Radiation Therapy / Radiotherapy
Traditional radiation therapy involves the delivery of fairly low doses of treatment spread across 10, 15 or even 30 treatment ‘fractions,’ also called sessions.
While the prescribed radiation dose given during each session is quite low, the total ‘volume’ of cells receiving that dose must be large enough to include all cancerous cells. With this method, healthy brain cells may be included in the overall treatment ‘volume.’
The goal of treatment is to blanket the targeted ‘volume’ of cells—both healthy and cancerous—with radiation during every session, but only so much so that the healthy brain cells can recover from the dose.
Patients who undergo radiation therapy are usually treated Monday through Friday over a period of several weeks, depending upon the diagnosis and doctor’s treatment plan. A certified radiation therapist administers the treatment and monitors patient progress. Most sessions take 15 to 45 minutes, although the actual ‘beam-on’ time is only a few minutes.
Stereotactic Radiosurgery
Stereotactic radiosurgery (SRS) is an advanced and targeted radiation delivery technique, generally considered ‘standard of care’ in the management of many types of brain cancer, especially small, benign tumors or tumors that have spread to the brain from another area of the body, called metastatic tumors. The treatment is typically delivered in a single, high dose of radiation directly to the tumor with very high precision.
High doses of radiation are deadly for both cancerous and healthy tissue cells. During stereotactic radiosurgery, special equipment and software are used to deliver the highest treatment dose of radiation directly to the tumor, while also limiting any dose to the surrounding healthy tissue.
The ability to limit dose to healthy tissue is accomplished by delivering the radiation treatment beam from many different angles around the patient’s head. While the radiation dose along the pathway of each beam remains rather low, a high concentration of dose is reached in the center where these beams meet. The patient is positioned is such a way that the focal point of the radiation hits the tumor, destroying those cells.
SRS is considered ‘surgical’ because of the dramatic effect it can have on tumor tissue. In contrast to traditional radiation therapy, accuracy of less than one millimeter is needed to deliver the exact ‘surgical’ dose of radiation only to the tumor and not to sensitive tissue and critical brain structures that surround it.
To explore stereotactic radiosurgery in-depth, click here
