We’ve done several columns on the need to reduce potential harm from radiation involved in diagnostic imaging studies (see our November 23, 2010 Patient Safety Tip of the Week “Focus on Cumulative Radiation Exposure”, which also links to our other columns). Then, in February, Bob Wachter in his healthcare blog “Wachter’s World” discussed an amazing statistic revealed by his colleague Rebecca Smith-Bindman: a 20-year old woman who gets an abdominal/pelvic CT scan has a 1 in 250 chance of developing cancer related to that single scan!
But a number of initiatives have been ongoing to help reduce that potential exposure to radiation. Some are clinical interventions designed to avoid imaging studies that utilize ionizing radiation. Others are technical interventions to reduce radiation dose and still others are interventions to help better track radiation exposure.
A study on a large population under the age of 18 (Dorfman 2011) showed that 7.9% of children received at least one CT scan. But another study (Nigrovic 2011) found that clinically observing children with blunt head trauma in the emergency department has the potential to significantly reduce the number needing CT scans. In their study of over 40,000 children with blunt head trauma, they found that use of observation was associated with almost 50% reduction in the number of CT scans done. They do note that further research is needed to determine the optimal period of observation needed.
Another study (Vaiman 2011) looked at the common practice in ENT for performing CT angiography to localize the vertebral arteries prior to surgery on the neck (so that anomalous vertebral arteries are avoided during the surgery). They performed ultrasound on 500 such patients who also had CT angriography and found a high correlation between the two modalities. They suggest that substantial amounts of radiation might be avoided by using ultrasound rather than CT angiography in such cases.
Technical interventions may also help reduce the dose of radiation. One study (Alibek 2011) looked at the impact of dose reduction software on both image quality and radiation exposure in children undergoing CT scanning of chest, abdomen or pelvis. They found that image quality remained acceptable and radiation dose was diminished approximately 30% on average.
And there is also activity at the national level. The American College of Radiology (ACR) and the American College of Emergency Physicians (ACEP) jointly sponsored a workshop on use of CT scanning in emergency departments. That group (Linton 2011) developed several recommendations:
· Educate health care providers and others of the status and appropriate applications of CT scanning in emergency medicine and acute care.
· Promote processes and skills to reduce the need for CT imaging when possible, such as the use of traditional radiography, ultrasound and emergency point-of-care ultrasound.
· Communicate concerns on the overutilization of CT to hospitals, together with recommended collaborative protocols to reduce variability in CT scanning utilization in emergency medicine.
· Develop mechanisms for reliable recording for emergency medicine patients of the number and doses received in CT scans and other imaging procedures.
· Develop evidence-based guidelines that address the benefits of CT imaging in emergency medicine, including improvements in patient treatments and outcomes.
But the impact of “education” on understanding of radiation exposure related to CT scanning remains unclear. A study by Horowitz (Yee 2011) found that a short lecture to clinical housestaff on the issue had no significant impact on ordering patterns for CT scans. That highlights the need for more real-time interventions such as use of clinical decision support tools during computerized order entry.
The American College of Radiology (ACR) has also launched a dose index registry that allows imaging facilities to compare their dose indices to those at comparable facilities.
But still lacking is a good system in which you carry with you (not literally but probably in your electronic personal health record) a tally of your cumulative radiation dose over a lifetime. Some day that will happen and hopefully that will be taken into account when decisions about the need for imaging studies are made.
Wachter R. A Game-Changing Statistic: 1 in 250. Wachter’s World 2011; February 11, 2011
Dorfman AL, Fazel R, Einstein AJ, et al. Use of Medical Imaging Procedures With Ionizing Radiation in Children. Population-Based Study. Arch Pediatr Adolesc Med. 2011; 165(5): 458-464
Nigrovic LE, Schunk JE, Foerster A, et al. The Effect of Observation on Cranial Computed Tomography Utilization for Children After Blunt Head Trauma. Pediatrics 2011; peds.2010-3373; published ahead of print May 9, 2011
Vaiman M, Beckerman I, Eviatar E. Detection of anomalous vertebral arteries by ultrasound as an alternative to radiological methods. European Archives of Oto-Rhino-Laryngology 2011; Online First, 12 March 2011
Alibek S, Brand M, Suess C. Dose Reduction in Pediatric Computed Tomography with Automated Exposure Control. Academic Radiology 2011; 18(6): 690-693
American College of Radiology. Dose Index Registry.
Linton O, Tenforde TS, Amis ES, et al. Summary of Workshop on CT in Emergency Medicine: Ensuring Appropriate Use
Journal of the American College of Radiology 2011; 8(5): 325-329
Yee KM. Does radiation dose education affect CT ordering practices?
AuntMinnie.com May 3, 2011