The application and theoretical problem of rare earth in medicine has been the research project emphasized by the whole world for a long term.  The pharmacological effects of rare earth have been found by human beings early.  The rare earth used in medicine at the earliest is the cerium salts.  For example, the cerous oxalate can be used to treat the nausea and vomiting of pregnancy, which has been recorded in the Pharmacopoeia.  In addition, the simple inorganic cerium salts can be used as the antiseptic for the wounds.  Since the 1960s, a series of special pharmacodynamic effects of the rare earth compounds has been found consecutively.  It is the rare earth compound used as the excellent antagonist of Ca2+ for sedation and analgesia, which can be extensively applied to treat burn, inflammation, dermatitis and thromboembolism, etc., that arouses the attentions of the people.

1. The application of rare earth in medicine

1)  Anticoagulation effect

Rare earth compounds enjoy a special position in anticoagulation effects.  When used inside or outside of the human body, they can reduce the blood coagulation.  Especially in the intravenous injection, they can produce the anticoagulation effects immediately, which can be kept for about a week.  As the anticoagulants, an important advantage of the rare earth compounds is they can produce the effect as quickly as the direct acted anticoagulants (such as heparin ), and the effects produced by the rare earth compounds can be kept for a long term.  The rare earth compounds has been broadly researched and applied for anticoagulation, while due to toxicity and accumulation of rare earth ions, the application of rare earth compounds in clinic is limited.  Though the rare earth belongs to the low-toxic range and is much safer than many transitional element compounds, many problems still have to be considered, including the excretion from the body. In recent years, there have been new developments of the rare earth as the anticoagulant.  The human beings make out a new material with anticoagulation effects by combining rare ear together with the high polymer materials.  The tubes and blood circulation device outside of the body made of by such high polymer materials can prevent from the blood coagulation.

2)  Drug for treating burn trauma

The anti-inflammatory property of the rare-earth cerium salts is the main factor to improve the effects of treating burn trauma.  The cerium salts contained medicines can reduce the inflammation of wounds and accelerate the healing.  The rare earth ions can restrict the cell proliferation in blood and the excessive leakage of fluid from the blood vessels to drive the growth of the granulation tissue and the metabolism of the epithelial tissue.  The cerous nitrate can control the wound infected severely fast and transform it into negative to create conditions for further treatment.

3)  Effects of sterilization and anti-inflammation

There have been many research reports of the rare earth compounds as the medicine for sterilization and anti-inflammation.  The rare earth medicines can treat the dermatitis, allergic dermatitis, gingivitis, rhinitis, phlebitis other inflammation effectively.  At present, the rare-earth anti-inflammation medicines are used externally mostly, while some scholars are still exploring to use them internally to treat the collagen diseases (rheumatic arthritis and rheumatic fever, etc.) and allergic diseases (urticaria, eczema and lacquer poisoning, etc.), which has great significance for the patients with contradictions of the corticosteroid medicines.  Now, many countries are engaged in the research of the rear earth anti-inflammation medicines.  All the people expect for a breakthrough of such research.

In recent years, the anti-atherosclerosis property of the rare earth compounds is found, which has aroused many attentions of the human beings.  Coronary arteriosclerosis is the primary cause of the death for incident diseases in the industrialized countries in the world.  Our country also has the same tendency in recent years. Therefore, the cause, prevention and treatment of the atherosclerosis have become the important issue for current medical research.  The rare earth, lanthanum can prevent and improve the aorta atherosclerosis and the coronary arteriosclerosis.

5)  Radioactive nuclide and antineoplastic effects

The anti-cancer property of rare earth has aroused people’s concern.  In using the rare earth to diagnose and treat the cancer, the earliest used element is the radioactive isotope, which was applied to treat the tumors related to the pituitary in 1965.  As the research upon the mechanism of anti-tumor effects of the rare earth showed, except for eliminating the internal harmful free radicals, the rare elements can also make the calmodulin in the cancer cells level decline and the level of the cancer suppressor gene improve.  In addition, it reveals that the anti-cancer effects of the rare earth are realized by the reduction of the metastatic potential of the cancer cells and the rare earth elements has underestimated prospect in the prevention and treatment of tumors.

Beijing Research Institute of Labor Protection has made the investigation of the seventeen-year cancer epidemiology of the workers in the rare earth industry in Gansu with the retrospective cohort method.  The result shows that the standardized mortality rates of the community within the area of the rare earth plants, community in the living area and the community in the area of Gansu are 23.89/105, 48.03/105 and 132.26/105, respectively with the ratio of 0.287:0.515:1.00. The data of the community in the area of rare earth plants is obviously lower than that of the comparison groups and Gansu, which represents the rare earth can restrict the tendency of the incidence of cancer.

2. The application of rare earth in medical devices

In medical devices, the laser knife made of the laser materials contained rare earth can used for microsurgery; the optical fiber made of the lanthanum glass can used as the optical tube to observe the pathological changes of the human stomach clearly; the rare earth, ytterbium can be used as the brain scanning portion for bran scan and chamber radiography; the shooting efficiency of the new-type intensifying screen of X ray made of rare earth phosphor materials is five to eight times of that of the original calcium-tungstate intensifying screen.  In addition, this new intensifying screen can shorten the exposure periods, decline the radiation dosage to human body and improve the definition of the pictures. Using the rare-earth intensifying screen can exactly diagnose the pathological changes that are difficult to diagnose out.

The MRI made of the rare-earth permanent magnetic materials are the new medical facilities used in 1980s, which take advantages of the stable and homogeneous large magnetic field to impose an electromagnetic pulse to the human body to make the hydrogen atomic produce the resonance and absorb energies.  If the magnetic field is shut down suddenly, all the energies absorbed by the hydrogen atomic will be released.  Due to the different distribution of the hydrogen atomic in human body tissues, the time of energies releasing is different.  The image of the internal organs of human body can be restored and analyzed through the analysis and treatment of the different information received by the electronic computers to tell the normality or abnormality of the organs and identify the properties of the pathological changes.  Compared with the X-ray tomoscan, MRI is safe, painless, harmless and high-contrast.  The appearance of MRI is named as the first technology revolution in the history of medical diagnosis.

The most extensive application of the rare earth magnetic materials in medical treatment is the acupoint magneto-therapy.  Due to that The rare earth permanent magnetic materials with high magnetism and not easy to demagnetized can be made into the magneto-therapy devices in different shapes, using these materials to act on the meridian points or pathologic regions will get much better effects than the traditional magneto-therapy.  Nowadays, the magnetic necklace for medical treatment, magnetic needles, magnetic health-care earrings, magnetic bracelets of fitness, magnetic cups, magnetic application, magnetic wooden combs, magnetic kneepads, magnetic shoulder pads, magnetic belts, magnetic massagers and other magnetic products for medical treatment, are all have the function of sedation, analgesia, anti-inflammation, anti-pruritus, hypotension and anti-diarrhea.