Doctors and Rad. Doses

["Estabrooks, Bates (IHK)" <estabrookshb@Y12.doe.gov>]

Oak Ridge biologist says radiation dosages confusing 

October 13, 2003 



A recent paper in the British Medical Journal suggested that physicians in

the United Kingdom weren't very knowledgeable about the radiation dose

patients got from X-ray exams and other radiological investigations. 

About 130 doctors at two separate hospitals completed a questionnaire on

radiation diagnostics, and the results were dismal. 

	

		

		

		

"None of them knew the approximate dose of radiation received by a patient

during a chest X-ray or even the measurement in units of radiation,'' the

BMJ authors noted. 

When asked about different medical investigations, six doctors did not

realize that ultrasound does not use ionizing radiation, and 11 did not

realize that magnetic resonance imaging doesn't use ionizing radiation. 

On doses associated with various radiological exams - such as abdominal

X-ray and barium swallow - 97 percent of the answers underestimated the

amount of radiation. 

In the comment section, the authors noted: 

"In a convenience sample of doctors, few had any knowledge about the level

of radiation that their patients were exposed to during radiological

investigations. Most patients entering the hospital will have at least one

X-ray investigation and usually many more subsequent X-rays. It is well

known to both the lay public and to medical professionals that although

radiological investigations are valuable, they represent a small but

definite potential risk to health through exposure to ionizing radiation.'' 

The BMJ paper stated 100 to 250 cancer deaths in the United Kingdom each

year are directly related to medical exposure to radiation. 

The knowledge of physicians at two hospitals may not reflect the medical

profession throughout the United Kingdom, "but it does seem that most

doctors have no idea as to the amount of radiation received by patients

undergoing commonly requested investigation,'' the report stated. 

"This lack of awareness of the degree of exposure to ionizing radiation

becomes particularly pertinent when we consider the number of patients who

receive inappropriate or repeat examinations.'' 

After reading these results, I was curious about the knowledge of American

doctors. So I called Robert Ricks, director of the Radiation Emergency

Assistance Center/Training Site in Oak Ridge. 

Ricks is a radiation biologist, not a physician, but he knows plenty. He has

interacted with thousands of medical professionals while conducting courses

for dealing with radiation emergencies. 

"It's been my observation that physicians in general don't have all the

knowledge about ionizing radiation, including the basis, that one might

expect,'' Ricks said. 

"And the reason is that a lot of physicians don't work in an area where

radiation is routinely used. They rely on someone else to perform these

tasks and know those answers.'' 

Ricks said he believes questions about radiation dosage are sometimes

confusing because they compare various diagnostic exams and use chest X-rays

as a standard. He said he prefers to compare the amount of radiation in

medical tests with the level it takes to produce a mild case of radiation

syndrome, such as blistering of the skin. 

The REACTS director, apparently unlike the authors of the British study, is

not a strong believer in the linear theory. That theory suggests that even

minute amounts of radiation pose some risk and that the risk goes up

incrementally with the dose. 

"I think there is a threshold for just about everything,'' Ricks said. 

He favors the theory of hormesis that suggests very low doses of radiation

or chemicals or whatever else may actually "tweak'' the body's immune system

and prove beneficial, not detrimental. 

"We don't really know what the risk is at low dose,'' Ricks said. 

That controversy may be the topic of another column, another time. 

Senior writer Frank Munger may be reached at 865-342-6329 or

munger@Knews.com <mailto:munger@Knews.com> .



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