NCI Dictionary of Cancer Terms

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The NCI Dictionary of Cancer Terms features 7,812 terms related to cancer and medicine.

Browse the dictionary by selecting a letter of the alphabet or by entering a cancer-related word or phrase in the search box.

proton
(PROH-ton)
A small, positively charged particle of matter found in the atoms of all elements. Streams of protons generated by special equipment can be used for radiation treatment.