Personalized Feedback on Staff Dose in Fluoroscopy-Guided Interventions: A New Era in Radiation Dose Monitoring

Assessment of extremity dose for medical staff involved in positron emission tomography/computed tomography imaging: Retrospective study

There has been an increase in positron emission tomography (PET)/computed tomography (CT) imaging procedures, and medical workers involved in PET/CT are at increased risk of occupational exposure. Data on extremity dose exposure are limited globally. The current study aimed to evaluate the occupational radiation dose for extremities for medical workers (nurses, radiographers/radiologic technologists, and nuclear medicine physicians) working in PET/CT scanners at 5 large hospitals in Turkey. Optically stimulated luminescence (OSL) and Thermoluminescent dosimeter (TLD) ring dosimeters were used to measure equivalent dose values. Hospitals 1, 2, and 5 used OSL, and 3 and 4 used TLD. A total of 502 readings were obtained from 55 workers. In millisievert (mSv), the average annual effective dose for all workers was 14.5 ± 17.7 (0.2-157.2). A radiography technologist received a maximum dose of 157.21. Nurses received the highest average annual effective dose (15.2 ± 19.46) (0.32-65.58), followed by radiography technologists (14.7 ± 18.03) (0.4-157.2), and nuclear medicine physicians demonstrated the least dose (8.6 ± 10.5) (1.2-24.4). The results show that the extremity dose is well below the annual dose limit of 500 mSv. However, there is a wide variation in dose among the workers, underlining a need for careful assessment of working conditions to ensure safe practices for all workers.

Occupational radiation exposure of neurointerventionalists during endovascular stroke treatment

BACKGROUND

Radiological neuro-interventions, especially endovascular stroke treatment (EST), are increasing in case numbers worldwide with increasing occupational radiation exposure. Aim of this study was to define the radiation exposure of neurointerventionalists (NI) during EST and to compare the accumulated dose reaching the left arm with the left temple.

METHODS

This is a prospective observational study in a tertiary stroke center conducted between 11/2021 and 07/2022. Radiation exposure was measured using real time dosimetry with dosimeters being carried by the NI during EST simultaneously at the left temple and left arm. The effective dose [µSV] per dose area product (DAP) and potential influencing factors were compared in univariate analysis between the two dosimeter positions.

RESULTS

In total, 82 ESTs were analyzed with a median DAP of 6179 µGy*m² (IQR 3271 µGy*m²-11720 µGy*m²). The accumulated dose at the left arm and left temple correlated with the DAP and fluoroscopy time of the EST (DAP and arm: p = 0.01, DAP and temple: p = 0.006). The radiation exposure (RE) showed a wide range and did not differ between the two dosimeter positions (median, IQR arm 7 µSV, IQR 3.1-16.9 µSV, min. 0.3 µSV max. 64.5 µSV) vs. head 7 µSv, IQR 3.2-17.4 µSV, min. 0.38 µSV, max. 48.6 µSV, p = 0.94). Occupational RE depends on the number of thrombectomy attempts, but not the target vessel occlusion location or the NI's body height.

CONCLUSION

Neurointerventionalists experience a generally low but very variable radiation exposure during EST, which depends on the intervention's fluoroscopy time and dose area product as well as thrombectomy attempts but does not differ between left temple and left arm.

Occupational and patient doses for interventional radiology integrated into a dose management system

OBJECTIVES

The International Commission on Radiological Protection recommends managing patient and occupational doses as an integrated approach, for the optimisation of interventional procedures. The conventional passive personal dosimeters only allow one to know the accumulated occupational doses during a certain period of time. This information is not enough to identify if there is a lack of occupational radiation protection during some procedures. This paper describes the use of a dose management system (DMS) allowing patient and occupational doses for individual procedures to be audited.

