Stereotactic radiation therapy (SRT) is also referred to as stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy (SABR). It is an advanced technique used to treat small, well-defined tumours or high-risk postoperative areas. It can be used to treat both primary and metastatic (sometimes referred to as secondary) tumours. These are tumours that have spread from other organs in the body to cancers in the brain, spine, bones, liver and lung.

The specialised technology allows a multiple, highly precise radiation beams to deliver a high dose of radiation to the tumour very accurately to a small target. This is made possible by the use of 3D treatment planning with advanced imaging technology (e.g. CT scans, PET, MRT) to localize the tumour accurately in four dimensions.

With the ability to treat with sub-millimetre accuracy, there is a steep dose gradient outside the tumour and the surrounding healthy tissue is not affected in a manner that is not achievable by conventional radiation therapy.

Due to the larger daily doses of radiation delivered to patients with stereotactic radiation therapy, treatments can be completed within a single treatment, or multiple treatments spanning over 2-10 days. Each daily treatment usually takes no longer than 20 minutes. This treatment can be done on an outpatient basis and normal activities can be resumed thereafter.