Study Finds Radiation Risk for Patients

The imaging craze has some doctors worried about exposing patients to too much radiation for dubious benefits. This story is from the New York Times

Study Finds Radiation Risk for Patients
Published: August 26, 2009

At least four million Americans under age 65 are exposed to high doses of radiation each year from medical imaging tests, according to a new study in The New England Journal of Medicine.

About 400,000 of those patients receive very high doses, more than the maximum annual exposure allowed for nuclear power plant employees or anyone else who works with radioactive material.

It did not estimate the number of cancer cases that the radiation might cause over the next several decades. But Dr. Rita Redberg, a cardiologist and researcher at the University of California, San Francisco, who has extensively studied the use of medical imaging, said it would probably result in tens of thousands of additional cancers.

Each individual patient is at relatively minor additional risk from the tests, Dr. Redberg said, but because they are given to so many people, the cumulative risk is significant.

“It’s certain that there are increased rates of cancer at low levels of radiation, and as you increase the levels of radiation, you increase cancer,” said Dr. Redberg, who was not connected with the new study.

The radioactive tests are given for hundreds of purposes. In the last two decades, they have become especially common in cardiology, where physicians use them to check for the buildup of plaque in the arteries and the heart’s ability to pump blood.

Some cardiologists now encourage their patients to have routine heart scans even if they do not have clinical symptoms of heart disease, like chest pain or shortness of breath. The study did not examine what percentage of the tests were medically necessary.

The use of the tests has risen sharply in the last two decades, as more and more physicians have bought CT and PET scanners and installed them in or near their offices. In 2007, the Department of Health and Human Services estimated that the number of CT scans given to Medicare patients had almost quadrupled from 1995 to 2005, while the number of PET scans had risen even faster.

The paper found that in at least one of the three years, 1.9 percent of the UnitedHealthcare patients received at least 20 millisieverts of radiation, or nearly seven times the average. Of that group, about 10 percent, or 0.2 percent of all patients, received at least 50 millisieverts, more than the annual maximum that nuclear regulators allow.

Those figures suggest that about four million Americans receive cumulative doses exceeding 20 millisieverts a year.

Federal rules allow physicians to profit from the use of machines they own or lease. But Dr. Harlan M. Krumholz, a cardiologist at Yale and an author of the paper, said financial incentives were only part of the reason the number of tests had risen so fast.

“I think the central driver is more about culture than anything else,” Dr. Krumholz said. “People use imaging instead of examining the patient; they use imaging instead of talking to the patient.

“Patients should be asking the question: ‘Do I really need this test? Is the information in this test going to help in the decision-making process?’ ”

In many cases, there is little evidence that the routine use of scans helps physicians make better decisions, especially in cases where the treatments that follow are also of questionable efficacy.

Yes, patients should be asking questions, but the average patient trusts the doctor to know which tests are necessary. People hear advertisements for full body scans, as though these are a wonderful invention. The history of medical attitudes toward subjecting patients to radiation is a scandal, and it appears those attitudes have become even more cavalier. At least the radiation dose required for mammography has decreased markedly with better technology, but mammography is still overused, particularly in USA. That some patients are subjected to more radiation from imaging tests than is allowed for nuclear power plant workers is gross malpractice. The only possible excuse for that would be radiation treatment for cancer, but it seems that is not the culprit.

As bad as it is for doctors to use unnecessary dangerous tests to make money, what Dr. Krumholz said is even more damning, that these tests are being used instead of examining or talking to the patient. If that is not malpractice, what is? What is the rationale behind pumping a patient full of radioactive poison to detect heart disease? There has to be a better way, even if it might cost more time and money. Doctors should remember they have a duty to do no harm! This study is more evidence of why the profit motive is inimical to health care.

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