METHODS

The DMS manages patient and occupational doses measured by electronic personal dosimeters. One dosemeter located at the C-arm is used as a reference for scatter radiation. Data have been collected from five interventional rooms. Dosimetry data can be managed for the whole procedure and the different radiation events. Optimisation is done through auditing different sets of parameters for individual procedures: patient dose indicators, occupational dose values, the ratio between occupational doses, and the doses measured by the reference dosemeter at the C-arm, and the ratio between occupational and patient dose values.

RESULTS

The managed data correspond to the year 2021, with around 4500 procedures, and 8000 records on occupational exposures. Patient and staff dose data (for 11 cardiologists, 7 radiologists and 8 nurses) were available for 3043 procedures. The DMS allows alerts for patient dose indicators and occupational exposures to be set.

CONCLUSIONS

The main advantage of this integrated approach is the capacity to improve radiation safety for patients and workers together, auditing alerts for individual procedures.

ADVANCES IN KNOWLEDGE

The management of patient and occupational doses together (measured with electronic personal dosimeters) for individual interventional procedures, using dose management systems, allows alerting optimisation on high-dose values for patients and staff.

The eye lens dose of the interventionalist: Measurement in practice

OBJECTIVE

Early 2018, the new eye lens dose limit of 20 mSv per year for occupational exposure to ionising radiation was implemented in the European Union. Dutch guidelines state that monitoring is compulsory above an expected eye lens dose of 15 mSv/year. In this study we propose a method to investigate whether the eye lens dose of interventionalists would exceed 15 mSv/year and to determine if the eye lens dose can be derived from the regular personal dosimeter measurements.

METHODS

The eye lens dose, Hp(3), of interventional radiologists (n = 2), cardiologists (n = 2) and vascular surgeons (n = 3) in the Máxima Medical Centre, The Netherlands, was measured during six months, using thermoluminescence dosimeters on the forehead. Simultaneously, the surface dose, Hp(0,07), and whole body dose, Hp(10), were measured using regular dosimeters outside the lead skirt at chest level. The dosimeters were simultaneously refreshed every four weeks. The eye lens dose was compared to both the body-worn dosimeter values. Measurements were performed in the angiography suite, Cath lab and hybrid OR.

RESULTS

A clear relation was observed between the two dosimeters: Hp(3) ≈ 0,25 Hp(0,07). The extrapolated year dose for the eye lens did not exceed 15 mSv for any of the interventionalists (average 3 to 10 studies/month).

CONCLUSIONS

The eye lens dose can be monitored indirectly through the regular dosimeter at chest level. Additionally, based on the measurements we conclude that all monitored interventionalists remain below the dose limit and compulsory monitoring limit for the eye lens dose.

What Is Worth Knowing in Interventional Practices about Medical Staff Radiation Exposure Monitoring: A Review of Recent Outcomes of EURADOS Working Group 12

EURADOS (European Radiation Dosimetry Group) Working Group 12 (WG12) SG1 activities are aimed at occupational radiation protection and individual monitoring in X-ray and nuclear medicine practices. In recent years, many studies have been carried out in these fields, especially for interventional radiology and cardiology workplaces (IC/IR). The complexity of the exposure conditions of the medical staff during interventional practices makes the radiation protection and monitoring of the exposed workers a challenging task. The scope of the present work is to review some of the main results obtained within WG12 activities about scattered field characterization and personal dosimetry that could be very useful in increasing the quality of radiation protection of the personnel, safety, and awareness of radiation risk. Two papers on Monte Carlo modelling of interventional theater and three papers on active personal dosimeters (APDs) for personnel monitoring were considered in the review. More specifically, Monte Carlo simulation was used as the main tool to characterize the levels of exposure of the medical staff, allowing to determine how beam energy and direction can have an impact on the doses received by the operators. Indeed, the simulations provided information about the exposure of the operator’s head, and the study concluded with the determination of an eye-lens protection factor when protection goggles and a ceiling shielding are used. Moreover, the review included the results of studies on active personal dosimeters, their use in IC/IR workplaces, and how they respond to calibration fields, with X-ray standard and pulsed beams. It was shown that APDs are insensitive to backscatter radiation, but some of them could not respond correctly to the very intense pulsed fields (as those next to the patient in interventional practices). The measurements during interventional procedures showed the potential capability of the employment of APDs in hospitals.

