:
- exact tumor targeting
- beam path visualization.
Real time thermometry
Temperature maps display the relative tissue temperature as a color map superimposed on an anatomical MR image. This allows the physician to observe temperature changes in real time during treatment. Based on these observed temperature changes, treatment parameters can be adjusted to ensure safe and effective thermal ablation.
Outcome assessment
T1 weighted MR images with Gadolinium contrast enable the physician to immediately assess the outcome and determine which regions are non-perfused (ablated).