Cardiac CT scan means high radiation exposure

Florida, February 5: Having a cardiacdefine CTdefine scan? Here is something you should know. A recent research shows that people who get the common heart test or CT scans are exposed to radiationdefine equivalent to that from 600 conventional chest X-rays at once.

The cardiacdefine computed tomographydefine or CTdefine scan costs about $800 and provide doctors clear 3D images of the coronary arteries without doing an invasive angiography. However, the latest study says that CT scans exposes people to potentially harmful radiationdefine and exactly how much has been unclear.

The exposure to radiation perks up the chance of developing cancerdefine and the risk differs from person to person, according to Andrew Einstein, a cardiologist from Columbia University in New York City and author of an editorial in the journal.

According to the lead author of the study, Dr. Thomas Gerber, a cardiologist at the Mayo Clinic branch in Jacksonville, Florida, it is better to avoid the scans if one does not have any pre-existing symptoms of heart disease, such as chest pain, shortness of breath or exercise intolerance.

For the study, the researchers zeroed in on 1,965 patients who received CT scans in 50 teaching and community hospitals worldwide, from February to December 2007, to assess the radiation exposures of the subjects.

Gerber and his colleagues found that there was a wide variation among median radiation dose from a heart CT scan (calculated by a measurement of absorbed radiation), at different hospitals, ranging from 5 to thirty millisieverts (mSv); the average effective radiation dose was 12 mSv, equivalent to 600 chest x-rays average exposure from cardiac CT scans.

Dr. Gerber, said, "We found that the scanner output varied approximately six-fold between the different imaging sites."

In the past two years, the numbers of CT scans has tripled in the American cardiologydefine practice and are expected to go up. However, concerns about increases in cancer risk from increased radiation exposure remain.

In many cases, doctors recommend CT scan to asymptomatic people to detect heart disease at an early stage, without any evidence supporting the practice.

The findings appear in tomorrow’s issue of the Journal of the American Medical Association.

A past study found that standard method such as catheterization --where doctor inserts a thin plastic tube into the patient’s arterydefine -- was more reliable for finding a heart disease as compared to the CT scans.