Effective dose and breast dose reduction in paediatric scoliosis X-ray radiography by an optimal positioning.

The purpose of this article is to recommend positioning to reduce the effective and breast-absorbed-doses in paediatric scoliosis radiography. Effective and breast-absorbed-doses were evaluated using Monte Carlo simulations. Head directed towards the anode (HTA) positioning rather than head directed towards the cathode (HTC) reduces the effective dose to 98 % in anterior posterior (AP), 98 % in left lateral (L LAT) and 96 % in right lateral (R LAT) projections. HTC in posterior anterior (PA) projection contributes a smaller effective dose than HTA by <1 %, but causes a breast-absorbed-dose excess (HTA/HTC breast dose ratios were 85 and 87 % for 10- and 15-y- olds). With the preferential HTA positioning, R LAT projection reduced effective dose to 85 and 84 % compared with L LAT, for 10 and 15 y olds. AP-HTA projection caused 183 and 181 % larger effective doses than PA-HTA and breast-absorbed-dose excesses of 550 and 879 %, for 10 and 15 y olds. When possible, use R LAT and PA projections to reduce effective dose; Of secondary importance, whenever possible, use HTA, with the exception that for 15 y olds, PA-HTC reduces the effective dose more than HTA (1 %) but causes a breast-absorbed-dose excess.