The goal of this interventional study is to see if the daily use of red light therapy called photobiomodulation can help sore skin and sore mouths in children having radiotherapy.

All children aged 0-16 years old who are receiving either proton or photon radiotherapy treatment, except to the brain only, will be asked if they would like to join the study.

The main questions it aims to answer are:

1. Does the use of red light therapy help the skin side effects in children and young people undergoing proton or photon therapy?
2. Does the use of red light therapy help the mouth side effects in children and young people undergoing proton or photon therapy in the head and neck area?

Researchers will compare the patients enrolled on to the study with a like for like historic patient to see if red light therapy improves the sore skin and sore mouths caused by proton or photon therapy.

Participants will have a daily treatment with red light therapy alongside their daily proton or photon treatment fraction.

Inclusion Criteria:

• Paediatric patient receiving a treatment course of either proton or photon therapy - Craniospinal treatment field, Head and Neck treatment fields and body treatment fields.

Exclusion Criteria:

• Paediatric patients receiving focal brain only proton or photon radiotherapy.
• Paediatric patients receiving a single fraction of proton or photon therapy.
• Total Body Irradiation patients.