SOURCE: www.raremetalblog.com

It was noted on RareMetalBlog – Week in Review August 9 –14th, that (paraphrased) ‘I had posted on a couple of fascinating uses of Rare Metals in the Medical field.  As many already know, I have always taken a fancy to learning where rare metals play a role in the health and medical sectors… be it in diagnostics, procedures or treatments’ True” That week, I shared two pieces—one on the role zirconium plays in hemodialysis (Zirconium to the Rescue -- Aug 9th) and the other, on the PillCam, a most widely used, patient-friendly tool for visualization of the entire small intestine (Rare Earths! Camera! Action! -- Aug 11th)"

These recent pieces seem to have struck a chord with a number of folks based on a flurry of off-line e-mails I received inviting me to share more on ‘REEs and medical applications’. My pleasure… but where to start! These weren’t the first pieces I’ve posted on general subject. There have been heart shunts, bone fracture repair hardware and new robotic surgery systems. I even shared some thoughts on a possible future contact lens technology that would integrate nano-devices and circuitry to measure body fluids and transmit messages if there were irregularities.

So in answer to my own question as to how to start… I don’t know, but how about a couple of tidbits to whet the appetite and to help me think through an approach to a series of upcoming posts.  Thanks.

First off... the rare earths play a key role wide range of health and medical applications, including drug treatments, diagnostic techniques and equipment. REE's act as catalysts in biomedical and chemical research, are used as tracing agents in imaging, and in laser and radio-isotopic treatment for cancer.

The largest single use of rare earths elements in the medical industry is probably the incorporation of REE permanent magnets to generate high strength magnetic fields for MRI imaging. REE permanent magnets are replacing expensive traditional systems of wire coils in liquid helium, where the helium super cooled the wire coil to reduce the electrical resistance.

There are also a significant number of laser-baser technologies that have been developed for cosmetic surgery (to removing tattoos, scars, stretch marks, sunspots, wrinkles, birthmarks and hairs) that utilize the unique characteristics of the REES such as neodymium or erbium or holium doped  YAG (Yttrium Aluminium Garnet -- Y₃Al₅O₁₂, a synthetic crystalline material commonly used as a host material in various solid-state lasers).  It is also understood that Nd:YAG lasers have been used in an experimental, robot-assisted radical prostate surgeries.

Laser technologies are also used for certain eye surgeries, as a scalpel device for general surgery, gynecological, urology, laparoscopic procedures, and in the  ‘No-Touch’ removal of tumours, especially of the brain and spinal cord.

In the hearing-aid field, the ‘cochlear implant’ is an electronic auditory prosthesis gaining widespread acceptance as a means of restoring partial hearing to the totally deaf. There are a number of engineering and biological challenges toward improving the existing implantable systems and development of multichannel systems. One hurdle seems to have been resolvable with the incorporation of small, permanent, rare-earth (SmCo₅) magnets with the coil assemblies thereby eliminated an unreliable mechanical supporting devices.

I know, the most generally known uses of yttrium is in making phosphors, such as the red ones used in television cathode ray tube displays and in LEDs. Other uses include the production of electrodes, electrolytes, electronic filters, superconductors; and as noted earlier lasers. But as mentioned earlier, the REEs are also playing a role in the treatment of certain cancers.

Natural yttrium is composed of only one non-radioactive isotope ⁸⁹Y. The are about a half dozen stable yttrium radioisotopes, including ⁸⁸Y whichwith a  half-life of 106 days and ⁹¹Y with a half-life of 58 days. The other isotopes have half-lives of less than a day except ⁸⁷Y which has a half-life of 80 hours, and ⁹⁰Y with 64 hours.

Well, the radioactive isotope yttrium-90 (⁹⁰Y) is used in drugs for the treatment of various cancers, including lymphoma, leukemia, ovarian, colorectal, pancreatic, and bone cancers. It is also understood that researchers has shown that low-risk patients with unresectable liver cancer (i.e. tumours that cannot be safely removed) appear to gain control over their malignancies for at least two years when treated with yttrium-90.

Yttrium-90 is also used in the treatment of inflamed joints, especially knees, in sufferers of such conditions as rheumatoid arthritis.

Rare earth materials have also found there way into dentistry …again, another subject for another day.

So my mission.. should I decide to accept (... I guess I have) is to focus my September diatribes on ‘Rare Earths and Medical Applications’, I am delighted to accept the mission, if it helps one lone reader get the help needed, and the RMB readership as a whole, gain a better appreciation of where science and rare earths can help.

Until soon… Ian