radiotherapy

American  

[rey-dee-oh-ther-uh-pee] / ˌreɪ di oʊˈθɛr ə pi /

noun

Medicine/Medical.

1. treatment of disease by means of x-rays or of radioactive substances.

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radiotherapy British  

/ ˌreɪdɪəʊˈθɛrəpɪ, ˌreɪdɪəʊˌθɛrəˈpjuːtɪk /

noun

1. the treatment of disease, esp cancer, by means of alpha or beta particles emitted from an implanted or ingested radioisotope, or by means of a beam of high-energy radiation Compare chemotherapy

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Other Word Forms

• radiotherapeutic adjective
• radiotherapeutically adverb
• radiotherapist noun

Etymology

Origin of radiotherapy

First recorded in 1900–05; radio- + therapy

Example Sentences

These patients often undergo radiotherapy near the mouth, which can damage salivary glands and reduce saliva production.

From Science Daily • Apr. 5, 2026

Dr Catherine Hanna, a consultant clinical oncologist at the Belfast Health Trust, said anal cancer is treatable - with radiotherapy - if diagnosed early.

From BBC • Mar. 18, 2026

"It could help explain why tumors of different origins, even when carrying the same mutations, often respond very differently to chemotherapy, radiotherapy, or targeted inhibitors," says Dr. Sdelci.

From Science Daily • Mar. 9, 2026

Although the trial was successful, the cancer returned shortly before a second transplant date in December, meaning she required additional full-body radiotherapy.

From BBC • Feb. 24, 2026

Her first round of chemo and radiotherapy is over, although she is still living with the disease.

From Barron's • Feb. 15, 2026