Medical x-rays and other routine radiation treatments may have helped cause over half the cases of coronary heart disease and cancer in the US, according to a new study by a prominent, albeit erratic, radiation expert. If the study’s findings hold up, they could prove to be of enormous consequence: cancer and coronary heart disease accounted for about half of US deaths in the last decade.
American doctors deliver some 200 million medical radiation procedures annually, not including dental x-rays, for everything from treating acne to monitoring pregnancies. The new study, by Dr. John Gofman, professor emeritus of molecular and cell biology at the University of California at Berkeley and chairman of the Committee for Nuclear Responsibility, is the first to establish a correlation between such radiation treatments and heart disease. Perhaps most disturbingly, as Gofman points out, there are currently almost no regulations on the use of low level radiation treatments.
High doses of radiation have long been known to cause cancerous mutations. Gofman, however, claims to have proved that low level radiation is also far more dangerous than commonly believed.
His study draws upon earlier research by the University of Washington School of Medicine, which showed that the buildup of plaque that can block the arteries taking blood from the heart may be caused in part by a single source. Gofman believes that single source to be the kind of radiation that is used in routine medical procedures. The radiation, Gofman claims, causes mutations in heart muscle cells. These mutated cells proliferate, much like a cancerous tumor, and plaque builds up around them in the artery, he contends.
Gofman is a prominent but controversial figure in the field of radiation research. He was a key figure in the Manhattan Project, which spawned America’s first atomic bomb. Many of his findings, such as his early connection between cholesterol and heart disease, have largely been incorporated into mainstream medical practice. “Dr. Gofman is a highly respected scientist in this field,” says Dr. Henry McGill of the Southwest Foundation for Biomedical Research in San Antonio. “He’s been something of a maverick, but he’s turned out to be right.”
But some of his other findings, like his 1996 study claiming that mammograms help cause 75 per cent of breast cancers, have always been challenged. Gofman’s latest study is likewise being met with skepticism. “His estimates are widely at variance with most people who are knowledgeable about radiation,” says Dr. Michael Thun, head of epidemiological research for the National Cancer Institute in Atlanta. Most experts estimate the risk of developing cancer from medical radiation to be less than four percent.
“The chances of getting cancer from medical radiation is extraordinarily low,” says Dr. Rodney Withers, a radiation oncologist at the University of California at Los Angeles’ Jonsson Cancer Center. However, he adds, “you could hit the bullseye with the very first dart.”
While many experts dispute Gofman’s statistics, there is widespread support for the second part of his study, which calls for more regulations on the use of low-dose medical radiation. Currently, there are no nationwide guidelines on radiation dosages, and virtually no licensing requirements for radiation equipment operators.
The federal Food and Drug Administration has no regulatory power over doses used in x-rays or any other radiation procedure. They only regulate the actual machinery. Radiation policy is left to each state. Variations in state laws make it difficult to estimate how many medical radiation procedures administered each year are unwarranted, says Charles Hardin, executive director of the Conference of Radiation Control Program Directors. “Some states have done very well [in minimizing exposures],” says Hardin. “Others have not done quite as good a job.”
Moreover, according to Dr. Fred Mettler Jr., Chairman of Radiology at University of New Mexico, aside from California, no state requires physicians to be certified to use radiation equipment. “If you have a medical degree, you can get a machine,” says Mettler.
As a result, Gofman maintains, thousands of patients are exposed to unnecessarily high doses of radiation, boosting their risk of cancer and heart disease.
Gofman’s study outlines ways in which medical procedures could reduce exposures by ninety per cent. To better assess the risks involved with low-dose radiation, Gofman also suggests using a dosimeter on each patient. “If we don’t start a national program [of minimum dose and keeping dose records], we condemn a certain number of people to cancer and heart disease,” he says.
While his linkage between radiation and heart disease remains contested, even Gofman’s critics concede he has a point.
“I agree 100% with Gofman that we’ve got to reduce radiation exposure,” says UCLA’s Withers.
