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:6/25/2016)... ... 25, 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX users can ... CEO of Pixel Film Studios. , ProHand Cartoon’s package transforms over 1,300 hand-drawn ... X . Simply select a ProHand generator and drag it above media or text ...
(Date:6/25/2016)... Canada (PRWEB) , ... June 25, 2016 , ... Conventional ... pursuit of success. In terms of the latter, setting the bar too high can ... risk more than just slow progress toward their goal. , Research from ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... ... Conference and Scientific Sessions in Dallas that it will receive two significant new ... the grants came as PHA marked its 25th anniversary by recognizing patients, medical ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... People across ... in Genome magazine’s Code Talker Award, an essay contest in which patients and their ... award to be presented at the 2016 National Society of Genetic Counselors (NSGC) Annual ...
(Date:6/24/2016)... ... ... National recruitment firm Slone Partners is pleased to announce the ... as Vice President of North American Capital Sales at HTG Molecular . ... team in the commercialization of the HTG EdgeSeq system and associated reagents in North ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... 23, 2016 , , , ... 7, 2016 , , , , LOCATION: , , , ... , , , EXPERT PANELISTS:  , , , Frost & Sullivan,s ... Christi Bird; Senior Industry Analyst, Divyaa Ravishankar and Unmesh Lal, Program ... global pharmaceutical industry is witnessing an exceptional era. Several new demand ...
(Date:6/23/2016)...  Guerbet announced today that it has been named ... . One of 12 suppliers to receive ... support of Premier members through exceptional local customer service ... to lower costs. ... outstanding customer service from Premier," says Massimo Carrara ...
(Date:6/23/2016)... -- The Biotechnology industry might still be ... opportunities to investors. assesses the recent performances of ... XON ), Vertex Pharmaceuticals Inc. (NASDAQ: ... ), and Regeneron Pharmaceuticals Inc. (NASDAQ: REGN ... complimentary trade alerts at: ...
Breaking Medicine Technology: