Establishing Local Diagnostic Reference Levels in IR Procedures with Dose Management Software.

PURPOSE: To obtain local diagnostic reference levels (DRLs) in diagnostic and therapeutic IR procedures with dose management software to improve radiation protection. MATERIALS AND METHODS: Dose data of various vascular and nonvascular IR procedures performed within 18 months were collected and analyzed with dose management software. To account for different levels of complexity, procedures were subdivided into simple, standard, and difficult procedures as graded by interventional radiologists. Based on these analyses, local DRLs (given as kerma-area product [KAP]) were proposed. Comparison with dose data of others was conducted, and Spearman correlation coefficients were calculated to evaluate relationships between dose metrics. RESULTS: Analysis included 1,403 IR procedures (simple/standard/difficult, n = 346/702/355). Within the same procedure, KAP tended to increase with level of complexity. Overall, very strong correlation between KAP (Gy ∙ cm2) and cumulative air kerma (KA,R; Gy) was observed, and moderate to strong correlation between KAP and time and KA,R and time was observed. For simple procedures, strong correlation was seen between KAP and time and KA,R and time; for standard and difficult procedures, only moderate correlation was seen. Correlation between KAP and time and KA,R and time was strong in nonvascular procedures but only moderate in vascular procedures. CONCLUSIONS: Dose management software can be used to derive local DRLs for various IR procedures, taking into consideration different levels of complexity. Proposed local DRLs can contribute to obtaining detailed national DRLs as part of efforts to improve patients' radiation protection further.

Does Real-Time Monitoring of Patient Dose With Dose Management Software Increase CT Technologists' Radiation Awareness?

OBJECTIVE: Dose management software can be used to increase patient safety. The purpose of the current study was to evaluate whether real-time monitoring of patient dose in CT examinations increases CT technologists' dose awareness. MATERIALS AND METHODS: Dose data of two scanners (clinical routine CT scanner, mainly outpatients; emergency CT scanner, predominantly emergency department and ICU patients) were analyzed before (period 1) and after (period 2) dose management software was implemented in clinical routine and technologists were advised to check for dose notifications (dose values above reference levels) after each examination (i.e., real-time monitoring). To assess statistically significant differences between both the scanners and the study periods, we used chi-square tests. RESULTS: A total of 6413 examinations were performed (period 1 = 3214 examinations, period 2 = 3199 examinations). Dose notifications were mainly because of patient miscentering (period 1 = 45% of examinations, period 2 = 23%), overweight patients (period 1 = 35%, period 2 = 49%), and scanning repetition (period 1 = 10%, period 2 = 15%). Overall, the number of dose notifications significantly declined in period 2 (period 1, n = 210; period 2, n = 120; p < 0.001). Miscentering was more often seen on the clinical routine CT examinations (period 1 = 46%, period 2 = 23%) than on the emergency CT examinations (period 1 = 44%, period 2 = 22%) and occurred significantly less frequently on both scanners in period 2 (period 1: n = 94; period 2: n = 27; p < 0.001). The relative values of dose notifications due to overweight patients or scanning repetition were higher in period 2, but these differences did not reach statistical significance (p > 0.05). CONCLUSION: Real-time monitoring of patient dose with dose management software increases CT technologists' dose awareness and leads to a reduced number of dose notifications due to human error.

Combined Use of a Patient Dose Monitoring System and a Real-Time Occupational Dose Monitoring System for Fluoroscopically Guided Interventions.

PURPOSE: To determine the effect on patient radiation exposure of the combined use of a patient dose monitoring system and real-time occupational dose monitoring during fluoroscopically guided interventions (FGIs). MATERIALS AND METHODS: Patient radiation exposure, in terms of the kerma area product (KAP; Gy ∙ cm(2)), was measured in period 1 with a patient dose monitoring system, and a real-time occupational dose monitoring system was additionally applied in period 2. Mean/median KAP in 19 different types of FGIs was analyzed in both periods for two experienced interventional radiologists combined as well as individually. Patient dose and occupational dose were correlated, applying Pearson and Spearman correlation coefficients. RESULTS: Although FGIs were similar in numbers and types over both periods, a substantial decrease was found for period 2 in total mean ± SD/median KAP for both operators together (period 1, 47 Gy ∙ cm(2) ± 67/41 Gy ∙ cm(2); period 2, 37 Gy ∙ cm(2) ± 69/34 Gy ∙ cm(2)) as well as for each individual operator (for all, P < .05). Overall, KAP declined considerably in 15 of 19 types of FGIs in period 2. Mean accumulated dose per intervention was 4.6 µSv, and mean dose rate was 0.24 mSv/h. There was a strong positive correlation between patient and occupational dose (r = 0.88). CONCLUSIONS: Combined use of a patient dose monitoring system and a real-time occupational dose monitoring system in FGIs significantly lessens patient and operator doses.