Novalis Tx™ Enhances Response to AVM

 

Arteriovenous malformations (AVMs) occur when blood vessels develop incorrectly during fetal growth. Although many symptomatic patients with AVM can be managed with brain surgery and/or endovascular techniques, state-of-the-art, noninvasive, radiation-based technology now enables physicians to treat some patients with especially challenging conditions.

 

Brain AVM is typically diagnosed after intracranial hemorrhage or seizure. cerebral arteriograms are the procedure of choice to define the important anatomic relationships of the AVM in order to determine the appropriate treatment. in some cases, endovascular techniques can be utilized to obliterate the AVM. follow-up arteriograms are then used to confirm whether or not the AVM has been eradicated.

 

When neither brain microsurgery or endovascular obliteration is feasible due to the location, size or complexity of the AVM, stereotactic radiosurgery may offer the best treatment option. in these situations, the Novalis Tx™ radiosurgery system can provide optimal results.

 

Successful AVM Treatment

The state-of-the-art Novalis Tx at Cancer Center of Santa Barbara -- the only system of its kind in the tri-county area -- combines accuracy, power and speed for better patient outcomes. the system captures angiogram images to define the AVM in 3-D perspective.

 

"Stereotactic techniques enable us to target and deliver a dose of radiation that in most cases is sufficient to destroy the AVM," says Thomas Weisenburger, MD, FACR, radiation oncologist and medical director of Cancer Center of Santa Barbara. "If left untreated or not completely removed during an initial intervention, an AVM can grow and become more difficult to correct. Novalis Tx provides one of the best options to treat vascular lesions located in sites previously considered inaccessible, thus lowering risk for potential future bleeding and subsequent neurological damage."

 

For more information about services at Cancer Center of Santa Barbara, visit www.ccsb.org. To refer a patient, call (805) 682-7300.

 

Coronal view of dose distribution with brainstem pictured in green

Sagittal view of dose distribution with brainstem in green and optic chiasm in blue

 

 

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Features and Benefits

 

The noninvasive Novalis Tx™ radiosurgery system can treat many malignancies previously considered inoperable by delivering precise radiation supported by a 2.5 mm HD120® high-definition beam shaper capable of sub-millimeter accuracy.

 

The precision of the Novalis Tx is matched by its power and speed- with up to 1,000 MU per minute dose rate, 6MV and HighX (10-20MV) power, and RapidArc SRS/SBRS speed-resulting in more powerful and effective treatment in a shorter amount of time. This creates a better patient experience.

 

Imaging capabilities include:

 •    adaptive gating and robotic couch that move with patient's breathing and correct pitch, roll and yaw positioning
 •    cone-beam computed tomography including an On-Board Imager® 3-D
 •    fluoroscopy
 •    MV Portal Vision™
 •    stereo X-ray targeting with ExacTrac X-Ray 6D

 

Case Study

Stereotactic Radiosurgery Resolves AVM

A 71-year-old male reported to his internist with a chief complaint of intermittent headaches starting in the back of his head and extending to the top. He also reported experiencing some dizziness. magnetic resonance imaging of the neck showed no remarkable findings. following magnetic resonance angiography of the brain, a 4 mm to 5 mm aneurysm in the right anterior communicating artery was discovered.

 

The patient was then seen by Alois Zauner, MD, neurosurgeon and neurointerventionalist at Santa Barbara Neuroscience Institute at Cottage Health System. Dr. Zauner confirmed the presence of the aneurysm using cerebral arteriography, which also revealed a small arteriovenous malformation (AVM) involving the vein of Galen.

 

The aneurysm was repaired, and an attempt was made to treat the AVM angiographically. The tortuosity of the vessels in the region of the AVM restricted catheter access to the feeding vessels, resulting in unsuccessful angiographic treatment. the patient was subsequently referred for treatment with stereotactic radiosurgery (SRS) and received one treatment session using the Novalis Tx. because it takes up to two years for the full effect of SRS to take place, the success of the treatment is usually confirmed by follow-up angiogram at the two-year mark. fourteen months following treatment, the patient is experiencing reduced incidence of headaches and no bleeding from the AVM.