Journal Club: Diagnostic CT Scans: Assessment of Patient, Physician, and Radiologist Awareness of Radiation Dose and Possible Risks

A news article titled "Patients, physicians unaware of CT radiation exposure" in Radiology 2004;231:393-398 and posted at Aunt Minnie talks about just how much patients and physicians don't know about radiation exposures from CT.

The article raises a some interesting points about the need to educate health professionals about radiation. About the only radiology education most physicians receive is a 3 or 4 month rotation through radiology where they learn what it is they're looking at when looking at an x-ray. Even some radiologists don't know as much about radiation as you might think. The trouble is, squeezing more education into the curriculum is difficult at best.

Yes, radiation exposures from CT are significantly higher than regular radiographic exposures. Yes, there might be an increase in the risk of getting cancer. It's a small risk but one that is dwarfed by risks from other activities such as smoking or environmental exposure to chemical carcinogens. Radiation can be bad for you, but saves lives when used properly.

Ultimately, when it comes to any diagnostic imaging involving radiation, it comes down to a risk versus benefit thing. This is one of the things I try to emphasize to residents when I'm teaching them. Does the benefit of diagnosing an immediate problem in the patient outweigh the small increased long term cancer risk? Will the exam provide significantly more information useful for treatment than another exam that uses less or now radiation?

For the past 7 years I've been involved in teaching radiology residents all about the physics of medical imaging. I teach them (try to anyway) about radiation, how it interacts with matter, the different imaging modalities and how they work and generate images, radiation safety and biology. It's part of the board exams they need to pass. But I don't teach them because they have to pass the board exam. I teach them because down the road, they will be the "radiation experts" in whatever community they end up working in. They're the ones that people expect to know about the risks and benefits of getting radiation. They're the ones that people will go to for answers.

And my education efforts go beyond the classroom as well. Dose/exposure charts for all the equipment I survey are generated and distributed for posting so that people can see (if they care to look) what kinds of exposures the machine produces. I probably need to advertise this a little more though.

It's one of the activities I enjoy about my job.

Abstract:

PURPOSE: To determine the awareness level concerning radiation dose and possible risks associated with computed tomographic (CT) scans among patients, emergency department (ED) physicians, and radiologists.

MATERIALS AND METHODS: Adult patients seen in the ED of a U.S. academic medical center during a 2-week period with mild to moderate abdominopelvic or flank pain and who underwent CT were surveyed after acquisition of the CT scan. Patients were asked whether or not they were informed about the risks, benefits, and radiation dose of the CT scan and if they believed that the scan increased their lifetime cancer risk. Patients were also asked to estimate the radiation dose for the CT scan compared with that for one chest radiograph. ED physicians who requested CT scans and radiologists who reviewed the CT scans were surveyed with similar questions and an additional question regarding the number of years in practice. The 2 test of independence was used to compare the three respondent groups regarding perceived increased cancer risk from one abdominopelvic CT scan.

RESULTS: Seven percent (five of 76) of patients reported that they were told about risks and benefits of their CT scan, while 22% (10 of 45) of ED physicians reported that they had provided such information. Forty-seven percent (18 of 38) of radiologists believed that there was increased cancer risk, whereas only 9% (four of 45) of ED physicians and 3% (two of 76) of patients believed that there was increased risk (22 = 41.45, P < .001). All patients and most ED physicians and radiologists were unable to accurately estimate the dose for one CT scan compared with that for one chest radiograph.

CONCLUSION: Patients are not given information about the risks, benefits, and radiation dose for a CT scan. Patients, ED physicians, and radiologists alike are unable to provide accurate estimates of CT doses regardless of their experience level.

© RSNA, 2004