Beliefs, Facilitating Factors, and Barriers in Using Personal Dosimeter among Medical Radiation Workers in a Middle-Income Asian Setting

This qualitative study explores the medical radiation workers' (MRWs) beliefs with the support of the theory of planned behaviour's constructs regarding the use of personal dosimeters in order to identify the facilitating factors and barriers to practising good personal dose monitoring. The exploration was conducted through semi-structured face-to-face interviews with 63 MRWs from the public, private, and university hospitals. Belief statements from the informants were organized under the behavioural, normative, and control belief, as guided by the theory. A thematic analysis found that a majority of informants acknowledged the benefits of using dosimeters. However, several factors influenced the actual usage. The informants were hesitant to use the dosimeter as the loss of the device involved an expensive penalty. They also mentioned that delayed dosimeter supplies due to late budget approval in the hospitals and some other reasons had got them disconnected from the monitoring system. The workers' attitudes and social norms highly induced their dosimeter usage as well; some perceived themselves to be at low risk for high exposure to radiation, and forgetfulness was also mentioned as a reason for lack of adherence. Device physical factor influenced low dosimeter use too. This study highlighted some unique findings in Asian settings. A better understanding of the underlying reasons for the lack of dosimeter use will be useful in developing strategies to increase good practices in personal radiation monitoring.

Challenges in Occupational Dosimetry for Interventional Radiologists

This review presents the challenges met by interventional radiologists in occupational dosimetry. The issues mentioned are derived from the recommendations of the International Commission on Radiological Protection, the CIRSE guidelines on "Occupational radiation protection in interventional radiology" and the requirements of the European directive on Basic Safety Standards. The criteria for a proper use of personal dosimeters and the need to introduce optimization actions in some cases are set out in this review. The pros and cons of the electronic real-time dosimeters are outlined and the potential pitfalls associated with the use of personal dosimeters summarized. The electronic dosimeters, together with the appropriate software, allow an active optimization of the interventional procedures.

Performance indicators for radiation protection management: suggestions from the European Society of Radiology

In 2013, the new European Basic Safety Standards Directive 2013/59/Euratom (BSS Directive), which defines the new legal framework for the use of ionising radiation in medical imaging and radiotherapy, was published. In 2014, the ESR EuroSafe Imaging Initiative was founded with a goal in mind “to support and strengthen medical radiation protection across Europe following a holistic, inclusive approach”. To support radiology departments in developing a programme of clinical audit, the ESR developed a Guide to Clinical Audit and an accompanying audit tool in 2017, with an expanded second edition released in 2019 and published under the name of Esperanto – ESR Guide to Clinical Audit in Radiology and the ESR Clinical Audit Tool, 2019. Audits represent specific aspects at a certain point in time, usually with retrospective evaluation of data. Key performance indicators (KPIs), on the other hand, are intended to enable continuous monitoring of relevant parameters, for example to provide warnings or a dashboard. KPIs, which can, for example, be recorded automatically and visualised in dashboards, are suitable for this purpose. This paper will discuss a selection of indicators covering different areas and include suggestions for their implementation.

Helping to know if you are properly protected while working in interventional cardiology

Occupational protection is still a challenge for interventional cardiology. One of the main problems is the occasional improper use of the ceiling suspended screen. We present a methodology to audit the correct use of the shielding using active electronic dosimeters. To improve the protection, we suggest the use of an alert based on the ratio between the occupational dose per procedure, measured by a personal electronic dosimeter over the lead apron, and the dose measured by an unshielded dosimeter, located at the C-arm. The new electronic dosimeters and the automatic dose management systems allow processing the dosimetric data for individual procedures and for the radiation events, sending the values (wireless) to a central database. We selected six interventional cardiologists and analysed 385 interventional procedures involving about 30 000 radiation events. Our results suggest that for individual procedures, standard values of the ratio between operator dose and the C-arm reference dose, should be between 1%-2% for a proper use of the shielding. Percentage values ≥5%-10% for individual procedures, require an analysis of the different radiation events to identify the lack of occupational protection and suggest corrective actions. In our sample, half of the operators should improve the use of the shielding in around 20% of the procedures. Using this ratio as an alert to operators allows optimising occupational radiation protection and discriminating between high occupational doses derived from complex procedures and high doses due to the improper use of the protective screen.

