Radiation Doses from Pediatric X-Ray Examinations
Diagnostic X-rays in children deliver very low radiation doses, typically ranging from <0.001 mSv to 1.6 mSv for common general radiography examinations, with chest X-rays being among the lowest at approximately 0.06-0.13 mSv effective dose. 1, 2
Specific Dose Ranges by Examination Type
Common General Radiography
- Chest X-rays: Effective doses range from 0.06-0.13 mSv, with the lowest doses in 5-year-olds and highest in 10-year-olds 2
- Skull, abdomen, and pelvis examinations: Effective doses range from approximately 4-150 μSv (0.004-0.15 mSv) for newborns through 1-year-old infants 3
- Entrance surface doses (ESD): Range from 26-700 μGy depending on examination type and patient age 3
Age-Related Dose Variations
- Radiation doses increase with patient age for most head and trunk examinations, though this relationship can be weak for certain projections like AP/PA chest 4
- The highest mean organ dose recorded was 0.085 mGy to the breast in AP projection for pediatric patients 2
Understanding Radiation Metrics
Key Dose Terminology
- Absorbed dose is measured in grays (Gy) or milligrays (mGy), where 1 mGy = 100 mrad 5
- Effective dose is measured in sieverts (Sv) or millisieverts (mSv), where 1 mSv = 100 mrem, and represents whole-body radiation burden weighted by organ sensitivity 5
- For X-rays, the weighting factor is 1, so absorbed and equivalent doses have equal numerical values but different units 5
Important Caveat
Current tissue weighting factors for effective dose are age- and sex-averaged values, which poses a significant limitation in characterizing patient-specific stochastic radiation risk, especially in children. 5 This means published effective doses may not accurately reflect individual risk for pediatric patients.
Associated Cancer Risk
The lifetime risk of cancer incidence from common pediatric general radiography ranges from 0.6 to 23.4 per million, categorized as negligible to low risk using the Calman risk model. 1
- Examinations delivering <0.001 mSv carry negligible risk 1
- Examinations up to 1.6 mSv carry low risk 1
- The risk of developing fatal malignancies from standard X-rays in newborns and 1-year-olds ranges between 0.6 and 23.4 per million 3
Dose Optimization Factors
Technical Factors Affecting Dose
- Film-screen system speed: Faster systems reduce dose 4
- Antiscatter grid use: Grids increase dose, particularly in younger children at specialist centers 4
- Tube voltage: Should be kept above 60 kV whenever possible to minimize radiation dose 3
- Fluoroscopy settings: Proper configuration and operator technique significantly impact cumulative dose 5
Institutional Variations
Doses for the same examination and age group can vary remarkably between hospitals, emphasizing the importance of institutional dose monitoring and optimization 2