Improving Patient Safety: Implementing Dose Monitoring Software in Fluoroscopically Guided Interventions

Technical specifications of dose management systems: An international atomic energy agency survey

PURPOSE

Dose management systems (DMS) have been introduced in radiological services to facilitate patient radiation dose management and optimization in medical imaging. The purpose of this study was to gather as much information as possible on the technical characteristics of DMS currently available, regarding features that may be considered essential for simply ensuring regulatory compliance or desirable to fully utilize the potential role of DMS in optimization of many aspects of radiological examinations.

METHODS

A technical survey was carried out and all DMS developers currently available (both commercial and open source) were contacted and were asked to participate. An extensive questionnaire was prepared and uploaded in the IAEA International Research Integration System (IRIS) online platform which was used for data collection process. Most of the questions (93%) required a "Yes/No" answer, to facilitate an objective analysis of the survey results. Some free text questions and comments' slots were also included, to allow participants to give additional information and clarifications where necessary. Depending on the answer, they were considered either as "Yes" or "No."

RESULTS

Given the way that the questions were posed, every positive response indicated that a feature was offered. Thus, the percentage of positive responses was used as a measure of adherence. The percentages of positive answers per section (and sub-section) are presented in graphs and limitations of this type of analysis are discussed in detail.

CONCLUSIONS

The results of this survey clearly exhibit that large differences exist between the various DMS developers. Consequently, potential end users of a DMS should carefully determine which of the features available are essential for their needs, prioritize desirable features, but also consider their infrastructure, the level of support required and the budget available before selecting a DMS.

Typical doses and typical values for fluoroscopic diagnostic and interventional procedures

To implement typical doses (TD) and typical values (TV) for fluoroscopic diagnostic and interventional procedures. A total of 3811 fluoroscopic procedures performed within 34 months on three devices were included in this retrospective study. Dose-, patient- and procedure-related information were extracted using the institutional dose management system (DMS). TD/TV were defined as median dose and calculated for the five most frequent procedures per device for dose area product (DAP), cumulative air kerma (CAK) and fluoroscopy time (FT). National diagnostic reference levels and other single facility studies were compared to our results. Additionally, the five procedures with the highest doses of each device were analysed. To evaluate the data coverage of the DMS compared to the picture archiving and communication system (PACS), procedure lists were extracted from the PACS and compared to the procedure information extracted from the DMS. TD/TV for 15 procedures were implemented. Among all devices, TD for DAP ranged between 0.6 Gycm²for port catheter control (n= 64) and 145.9 Gycm²for transarterial chemoembolisation (n= 84). TD for CAK ranged between 5 mGy for port catheter control and 1397 mGy for aneurysm treatment (n= 129) and TV for FT ranged between 0.3 min for upper cavography (n= 67) and 51.4 min for aneurysm treatment. TD for DAP and CAK were lower or within the range of other single facility studies. The five procedures with the highest median DAP per device were identified, 6 of 15 procedures were also found to be among the most frequent procedures. Data coverage of the DMS compared to the PACS ranged between 71% (device 2, stroke treatment) and 78% (device 1, lower limb angiography) for the most common procedure per device. Thus, in 22%-29% of cases dose data of the performed procedure was not transferred into the DMS. We implemented TD/TV for fluoroscopic diagnostic and interventional procedures which enable a comprehensive dose analysis and comparison with previously published values.

LOCAL DIAGNOSTIC REFERENCE LEVELS FOR PEDIATRIC RETROGRADE WEDGE PORTOGRAPHY INTERVENTIONAL PROCEDURES USING A DOSE MONITORING SOFTWARE AT A TRANSPLANTATION INSTITUTE

The aim of this work was to establish local diagnostic reference levels (DRLs) for retrograde wedge portography (RWP) performed on pediatric patients assessing the usefulness of radiation dose monitoring software in the establishing process. Between September 2016 and April 2020, 66 consecutive RWP were performed at a transplantation institute and were included in our study. Patients were divided in three groups according to age: n = 25 infants, n = 20 middle childhood and n = 21 early adolescence. The third quartile of both Air Kerma at the reference point (Ka,r) and air kerma-area product (PKA) were evaluated to establish local DRLs (lDRLs). In addition, to control high Ka,r levels during procedures, the software notified to operators if Ka,r exceeded the dose 'alert' threshold set at 2 Gy. lDRLs were established for all three groups using PKA and Ka,r: infant group: 5.6 Gy.cm 2 and 0.034 Gy; middle childhood: 6.4 Gy.cm2 and 0.018 Gy and early adolescence: 12.8 Gy.cm2 and 0.059 Gy. The dose threshold 'alert' was never encountered (alert quota: 0%). The dose monitoring system supports the feasibility of accurate and easier lDRLs' establishment.