Absorbed dose in the operator's brain in interventional radiology practices: evaluation through KAP value conversion factors

In order to address the recent concerns over a possible increasing in brain tumour mortality among interventional radiologists and cardiologist, this work evaluated the exposure conditions of the operator's brain during interventional procedures using Monte Carlo simulations with anthropomorphic phantoms. The absorbed doses in several predefined segments of the operator's brain were estimated in a typical interventional radiology irradiation scenario. The doses were normalized to the KAP values simulated for ten X-ray beam qualities and four projections (PA, RAO 25°, LAO 25° and CRA 25°). For the interventional radiology scenario, because of the position of the operator, no difference was found in the exposure between the left and right regions of the brain for the first operator. However, for the second operator standing at a farer distance from the tube, the exposure of the left part of the brain is up to two times higher than that of the right part. The results are in agreement with dose measurements reported in the literature. The conversion factors, obtained as the absorbed dose per KAP, can be used to obtain a first estimate of the exposure of the brain of the operators during interventional procedures.

Neurointerventionalist and Patient Radiation Doses in Endovascular Treatment of Acute Ischemic Stroke

PURPOSE

To evaluate the patient and the neurointerventionalist radiation dose levels during endovascular treatment of acute ischemic stroke, and to analyze factors affecting doses.

MATERIALS AND METHODS

From October 2017 to January 2019, we prospectively collected patient radiation data and neurointerventionalist data from real-time dosimetry from all consecutive thrombectomies. Multivariate analysis was performed to analyze patient total dose area product (DAP) and neurointerventionalist dose variability in terms of clinical characteristics and the technical parameters of thrombectomies. Local dose reference levels (RL) were derived as the 75th percentile of the patient dose distributions.

RESULTS

A total of 179 patients were treated during the study period and included in this study. Local dose RL for thrombectomy was derived for total DAP to 34 Gy cm², cumulative air kerma of 242 mGy and fluoroscopy time of 12 min. The mean neurointerventionalist dose for thrombectomy was 7.7 ± 7.4 µSv. Height (P = 0.018), weight (P = 0.004), body mass index (P = 0.015), puncture to recanalisation (P < 0.001), fluoro time (P < 0.001), number of passes (P < 0.001), thrombolysis in cerebral infarction 2b/3 recanalisation (P = 0.034) and aspiration thrombectomy (P < 0.001) were independent factors affecting patient total DAP, whereas baseline National Institutes of Health Stroke Scale (P = 0.043), puncture to recanalisation (P = 0.003), fluoroscopy time (P = 0.009) and number of passes (P = 0.009) were factors affecting the neurointerventionalist dose.

CONCLUSION

New reference patient doses lower than those in previously published studies were defined. However, the operator's doses were higher than those in the only available study reporting on operator's dose during cerebral interventions.

OCCUPATIONAL DOSE AND RADIATION PROTECTION PRACTICE IN UAE: A RETROSPECTIVE CROSS-SECTIONAL COHORT STUDY (2002-2016)

A two-phased retrospective cross-sectional study analysed the occupational dose and radiation protection practice among medical workers in two hospitals in the UAE. Phase 1 evaluated radiation protection practice using a questionnaire, whereas phase 2 assessed the occupational dose. Readings of 952 thermoluminescence dosimeters were analyzed. The result showed 52% of medical workers have a good level of radiation protection practice. Readings of 952 thermoluminescence dosimeters were analyzedAverage annual effective dose per worker ranged from 0.39 to 0.83 mSv. Cardiologists and nurses displayed a higher average of occupational radiation dose compared to other workers. There were no significant correlations between radiation protection practice and hospital, occupation or department. Finally, the occupational dose was within the international and national limits, but the reduction of radiation dose to cardiologist and nurses is essential. Moreover, training is essential to promote radiation safe practice among medical workers.

