Navigation Links
CT scans: Too much of a good thing can be risky

OAK BROOK, Ill. Patients who undergo numerous CT scans over their lifetime may be at increased risk for cancer, according to a study published in the April issue of Radiology.

"We found that while most patients accrue small cumulative cancer risks, 7 percent of the patients in our study had enough recurrent CT imaging to raise their estimated cancer risk by 1 percent or more above baseline levels," said Aaron Sodickson, M.D., Ph.D., assistant director of Emergency Radiology at Brigham and Women's Hospital and researcher at the Center for Evidence-Based Imaging in Boston. "The techniques implemented in our study can be used to identify higher risk patients who might benefit from enhanced radiation protection efforts."

CT has proven to be a valuable clinical tool, and its use has grown rapidly. According to a 2008 IMV Medical Information Division report, approximately 68.7 million CT exams were performed in the U.S. in 2007, up from 62 million in 2006. CT provides detailed images of internal organs and is a common technique used to make medical diagnoses and help guide medical treatment decisions. However, CT uses a higher radiation dose than most other imaging exams.

For the study, the researchers developed new methodology to estimate cumulative CT radiation doses and associated radiation-induced cancer risks at the level of the individual patient, by extracting each patient's CT history from the electronic medical record and applying standard risk-estimation models that incorporate patient gender and age at exposure.

The study group was comprised of 31,462 adult patients who had diagnostic CT scans at Brigham and Women's Hospital or the Dana-Farber Cancer Center in 2007 and had undergone a total of 190,712 CT exams over the prior 22 years. Approximately 33 percent of the patients underwent five or more lifetime CT exams, 5 percent underwent more than 22 exams, and 1 percent underwent more than 38 exams. Fifteen percent received estimated cumulative effective radiation doses of more than 100 millisieverts (mSv), equivalent to the dose one would receive from 1,000 chest x-rays. Four percent received over 250 mSv, and 1 percent received over 399 mSv.

The researchers used the BEIR-VII (Biological Effects of Ionizing Radiation) risk model to estimate lifetime attributable risk (LAR) of cancer for each patient, based on their CT exposures. Approximately 7.3 percent of the study group had an estimated LAR of greater than 1 percent, meaning that due to cumulative CT radiation exposure, their risk of developing cancer increased by 1 percent above the baseline US cancer risk rate of 42 percent. Among the 315 patients in the top percentile of cumulative LAR, risk increased by 2.7 to 12 percent.

"CT is an excellent diagnostic tool of tremendous clinical value in many situations," Dr. Sodickson said. "Individual decisions about its use should balance the expected clinical benefits against the potential cumulative risks of recurrent imaging."

Dr. Sodickson points out that for patients who have not undergone a large number of CT scans, the benefits of appropriate CT exams typically outweigh the potential risks.

"However, we feel that a higher clinical threshold is warranted in patients undergoing a large amount of recurrent CT imaging," Dr. Sodickson said, "particularly if many of their prior CT scans have been negative. This scenario may result in a combination of high cumulative risk with low clinical benefit."

Dr. Sodickson hopes that these findings will raise awareness of cumulative radiation exposure concerns, so that physicians will be better able to incorporate patient-specific radiation risk estimates into the CT decision-making process.


Contact: Linda Brooks
Radiological Society of North America

Related medicine news :

1. CT Scans: Too Much of a Good Thing Can Be Risky
2. High-tech CT scans: not a bad choice to test for clogged arteries
3. Swallowing-Breathing Dysfunction Worsens Lung Disorder
4. ING Names Winners of ING Run For Something Better Student Essay Contest
5. Cardiac arrhythmias are often accompanied by sleep-disordered breathing
6. Nothing But Nets, Gavin DeGraw and Tom Cavanagh Help Save Lives in Uganda
7. AirWare, Inc., Maker of Brez(R) Premium Breathing Aids Offers Tips for Safely and Soundly Springing Ahead During the Switch to Daylight Savings Time
8. DRE AV-S Ventilator Now Has Multiple Spontaneous Breathing Modes
9. Americas Peanut Farmers to Travel to New York City to Meet Consumers, Work to Rebuild Trust in All Things Peanut
10. ING Run For Something Better Receives Healthy Youth for a Healthy Future Champion Award
11. Disability Community Humble Beginnings Lead to Great Things at Disabled World
Post Your Comments:
(Date:11/24/2015)... ... November 24, 2015 , ... American Family Care (AFC), the ... of a holiday pop-up clinic located in Metro Atlanta’s North Point Mall. The clinic ... and different way. The location is scheduled to operate through Dec. 24. , Holiday ...
(Date:11/24/2015)... Danbury, CT (PRWEB) , ... November 24, 2015 , ... ... Network (WCHN) today announced an innovative study designed to yield insights into how to ... potential development of biomarkers for pancreatic cancer from small, non-coding RNA molecules (ncRNA), genetic ...
(Date:11/24/2015)... ... November 24, 2015 , ... ... Cleveland University-Kansas City (CU-KC), in Overland Park, Kansas. Benson, a fifth-trimester ... University President Carl S. Cleveland III on October 16. , “Katie is very ...
(Date:11/24/2015)... ... November 24, 2015 , ... American Specialty ... Program have announced their endorsement of the Medical Fitness Network (MFN), a ... proud to have the MFN as one of our endorsed organizations,” said ASH ...
(Date:11/24/2015)... ... ... Dr. Kevin Day, local family chiropractor in Warsaw , is hosting a ... During the Indiana winter months, Vitamin D deficiency can lead to Seasonal Affective Disorder ... help provide the tools needed to combat it this year! , “Stress kills us,” ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... , November 25, 2015 - Will ... Medical Education (CME) --> - Will ... Continuing Medical Education (CME) --> ... Continuing Medical Education (CME) ... products and services, will feature latest diagnostic imaging textbooks and decision ...
(Date:11/25/2015)... DUBLIN , Nov. 25, 2015 Research ... of the "Membranes Market - Global Forecast to ... Asia-Pacific , accounting for 37.21% of the ... Asia-Pacific region is projected to ... This growth has been attributed primarily to the fast ...
(Date:11/25/2015)... 2015 --> ... Lizenz für das Patent über eine neue Hepatitis-B-Behandlung, welches ... innehaben, an Enyo Pharma vergeben haben. Im ... gerufenen und von Edelris gemeinsam mit seinen Partnern Inserm ... für HBV identifiziert, und es wurden neue Inhaltsstoffe entdeckt, ...
Breaking Medicine Technology: