CT Scans Deliver More Radiation to Obese People:
FRIDAY, April 13 (HealthDay News) -- Obese and overweight
patients who undergo CT scans are exposed to much more radiation
than people of normal weight, researchers say.
The challenge for heavier people is that more radiation is
needed to scan their bodies, a radiation specialist said.
"One has to customize the dose based on patient size, increase the power of the X-rays and the quantity that are going inside," said Dr. Dushyant Sahani, director of CT imaging services at Massachusetts General Hospital and an associate professor of radiology at Harvard Medical School.
Nearly 60 percent of U.S. adults are overweight or obese,
according to the study. As obesity-related health challenges
surface, so do orders for medical scans, the authors said. Because
radiation can cause cancer and other ill effects, researchers have
been concerned about the risks of exposure derived from medical
However, Sahani, who was not involved in the study, said the
excess body fat of extra-large patients absorbs much of the
radiation, meaning that they may face no extra danger.
"Fat is not as sensitive to undergoing any bad changes as the other tissues," said Sahani.
Even if an obese patient gets twice the radiation as a smaller
person of the same age, the risk of radiation damage would be
higher for the smaller person, he said.
The study authors, all from the Rensselaer Polytechnic Institute
in Troy, N.Y., launched their research to better understand how
radiation in CT scans affect the bodies of heavier people.
Statistics about their radiation haven't been previously available,
the study authors said. "We want to fill this gap," said study lead
author Aiping Ding, a research associate at the institute.
CT scans are used to create images that divide the body's organs
into sections, or slices. Sahani said, "They produce a detailed
anatomic picture, as if someone's body has been actually
In the new study, the researchers created 10 computerized male
and female "phantoms" that represented people of various body
types, ranging from normal to morbidly obese. (Previous research
using phantoms had mostly looked at average-sized people).
The researchers then calculated how much radiation would enter
the bodies during CT scans. In some cases, the dose that reached
organs was as much as 57 percent higher in the obese patients.
"We want to tell people that obese patients receive high doses and that we can use our phantom to quantify the specific dose for the patient," Ding said. "Our study can be a good reference for radiologists."
What should patients do with this information? Ding suggests
that they ask their radiologist about the risk they face when they
undergo a CT scan. Patients are at especially high risk at
hospitals that take multiple CT scans of individual patients in a
day, Ding said.
The study appeared recently in the journal
Physics in Medicine & Biology.
For more about
obesity, visit the U.S. National Library of Medicine.
Copyright © 2012
. All rights reserved.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.