ExAblate treatment is conducted while the patient lies on a patient table inside the Magnetic Resonance scanner. The patient is conscious, able to communicate with the physician during the treatment, and is provided with sedation medication prior to the first sonication. The entire procedure is planned and carried out from the ExAblate operator console located next to the MR workstation in the control room.
There are four major steps in the ExAblate treatment:
MR images are taken in three orientations to locate the target tissue and surrounding organs. These images are used to position the patient and determine the optimal path to the tumor for the focused ultrasound beam.
(Refer to Figure 1 below)
Treatment planning and editing
The physician uses the MR images to identify the target anatomy and evaluates the structures surrounding the fibroid to decide on a treatment region. Contours of the treatment area are drawn on the MR images and verified in three orientations. The ExAblate system calculates the volume of the tissue to be treated and the number of treatment spots required. The beam path is visualized to verify that nothing inteferes in any plane.
(Refer to Figure 2 below)
Treatment consists of multiple sonications to ensure tumor ablation. During each sonication, phase sensitive MR images are acquired, and real-time quantitative temperature maps are produced to confirm tissue heating. These temperature maps provide feedback to the physician who can then adjust treatment parameters to optimize thermal ablation. After each sonication, the transducer and MR scan plane are automatically directed to the sucessding point, and the process is repeated until the entire target volume has been treated.
(Refer to Figure 3 below)
At the end of treatment contrast enhanced MR images are acquired to measure the degree of contrast agent uptake. Regions without contrast agent uptake (non-perfused) have been destroyed by the thermal effects of the focused ultrasound. The physician can determine whether sufficient tissue has been treated, or if a repeat treatment is necessary.
(Refer to Figure 4 below)