FLUOROSCOPY-GUIDED BILIARY PROCEDURES IN A PREGNANT, LIVER TRANSPLANT PATIENT: FETUS RADIATION PROTECTION

We report three cases of clinically necessary, fluoroscopy-guided, percutaneous biliary procedures performed safely in a pregnant, liver transplant recipient using three different angiography suites. The uterine cumulative equivalent dose was 0.25 mSv, a value obtained by adding the doses of the three procedures described above, and which is relatively low when compared with the naturally occurring background radiation exposure for a 9-month pregnancy (~0.5-1 mSv). Our experience shows that staff knowledge, awareness and liaison promote the application of all dose reduction strategies possible while still achieving the clinical aim despite using different angiographic equipment.

Fluoroscopically-guided interventions with radiation doses exceeding 5000 mGy reference point air kerma: a dosimetric analysis of 89,549 interventional radiology, neurointerventional radiology, vascular surgery, and neurosurgery encounters

Purpose

To quantify and categorize fluoroscopically-guided procedures with radiation doses exceeding 5000 mGy reference point air kerma (K_a,r). K_a,r > 5000 mGy has been defined as a “significant radiation dose” by the Society of Interventional Radiology. Identification and analysis of interventions with high radiation doses has the potential to reduce radiation-induced injuries.

Materials and methods

Radiation dose data from a dose monitoring system for 19 interventional suites and 89,549 consecutive patient encounters from January 1, 2013 to August 1, 2019 at a single academic institution were reviewed. All patient encounters with K_a,r > 5000 mGy were included. All other encounters were excluded (n = 89,289). Patient demographics, medical specialty, intervention type, fluoroscopy time (minutes), dose area product (mGy·cm²), and K_a,r (mGy) were evaluated.

Results

There were 260 (0.3%) fluoroscopically-guided procedures with K_a,r > 5000 mGy. Of the 260 procedures which exceeded 5000 mGy, neurosurgery performed 81 (30.5%) procedures, followed by interventional radiology (n = 75; 28.2%), neurointerventional radiology (n = 55; 20.7%), and vascular surgery (n = 49; 18.4%). The procedures associated with the highest K_a,r were venous stent reconstruction performed by interventional radiology, arteriovenous malformation embolization performed by neurointerventional radiology, spinal hardware fixation by neurosurgery, and arterial interventions performed by vascular surgery. Neurointerventional radiology had the highest mean K_a,r (7,799 mGy), followed by neurosurgery (7452 mGy), vascular surgery (6849 mGy), and interventional radiology (6109 mGy). The mean K_a,r for interventional radiology performed procedures exceeding 5000 mGy was significantly lower than that for neurointerventional radiology, neurosurgery, and vascular surgery.

Conclusions

Fluoroscopically-guided procedures with radiation dose exceeding 5000 mGy reference point air kerma are uncommon. The results of this study demonstrate that a large proportion of cases exceeding 5000 mGy were performed by non-radiologists, who likely do not receive the same training in radiation physics, radiation biology, and dose reduction techniques as radiologists.

Accuracy of mammography dosimetry in the era of the European Directive 2013/59/Euratom transposition

PURPOSE

To evaluate the impact of increasing levels of accuracy for mean glandular dose (MGD) evaluation in the era of the European Directive 2013/59/Euratom transposition.

METHOD

4028 women who had a mammography examination by one of five mammography units using different detector technologies were included in this study. 16,006 images were processed by a software algorithm that determines breast glandularity quantitatively and uses this to estimate patient-specific MGD (psMGD). Entrance dose (ED) values and half value layers (HVLs) measured for each mammography system were collected to evaluate the effect of equipment calibration in psMGD calculation. The psMGD values adjusted for system calibration were compared with organ dose (OD) provided by manufacturers as image metadata.

RESULTS

Overall median relative difference between calibrated psMGD and organ dose was below 3%, with larger differences for individual systems. The psMGD adjustment for system calibration was particularly useful for one system for which ED had an evident miscalibration issue. The mean difference between psMGD with calibration and organ dose provided by manufacturers was 4.1 %, ranging from -16.3 % to +24.5 %. The proportion of images for which organ dose was more than 10 % 'inaccurate' compared to psMGD was between 11 % and 46 %, depending on the mammography system.

CONCLUSION

Patient-specific mean glandular dose, possibly adjusted for system calibration, allows more accurate individual breast dosimetry than what would be performed using organ dose provided by manufacturers. Conversely, definition of diagnostic reference levels could be achieved using either psMGD or organ dose.

Patient radiation dose in percutaneous biliary interventions: recommendations for DRLs on the basis of a multicentre study

OBJECTIVE

Percutaneous biliary interventions (PBIs) can be associated with a high patient radiation dose, which can be reduced when national diagnostic reference levels (DRLs) are kept in mind. The aim of this multicentre study was to investigate patient radiation exposure in different percutaneous biliary interventions, in order to recommend national DRLs.

METHODS

A questionnaire asking for the dose area product (DAP) and the fluoroscopy time (FT) in different PBIs with ultrasound- or fluoroscopy-guided bile duct punctures was sent to 200 advanced care hospitals. Recommended national DRLs are set at the 75th percentile of all DAPs.

