Frameless Stereotactic Radiosurgery
Adults with brain metastases (BM) have the most common type of intracranial tumors. BM affects 20% to 40% of cancer patients, with treatment options including surgery and radiation. Stereotactic radiosurgery (SRS) is an effective treatment for BM, either alone or with previous surgical resection (Sx) or whole-brain radiation treatment (WBRT).
SRS delivers high-dose radiation precisely to a specific area, minimizing exposure to healthy tissue. Dr. Lars Leksell introduced conventional radiosurgery with the Gamma Knife in 1951, requiring a hard head frame for patient immobilization. This method, while accurate, caused discomfort and anxiety and needed a neurosurgeon for frame installation.
Modern frameless SRS systems use linear particle accelerator (LINAC) technology, eliminating the need for a surgical frame. These systems better conform to irregular lesions and protect critical areas. Patients are immobilized with a personalized thermoplastic mask, sometimes with an intra-oral component for added stability, created 30 to 45 minutes before the procedure.
After mask creation, a contrast-enhanced CT scan with 1 to 1.5 mm slice thickness is performed and combined with a gadolinium-enhanced MRI. A radiation oncologist contours the lesion and adds a 1 to 3 mm margin to define the planned target volume (PTV). A second oncologist reviews these contours and the organs at risk before dosimetry planning.
The Elekta Synergy-S® system verifies patient positioning with on-board cone-beam CT and adjusts it with a HexaPODTM table, allowing repositioning along all axes, including rotations. Treatment can be delivered in a single dose or fractionated doses, with the PTV receiving 12 to 24 Gy, typically around 15 Gy, depending on tumor size and location. Volumes receiving more than 10 Gy (V10) or 12 Gy (V12) are considered to minimize the risk of radionecrosis (RN).
Our institution's use of LINAC-based frameless SRS for BM treatment has shown overall and progression-free survival rates comparable to both frameless and traditional frame-based SRS, with reduced invasiveness and improved patient comfort. Our findings suggest that LINAC-based frameless SRS is a safe and effective treatment for BM, with low incidences of radiation necrosis.
Changing lives with Outstanding
Neuro & Spine care,
One patient at a time.
Dr. V Bramha Prasad
Dr. V Bramha Prasad, a distinguished Spine Surgeon with 21 years of experience, is renowned for his expertise in treating brain and spine diseases. He specializes in complex spine disorders and pain management, making him one of the finest neurosurgeons in Hyderabad.
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