GliaSite RTS Procedure / Dosimetry & Treatment Planning

During tumor resection surgery, the neurosurgeon positions the balloon portion of the GliaSite catheter within the cavity created by removal of a malignant brain tumor. The injection port at the other end of the catheter is fixed on top of the skull and concealed underneath the skin. Once the patient recovers from surgery, a combination of Iotrex^® Radiotherapy Solution (the ¹²⁵I radiation source) and saline is injected into the catheter and fills the balloon allowing for size and placement verification of the balloon with an MRI scan. The Iotrex Radiotherapy Solution dwells for 3 to 7 days, delivering the prescribed dose of radiation. At the end of this period, the Iotrex Radiotherapy Solution and saline are withdrawn and the balloon catheter is then removed during a brief surgical procedure.

How the therapy works
The GliaSite Radiation Therapy System (RTS) has been designed to deliver internal radiation into the tissue surrounding the cavity created by surgical removal of a malignant brain tumor. The use of the balloon catheter and Iotrex Radiotherapy Solution minimizes the complications and extensive treatment planning associated with other forms of internal radiation therapy. However, the benefits remain:

• Highest dose of radiation is delivered directly to the tissue most likely to contain residual cancer cells
• Radiation decreases in intensity as it travels outward, minimizing exposure to healthy brain tissue
• Therapy delivered directly into cancerous tissue minimizes the potential for debilitating side effects typically associated with external beam radiation
• GliaSite RTS treatment is usually completed within a week, compared to the 6 weeks often needed for external beam radiation therapy