<?xml version="1.0" encoding="utf-8"?><metadata xmlns:dc="http://purl.org/dc/elements/1.1/"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:dcterms="http://purl.org/dc/terms/"><dc:title xml:lang="en">radioisotopes</dc:title><dc:identifier>http://AATesaurus.cultura.gencat.cat/aat/getty_en?tema=31343601</dc:identifier><dc:language>en</dc:language><dc:publisher xml:lang="en">Getty Institute</dc:publisher><dcterms:created>2026-03-30 20:32:40</dcterms:created><dcterms:isPartOf xsi:type="dcterms:URI">http://AATesaurus.cultura.gencat.cat/aat/getty_en</dcterms:isPartOf><dcterms:isPartOf xml:lang="en">Tesaurus d&apos;Art i Arquitectura</dcterms:isPartOf><dc:format>text/html</dc:format> <dcterms:alternative xml:lang="en">radioactive isotopes</dcterms:alternative> <dc:description xml:lang="en"><![CDATA[ All chemical elements possess one or more types of unstable as well as stable isotopes. The former are known as radioisotopes or radioactive isotopes. Their nuclei dissipate excess energy as alpha, beta, and gamma rays. This radioactive decay forms the basis for the measuring processes of radioactive dating.   ]]></dc:description></metadata>