Preliminary diagnostic reference levels for endoscopic retrograde cholangio-pancreatography in Greece

• National preliminary DRLs for KAP and Tf, during ERCPs in Greece.
• Determination of the relation between KAP and Tf.
• Comparison of the results with past studies.

The main objective of this study was to determine the preliminary Diagnostic Reference Levels (DRLs) in terms of Kerma Area Product (KAP) and fluoroscopy time (Tf) during Endoscopic Retrograde Cholangio-Pancreatography (ERCP) procedures. Additionally, an investigation was conducted to explore the statistical relation between KAP and Tf.Data from a set of 200 randomly selected patients treated in 4 large hospitals in Greece (50 patients per hospital) were analyzed in order to obtain preliminary DRLs for KAP and Tf during therapeutic ERCP procedures. Non-parametric statistic tests were performed in order to determine a statistically significant relation between KAP and Tf.The resulting third quartiles for KAP and Tf for hospitals (A, B, C and D) were found as followed: KAPA = 10.7 Gy cm2, TfA = 4.9 min; KAPB = 7.5 Gy cm2, TfB = 5.0 min; KAPC = 19.0 Gy cm2, TfC = 7.3 min; KAPD = 52.4 Gy cm2, TfD = 15.8 min. The third quartiles, calculated for the total 200 cases sample, are: KAP = 18.8 Gy cm2 and Tf = 8.2 min. For 3 out of 4 hospitals and for the total sample, p-values of statistical indices (correlation of KAP and Tf) are less than 0.001, while for the Hospital A p-values are ranging from 0.07 to 0.08. Using curve fitting, we finally determine that the relation of Tf and KAP is deriving from a power equation (KAP = Tf1.282) with R2 = 0.85.The suggested Preliminary DRLs (deriving from the third quartiles of the total sample) for Greece are: KAP = 19 Gy cm2 and Tf = 8 min, while the relation between KAP and Tf is efficiently described by a power equation.