'Modification of chest radiography exposure parameters using a neonatal chest phantom': reply to Schneider
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LETTER TO THE EDITOR
'Modification of chest radiography exposure parameters using a neonatal chest phantom': reply to Schneider Stefan B. Schäfer 1 & Gabriele A. Krombach 1 Received: 17 June 2020 / Revised: 17 June 2020 / Accepted: 6 July 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Dear Editors, Professor Schneider [1] is concerned about whether it makes sense to optimize the radiographic technique of infant chest radiographs using the Gammex 610 Neonatal Chest Phantom since this is a fixed phantom. We thank Schneider and are pleased to clarify. Our paper [2] evaluated whether dose optimization is possible in the diagnosis of pneumothorax and of hyaline membrane disease with respiratory distress syndrome Grade I taking into account the assessment criteria following the guidelines of the Federal Medical Association for Quality Assurance in Radiology. The results specified in the paper should demonstrate that a dose reduction of chest radiographs in neonates regarding this clinical issue, using a digital X-ray system, is in principle possible by lowering the tube voltage and adjusting the current–time product (mAs) values. Neither a specific phantom should be recommended nor are the results readily transferable to other types of examinations. On the one hand, the comparability is limited by different radiographic techniques in the examination of different body regions and even at different relevant anatomical structures. On the other hand, manufacturer- and device-specific differences, such as different types of image post-processing and, in particular, the use of nonlinear characteristics must be taken into account. For these reasons, radiographs should be performed on a phantom or specimen before transferring the specified settings to reduce the dose. Anthropomorphic phantoms of different sizes have frequently been used to assess dose optimization without considering motion artefacts. Such studies nevertheless allow a prospective study of image quality. * Stefan B. Schäfer [email protected] 1
Department of Diagnostic and Interventional Radiology, University Hospital Giessen, Justus-Liebig University Giessen, Klinikstrasse 33, 35392 Giessen, Germany
Of course, a fixed phantom does not depict motion and blurring artefacts caused by moving structures, e.g., heart, diaphragm, pulmonary interstitial structures. However, these can be minimized by a relatively short exposure time, as Schneider also notes. According to the Federal Medical Association, which takes the European Guidelines EUR 16261 into account, an exposure time of ≤5 ms is recommended for this type of examination. The exposure times for the results specified in the paper were below 5 ms and only once was the exposure time slightly higher. It should be mentioned that the statement “On the other hand, the increased mAs would lead to longer exposure time and consequently more motion artefacts” is not completely correct. An increase in the current–time product is also possible by increasing the tube current, s
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