Evaluation of the impact of a system for real-time visualisation of occupational radiation dose rate during fluoroscopically guided procedures

Occupational doses in interventional angiography after radiological protection training and use of a real-time direct display dosimeter

Vascular x-ray guided interventions are complex and may result in high occupational doses to ionising radiation if staff do not take appropriate actions to minimise their exposure. In this prospective intervention study, ten staff members wore an extra personal dosimeter on the upper body above their regular protective clothing during four consecutive periods. Between each period either additional practical radiological protection training was given or a real-time direct display dosimeter were provided to the staff. Each staff's personal dose equivalent, Hp(10) normalised to the total air kerma-area product for the procedures where each staff were involved, KAPt, was used as the dependent variable. A focus-group interview with the staff were performed about the usefulness of the training and real-time dose rate display system. Our aim was to investigate if the interventions (practical training or real-time dose rate display) did affect the staff doses in the short and long term (five months later). Significant (p < 0.05) reductions of staff doses Hp(10)/KAPt were found after practical radiological protection training, but not after using real-time dose rate displays. Significant reductions were maintained after five months without additional interventions. The results from the focus-group interview indicated that making radiation 'visible', during practical training and usage of real-time direct display dosimeter, made it easier to understand how to act to lower occupational doses.

DOES RADIOLOGICAL PROTECTION TRAINING OR A REAL-TIME STAFF DOSEMETER DISPLAY REDUCE STAFF DOSES DURING X-RAY-GUIDED PULMONARY BRONCHOSCOPY?

X-ray-guided interventions have increased in number and complexity. Mandatory radiological protection training includes both theoretical and practical training sessions. A recent additional training tool is real-time display dosemeters that give direct feedback to staff on their individual dose rates. Ten staff members who regularly perform pulmonary bronchoscopy wore an extra dosemeter during four 2-month periods. We controlled for the patient air kerma area product and the number of procedures in each period. Between periods 1 and 2, radiological training sessions were held and during period 3 the staff used the real-time display system. Focus-group interviews with the staff were held to obtain their opinion about learning radiological protection. We hypothesised that neither training nor the additional real-time dose rate display alters the personal dose equivalent, Hp(d); d = 0.07 and 10 mm. Useful experiences from radiological protection training were obtained, and median staff doses did decrease, however not significantly.

Occupational dose and associated factors during transarterial chemoembolization of hepatocellular carcinoma using real-time dosimetry: A simple way to reduce radiation exposure

Transarterial chemoembolization is the standard treatment option for intermediate-stage hepatocellular carcinoma (HCC). However, during the interventional procedure, occupational radiation protection is compromised. The use of real-time radiation dosimetry could provide instantaneous radiation doses. This study aimed to evaluate the occupational dose of the medical staff using a real-time radiation dosimeter during transarterial chemoembolization (TACE) for HCC, and to investigate factors affecting the radiation exposure dose.This retrospective observational study included 70 patients (mean age: 66 years; age range: 38-88 years; male: female = 59: 11) who underwent TACE using real-time radiation dosimetry systems between August 2018 and February 2019. Radiation exposure doses of operators, assistants, and technicians were evaluated. Patients' clinical, imaging, and procedural information was analyzed.The mean dose-area product (DAP) and fluoroscopy time during TACE were 66.72 ± 55.14 Gycm2 and 12.03 ± 5.95 minutes, respectively. The mean radiation exposure doses were 24.8 ± 19.5, 2.0 ± 2.2, and 1.65 ± 2.0 μSv for operators, assistants, and technicians, respectively. The radiation exposure of the operators was significantly higher than that of the assistants or technicians (P < .001). The perpendicular position of the adjustable upper-body lead protector (AULP) on the table was one factor reducing in the radiation exposure of the assistants (P < .001) and technicians (P = .040). The DAP was a risk factor for the radiation exposure of the operators (P = .003) and technicians (P < .001).Occupational doses during TACE are affected by DAP and AULP positioning. Placing the AULP in the perpendicular position during fluoroscopy could be a simple and effective way to reduce the radiation exposure of the staff. As the occupational dose influencing factors vary by region or institution, further study is needed.

