REEs are also used for their optical properties in many imaging techniques such as CAT scans, MRIs, PET imaging and X-rays. The biggest and most important component in an MRI system is actually the magnet that rare earths help produce. In an MRI, the main MRI magnet creates a static magnetic field, forming the basis for measurable macroscopic magnetization. MRI machines are the single largest application of REEs in the medical sphere using more than 1500 pounds of magnets.
Previously, MRI machines used coils of electric wire, cooled in helium, as magnets. But with new MRI systems powered by rare earth magnets, they are now lighter and strong enough to provide an alternative to the older, costly technologies. MRI machines that use rare earth magnets can also be made wider than the older machines which create a less claustrophobic experience for patients. Gadolinium enhances MRI images of tumors, and its magnetic properties are also of use in intravenous radio-contrast agents in MRI scans.
Another REE, neodymium, provides irreplaceable components of the magnets used to power the non-ionic radiation MRI technique, which uses magnetic wave generation. Another REE component of MRIs can be found in the energy efficient lamps and bulbs used in the MRI machines, called lanthanum phosphors. Patients receive 75 percent less radiation from X-rays and several other lasers because of lanthanum phosphors.
Thulium isotopes produced in nuclear reactors are used as power sources in portable X-ray devices allowing them to be used for medical and dental purposes in areas without electricity. Cerium-doped lutetium (doped means covered) orthosilicate is a scintillator that is used primarily for Positron Emission Tomography (PET imaging), a type of test that reveals tissue and organ function. In PET imaging or other medicinal radiography, X-rays are converted to blue or green light using rare earth based phosphors, to which photographic emulsions are more sensitive than other chemicals.
REEs are also used for laser and radioscopic cancer treatments. Examples include:
A radioisotope of samarium, samarium-153, is used to treat severe pain in patients whose cancers have advanced into bone tissues.
Lutetium is being researched for its potential uses in targeted radiotherapy, for the advancement of new cancer therapies.
Neodymium is used in lasers as crystals and is employed in the treatment of skin cancers, as well as laser hair removal.
Holmium based solid-state lasers are used for non-invasive medical procedures for treating cancers and kidney stones.
Erbium-based lasers are used in medical and dental practice also, as they provide the appropriate energy delivery without heat buildup in human tissue. The clear visibility and power neodymium light lasers provide make them the preferred instrument for non-invasive surgical procedures. Yttrium aluminum garnet medical lasers use erbium and are doped or covered by thulium. These lasers are used for skin resurfacing for acne scars removal, mole and wart removal and tattoo removal. Dysprosium, another rare earth element, is integral to the effective operation of electric motors in surgical robots.