What is Stereotactic Surgery?
Stereotactic surgery is a clinical procedure which makes use of a three-dimensional coordinate system to precisely locate small targets inside the body.
The combination usage of a stereotactic apparatus and radiation beams has two modalities:
- Stereotactic Radiosurgery (SRS)
- Stereotactic Radiotherapy (SRT)
Stereotactic Radiosurgery (SRS)
SRS is a “non-invasive” technique that delivers high doses of radiation for small intracranial targets. It avoids normal tissues and critical structures. There are two types of machines can be used for stereotactic radiosurgery in the brain and other parts of the body:
Gamma knife is a non-invasive neurosurgical procedure which uses powerful doses of radiation to target and treat affected brain tissue while leaving surrounding tissue intact. The ‘knife’ refers to 192 or 201 small beams of gamma rays to target and treat cancerous and noncancerous brain abnormalities. Gamma Knife machines are used primarily for small to medium tumors and lesions in the brain associated with a variety of conditions.
- Linear accelerator (LINAC)
Linear accelerator (LINAC) is a machine that uses X-rays to treat abnormalities in the brain and other parts of the body. LINAC machines are also known by the brand name of the manufacturer, such as CyberKnife and TrueBeam. LINAC is also capable of rotating around a patient lying on a treatment couch, treating the tumor from different angles.
Stereotactic Radiotherapy (SRT)
SRT employs the same stereotactic techniques used for SRS and refers to delivering collimated beams of radiation in multiple fractions, to a stereotactically located target. Usually it will be between 1 to 8 treatments. Stereotactic treatments for the body are also known as stereotactic body radiotherapy (SBRT) or stereotactic ablative radiotherapy (SABR).
Stereotactic Body Radiation Therapy (SBRT)
SBRT employs the same stereotactic techniques used for SRS and refers to delivering collimated beams of radiation in multiple fractions, to a stereotactically located target. Usually, it will be between 1 to 5 treatments.
This type of radiotherapy is mainly used to treat very small cancers, including:
- cancer in the lung
- cancer that started in the liver or cancer that has spread to the liver
- cancers in the lymph nodes
- spinal cord tumours
- cancer spread in the brain