radiotherapy

noun

ra·​dio·​ther·​a·​py ˌrā-dē-ō-ˈther-ə-pē How to pronounce radiotherapy (audio)
: the treatment of disease with radiation (such as X-rays)
radiotherapist
ˌrā-dē-ō-ˈther-ə-pist How to pronounce radiotherapy (audio)
noun

Examples of radiotherapy in a Sentence

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Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Schilling said that, by December, the cancer had spread to her brain and, despite radiotherapy sessions, could not be cured. — Amarachi Orie, CNN Money, 24 Mar. 2026 The breakthrough means that doctors no longer have to rely on chemotherapy or radiotherapy, which can be especially harmful for young children, to treat that specific type of cancer. — Solcyré Burga, Time, 26 Dec. 2025 The ionization chambers used in standard radiotherapy can’t respond accurately when dose rates spike hundreds of times higher in a matter of microseconds. — IEEE Spectrum, 6 Mar. 2026 Prostate biopsies carry high risk of infection, and surgeries to remove tumors can lead to erectile dysfunction, while radiotherapy and other aggressive treatments have life-altering side effects. — Annalisa Merelli, STAT, 14 May 2026 See All Example Sentences for radiotherapy

Word History

Etymology

International Scientific Vocabulary

First Known Use

1902, in the meaning defined above

Time Traveler
The first known use of radiotherapy was in 1902

Rhymes for radiotherapy

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Browse Nearby Words

radio telescope
radiotherapy
radiothermics
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Cite this Entry

“Radiotherapy.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radiotherapy. Accessed 8 Jul. 2026.

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Medical Definition

radiotherapy

noun
ra·​dio·​ther·​a·​py ˌrād-ē-ō-ˈther-ə-pē How to pronounce radiotherapy (audio)
plural radiotherapies
: the treatment of disease by means of radiation (as X-rays)

called also radiation therapy, radium therapy

compare radiodiagnosis

More from Merriam-Webster on radiotherapy

Britannica.com: Encyclopedia article about radiotherapy

Last Updated: - Updated example sentences
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