Monday, November 16, 2009

Acute heart attack patients receiving high ionizing radiation dose

http://www.practicevelocity.com/urgent_care/uploaded_images/chest_xray.jpgAcute heart attack patients received an average total dose of ionizing radiation equal to 725 chest X-rays from medical tests during their hospital stay, according to research presented at the American Heart Association’s Scientific Sessions 2009.

In the first large study to examine total radiation dosage in heart attack patients, researchers found those admitted to academic hospitals had a cumulative effective radiation dose of 14.5 millisieverts (mSv) — about one-third the annual maximum accumulation permitted for workers in nuclear power plants and other ionizing radiation environments.

“It’s potentially a new way to consider radiation exposure and safety,” said Prashant Kaul, M.D., lead author of the study and a fellow in cardiovascular medicine at Duke University Medical Center in Durham, N.C. “We think physicians should not only have a greater awareness of dose accumulation from the tests they are ordering, but also understand the testing patterns they use for common diagnoses.”

Total short term exposure likely counts, he said. A person’s lifetime exposure to ionizing radiation can potentially increase the risk of cancer. However, risk estimates vary for developing malignancies at specific exposure levels.

Physicians perform several billion imaging studies annually worldwide, about one-third of them in cardiovascular patients. The collective dose received annually from ionizing radiation medical tests increased an estimated 700 percent between 1980 and 2006, according to the American Heart Association.

Kaul urged increased efforts to better determine the appropriate use of various radiation-based tests when assessing and treating heart attack patients.

“We should not withhold necessary, appropriate tests that involve ionizing radiation — they provide very important information,” Kaul said. “What we should do is evaluate and understand the clinical indications for tests that involve ionizing radiation. We need to be sure they are being done appropriately.”

via Acute heart attack patients receiving high ionizing radiation dose.

I had two chest x-rays when I went to the ER with chest pains because they screwed up the first x-ray.  I was angry about that. They wanted to do a "Cardiolight" test.  I asked if it was a nuclear test. They said yes. I said that I'm a scientist and having worked in labs with radiation, I try to limit my expose to it. The test involved injecting radiation into my blood. It is true that the isotope they use has a very short half life, but all radiation does some random damage to your DNA. Most things are repaired, or ignored or destroyed by your body's defenses, but you might get unlucky and cause cancer.

I declined in favor of a less invasive stress echo test based on my overnight readings. The cardiologist said both test had about equal diagnostic value.  (Although I had an abnormality that resulted in my being kept overnight for observation, the pain turned out to be an internal injury which reopened a hiatal hernia, in other words, stomach acid. This happened when I was moving some heavy furniture).

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