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

Development, Feasibility, and Knowledge Impact of a Massive Open Online Course on Radiation Safety: A Multicentre Prospective Cohort Study

OBJECTIVE

This study reports the development of an innovative, interactive Massive Open Online Course (MOOC) teaching radiation safety principles in the vascular workplace, using stepwise e-learning with multiple choice question tests (MCQs), educational videos, and a serious game. The aim was to study the MOOC impact on radiation safety knowledge and assess its feasibility and acceptability.

METHODS

An international multicentre prospective study included team members active in the hybrid operating room. The MOOC was offered voluntarily via a secure online learning platform. A standardised MCQ test (15 questions) assessed radiation safety knowledge pre- and post-course (range 0 - 100%). Acceptability and feasibility were tested via the previously validated, Evaluating e-learning system success (EESS) model, using five point Likert scales.

RESULTS

In eight centres across four countries, 150 of 203 invited endovascular team members consented. Over a seven week study period, surgeons (28%, including vascular surgery trainees and consultants), nurses (27%, including scrub, circulating and anaesthetic nurses), anaesthetists (43%, including trainees and consultants), and radiographers (3%) participated. Of those, 67% completed the course. The average radiation knowledge improved by 22.8% (95% CI 19.5 - 26.0%; p < .001) after MOOC completion, from 48% to 71% (standard deviation [SD] 14 and 15% respectively), requiring a mean time investment of 169 minutes (SD 89 minutes). In centres with a radiographer, mean knowledge gain after MOOC completion was significantly smaller (14%, SD 19% vs. 24%, SD 16%, p = .036). The course was deemed feasible and acceptable according to the EESS model with a total mean score of 3.68/5.

CONCLUSION

This newly developed, multimodal MOOC was deemed feasible and effective across multiple international centres. The MOOC significantly contributes to radiation safety education of the entire endovascular team, improving radiation safety knowledge. The course may optimise workplace radiation safety behaviour and therefore enhance team and patient safety.

Trends and predictors of radiation exposure in percutaneous coronary intervention: the PROTECTION VIII study

BACKGROUND

Percutaneous coronary intervention (PCI) is indispensable in cardiology; however, exposure to potentially harmful ionising radiation remains a concern.

AIMS

This study was designed to assess the PCI-related radiation dose over the last decade and to identify predictors of increased dose exposure.

METHODS

The PROcedural radiaTion dose Exposure in percutaneous Coronary intervenTION (PROTECTION VIII) study included all PCIs reported to a German quality assurance programme between 2008 and 2018. Dose area product (DAP) and radiation time were analysed. Effective dose (ED) was estimated (ED=DAP*k; conversion coefficient k=0.0022 mSv/cGy*cm²). Multivariate linear regression analysis was used to identify predictors associated with a clinically relevant increase of radiation dose (ED ≥1 mSv).

RESULTS

We enrolled 3,704,986 patients undergoing PCI (median age 70 years, 30% female). Indications were chronic coronary syndrome (37.5%), unstable angina pectoris and non-ST-segment elevation myocardial infarction (non-STEMI; 33.2%) and STEMI (18.5%). Median DAP was 4,203 (interquartile range [IQR] 2,313-7,300) cGy*cm, ED was 9.2 mSv and median radiation time was 9.2 (IQR 5.8-15.0) min. Within the 10-year period, radiation exposure was reduced by 36% (p<0.001) and resulted in a median DAP of 3,070 cGy*cm (ED 6.8 mSv) in 2018. A significant 5.3-fold variability of median DAP was observed between catheterisation laboratories (p<0.001). We identified patient-related (gender, coronary artery bypass graft surgery, heart failure) and procedure-related (coronary occlusion PCI, ostial lesion PCI, left main PCI, multivessel PCI) predictors of increased radiation dose (all p<0.001).

CONCLUSIONS

This radiation dose survey demonstrates a considerable reduction of PCI radiation exposure during the last decade. However, large variability between catheterisation laboratories underlines the need for further radiation dose reduction.

Patient radiation dose during angiography and embolization for abdominal hemorrhage: the influence of CT angiography, fluoroscopy system, patient and procedural variables

Background

Angiography and embolization (AE) is a lifesaving, high radiation dose procedure for treatment of abdominal arterial hemorrhage (AAH). Interventional radiologists have utilized pre-procedure CT angiography (CTA) and newer fluoroscopic systems in an attempt to reduce radiation dose and procedure time.

Purpose

To study the factors contributing to the radiation dose of AE for AAH and to compare to the reference standard.

Materials and methods

This retrospective single-centre observational cohort study identified 154 consecutive AE procedures in 138 patients (median age 65 years; interquartile range 54–77; 103 men) performed with a C-arm fluoroscopic system (Axiom Artis DTA or Axiom Artis Q (Siemens Healthineers)), between January 2010 and December 2017. Parameters analysed included: demographics, fluoroscopy system, bleeding location, body mass index (BMI), preprocedural CT, air kerma-area product (PKA), reference air kerma (K_a,r), fluoroscopy time (FT) and the number of digital subtraction angiography (DSA) runs. Factors affecting dose were assessed using Mann–Whitney U, Kruskal–Wallis one-way ANOVA and linear regression.

Results

Patients treated with the new angiographic system (NS) had a median PKA, median K_a,r, Q3 PKA and Q3 K_a,r that were 74% (p < 0.0005), 66%(p < 0.0005), 55% and 52% lower respectively than those treated with the old system (OS). This dose reduction was consistent for each bleeding location (upper GI, Lower GI and extraluminal). There was no difference in PKA (p = 0.452), K_a,r (p = 0.974) or FT (p = 0.179), between those who did (n = 137) or did not (n = 17) undergo pre-procedure CTA. Other factors significantly influencing radiation dose were: patient BMI and number of DSA runs. A multivariate model containing these variables accounts for 15.2% of the variance in K_a,r (p < 0.005) and 45.9% of the variance of PKA (p < 0.005).

