Neuro Imaging


Schwannoma Case Study:
Use of Novalis Tx™ Technology for Treatment of Cranial Nerve Lesion

 

 

•    Director's Letter
•    NOVA
•    Schwannoma Case
•    Chiari Malformations
•    Neuroscience at UCSB
•    Neurogenic Thoracic Outlet Syndrome
  PFO Closure Device

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Radiation planning axial CT with contrast revealing isodose treatment lines with 95 percent of dose delivered in green area, which corresponds to tumor and minimal subclinical doses received by adjacent brainstem and temporal lobe

Thomas
Weisenburger, MD
Radiation Oncologist

 

Case Presentation: A 48-year-old male presented with intermittent facial spasms resulting from a benign tumor which was also compressing the brainstem. The patient had been suffering from intermittent facial spasms for approximately one year before the tumor was diagnosed.

 

Before determining the best treatment option, the patient’s neurologist, Richard Lowenthal, MD, conferred with Thomas H. Jones, MD, neurosurgeon and medical director of the Santa

 

Barbara Neuroscience Institute, and Thomas Weisenburger, MD, FACR, radiation oncologist and medical director of the Cancer Center of Santa Barbara.

 

The team decided that stereotactic radiosurgery would be the safest, most cost-effective, and also efficacious option. They also decided—given the close proximity of the tumor (most likely a trigeminal schwannoma) to the brainstem and cranial nerves— that fractionated rather than single dose treatment would be safest for the patient.

 

The patient came to the Cancer Center of Santa Barbara five days a week for a total of 28 treatments, each 20 minutes in duration. Before each treatment, the patient was positioned and stereoscopic images taken with the Novalis ExacTrac 6-D stereo X-ray targeting system. ExacTrac utilizes a robotic couch that precisely positions the patient without requiring the use of a head ring to synchronize algorithms.

 

Treatment involved eight arcs, each lasting about one-third of a minute, making the total radiation exposure time about four minutes per visit. The total radiation dosage that the patient received was 50.4Gy, and the range of the high-energy beam was 6Mev.

 

The patient tolerated treatment very well, experiencing only mild fatigue, and continued to work full time throughout the course of treatment. His outcome was successful.

 

State-of-the-Art Technology

 

Radiation therapy for the treatment of schwannomas is successful in 95 percent of cases. Using the Novalis Tx radiosurgery system, patients benefit from the most minimally invasive and cost-effective treatment available. Novalis Tx offers a highly versatile platform for radio-guided imaging therapy and procedures, and has proven successful in treating tumors located in the brain with wide indication for tumors of the lung, liver, spine and kidney.

 

“We are able to treat patients with tumors considered inoperable right here in Santa Barbara rather than sending them to facilities in Los Angeles,” says Dr. Weisenburger. “Novalis Tx delivers precisely focused high-energy radiation to sensitive locations. The shortened treatment time possible with this system results in lower overall radiation exposure for the patient compared with traditional technology.”

Axial T1 MRI with gadolinium showing the enhancing white tumor on R compressing the brainstem and involving the fifth cranial nerve

 

Pathophysiology and Treatment of Schwannomas

Patients with these tumors often present with loss of function in the distribution of the nerves involved. If a patient is asymptomatic, a lesion may be incidentally discovered during computed tomography or magnetic resonance imaging for another purpose. Schwannomas arise from the nerve sheath and may exhibit a growth pattern of compact, elongated spindle cells in irregular streams or looser mixes of cystic spaces and tissue. They account for between 6 and 8 percent of intracranial neoplasms and can result in nerve dysfunction and brainstem compression. With stereotactic radiosurgery, rates of tumor control in vestibular schwannomas measuring less than 3cm exceeds 95 percent.

 

For more information about the Cancer Center of Santa Barbara or to refer a patient, call (805) 682.7300. To learn more about the Cancer Center's services, visit www.ccsb.org.