RESULTS

Twenty-three facilities (9 interventional radiology depts. and 14 gastroenterology depts.) returned the questionnaire (12%). Five hundred sixty-five PBIs with 19 different interventions were included in the analysis. DAPs (range 4-21,510 cGy·cm2) and FTs (range 0.07-180.33 min) varied substantially depending on the centre and type of PBI. The DAPs of initial PBIs were significantly (p < 0.0001) higher (median 2162 cGy·cm2) than those of follow-up PBIs (median 464 cGy·cm2). There was no significant difference between initial PBIs with ultrasound-guided bile duct puncture (2162 cGy·cm2) and initial PBIs with fluoroscopy-guided bile duct puncture (2132 cGy·cm2) (p = 0.85). FT varied substantially (0.07-180.33 min).

CONCLUSIONS

DAPs and FTs in percutaneous biliary interventions showed substantial variations depending on the centre and the type of PBI. PBI with US-guided bile duct puncture did not reduce DAP, when compared to PBI with fluoroscopy-guided bile duct puncture. National DRLs of 4300 cGy·cm2 for initial PBIs and 1400 cGy·cm2 for follow-up PBIs are recommended.

KEY POINTS

• DAPs and FTs in percutaneous biliary interventions showed substantial variations depending on the centre and the type of PBI. • PBI with US-guided bile duct puncture did not reduce DAP when compared to PBI with fluoroscopy-guided bile duct puncture. • DRLs of 4300 cGy·cm2for initial PBIs (establishing a transhepatic tract) and 1400 cGy·cm2for follow-up PBIs (transhepatic tract already established) are recommended.

Monitoring and Follow-Up of High Radiation Dose Cases in Interventional Radiology

RATIONALE AND OBJECTIVES

To assess the implementation of radiation dose monitoring software, create a process for clinical follow-up and documentation of high-dose cases, and quantify the number of patient reported radiation-induced tissue reactions in fluoroscopically guided interventional radiology (IR) and neuro-interventional radiology (NIR) procedures.

MATERIALS AND METHODS

Web-based radiation dose monitoring software was installed at our institution and a process to flag all procedures with reference point air kerma (K_a,r) > 5000 mGy was implemented. The entrance skin dose was estimated and formal reports generated, allowing for physician-initiated clinical follow-up. To evaluate our process, we reviewed all IR and NIR procedures performed at our hospital over a 1-year period. For all procedures with K_a,r > 5000 mGy, retrospective medical chart review was performed to evaluate for patient reported tissue reactions.

RESULTS

Three thousand five hundred eighty-two procedures were performed over the 1-year period. The software successfully transferred dose data on 3363 (93.9%) procedures. One thousand three hundred ninety-three (368 IR and 1025 NIR) procedures were further analyzed after excluding 2189 IR procedures with K_a,r < 2000 mGy. Ten of 368 (2.7%) IR and 52 of 1025 (5.1%) NIR procedures exceeded estimated skin doses of 5000 mGy. All 10 IR cases were abdominal/pelvic trauma angiograms with/without embolization; there were no reported tissue reactions. Of 52 NIR cases, 49 were interventions and 3 were diagnostic angiograms. Five of 49 (10.2%) NIR patients reported skin/hair injuries, all of which were temporary.

CONCLUSION

Software monitoring and documentation of radiation dose in interventional procedures can be successfully implemented. Radiation-induced tissue reactions are relatively uncommon.

Evaluation of patient and staff exposure with state of the art X-ray technology in cardiac catheterization: A randomized controlled trial

INTRODUCTION

Cardiac catheterization procedures result in high patient radiation exposure and corresponding staff doses are reported to be among the highest for medical staff. The purpose of current randomized controlled study was to quantify the potential radiation dose reduction for both patient and staff, enabled by recent X-ray technology. This technology is equipped with advanced image processing algorithms, real-time dose monitoring, and an acquisition chain optimized for cardiac catheterization applications.

METHODS

A total of 122 adult patients were randomly assigned to one of two cath labs, either the reference X-ray modality (Allura Xper FD10, Philips Healthcare, the Netherlands) or the new X-ray system (AlluraClarity FD20/10 Philips Healthcare, the Netherlands). Exposure parameters and staff dosimeter readings were recorded for each exposure. Technical measurements were performed to define the radiation scatter behavior.

RESULTS

With the newer equipment, patient radiation dose is reduced (as total dose-area product) by 67% based on geometric means with 95%CI of 53%, 77% for diagnostic and interventional procedures. The C-arm and leg dosimeter readings were both reduced with 65% (P < 0.001), while for the collar and chest dosimeter readings no statistically significant reduction was noticed.

CONCLUSION

The new x-ray and image processing technology, significantly reduces patient dose in coronary angiographies, and PCIs by 67%. In general, scatter dose was also reduced, yet for some dosimeters the reduction was limited and not statistically significant. This study clearly indicates that the scatter behavior is highly dependent on C-arm rotation, operator movement and height, dosimeter position, beam filtration, clinical procedure type and system geometry.

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.