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External radiotherapy

Planning external radiotherapy

Your radiotherapy treatment plan is individual to you. 

You have a planning scan that will be used to create your radiotherapy plan. The planning scan is usually a CT or MRI scan. The radiotherapy team then works out the dose of radiotherapy you need and exactly where you need it.

You might have to wait a few days or up to 3 weeks before you start treatment.

Planning your external radiotherapy

Your radiotherapy team carefully work out how much radiation you need to treat the cancer and exactly where you need it.

Radiotherapy tattoos

Skin markings, such as tattoos, help make sure you have external radiotherapy in exactly the right place every time you have treatment. Your radiographer can mark your skin in different ways.

Radiotherapy masks and moulds

You might have moulds or masks made for you before you start radiotherapy. Find out about the different types and how they're made.

Creating your radiotherapy plan

The radiotherapy team will create a treatment plan for you. This involves using scans to work out exactly where to treat and how many radiation beams you need.

Last reviewed: 27 Oct 2023

Next review due: 27 Oct 2026

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