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

As the cancer had not spread, the father of three did not need chemotherapy or radiotherapy and was back working within six months.

From BBC • Mar. 31, 2026

Trish is, similarly, calling for a clinic to deal with the after-effects of pelvic radiotherapy.

From BBC • Mar. 18, 2026

"Despite subsequent radiotherapy sessions, my oncology team have now told me there is nothing further they can do," she wrote.

From BBC • Mar. 12, 2026

Standard radiotherapy is unsafe as it can cause harm to vital organs such as the heart, but the proton beam directs high-dose radiation precisely at the affected area.

From BBC • Mar. 11, 2026