Reduction of radiation exposure to operating physician and assistant using a real-time auditory feedback dosimeter during femoral artery puncturing: a study on swine model

Background

Real-time dosimeters may create a relatively safer environment not only for the patient but also for the physician and the assistant as well. We propose the use of a real-time radiation measurement dosimeter having auditory feedback to reduce radiation exposure.

Methods

Radiation dose rates were measured for 30 fluoroscopy-guided puncturing procedures of femoral arteries in swine. Fifteen puncturing procedures were performed with real-time radiation measurement dosimeter having auditory feedback and other 15 were performed without auditory feedback dosimeter by an interventional cardiologist with 10 years of experience.

Results

The left body side of the operating physician (38%, p < 0.001) and assistant (25%, p < 0.001) was more exposed as compared to the right body side. Radiation dose rate to the left hand, left arm and left leg were reduced from 0.96 ± 0.10 to 0.79 ± 0.12 mSv/h (17% reduction, p < 0.001), from 0.11 ± 0.02 to 0.07 ± 0.01 mSv/h (36% reduction, p < 0.001) and from 0.22 ± 0.06 to 0.15 ± 0.02 mSv/h (31% reduction, p < 0.001) with the use of auditory feedback dosimeter, respectively. The mean fluoroscopic time was reduced from 4.8 ± 0.43 min to 4.2 ± 0.53 min (p < 0.001). The success rate of performing arterial puncturing was 100%.

Conclusions

The use of auditory feedback dosimeter resulted in reduction in effective dose. The sound beep alerted the physician from the danger of exposure, and this approach induced awareness and protective mindset to the operating physician and assistant.

Simulation of H p (10) and effective dose received by the medical staff in interventional radiology procedures

Interventional radiology and cardiology are widespread employed techniques for diagnosis and treatment of several pathologies because they avoid the majority of the side-effects associated with surgical treatments, but are known to increase the radiation exposure to patient and operators. In recent years many studies treated the exposure of the operators performing cardiological procedures. The aim of this work is to study the exposure condition of the medical staff in some selected interventional radiology procedures. The Monte Carlo simulations have been employed with anthropomorphic mathematical phantoms reproducing the irradiation scenario of the medical staff with two operators and the patient. A personal dosemeter, put on apron, was modelled for comparison with measurements performed in hospitals, done with electronic dosemeters, in a reduced number of interventional radiology practices. Within the limits associated to the use of numerical anthropomorphic models to mimic a complex interventional procedure, the personal dose equivalent, H _p (10), was evaluated and normalised to the simulated Kerma-Area Product, KAP, value, indeed the effective dose has been calculated. The H _p (10)/KAP_value of the first operator is about 10 μSv/Gy.cm², when ceiling shielding is not used. This value is calculated on the trunk and it varies of +/-30% moving the dosemeter to the waist or to the neck. The effective dose, normalised to the KAP value, varies between 0.03 and 0.4 μSv/Gy.cm². Considering all the unavoidable approximation of this kind of investigations, the comparisons with hospital measurement and literature data showed a good agreement allowing to use of the present results for dosimetric characterisation of interventional radiology procedures.

Optimizing Staff Dose in Fluoroscopy-Guided Interventions by Comparing Clinical Data with Phantom Experiments

PURPOSE

To evaluate conditions for minimizing staff dose in interventional radiology, and to provide an achievable level for radiation exposure reduction.

