Linac radiotherapy machine

A linac has a treatment head that produces high-energy radiation and a gantry that can rotate around the couch. Computer planning uses scans to select beam directions, shape the field and account for organs close to the target. Imaging may be used to check your position before radiation is delivered. The machine is operated by trained therapists who watch and communicate with you from outside the room.

Linac treatment can be used for several cancer sites, including skin, brain, breast, cervix, bowel, womb and head and neck cancers. The machine is adjusted to the treatment plan; it is not a single treatment with the same settings for everyone.

Your planning visit may include a scan, marks or a custom support such as a mask or mould. Arrive with enough time for positioning and tell the team about pain, claustrophobia, pregnancy or an implanted device. During delivery, keep the planned position and follow breathing instructions if they are part of your plan. Wear gentle clothing, follow any skin-care instructions and keep a note of new symptoms between visits.

Call your treatment centre about increasing pain, skin breakdown, fever, persistent vomiting, diarrhoea, difficulty swallowing or new weakness. Go to emergency care for severe breathing trouble, a seizure, sudden confusion, collapse or a rapidly worsening condition. A side effect may be manageable when reported early, and symptoms can also signal an unrelated illness that needs assessment.

What will the planning scan show? How will my position be reproduced? Which nearby organs are being protected? What changes should I expect at the treatment site? What number should I use if symptoms occur outside clinic hours?