SBRT - What is Stereotactic Body Radiotherapy

SBRT

Stereotactic body radiotherapy (SBRT) is a highly precise form of radiation therapy to targets in the body where delivery is accurate to within one to two millimeters. SBRT is a non-surgical treatment that delivers precisely-targeted radiation at much higher doses, in only a single or few treatments, as compared to traditional radiation therapy. This treatment is only possible due to the development of highly advanced radiation technologies that permit maximum dose delivery within the target while minimizing dose to the surrounding healthy tissue. The goal is to deliver doses that will destroy the tumor and achieve permanent local control. SBRT rely on several technologies: (1) three-dimensional imaging and localization techniques that determine the exact coordinates of the target within the body (CT, MRI, PET scan); (2) systems to immobilize and carefully position the patient and maintain the patient position during therapy; (3) highly focused gamma-ray or x-ray beams that converge on a tumor or abnormality; (4) image-guided radiation therapy (IGRT) which uses medical imaging to confirm the location of a tumor immediately before, and in some cases, during the delivery of radiation. IGRT improves the precision and accuracy of the treatment.


Exact Coordinates With SBRT Treatment

Three-dimensional imaging, such as CT, MRI, and PET/CT is used to locate the tumor or abnormality within the body and define its exact size and shape. These images also guide the treatment planning—in which beams of radiation are designed to converge on the target area from different angles and planes—as well as the careful positioning of the patient for therapy sessions.

Stereotactic Body Radiotherapy

SBRT can be delivered as one, three or up to five daily treatments. The higher number of treatments is important for tumors larger than one inch in diameter as the surrounding normal tissue exposed to the single high dose of radiation must be respected and limited, and the volume of normal tissue treated increases proportionally to the tumor size. Delivering the radiation in a few sessions as opposed to one, can improve safety and allow the normal tissue to heal in between treatments. SBRT is important alternative to invasive surgery, especially for patients who are unable to undergo surgery and for tumors and abnormalities that are hard to reach, located close to vital organs/anatomic regions, subject to movement within the body. SBRT is currently used in treating malignant or benign small-to-medium size tumors in the body and common disease sites, including the lung, liver, abdomen, spine, prostate, head and neck.

(REFERENCE. RadiologyInfo.org from ACR and RSNA)