Radiation Oncology

Proton therapy is a form of external beam radiation therapy that uses protons rather than X-rays. The physical properties of protons allow the radiation dose to be shaped so that less radiation may continue beyond the target, potentially reducing exposure to selected nearby tissues. It may be considered when this dose distribution offers a meaningful clinical advantage, but it is not necessary or superior for every patient or every cancer.

Zap-X is a dedicated platform used to deliver stereotactic radiosurgery to selected targets in the brain, head, and upper neck. It directs multiple precisely focused radiation beams at the target while limiting the dose to surrounding tissue. Despite its name, radiosurgery does not involve an incision; suitability depends on the diagnosis, size, number, and location of the lesions and any previous treatment.

CyberKnife is a robotic radiation-delivery system used for stereotactic radiosurgery and stereotactic body radiation therapy. It delivers radiation from multiple angles and uses image guidance to track the target and adjust for positioning or certain types of movement during treatment. It may be used for selected tumours in the brain or body, but the technology is chosen only when clinically appropriate.

External beam radiation therapy delivers high-energy radiation from a machine outside the body. The machine directs radiation at a planned treatment area and does not touch the patient. Treatment is usually divided into sessions called fractions, although the number and schedule vary according to the diagnosis and treatment goal. Patients do not become radioactive after standard external beam treatment.

Three-dimensional conformal radiation therapy, or 3D-CRT, uses imaging and computerised planning to shape radiation beams to the three-dimensional outline of the target. Beams are delivered from different directions to treat the planned area while reducing unnecessary exposure to nearby tissues. It may be appropriate when the target and surrounding anatomy can be treated safely without more complex modulation.

Intensity-modulated radiation therapy, or IMRT, is an advanced form of external beam treatment that varies the intensity of radiation across multiple beams. This allows the dose to conform closely to complex target shapes and helps limit exposure to selected nearby organs. IMRT requires detailed planning and quality assurance before treatment begins.

Volumetric modulated arc therapy, or VMAT, is a form of intensity-modulated radiation therapy delivered while the treatment machine rotates around the patient. The beam shape, intensity, and delivery rate can change during rotation, allowing a planned dose to be delivered efficiently to complex targets while limiting exposure to surrounding structures.

Image-guided radiation therapy, or IGRT, uses imaging before or during treatment to confirm the position of the patient and target. The team can make positioning corrections before delivering radiation, helping account for daily anatomical variation or movement. IGRT is commonly combined with techniques such as IMRT, VMAT, SBRT, and stereotactic radiosurgery rather than being a separate type of radiation dose.

Stereotactic body radiation therapy, or SBRT, delivers highly focused radiation to selected targets outside the brain, usually in a small number of treatment sessions. It requires precise immobilisation, imaging, treatment planning, and motion management when the target moves with breathing. SBRT is suitable only for selected patients based on the size, number, and location of lesions and their proximity to sensitive organs.

Stereotactic radiosurgery, or SRS, delivers a highly focused dose of radiation to selected targets in the brain or other intracranial structures, usually in one or a few sessions. It does not involve an incision and may be delivered using different treatment platforms. Suitability depends on the diagnosis, size, number, and location of the targets and their relationship to critical structures.

Brachytherapy is a form of internal radiation therapy in which a sealed radioactive source is placed inside or close to the treatment area. This allows a high radiation dose to be delivered over a short distance while limiting exposure to more distant tissues. Depending on the procedure, the source may be temporary or permanent, and specific radiation-safety instructions may be required.

Total body irradiation, or TBI, delivers radiation to the whole body and may be used as part of the conditioning regimen before selected stem cell or bone marrow transplants. Its purpose may include treating remaining abnormal cells and suppressing the immune system to help donor cells establish themselves. TBI requires careful planning and close coordination between radiation oncology and the hemato-oncology and transplant teams.