## 2 Materials and Methods
Fetal doses were measured for conventional radiography of the abdomen, CT of the abdomen, and CT for polytrauma in an additional 3 radiography and 7 CT units in all hospitals using their own protocols. Selected clinical scenarios, imaging modalities, \begin{table}
\begin{tabular}{p{85.4 pt} p{85.4 pt} p{85.4 pt} p{85.4 pt} p{85.4 pt}} \hline
**Clinical Scenario** & **Imaging Modality** & **Unit** & **Imaging Protocol** & **Imaging Parameters** \\ \hline Non-specific abdominal pain & Radiography & Siemens Luminos dRF Max & Abdomen and pelvis in two positions & 80.8 kV; 18.85 mAs \\ \hline Nephrostomy tube placement & Fluoroscopy & Siemens Uroskop Omnia Max & Pulsed fluoroscopy, collimated field & \(\mathrm{N/A}\) \\ \hline Nephrolithiasis, appendicitis, abdominal pain & CT & GE Revolution Frontier & NCCT abdomen and pelvis (lung bases—great trochantes) & 120 kV; auto mAs (range 50–750); noise index 13.3; section thickness 5 mm; pitch 1.375:1 \\ \hline Polytrauma & CT & GE Revolution Frontier & NCCT C spine & 120 kV; 335 mAs section thickness 0.625 mm; pitch 0.516:1 \\ \hline \multirow{2}{*}{Ischemic stroke} & \multirow{2}{*}{CT} & \multirow{2}{*}{GE Revolution Frontier} & \multirow{2}{*}{CT angiography of PA with “ bolus tracking” (5\(\times\))} & 120 kV; auto mAs (range 100–800); noise index 28; section thickness 0.625 mm; pitch 1.375:1 \\ \cline{3-4}  & & & NCCT head & 120 kV; auto mAs (range 80–700); noise index 8.94; section thickness 1.25 mm; pitch 0.984:1 \\ \hline \multirow{2}{*}{Fluroscopy and DSA} & \multirow{2}{*}{Philips Azurion} & \multirow{2}{*}{2 Passed fluoroscopy and MT DSA run for pre- and post-procedure angiography (6 fps)} & 120 kV; auto mAs (range 80–700); noise index 8.94; section thickness 1.25 mm; pitch 0.984:1 \\ \cline{3-4}  & & & 2 pass MT: Pulsed fluoroscopy for selective catheterization and MT DSA run for pre- and post-procedure angiography (6 fps) & 75 kV; 7–22 mAs Rotation 0\({}^{\circ}\), LAO 45\({}^{\circ}\), LAO 89\({}^{\circ}\) \\ \hline \end{tabular}
\end{table} 
Table 2: Clinical scenarios performed in Hospital 1, imaging modalities, scanning protocols, and imaging parameters used in Hospital 1. \(\mathrm{N/A}\)—not available, CT—computed tomography, NCCT—non-contrast CT, CECT—contrast-enhanced CT, CTA—CT angiography, PA—pulmonary artery, MT—mechanical thrombectomy, DSA—digital subtraction angiography. equipment used, scanning protocols, and imaging parameters are summarized in Table 3 for all three hospitals. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Clinical Scenario** & \begin{tabular}{c} **Imaging** \\ **Modality** \\ \end{tabular}  & **Hospital** & **Unit** & **Imaging Protocol** & **Imaging Parameters** \\ \hline \multirow{6}{*}{ \begin{tabular}{c} Non-specific \\ abdominal pain \\ \end{tabular}  } & \multirow{3}{*}{Radiography} & \multirow{3}{*}{1} & Siemens Luminos (R1) & Abhomen and pelvis in two positions & 80.8 kV; 18.85 mAs \\ \cline{3-5}  & & & (R2) & 72.9 kV; 40.7 mAs \\ \cline{3-5}  & & & & Siemens Ysio Max (R2) & Abhomen and pelvis in AP projection & 72.9 kV; 34.99 mAs \\ \cline{3-5}  & & & & Siemens Luminos (R1) & Abhomen and pelvis in AP projection & 72.9 kV; 62.44 mAs \\ \cline{3-5}  & & & & Siemens Aristos (R1) & Abhomen and pelvis in two positions & 81 kV; 22 mAs \\ \cline{3-5}  & & & & & 81 kV; 76 mAs \\ \hline \multirow{6}{*}{\ \begin{tabular}{c} Nephholitiasis, \\ appendicitis, \\ abdominal pain \\ \end{tabular}