Conclusion

Radiation dose for AE in AAH is significantly reduced by new fluoroscopic technology. Higher patient body mass index is an independent key parameter affecting patient dose. Radiation dose was not influenced by haemorrhage site or performance of pre-procedure CTA.

Occupational radiation exposure in doctors: an analysis of exposure rates over 25 years

OBJECTIVES

Healthcare professionals' occupational exposure to ionising radiation may be increasing due to increasing use of imaging and image-guided intervention. This study aims to assess the occupational exposure of doctors over a 25-year period at an NHS teaching hospital.

METHODS

Dosemeter measurements were collected prospectively from 1995 to 2019. Two retrospective analyses were performed over time (first including all measurements, second excluding "zero-dose" measurements), and by speciality. Group comparisons were undertaken using multilevel linear regression; a p-value <0.05 was deemed significant.

RESULTS

8,892 measurements (3,983 body, 1,514 collar, 649 eye, 2,846 hand), of which 3,350 were non-zero measurements (1,541 body, 883 collar, 155 eye, 771 hand), were included. Whole dataset analysis found a significant decrease in exposure for radiologists and cardiologists, as measured by body, hand and collar dosemeters over the last 25 years (p < 0.01 for all). The non-zero readings reflect the whole cohort analysis except in the case of eye dosemeters, which showed a significant decrease in exposure for cardiologists (p < 0.01), but a significant increase for radiologists and surgeons/anaesthetists (p < 0.01 for both).

CONCLUSIONS

Whilst ionising radiation remains an occupational risk for doctors, the overall decreasing trend in occupational exposure is reassuring. However, a significant rise in eye dose for radiologists, surgeons and anaesthetists is concerning, and close monitoring is required to prevent future issues.

ADVANCES IN KNOWLEDGE

This paper is one of few evaluating the occupational radiation exposure to doctors over a 25-year period, showing that although most dosemeter measurements reflect decreasing exposure, the increase in eye exposure warrants caution.

High filtration in interventional practices reduces patient radiation doses but not always scatter radiation doses

OBJECTIVES

In fluoroscopy-guided interventional practices, new dose reduction systems have proved to be efficient in the reduction of patient doses. However, it is not clear whether this reduction in patient dose is proportionally transferred to operators' doses. This work investigates the secondary radiation fields produced by two kinds of interventional cardiology units from the same manufacturer with and without dose reduction systems.Methods:Data collected from a large sample of clinical procedures over a 2-year period (more than 5000 procedures and 340,000 radiation events) and the DICOM radiation dose structured reports were analysed.

RESULTS

The average cumulative H_p(10) per procedure measured at the C-arm was similar for the standard and the dose reduction systems (452 vs 476 μSv respectively). The events analysis showed that the ratio H_p(10)/KAP at the C-arm was (mean ± SD) 5 ± 2, 10 ± 4, 14 ± 4 and 14 ± 6 μSv·Gy^-1·cm^-2 for the beams with no added filtration, 0.1, 0.4 and 0.9 mm Cu respectively and suggested that the main cause for the increment of the ratio H_p(10)/KAP vs the "standard system" is the use of higher beam filtration in the "dose reduction" system.

CONCLUSION

Dose reduction systems are beneficial to reduce KAP in patients and their use should be encouraged, but they may not be equally effective to reduce occupational doses. Interventionalists should not overlook their own personal protection when using new technologies with dose reduction systems.

ADVANCES IN KNOWLEDGE

Dose reduction technology in interventional systems may increase scatter dose for operators. Personal protection should not be overlooked with dose reduction systems.

Combining Optimized Image Processing With Dual Axis Rotational Angiography: Toward Low-Dose Invasive Coronary Angiography

Background

Dual axis rotational coronary angiography (DARCA) reduces radiation exposure during coronary angiography on older x‐ray systems. The purpose of the current study is to quantify patient and staff radiation exposure using DARCA on a modality already equipped with dose‐reducing technology. Additionally, we assessed applicability of 1 dose area product to effective dose conversion factor for both DARCA and conventional coronary angiography (CCA) procedures.

Methods and Results

Twenty patients were examined using DARCA and were compared with 20 age‐, sex‐, and body mass index–matched patients selected from a prior study using CCA on the same x‐ray modality. All irradiation events are simulated using PCXMC (STUK, Finland) to determine organ and effective doses. Moreover, for DARCA each frame is simulated. Staff dose is measured using active personal dosimeters (DoseAware, Philips Healthcare, The Netherlands). With DARCA, median cumulative dose area product is reduced by 57% (ie, 7.41 versus 17.19 Gy·cm²). Effective dose conversion factors of CCA and DARCA are slightly different, yet this difference is not statistically significant. The occupational dose at physician's chest, leg, and collar level are reduced by 60%, 56%, and 16%, respectively, of which the first 2 reached statistical significance. Median effective dose is reduced from 4.75 mSv in CCA to 2.22 mSv in DARCA procedures, where the latter is further reduced to 1.79 mSv when excluding ventriculography.

Conclusions

During invasive coronary angiography, DARCA reduces radiation exposure even further toward low‐dose values on a system already equipped with advanced image processing and noise reduction algorithms. For both DARCA and CCA procedures, using 1 effective dose conversion factor of 0.30 mSv·Gy⁻¹·cm⁻² is feasible.