Metastatic brain tumors are the most frequently encountered type of brain tumors in adults. Lung, breast and colon cancer are among the more common sources of disease in this setting, although virtually any cancer can spread to the brain or spine. Surgery offers a rapid and effective method of removing relatively accessible intracranial lesions in otherwise healthy people. For deep-seated lesions, or in patients too weak to undergo surgical removal of metastatic brain tumors, Novalis Stereotactic Radiosurgery offers a rapid, safe and effective alternative to surgery or conventional whole brain radiotherapy.

Stereotactic Radiosurgery (SRS) is a method in which multiple photon or x-ray beams are focused on a radiographically (MRI scan, CT scan, angiogram, PET scan etc.) defined target volume within the brain. Unlike conventional fractionated radiotherapy, the extreme precision with which radiosurgery can be administered allows for the delivery of a single massive dose of radiation as opposed to a several week course of daily fractionated treatments. This technology was originally developed for the non-surgical treatment of arteriovenous malformations (AVMs). Currently, metastatic brain tumors make up the majority of lesions treated. Meningiomas, gliomas, acoustic neuromas and trigeminal neuralgia account for most of the remaining accepted indications for treatment. Although treatment is usually completed in a matter of minutes, the extreme precision demanded by this procedure typically involves the temporary placement of a special ring or halo on the head in order to insure maximum stability.

Fractionated Stereotactic Radiotherapy (FSR, SRT) is a method of delivering the same high-precision type treatments but in divided doses over an extended period of time (anywhere from one to five weeks). Properly performed fractionation can reduce the chance of side effects in cases where the potential risk of brain injury from single fraction radiosurgery is too high. Previously irradiated brain tumors, large brain tumors or tumors located near sensitive areas (eye and optic nerves) are good candidates for this form of treatment. Patients with acoustic neuromas who want to maximize their chance of retaining useful hearing are often best treated by FSR. Tumors with certain growth characteristics (meningiomas etc.) may also respond better to FSR than SRS.

Intensity Modulated Radiation Therapy (IMRT) offers a highly customized form of conformal radiotherapy. Using this technique, both the edge/shape and depth/intensity of the radiation field is rapidly changed over time, thereby sculpting a precisely defined 3-dimensional cloud of radiation. IMRT is particularly useful for larger, more complex tumor shapes adjacent to critical brain structures.


Primary Brain Tumors such as gliomas, astrocytomas and glioblastoma may benefit from a combination of these techniques. Compared to conventional radiotherapy, side effects in nearby normal brain can be dramatically reduced with careful planning by the radiation oncologist and neurosurgeon.

The meningioma shown inside the white oval can be seen pressing on the brain stem and growing upwards and displacing the optic nerve. Novalis Stereotactic Radiotherapy resulted in a significant shrinkage of the tumor in less than six months. At last visit, the patient's symptoms have disappeared and there is no evidence of radiation injury.