ExAblate 2000 works in conjunction with a General Electric Healthcare MRI scanner.  In about 10 minutes, the scanner room can be converted from a diagnostic suite to a suite for non-invasive image guided therapy.

ExAblate Components

Operator Console:

The operator console is located in the control room next to the GE SIGNA workstation. It is the main control mechanism and all treatment planning, registration, and treatment is conducted from this console. The Stop Sonication safety feature enables treatments to be immediately terminated by pressing a stop sonication button.
 
Patient Table:

The detachable patient table is docked to the MR scanner.  It incorporates a transducer immersed in a sealed water bath, with an automated positioning system that generates the focused ultrasound energy beams.

Equipment Cabinet:

The equipment cabinet includes the interface electronics to the patient table, to the MR scanner and to the operator console. It is located in the adjacent MR equipment room.
 
Operator console.

The physician plans and executes the MRgFUS treatment from the operator console. The console communicates with the MR system to retrieve images used during treatment.  

 Patient table.

During treatment, the patient lies on the patient table inside the MR scanner. The patient table houses the focused ultrasound transducer in a water bath. The patient table docks to the MRI scanner. 
 
Equipment cabinet.

The equipment cabinet houses the electronics used to process commands from the operator console, and the power amplifiers used to generate the focused ultrasound.  
 

ExAblate Treatment Procedure 
 
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:

Target localization

 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.

 «ExAblate»

MRT

Treatment

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.

Treatment outcome

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.