Pearls From Your Peers: How I Read It

Grace Kim, MD, Matthew Maksimoski, MD, Karthik Balakrishnan, MD, MPH, Douglas R. Sidell, MD, Mai Thy T. Truong, MD, Ryan H. Belcher, MD, MPH, and Torrey L. Fourrier, MD, on behalf of the Pediatric Otolaryngology Education Committee

A recent New England Journal of Medicine study by Smith-Bindman and colleagues examined more than 3.7 million children (born between 1996-2016) from six health systems in the United States and Ontario, Canada.¹ The authors found a dose-response relationship between cumulative radiation exposure from medical imaging and hematologic cancer risk. Children exposed to 15-30 mGy showed a 1.8-fold increased risk of hematologic malignancy.¹ Practically, this is equivalent to the exposure from one or two head CT scans. This risk climbed to 3.6-fold for exposures of 50-100 mGy. The study estimated that 10.1% of hematologic cancers in their cohort were attributable to medical imaging.¹ Head CT contributed to approximately 25% of these radiation-associated cancers.¹

Matthew Maksimoski, MD, provided an important perspective on absolute versus relative risk in his reflections on this article. While the relative risk increase is substantial, the absolute incidence remains low—approximately 8.3 cases per million person-years attributable to radiation exposure. He draws a thoughtful parallel: Just as therapeutic interventions carry risks (such as post-tonsillectomy hemorrhage), so do diagnostic tests. The key is maintaining diagnostic acumen—recognizing that peritonsillar abscesses, otitis externa, and nasal fractures often don't require imaging.

For otolaryngologists, CT is a commonly used diagnostic modality in pediatric and adult populations. Some good news: Many of our most-ordered scans typically deliver a lower radiation dose than a head CT. Radiation burden can vary by patient age, scanner technology and reconstruction protocols, and body size. Dose-length product (DLP) is a measure of radiation burden which can be converted to effective dose using age- or size-specific coefficients.² Pediatric conversion factors are generally four- to 13-fold higher than adult values, secondary to smaller body size, greater radiosensitivity, and longer life expectancy to experience radiation-associated effects.²

Grace Kim, MD, appreciated that this study "put some numbers on it"—transforming abstract risk into quantifiable data. She advocates for low-dose CT protocols when imaging is truly necessary, acknowledging that technology continues to improve. The American College of Radiology recommends the ALARA principle (“as low as reasonably achievable”) as a strategic, quantitative benchmark to meet accreditation standards.³ On average, U.S. children’s hospitals typically achieve 19% lower doses than non-pediatric children’s hospitals.⁴  For example, temporal bone CT (1.6-1.9 mGy) often leverages reconstruction techniques to allow for significant dose reduction to maintain diagnostic quality.⁵ Pediatric sinus CT with navigation protocol is estimated to range from 3.1-7.8 mGy depending on the scanner and protocol;⁶ contrasted neck CT is estimated to be ~13mGy in adults⁷—there is some variability in the literature regarding pediatric radiation burden for contrasted neck CT.

Should We Be Ordering Fewer CT Scans?

The challenge of balancing risks was a common reflection on the data presented. Karthik Balakrishnan, MD, MPH, now discusses CT risks explicitly with parents, weighing long-term cancer risk against the immediate need for diagnostic information and the alternative risks of MRI sedation in young or developmentally delayed children. Some of the families he sees now request coordinating MRI with operative procedures to minimize anesthesia exposure—though, as he notes, we lack data comparing a single longer versus multiple shorter anesthetic episodes—and, logistically, combining imaging and other procedures is not feasible. Torrey L. Fourrier, MD, and Mai Thy T. Truong, MD, both acknowledge potential confounders in this observational study while emphasizing the practical message: be judicious. Dr. Truong notes that the study particularly "opened [her] eyes" to the risks of head CTs in adolescents—a population we might consider more resilient, but who remain vulnerable.

As Ryan H. Belcher, MD, MPH, reflected, “This was an incredibly high-powered study. I like that they excluded the patients who received significant radiation that was related to the workup for their hematologic cancer. As someone with a significant pediatric head and neck practice, it makes me very conscious of utilizing ultrasound and MRI for imaging as much as possible over CT scans.” This study doesn't demand abandoning CT imaging—sometimes it's irreplaceable. Instead, it challenges us to make each imaging decision deliberately.

The Bottom Line

Douglas R. Sidell, MD, responded, “This article reinforces my longstanding approach to imaging studies that involve ionizing radiation. I routinely reassess the necessity of such studies, consider alternative imaging modalities when clinically appropriate, and emphasize educating referring clinicians on the judicious use of CT imaging in the head and neck. While definitive evidence of harm may be limited in some settings, the absence of evidence should not be interpreted as evidence of absence. In a clinical environment where imaging studies that utilize ionizing radiation are readily accessible, they can easily become the default ‘next step.’ It is therefore important that we continue to critically evaluate the indication for these studies rather than adopting them reflexively.”

References

1. Smith-Bindman R, Alber SA, Kwan ML, et al. Medical Imaging and Pediatric and Adolescent Hematologic Cancer Risk. N Engl J Med. 2025;393(13):1269-1278. doi:10.1056/NEJMoa2502098
2. Chu PW, Kofler C, Mahendra M, et al. Dose length product to effective dose coefficients in children. Pediatr Radiol. 2023;53(8):1659-1668. doi:10.1007/s00247-023-05638-1
3. Marin JR, Lyons TW, Claudius I, et al. Optimizing Advanced Imaging of the Pediatric Patient in the Emergency Department: Technical Report. Pediatrics. 2024;154(1):e2024066855. doi:10.1542/peds.2024-066855
4. Kanal KM, Graves JM, Vavilala MS, Applegate KE, Jarvik JG, Rivara FP. Variation in CT pediatric head examination radiation dose: results from a national survey. AJR Am J Roentgenol. 2015;204(3):W293-301. doi:10.2214/AJR.14.12997
5. Kim CR, Jeon JY. Radiation dose and image conspicuity comparison between conventional 120 kVp and 150 kVp with spectral beam shaping for temporal bone CT. Eur J Radiol. 2018;102:68-73. doi:10.1016/j.ejrad.2018.03.004
6. Chi J, Xu D, Yin S, et al. Reducing the radiation dose of pediatric paranasal sinus CT using an ultralow tube voltage (70 kVp) combined with iterative reconstruction: Feasibility and image quality. Medicine (Baltimore). 2020;99(34):e21886. doi:10.1097/MD.0000000000021886
7. Scholtz JE, Wichmann JL, Hüsers K, et al. Third-generation dual-source CT of the neck using automated tube voltage adaptation in combination with advanced modeled iterative reconstruction: evaluation of image quality and radiation dose. Eur Radiol. 2016;26(8):2623-2631. doi:10.1007/s00330-015-4099-z