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

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=10.7Gycm(2), TfA=4.9min; KAPB=7.5Gycm(2), TfB=5.0min; KAPC=19.0Gycm(2), TfC=7.3min; KAPD=52.4Gycm(2), TfD=15.8min. The third quartiles, calculated for the total 200 cases sample, are: KAP=18.8Gycm(2) and Tf=8.2min. 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=Tf(1.282)) with R(2)=0.85. The suggested Preliminary DRLs (deriving from the third quartiles of the total sample) for Greece are: KAP=19Gycm(2) and Tf=8min, while the relation between KAP and Tf is efficiently described by a power equation.

THE IMPACT OF X-RAY UNIT TYPE USED FOR ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY PROCEDURES ON PATIENT DOSES.

To investigate whether the X-ray unit type used for interventional endoscopic retrograde cholangiopancreatography (ERCP) procedures may affect patient radiation doses. A total of 471 ERCP procedures performed in 4 hospitals with 4 types of X-ray units were studied. Kerma-area product (KAP), fluoroscopy time (T) and total number of radiographs acquired (F) were recorded. KAP, T and F values exhibited a great variation, ranging from 0.1 to 130.2 Gy cm2 (mean 16 Gy cm2), 0.13 to 33.7 min (mean 5.4 min) and 0 to 26 radiographs (mean 3.5), respectively. The respective mean values for the four types of X-ray units that were investigated were as follows: KAP: 17.4, 12.5, 5.6 and 36.3 Gy cm2, T: 4.7, 5.2, 3.8 and 11.5 min and F: 1.7, 7.4, 1.9 and 4.6 radiographs. The type of the X-ray unit seems to significantly affect patient radiation dose, with the C-arm delivering the lowest and the angiography unit the highest patient doses.

Patient and endoscopist radiation doses during ERCP procedures.

The aim of the study was to calculate radiation doses for patients and staff during interventional Endoscopic retrograde cholangiopancreatography (ERCP) procedures. Patient age (A), kerma-area product (KAP), fluoroscopy time (T) and total number of films (F) were collected for 157 interventional ERCP procedures. One endoscopist (>10 y of experience) monitored using a thermoluminescent dosemeter worn over the lead apron performed the ERCPs. Median (range) KAP was 3.1 Gy cm(-2) (0.1-106.7 Gy cm(-2)). Median (range) A, T and F were 72 y, 2.6 (0.2-26.0) min and 2 (1-4) images, respectively. No correlation was observed between KAP and A, T or F. Monthly endoscopist dose was negligible due to the use of lead apron, collar and two lead-articulated ceiling mounted shields. The endoscopist dose is minimal when using appropriate protective measures. Patient doses showed large variation that has to be further investigated.

Radiation doses to patients from endoscopic retrograde cholangiopancreatography examinations and image quality considerations.

The purpose of this investigation was to measure the dose-area product (DAP) and the other relevant dosimetric quantities in diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). Furthermore, the dependence of patient dose and image quality on the tube potential was investigated. A DAP meter was used for dose monitoring in seven diagnostic and 21 therapeutic ERCPs. For each ERCP the DAP meter readings, fluoroscopy time, number of radiographs and exposure data were recorded. From these data the fluoroscopy and radiography contributions to DAP, the entrance skin dose and the effective dose for each examination were estimated. For the investigation of the effect of tube potential on patient dose and image quality, a water phantom containing syringes filled with diluted contrast media was used. The average DAP was 13.7 Gy cm2 in diagnostic and 41.8 Gy cm2 in therapeutic ERCP whereas the average fluoroscopy times were 3.1 and 6.0 min respectively. DAP was strongly correlated to the fluoroscopy time. Measurements in the phantom showed that a good compromise between image quality and patient dose is obtained for tube potentials around 80 kV. Therapeutic ERCPs deliver on average higher doses to patients than diagnostic ERCPs. However, for a difficult diagnostic ERCP more patient exposure may be required than for a simple therapeutic ERCP.