What is stereotactic radiosurgery?
Stereotactic radiosurgery (SRS) delivers high doses of radiation with sub millimetre precision positioning. It is often used to treat small tumours with well-defined edges.
It is most commonly used to treat primary brain or spinal tumours – as well as secondary brain tumours.
For the treatment of some brain metastases, radiation therapy to the entire brain (called whole-brain radiation therapy), as well as SRS, may be recommended.
What is stereotactic body radiation therapy?
Stereotactic body radiation therapy (SBRT) delivers radiation therapy in fewer sessions, using smaller radiation fields and higher doses than 3D-CRT in most cases.
SBRT treats tumours that lie outside the brain and spinal cord.
Because these tumours are more likely to move with the normal motion of the body, they can’t be targeted as accurately as tumours within the brain or spine.
As a result, SBRT is usually given in more than one dose.
SBRT can be used to treat only small, isolated tumours, including cancers in the lung and liver.
What is proton therapy?
External beam radiation therapy can be delivered by proton beams as well as by photon beams.
Proton beams differ from photon beams mainly in the way they deposit their energy in living tissue.
- Photons deposit energy in small packets, all along their path, through tissue
- Protons deposit much of their energy at the end of their path, and deposit less energy along the way
In theory, the use of protons should reduce the exposure of normal tissue to radiation, possibly allowing the delivery of higher doses of radiation to a tumour.
Proton therapy hasn’t yet been compared with standard external beam radiation therapy in clinical trials.
You can discuss these different methods of radiation therapy with your medical team to see if it is available to treat your type of cancer – or, if it is available through a clinical trial.