Erin Simon Schwartz

Radiation risks have received a large amount of attention in the lay press, some of it actually warranted, while other concerns have been quite overblown. The most recent, available review of data provides support for the linear nonthreshold model of carcinogenic effects of radiation; however, the “risks from a few tens of mGy are uncertain and are predicted to be very small.”¹ The noncarcinogenic effects, most commonly cardiovascular, are less well substantiated. All practicing radiologists should be familiar with the ALARA (as low as reasonably achievable) practice, and to date there have been over 100,000 pledges to Image Gently and Image Wisely, which are pediatric and adult initiatives to reduce radiation exposure, respectively. Step Lightly, the program to reduce radiation dose during fluoroscopic and angiographic procedures, may be less familiar to some. I urge every reader to familiarize themself with the materials available from these programs, as well as to incorporate the strategies outlined in the following papers.

In the first paper featured in this edition of the AJNR News Digest, Sadigh and colleagues utilized the CT Dose Index Registry of the American College of Radiology to determine the variation in head CT doses for pediatric patients throughout the United States. Their analyses revealed “considerable” variation; however, the volume CT dose indices were consistently lower at children’s hospitals and Level I trauma centers than in academic centers, nontrauma centers, and community hospitals. The authors encourage dedicated pediatric teams to create pediatric CT protocols that optimize the balance between minimizing radiation dose and preserving diagnostic image quality, in line with the recommendations from the Image Gently Alliance.

Similarly, in the pediatric neck, the goal is always to reduce radiation dose while maintaining high image quality. Tipnis and colleagues assessed image quality in a population of children undergoing clinical neck CT prior to, and following, the implementation of a “low-dose” protocol. While the image quality in the low-dose studies was slightly lower in adolescents, nearly all studies were considered to have sufficient image quality for diagnosis. Further dose reductions with newer iterative reconstruction algorithms are anticipated.

However, dose reduction is not only for pediatric applications. The exponential growth of image-guided procedures makes radiation reduction particularly relevant for neuroradiologists and their patients. Shpilberg and colleagues demonstrated that those who perform low-dose, CT-guided spine biopsies in patients with suspected malignancy can expect adverse effects on diagnostic tissue yield, the number of scans obtained, or procedure duration. One would expect similar results when a biopsy is performed for nonneoplastic indications.

Diagnostic neuroangiographic and neurointerventional examinations can also be successfully modified to reduce radiation exposure to both the patient and the physician. van der Marel and colleagues described their experience with a commercially available angiographic imaging platform that applies flexible dose reduction strategies to digital fluoroscopy and digital subtraction angiography. They successfully applied these strategies across a broad representation of neurovascular procedures in a large series of patients.

Whether your practice is exclusively pediatric, adult, or you care for patients of all ages, we all have a responsibility to use every technologic advantage to make all of our ionizing radiation doses as low as reasonably achievable.

References

1. Shore RE, Beck HL, Boice JD, et al. Implications of recent epidemiologic studies for the linear nonthreshold model and radiation protection. J Radiol Prot 2018;38:1217-33, 10.1088/1361-6498/aad348

Image from: van der Marel K, Vedantham S, van der Bom IM, et al. Reduced patient radiation exposure during neurodiagnostic and interventional X-ray angiography with a new imaging platform. AJNR AM J Neuroradiol 2017; 38:442-49, 10.3174/ajnr.A5049.