Stereotactic radiosurgery (SRS) is used to treat a number of abnormalities in the brain. The Novalis unit at the Alberta Radiosurgery Centre is also capable of treating lesions outside the brain. In 2004/05, the program will focus on lesions within the brain and spine only, but will expand to treat lesions elsewhere in the body sometime in 2005.
It is important that a patient has generally good health, with a reasonably good performance status.
Not all patients are appropriate for SRS, as some tumour locations or pathologies may not be amenable to SRS. In some cases, we will advise that the patient return to their primary neurosurgeon/oncologist for conventional treatment.
Non Malignant Tumors
Arteriovenous Malformations (AVM)
Functional Disorders (e.g. movement disorders, trigeminal neuralgia)
Stereotactic radiosurgery is used in the treatment of brain metastasis. SRS can either be used as the primary treatment for brain metastasis or retreat for failures after previous resection or whole brain irradiation.
The criteria for this treatment is that there should be 3 or less lesions in the brain, and the lesions must be <3.5centimeters in largest diameter. If there is any disease present outside the brain, it must be under control with treatment. Preferably their primary disease has been under control for the previous 6 months. The patient's survival is expected to benefit from stereotactic radiosurgery treatment.
Stereotactic radiosurgery is not used for the treatment of primary brain tumours such as malignant gliomas/astrocytomas because the mechanism of growth of these tumours is more diffuse and not focal. Conventional 3-D conformal radiotherapy remains the mainstay of treatment for gliomas (see frequently asked questions)
The Alberta Radiosurgery Centre will request that MRI used to diagnose the brain metastasis. This is essential in assessing the number and size of the lesion(s). Additionally, a creatinine and complete blood count should have been done no more than 2 months prior to referral.
Stereotactic radiosurgery is sometimes used as an alternative to surgery to treat non-malignant lesions in the brain.
Acoustic Neuromas can be treated with either single treatment in 1 day or multiple treatments sessions over weeks. If the acoustic neuroma is less than 3 centimeters and/or there is no functional hearing, then the treatment can generally be accomplished in a single fraction. If the neuroma is greater than 3 centimeters and/or there is preservable functional hearing, then the treatment may be given in multiple treatment sessions (FSRT). ARC physicians (in consultation with the referring surgeon) may sometimes recommend a combination of conventional surgery for partial resection followed by radiosurgery for the residual tumour.
The Alberta Radiosurgery Centre will request copies of audiometry and MRI ordered by the ENT-neurosurgeon to determine the appropriateness of the referral.
Sellar and Parasellar tumors close to the optic chiasm, pituitary gland or within the cavernous sinus may be treated with Fractionated Stereotactic Radiotherapy (FSRT). The Alberta Radiosurgery Centre will request that a recent MRI be sent to us for review and we may request that a visual field and pituitary function tests be performed as well.
Meningiomas, some Hemangiomas and other benign lesions can be treated with Stereotactic radiosurgery depending on the location and type of lesion. If less than 3.5 cm in maximal dimension then a single treatment will generally be used. If the lesion is greater than 3.5 centimeters, fractionated treatment will likely be recommended. The Alberta Radiosurgery Centre will request that a recent MRI or CT be sent to us for review.
Stereotactic radiosurgery can be very effective at treating AVMs. A single treatment may be recommended if the AVM is less than 3.5 centimeters. Treatment may be considered for AVMs greater than 3.5 centimeters, but fractionated or planned staged Stereotactic radiosurgery may be required. The Alberta Radiosurgery Centre will request that the MRI and angiogram be sent for review.
Certain functional disorders such as trigeminal neuralgia and obsessive-compulsive disorders may be treated at ARC. At present there is little indication to treat movement disorders or epilepsy with stereotactic radiosurgery, outside of clinical trial protocols. Consultation regarding these indications should be directed to Dr. Kiss.
While the Alberta Radiosurgery Centre attempts to use diagnostic scans that have already been performed, we occasionally require another scan or diagnostic procedure be done using special protocols to assist in the imaging and planning process.