President Barack Obama says the United States and several European countries have struck an agreement meant to sustain the supply of lifesaving isotopes without the use of highly enriched uranium.
Medical isotopes are used to treat cancer and heart disease worldwide. Scientists have been working on using low enriched uranium because highly enriched uranium can be used to create nuclear bombs.
Obama announced the agreement on Monday during a nuclear security summit in Seoul. The other countries are Belgium, France and the Netherlands.
World leaders are in Seoul to seek ways to improve nuclear security.