Since our April 2013 What’s New in the Patient Safety World column “Radiation Risk of CT Scans: Debate Continues” and our June 4, 2013 Patient Safety Tip of the Week “Reducing Unnecessary CT Scans” another key study highlighting the risks of cancer related to CT scanning in the pediatric population has been reported (Miglioretti 2013). This was rapidly followed by a statement from the American College of Radiology that cautioned parents not to overreact to that study (ACR 2013). And while the headlines would make you suspect that the two “camps” were diametrically opposed on the issue, they really are aligned when you read the details.
The Miglioretti study, published online in JAMA Pediatrics, looked at CT scans done in children younger than 15 years old between 1996 and 2010. They looked at frequency and type of CT exams done, radiation doses, and then projected the number of cases of potential lifetime cancer using a model based upon the Life Span Study (on Japanese A-bomb survivors). They found that overall use of CT scans increased 2-3 times in this population over this time span, though the rates plateaued in 2006-2007 and then decreased slightly since then. They estimated that that the over 4 million CT scans done on patients in this age group annually would result in 4870 future cancers.
Risks of future cancer were projected to be higher in girls and children younger than 5 years and higher for those undergoing CT scans of the abdomen/pelvis or spine.
The authors estimate that reducing the dose of radiation in the highest 25% of cases down to the median dose could prevent 43% of projected cancers (this would be under the control of the radiologist), compared to a 33% reduction of projected cancers if fewer CT scans were ordered (this would be mostly under control of the ordering physicians).
The same day the Miglioretti study was published the American College of Radiology released a statement on the raditation risks from pediatric CT scans (ACR 2013). The message was that parents should not forgo necessary imaging scans for their children. It pointed out that the risk of children developing cancer after a CT scan was actually very low and, while it encouraged parents to ask all the right questions, noted that CT scans in many cases are the diagnostic test of choice and parents should not preclude their child from getting that most appropriate test. It discourages parents from saying no to a CT scan that might be life-saving for their child. And while you might look at the ACR statement as a blatant attempt to preserve their “turf”, the gist of their statements are very similar to that of the Miglioretti paper.
The ACR statement encourages parents to ask how the scan would improve their child’s care, whether there are alternatives that might be equally effective without radiation exposure, whether “child-sized” radiation doses will be used, and whether the facility is accredited. It recommends using ACR Appropriateness Criteria in deciding whether a CT scan is appropriate or not. It points out that modern CT scanners use up to 90% lower doses than those done just 10 years ago. It points out that the ACR has participated in the Imaging Gently and Imaging Wisely campaigns and the Choosing Wisely project that have probably helped reduce the number of pediatric CT scans since 2007.
The editorial accompanying the Miglioretti study (Schroeder 2013) has a small table with examples of how and when alternative studies not utilizing ionizing radiation might be used instead of CT scans. One example is use of ultrasound as a first test for suspected appendicitis. Another is use of clinical prediction “rules” to help decide when observation for mild head trauma may be sufficient. We’ve discussed use of such rules in several of our previous columns. They also note that there may be downsides to CT scans other than the radiation dose. These include financial costs, possible need for sedation in some cases, overdiagnosis and need for additional testing for false positive results. They also attribute much of the recent decrease in CT scanning in children to the Imaging Gently and Choosing Wisely campaigns. Both this editorial and the ACR statement encourage parents to track the number of radiology studies and radiation dosages for their children.
We’ve noted previously that sometimes both the circumstances and the urgency of the situation may dictate what study gets done. For example, some rural hospitals may lack nighttime ultrasound coverage or might not have an MRI scanner. In such cases, one must weigh the risks associated with transfer of the patient to another facility having these resources against the small lifetime risk of a CT scan. There might also be circumstances where sedation might be required in a young child and a CT scan might be considerably faster than an MRI, reducing the duration of sedation and its attendant risks.
Our June 4, 2013 Patient Safety Tip of the Week “Reducing Unnecessary CT Scans” had a good discussion of ways to reduce overall utilization of CT scans.
The message of both the Miglioretti study and the ACR statement is clear: eliminate those CT scans that are not necessary and use the lowest possible radiation dose for those CT scans that are necessary. Neither paper suggests not doing CT scans when the clinical information likely to be gained is important and other alternatives are not as good.
Some of our previous columns on the issue of radiation risk:
· February 2, 2010 “The Hazards of Radiation”
· November 23, 2010 “ ”
· March 2010 “More on Radiation Safety”
· June 2011 “Progress in Reducing Radiation from CT Scans”
· April 2013 “Radiation Risk of CT Scans: Debate Continues”
· June 4, 2013 “Reducing Unnecessary CT Scans”
Miglioretti D, Johnson E, Williams A, et al. The Use of Computed Tomography in Pediatrics and the Associated Radiation Exposure and Estimated Cancer Risk. JAMA Pediatr. 2013; (): 1-8. Published online June 10, 2013
Schroeder AR, Redberg RF. The Harm in Looking. (Editorial) JAMA Pediatr. 2013; ():1-3. Published online June 10, 2013
ACR (American College of Radiology). Press release. ACR Statement on JAMA Pediatrics Study on Radiation Risk from Pediatric CT Scans. Parents Should Not Forgo Necessary Imaging Scans for Their Children. June 10, 2013
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