National Geographic : 1954 Jan
Man's New Servant, the Friendly Atom friction and deposited in the lubricating oil could be detected easily with a Geiger counter. The oil that showed up with the least amount of radioactivity obviously was most efficient in preventing friction. From such tests have come improved motor oils now on the market. The tests also showed, incidentally, that high-speed driving on the highway causes only about a third as much wear on piston rings as city driving. Cobalt metal, after being bombarded in a pile, gives off powerful radiations like X rays. These cobalt units are far easier and cheaper to make and use than X-ray machines. Their rays can be used to treat cancer (but so far not to cure it), to locate hidden flaws in castings and welds, and to learn how animals are affected by radiation-a clue to its effect on humans in case of accidental exposure or atomic-bomb attack. "Tagged" Atoms Boon to Medicine "For doctors and medical researchers, radio isotopes provide an almost magical tool for learning more about how the human body works and how its functions are altered by disease," Dr. Charles Dunham, of the Atomic Energy Commission's Biology and Medicine Division, told me. "Vitamins, minerals, sugars, medicines, and even secretions of the adrenal glands can be tagged with radioisotopes and traced in the body to learn where they go, how they are utilized by the system, and the changes they undergo. It is almost as though the body were made transparent. "Injecting radiosodium into the body has revealed, for example, that salt travels so fast to the tissue fluids that some of it emerges again in perspiration in only 75 seconds. It goes more slowly to fluids of the eye and spinal cord, slower still to bones and teeth. "To test how efficiently a patient's heart is pumping blood, radioactive material may be injected into the blood stream and its course traced with Geiger counters. Radioiron has been used to tag red blood cells to learn where they go in the body. "Bedridden persons sometimes have poor circulation in legs and feet, with a risk of blood clots forming. If radiosodium is in jected into the blood stream, the clicks of a Geiger counter will show how fast blood is reaching the right foot as compared with the left. If an artery is blocked, a Geiger counter may help locate the site of obstruction by revealing where blood flow is shut off." Doctors hoped at first that radioisotopes would be useful in curing cancer, but so far only a few of these hopes have been realized. One difficulty is that radioactivity can damage normal tissue. If a radioisotope stays in a healthy vital organ too long, it can create serious trouble and even cause cancer. Radio isotopes have arrested some cancerous growths, however, and have alleviated pain. One method of treating brain tumors, though it so far has saved no lives, is a spec tacular demonstration of what atomic energy can do. When boron is injected into the blood stream of a person with a certain type of brain tumor, it concentrates in the growth. A few people having tumors that could not be re moved by surgery have been given injections of a non-radioactive isotope of boron. The patient is placed directly on top of the atomic pile at the Brookhaven National Laboratory, Long Island. Through an open ing in the pile, a beam of neutrons is released. It enters the skull and the brain, directed as precisely as possible toward the area in which the tumor is located. In the tumor the boron captures neutrons and becomes radioactive, giving off alpha rays which attack the growth from within. Lives of patients so treated have been pro longed up to several months, and their pain often relieved. Autopsies show that in every case some of the tumor has been destroyed. Doctors hope that ultimately tumors can be completely arrested by this treatment. Tracers Help Locate Tumors Radioactive phosphorus and arsenic also tend to concentrate in certain types of brain tumors more than in healthy brain tissue. Injected before an operation, they go to the tumor and send out rays which reveal to the surgeon the location and size of the growth. Even during the operation, tiny probes in serted in the brain tissue and connected to counters help locate bits of tumor the surgeon is unable to distinguish clearly, since all the diseased tissue "soaks up" the radioactive material. When iodine enters the human body, it concentrates within 24 to 48 hours in the thyroid gland. This gland, in the neck, governs the body's metabolism. An over active thyroid can so overstimulate a person that nerves are put on edge, weight is lost, and the heart is unduly burdened. Radioac tive iodine likewise concentrates in the gland and often helps to slow thyroid activity.