Use of weight-based vs age-based groupings in the study of typical values of air kerma area product (P_KA) for paediatric radiographs of chest and abdomen

Abstract

Objective: To compare age groupings versus weight groupings in the calculation of typical air kerma area product (PKA) values in paediatric X-ray exams of chest and abdomen in our hospital. Methods: Data were analysed from 687 abdominal and 1374 chest X-ray examinations. The PKA of exams was extracted with Radimetrics, and patient weights were collected from electronic records. Data were organised in different age groups and typical PKA values were estimated. The process was repeated by organising data in different weight groups. Results: Typical PKA values for the four younger age groups (<1m, 1m - < 4y, 4y - < 10y and 10y - < 14y) were comparable to typical values for their equivalent weight groups (<5 kg, 5–15 kg, 15–30 kg and 30–50 kg, respectively). However, typical PKA values at the late adolescent age group (14y - < 18y) were much lower than its equivalent weight group (>50 kg). Conclusions: Age and weight groupings were found at our site to be interchangeable for the calculation of typical paediatric PKA values. The only exception was the late adolescent group, whose weight distribution can account for the difference in typical PKA results within its equivalent weight group. Advances in knowledge: In calculating typical PKA values for radiological paediatric body examinations, departments must ascertain if using age groups, which is typical practice, is equivalent to using weight groups. Otherwise, results may misrepresent local practice.