Linac for radiotherapy

A linear accelerator, often called a linac, produces radiation without placing a radioactive source inside your body. The treatment head can rotate around you while the couch holds you in the planned position. The team uses scans and measurements to design beams that cover the target while limiting exposure to nearby organs. Different settings can shape the beam and vary its intensity. The machine does not touch you, and the treatment room is monitored from outside during delivery.

A linac may be used for cancers in areas such as the breast, brain, cervix, bowel, skin, womb or head and neck. The same equipment can deliver different radiotherapy techniques, depending on the target, its movement and the surrounding tissues.

Before the first session, you may have a planning scan and a positioning appointment. Follow instructions about bladder or bowel preparation when given, and wear comfortable clothing that allows access to the treatment area. Keep the treatment area clean and tell the team about implanted devices, pregnancy or medicines that affect the skin. During each visit, lie still and follow breathing instructions if requested. The beam is not felt, but the appointment includes careful positioning and safety checks.

Tell your radiotherapy team about increasing skin soreness, difficulty swallowing, persistent diarrhoea, repeated vomiting, new weakness or breathlessness. Seek urgent help for severe breathing difficulty, sudden confusion, a seizure, collapse or rapidly worsening symptoms. Side effects depend on the treated body area and may develop during treatment or after it, so record changes and ask where to call outside appointment hours.

What area will be treated, and which organs are nearby? Which technique will the linac deliver? How should I prepare for the planning scan and each session? What skin, bowel, bladder or swallowing changes are expected? Who should I contact overnight or at weekends?