Pediatric Medical Imaging and Hematologic Cancer Risk: NEJM Study
In this article
NEJM study of 3.7 million children: cumulative bone-marrow radiation dose is linked to a small but significant increase in hematologic cancer risk.
Key takeaway: Exposure ≥30 mGy was associated with a 1.76× higher risk; about 10.1% of cases could be attributable to higher-dose imaging (e.g., CT). (1 head CT ≈ 13.7 mGy)
📊 Cohort & Follow-up
3,724,623 children; 35.7M person-years (mean 10.1y).
🧪 Outcomes
2961 hematologic cancers: 79.3% lymphoid, 15.5% myeloid/acute leukemia, 4.4% histiocytic/dendritic.
📈 Excess Incidence
Among ≥30 mGy (mean 57 mGy), excess by age 21 ≈ 25.6 per 10,000.
% Attributable
10.1% (95% CI 5.8–14.2) attributable to imaging-related radiation.
📏 Dose Guide (mGy)
- Chest X-ray: ~0.1 mGy (ionizing)
- Head CT: ~13.7 mGy (ionizing)
- Abdominal CT: ~15–20 mGy (ionizing)
- Ultrasound & MRI: No ionizing radiation
Remember: Risk relates to cumulative dose — repeated CTs add up.
📈 Dose–Risk Relationship
⚡ Uses Ionizing Radiation
- X-ray
- CT (Computed Tomography)
- Nuclear medicine (e.g., PET, scintigraphy)
🛡️ No Ionizing Radiation
- Ultrasound
- MRI (Magnetic Resonance Imaging)
🎯 Practical Actions (ALARA)
- Justify each CT: will it change management?
- Optimize pediatric protocols; avoid repeats; size-based settings.
- Prefer US/MRI when clinically adequate.
- Track cumulative dose; communicate risks to families clearly.
📋 Relative Risk by Dose Band
| Cumulative Dose (mGy) | RR vs 0 mGy | 95% CI |
|---|---|---|
| 1–<5 | 1.41 | 1.11–1.78 |
| 15–<20 | 1.82 | 1.33–2.43 |
| 50–<100 | 3.59 | 2.22–5.44 |
| Per 100 mGy: ERR ≈ 2.54 (95% CI 1.70–3.51). 30 vs 0 mGy: RR ≈ 1.76 (95% CI 1.51–2.05). | ||
Source
Smith-Bindman R, Alber SA, Kwan ML, et al. Medical Imaging and Pediatric and Adolescent Hematologic Cancer Risk. NEJM, Sept 17, 2025. DOI: 10.1056/NEJMoa2502098
Was this article helpful?
Your feedback helps us improve our content.
Reader comments
Share your comment
Your name and comment are published only after administrator approval. Your email address is never shown to visitors.
Be the first to comment.