Editor’s Note: This post is Part 5 of a series that examines the wide range of industrial, medical, and electronic applications of the six platinum group metals (PGMs), which are platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru) and osmium (Os).
The most famous Platinum Group Metals (PGMs), platinum and palladium, are best known as jewelry and as primary components in automotive catalytic converters, but they’re also biocompatible materials that have several less-known but very important, even life-saving, medical applications. Here’s a summary; for more details, please visit the the International Platinum Group Metals Association web site.
Platinum and palladium have been active chemotherapy agents since the 1970s and an estimated half or more of all cancer patients who receive chemotherapy are treated with drugs containing platinum. Cisplatin, carboplatin and oxaliplatin are all platinum compounds that have been particularly successful in the treatment of testicular and ovarian cancers.
Platinum and palladium also play active roles in cancer radiation therapy. Palladium-103, a radioactive isotope of palladium, shows promise for the treatment of breast and prostate cancer. The outpatient procedure involves permanently implanting small time-release seeds of palladium-103 directly into the tumor to deliver the highest possible dose directly to the source while sparing the surrounding tissue.
Medical devices and implants
Platinum is inert, rarely causes allergic reactions, has good electrical conductivity, and can be fabricated into tiny components, all qualities that make it an ideal material for pacemakers, stents, implantable defibrillators, and catheters. Most pacemakers contain at least two platinum-iridium electrodes. Platinum marker bands and guide wires are commonly used to place stents, and now even the stents themselves may be made with platinum alloys. Platinum marker bands are also placed on catheters and guide wires to help surgeons with device placement. Platinum-iridium electrodes are used in neuromodulators such as aural and retinal implants as well as devices used to treat Parkinson’s disease and chronic pain.
Palladium, and occasionally platinum, ruthenium or iridium are used to enhance the strength and durability of dental inlays, crowns and bridges. The PGMs are usually mixed with gold, silver, copper or zinc to produce alloys for dentistry.
Many electronic and automotive devices containing PGMs are recycled to recover and reuse the metal, but some of the medical devices mentioned above, such as defibrillators, are recyclable as well. Whether from primary or secondary sources, PGMs must be meticulously refined to separate the PGMs from base metals and contaminants, analyzed for purity, and fabricated to produce medical-grade material. Lab-based PGM analysis includes careful sample preparation and multi-step assaying to detect all minor and trace elements and to ensure the PGM is of pure enough quality for medical applications. Testing technologies to determine precious metal concentrations may include:
ICP-OES: Inductively Coupled Plasma – Optical Emission Spectrometry (ICP-OES) , also known as ICP-AES, is an analytical technique used to detect minor and trace elements in a variety of sample types.
ICP-MS ICP-MS is a technique for the analysis and quantification of trace elements in both solid and liquid samples.
X-ray fluorescence (XRF): XRF a non-destructive analytical technique used to determine the qualitative and quantitative elemental composition of materials.
Learn more about each of these elemental analysis techniques.