ORIGINAL ARTICLE Paediatric dose measurement in a full-body digital radiography unit Gert Johannes Maree & Benjamin John Irving & Egbert Raymond Hering Received: 6 February 2007 / Revised: 21 May 2007 / Accepted: 11 June 2007 / Published online: 1 September 2007 # Springer-Verlag 2007 Abstract Background Ionizing radiation has a detrimental effect on the human body, particularly in children. Thus it is important to minimize the dose. Linear slit-scanning X- ray units offer the possibility of dose reductions. In order to further develop linear slit-scanning radiography, the dose needs to be accurately calculated for various examinations. Objective To measure the entrance dose (free-in-air) and calculate the effective doses for various radiological examinations in children on Lodox Statscan and Shimadzu radiography units. Materials and methods Entrance doses (free-in-air) were measured using a dose meter and ionization chamber on the Statscan and Shimadzu units at two South African hospitals. The entrance doses were measured for a number of common examinations and were used to compute the effective dose using a Monte Carlo program. Results The standard deviation of the entrance doses was in the range 0–0.6%. The effective dose from the Statscan unit was well below that from the Shimadzu unit as well as that found in other radiological studies from around the world in children. The one exception was chest examination where the dose was similar to that in other studies worldwide due to the use of Chest AP projection compared to Chest PA used in the comparitive studies. Conclusion Linear slit-scanning systems help reduce the dose in radiological examinations in children. Keywords Effective dose . Slit scanning . Radiography . Children Introduction Ionizing radiation has a detrimental effect on the human body, which makes it important to monitor the radiation dose from radiographic examinations [1]. According to the International Commission on Radiological Protection (ICRP) [1] these effects can be divided into two categories, deterministic effects and stochastic effects. Deterministic effects are defined as killing cells in large quantities, so much so that tissue functioning is affected. Below a certain threshold this effect is negligible. On the other hand, stochastic effects are more subtle, the cells are modified by the radiation. These cells then have a small risk of becoming cancerous or producing genetic effects. The risk of cancer from each examination increases with the radiation dose of the examination. Thus, it is important to minimize the dose wherever possible. In minimizing radiation dose it is important to weigh up the risk versus the benefit of an examination [1–3]. Slovis [2] reiterates the importance of having a good understand- ing of the patient dose for each scan. If we know the radiation dose, we can determine whether the scan is worth the risk or whether the dose should be reduced. Minimizing radiation dose is particularly important in children, as children have a much higher sensitivity to radiation [1, 2]. Pediatr Radiol (2007) 37:990–997 DOI 10.1007/s00247-007-0565-3 G. J. Maree : E. R. Hering Division of Medical Physics, Groote Schuur Hospital & University of Cape Town, Observatory, Cape Town 7925, South Africa B. J. Irving (*) MRC/UCT Medical Imaging Research Unit, Department of Human Biology, University of Cape Town, Observatory, Cape Town, Western Cape 7925, South Africa e-mail: Benjamin.Irving@uct.ac.za