CT utilization has grown approximately 10 percent annually over the last 15 years in the U.S., raising fears of an increase in radiation-induced cancers. However, discussions of radiation-induced cancer risk often fail to take into account the condition of the patients being imaged, according to Susanna Lee, M.D., Ph.D., chief of women's imaging at Massachusetts General Hospital and assistant professor of radiology at Harvard Medical School in Boston.
"The impetus for our study was the concern that the lay press often focuses on potential harm caused to patients by CT imaging," Dr. Lee said. "Lacking in this discussion is a sense of how sick these patients already are."
To better understand the risks and benefits of CT in young adults, the research team lead by Dr. Lee and researcher Robert L. Zondervan, M.S., analyzed imaging records of patients 18 to 35 years old who underwent chest or abdominopelvic CT exams between 2003 and 2007 at one of three university-affiliated hospitals in Boston. Children and young adults are more susceptible to ionizing radiation and more likely to live for the approximately 10 to 20 years considered necessary to develop a radiation-induced malignancy.
The researchers had access to records from 22,000 patients, including 16,851 chest and 24,112 abdominopelvic CT scans. During the average 5.5-year follow-up period, 7.1 percent of young adults who underwent chest CT and 3.9 percent of those who had abdominopelvic CT died: figures that were much greater than the 0.1 percent long-term risk of death from radiation-induced cancer predicted by statistical models in both groups.
"It was a bit surprising to see how high the five-year mortality rate was in this group," Dr. Lee said. "To put it in context, the average young adult has only a 1 percent chance of dying in the next five years."
The most common reasons for exam were trauma and cancer for chest CT and abdominal pain and trauma and cancer for abdominopelvic CT. While many of the patients who underwent CT were cancer patients with a bleak prognosis, Dr. Lee pointed out that the major differences in risk were evident in the other groups who had CT, such as those suffering from trauma, abdominal pain and difficulty breathing.
"When we subtracted out cancer patients from the data set, the risk of death in the study group ranged from 2.5 to 5 percent—still well above the risk in the general population," she said.
Dr. Lee and colleagues also found that the patients who were scanned only one or two times represented the overwhelming proportion of exams.
"This finding shows that radiation reduction efforts should also focus on patients who are very rarely scanned, and not just those who are scanned repeatedly," Dr. Lee said.
Dr. Lee noted that the study group was imaged between 2003 and 2007, before radiation dose awareness and reduction programs like Image Wisely and Image Gently took effect. She said that the risk of radiation-induced cancer from CT likely would be lower today, making the difference in mortality even more pronounced.
"We're not saying be complacent about the radiation risk from CT," Dr. Lee added. "But these people being imaged might have been in a motor vehicle accident, or have a perforated appendix or life-threatening cancer, and we're trying to gain information from scans that can help them. That's the part that gets lost in the debate."
"Body CT Scanning in Young Adults: Examination Indications, Patient Outcomes, and Risk of Radiation-induced Cancer." Collaborating with Dr. Lee and Robert L. Zondervan were Peter F. Hahn, M.D., Ph.D., Cheryl A. Sadow, M.D., and Bob Liu, Ph.D.
Radiology is edited by Herbert Y. Kressel, M.D., Harvard Medical School, Boston, Mass., and owned and published by the Radiological Society of North America, Inc. (http://radiology.rsna.org/)
RSNA is an association of more than 51,000 radiologists, radiation oncologists, medical physicists and related scientists promoting excellence in patient care and health care delivery through education, research and technologic innovation.
The Society is based in Oak Brook, Ill. (RSNA.org)
For patient-friendly information on CT, visit RadiologyInfo.org.
Linda Brooks | EurekAlert!
Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine
Flexible sensors can detect movement in GI tract
11.10.2017 | Massachusetts Institute of Technology
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
It's possible to produce hydrogen to power fuel cells by extracting the gas from seawater, but the electricity required to do it makes the process costly. UCF...
Mercury, our smallest planetary neighbor, has very little to call an atmosphere, but it does have a strange weather pattern: morning micro-meteor showers.
Recent modeling along with previously published results from NASA's MESSENGER spacecraft -- short for Mercury Surface, Space Environment, Geochemistry and...
10.10.2017 | Event News
10.10.2017 | Event News
28.09.2017 | Event News
16.10.2017 | Physics and Astronomy
16.10.2017 | Earth Sciences
16.10.2017 | Physics and Astronomy