Filters for Dose Reduction in Conventional X-Ray Examinations of Children

Abstract

The effects of five filtrations on dose reduction and image quality in paediatric chest radiography with a high voltage technique are presented. The radiographs were performed using a Sieregraph unit (Siemens) with 3.5 mm Al of primary total filtration, and added: 1 mm Al + 0.1 mm Cu, 1 mm Al + 0.2 mm Cu, 4 mm Al, 4 mm Al + 0.1 mm Cu. The entrance air kerma (including backscatter) for each child examined was measured using TLD-100, and the parameters of exposure were recorded. The absorbed organ doses and effective doses were calculated using Monte Carlo simulation. The authors' computer code was used for this purpose. The children were divided into three groups according to weight and height, corresponding to the mathematical human phantoms representing 5 year, 10 year and 15 year children. Additional filtrations exceeding 4 mm Al allowed for significant reduction of doses (nearly 50%). Although the visualisation of the anatomical structures in the filter groups were slightly reduced, nevertheless the films were acceptable for the given clinical questions.