MATERIALS AND METHODS

Comprehensive phantom experiments were performed in an angiography suite to evaluate the effects of several parameters on operator dose, such as patient body part, radiation shielding, x-ray tube angulation, and acquisition type. Phantom data were compared with operator dose data from clinical procedures (n = 281), which were prospectively acquired with the use of electronic real-time personal dosimeters (PDMs) combined with an automatic dose-tracking system (DoseWise Portal; Philips, Best, The Netherlands). A reference PDM was installed on the C-arm to measure scattered radiation. Operator exposure was calculated relative to this scatter dose.

RESULTS

In phantom experiments and clinical procedures, median operator dose relative to the dose-area product (DAP) was reduced by 81% and 79% in cerebral procedures and abdominal procedures, respectively. The use of radiation shielding decreased operator exposure up to 97% in phantom experiments; however, operator dose data show that this reduction was not fully achieved in clinical practice. Both phantom experiments and clinical procedures showed that the largest contribution to relative operator dose originated from left-anterior-oblique C-arm angulations (59%-75% of clinical operator exposure). Of the various x-ray acquisition types used, fluoroscopy was the main contributor to procedural DAP (49%) and operator dose in clinical procedures (82%).

CONCLUSIONS

Achievable levels for radiation exposure reduction were determined and compared with real-life clinical practice. This generated evidence-based advice on the conditions required for optimal radiation safety.

Procedure and step-based analysis of the occupational radiation dose during endovascular aneurysm repair in the hybrid operating room

OBJECTIVE

This study measured the cumulative occupational X-ray radiation dose received by support staff during endovascular aortic procedures and during additional intraoperative steps in the hybrid operating room.

METHODS

Radiation dose measurements were performed during interventions on 65 patients receiving 90 stent grafts during endovascular aneurysm repair (EVAR), bifurcated EVAR, thoracic EVAR, iliac branched device deployment, aortouni-iliac stenting, and fenestrated/branched EVAR (F/BrEVAR). X-ray imaging was acquired using the Philips Allura FD20 Clarity System (Philips Medical Systems, Best, The Netherlands). The occupational radiation dose (also referred to as the estimated effective dose, E, measured in millisieverts) was measured with the DoseAware Xtend system (Philips Medical Systems) personal dosimeters. E was reported per staff member (E_STAFF), where "staff" was a generic term for each staff member included in the study: the first operator (FO), the second operator (ESO), a virtual maximum operator (MO), and all additional supporting staff, including the sterile nurse, nonsterile nurse, anaesthesiologist, and radiation technician. The primary outcome was the median cumulative E_STAFF (or E_FO, E_MO, and so on), which was presented as the median cumulative dose per intervention and stratified for several within-interventional EVAR and F/BrEVAR steps or stents. The second outcome was the percentage of the absorbed E by a supporting staff member in relation to the E measured by the reference badge attached on the C-arm (E_STAFF% or E_FO%, E_MO%, and so on). All outcomes are presented as median with interquartile range, unless stated differently.

RESULTS

The occupational effective dose in millisieverts of the MO (E_MO) was 0.055 (0.029-0.082) for aortouni-iliac stenting (n = 6), 0.084 (0.054-0.141) during thoracic EVAR (n = 14), 0.036 (0.026-0.068) during bifurcated EVAR (n = 38), 0.054 (0.035-0.126) during iliac branched device deployment (n = 8), and 0.345 (0.235-0.757) during F/BrEVAR (n = 24). The median E_MO in millisieverts was 0.025 (0.012-0.062) per renal target vessel (TV) and 0.146 (0.07-0.315) for a nonrenal visceral TV. During all noncomplex interventions, the E_MO% was 4.4% (2.7%-7.3%), with the lowest median rate at 3.5% (2.5%-5%) for EVAR. The highest median rate E_MO% was found for F/BrEVAR procedures: 8.2% (5.0%-14.4%).

CONCLUSIONS

With maximum operator shielding during femoral access, relative occupational radiation risk can be minimized. However, digital subtraction angiography image acquisition, recanalization of TVs, recanalization of superior mesenteric artery or celiac artery, and recanalization of branched TVs are predictors for increased occupational radiation dose risks caused by increased radiation doses to the patient and reduced options for shielding of the operator.