European Journal of Radiology Current CT practice in Germany: Results and implications of a nationwide survey  Alexander A. Schegerer, Hans-Dieter Nagel, Georg Stamm, Gerhard Adam, Gunnar Brix  European Journal of Radiology  Volume 90, Pages 114-128 (May 2017) DOI: 10.1016/j.ejrad.2017.02.021 Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 1 Total number of CT scanners considered in the survey. For each of the four large manufacturers presented on the German market, data are stratified to scanners with a different number of detector rows. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 2 Number of CT examinations performed per scanner and year in practices, non-academic hospitals, and university hospitals. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 3 Box and whisker plots of (a) CTDIvol, (b) L, (c) DLP, and (d) Deff for the 34 CT standard examination defined in Table 1. The boxes are drawn around the 25th and 75th percentiles and divided by the 50th percentile. The whiskers extend out to the 10th and 90th percentiles. Fig. 3(e) standard scan length (cf. Table 1) and mean realized scan length L computed from the ratio of DLP and CTDIvol. The examinations are sorted in ascending order of mean values. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 3 Box and whisker plots of (a) CTDIvol, (b) L, (c) DLP, and (d) Deff for the 34 CT standard examination defined in Table 1. The boxes are drawn around the 25th and 75th percentiles and divided by the 50th percentile. The whiskers extend out to the 10th and 90th percentiles. Fig. 3(e) standard scan length (cf. Table 1) and mean realized scan length L computed from the ratio of DLP and CTDIvol. The examinations are sorted in ascending order of mean values. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 3 Box and whisker plots of (a) CTDIvol, (b) L, (c) DLP, and (d) Deff for the 34 CT standard examination defined in Table 1. The boxes are drawn around the 25th and 75th percentiles and divided by the 50th percentile. The whiskers extend out to the 10th and 90th percentiles. Fig. 3(e) standard scan length (cf. Table 1) and mean realized scan length L computed from the ratio of DLP and CTDIvol. The examinations are sorted in ascending order of mean values. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 3 Box and whisker plots of (a) CTDIvol, (b) L, (c) DLP, and (d) Deff for the 34 CT standard examination defined in Table 1. The boxes are drawn around the 25th and 75th percentiles and divided by the 50th percentile. The whiskers extend out to the 10th and 90th percentiles. Fig. 3(e) standard scan length (cf. Table 1) and mean realized scan length L computed from the ratio of DLP and CTDIvol. The examinations are sorted in ascending order of mean values. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 3 Box and whisker plots of (a) CTDIvol, (b) L, (c) DLP, and (d) Deff for the 34 CT standard examination defined in Table 1. The boxes are drawn around the 25th and 75th percentiles and divided by the 50th percentile. The whiskers extend out to the 10th and 90th percentiles. Fig. 3(e) standard scan length (cf. Table 1) and mean realized scan length L computed from the ratio of DLP and CTDIvol. The examinations are sorted in ascending order of mean values. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 4 Effects of innovative CT scan and image reconstruction techniques on CTDIvol, L, and Deff, based on an evaluation of the corresponding normalized quantities Xˆm,k that can statistically be analyzed across the 34 standard CT examinations. (a) Spiral mode, (b) tube current modulation (TCM), and (c) iterative image reconstruction (IR; FBP: filtered-back projection). Data are given relative to the scan and reconstruction technique indicated in each plot by the dark gray bars. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 4 Effects of innovative CT scan and image reconstruction techniques on CTDIvol, L, and Deff, based on an evaluation of the corresponding normalized quantities Xˆm,k that can statistically be analyzed across the 34 standard CT examinations. (a) Spiral mode, (b) tube current modulation (TCM), and (c) iterative image reconstruction (IR; FBP: filtered-back projection). Data are given relative to the scan and reconstruction technique indicated in each plot by the dark gray bars. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 4 Effects of innovative CT scan and image reconstruction techniques on CTDIvol, L, and Deff, based on an evaluation of the corresponding normalized quantities Xˆm,k that can statistically be analyzed across the 34 standard CT examinations. (a) Spiral mode, (b) tube current modulation (TCM), and (c) iterative image reconstruction (IR; FBP: filtered-back projection). Data are given relative to the scan and reconstruction technique indicated in each plot by the dark gray bars. European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 5 Mean CTDIvol, L and Deff values evaluated for CT scanners produced by four different manufacturers based on an evaluation of the corresponding normalized quantities Xˆm,k that can statistically be analyzed across the 34 standard CT examinations. Data are given relative to data for manufacturer A for examinations performed (a) without and (b) with TCM (for manufacturer D, data are not presented due to the reason given in the text). European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions

Fig. 5 Mean CTDIvol, L and Deff values evaluated for CT scanners produced by four different manufacturers based on an evaluation of the corresponding normalized quantities Xˆm,k that can statistically be analyzed across the 34 standard CT examinations. Data are given relative to data for manufacturer A for examinations performed (a) without and (b) with TCM (for manufacturer D, data are not presented due to the reason given in the text). European Journal of Radiology 2017 90, 114-128DOI: (10.1016/j.ejrad.2017.02.021) Copyright © 2017 Elsevier B.V. Terms and Conditions