A case study of cost-benefit analysis in occupational radiological protection within the healthcare system of Sweden

The aim of the present study was to demonstrate cases of cost-benefit analysis within healthcare, of how economic factors can be considered in occupational radiological protection, in agreement with the as low as reasonably achievable principle and present Swedish legislations. In the first part of the present study, a comparison of examples within health economics used by authorities and institutes in Sweden was made. The comparison focused on value of a statistical life, quality-adjusted life year, and monetary cost assigned to a unit of collective dose for radiation protection purposes (α-value). By this comparison, an α-value was determined as an interval between $45 and $450 per man-mSv, for the Swedish society in 2021. The α-value interval can be interpreted as following: Less than $45 per man-mSv is a good investment. From $45 to $450 per man-mSv, other factors than costs and collective dose are important to consider. More than $450 per man-mSv is too expensive. In the second part of the present study, seven cases of cost-benefit analyses in occupational radiological protection were provided. The present study focused specifically on cases where the relevant factors were costs and collective dose. The present case study shows a large variation in costs per collective dose from different types of occupational radiological protection, used at Skaraborg Hospital in Sweden.

Occupational radiation exposure to the head is higher for scrub nurses than cardiologists during cardiac angiography

AIMS

This study aimed to compare the head dose of a cardiologist to scrub and scout nurses during cardiac angiography.

DESIGN

A correlational longitudinal quantitative design was used to examine the relationship between the variable of occupational dose to the medical operator when compared with the dose to the scrub and scout nurses.

METHODS

A quantitative analysis was performed on data collected during coronary angiograms (N = 612) for one cardiologist and 22 nurses performing either the scrub or scout role between May 2015 and February 2017. Analysis was based on log-transformed dose levels and reported as geometric means and associated 95% confidence intervals.

RESULTS

It was found that scrub nurses received on average 41% more head dose than the cardiologist during diagnostic procedures and 52% higher doses during interventional cases.

CONCLUSION

Nurses working in fluoroscopic cardiovascular procedures should be provided with appropriate training and protective equipment, notably lead skull caps, to minimize their occupational radiation exposure.

IMPACT

There is a notable lack of research evaluating the occupational head and eye exposure to nurses involved in fluoroscopic procedures. This study found that during diagnostic coronary angiograms, the scrub nurses received 41% more occupational head dose than the cardiologist and 52% higher head doses during interventional cases. Radial access resulted in higher doses to scrub nurses than femoral artery access. It is advisable that staff wear protective lead glasses and skull caps and use appropriately positioned ceiling mounted lead shields to minimize the risk of adverse effects of occupational exposure to ionizing radiation.

Occupational radiation exposure to nursing staff during cardiovascular fluoroscopic procedures: A review of the literature

Fluoroscopy is a method used to provide real time x-ray imaging of the body during medical procedures to assist with medical diagnosis and treatment. Recent technological advances have seen an increase in the number of fluoroscopic examinations being performed. Nurses are an integral part of the team conducting fluoroscopic investigations and are often located close to the patient resulting in an occupational exposure to radiation. The purpose of this review was to examine recent literature which investigates occupational exposure received by nursing staff during cardiovascular fluoroscopic procedures. Articles published between 2011 and 2017 have been searched and comprehensively reviewed on the referenced medical search engines. Twenty-four relevant studies were identified among which seventeen investigated nursing dose comparative to operator dose. Seven researched the effectiveness of interventions in reducing occupational exposure to nursing staff. While doctors remain at the highest risk of exposure during procedures, evidence suggests that nursing staff may be at risk of exceeding recommended dose limits in some circumstances. There is also evidence of inconsistent use of personal protection such as lead glasses and skull caps by nursing staff to minimize radiation exposure. Conclusions: The review has highlighted a lack of published literature focussing on dose to nurses. There is a need for future research in this area to inform nursing staff of factors which may contribute to high occupational doses and of methods for minimizing the risk of exposure, particularly regarding the importance of utilizing radiation protective equipment.

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.

Defining the Key Competencies in Radiation Protection for Endovascular Procedures: A Multispecialty Delphi Consensus Study

OBJECTIVES

Radiation protection training courses currently focus on broad knowledge topics which may not always be relevant in daily practice. The goal of this study was to determine the key competencies in radiation protection that every endovascular team member should possess and apply routinely, through multispecialty clinical content expert consensus.

METHODS

Consensus was obtained through a two round modified Delphi methodology. The expert panel consisted of European vascular surgeons, interventional radiologists, and interventional cardiologists/angiologists experienced in endovascular procedures. An initial list of statements, covering knowledge skills, technical skills and attitudes was created, based on a literature search. Additional statements could be suggested by the experts in the first Delphi round. Each of the statements had to be rated on a 5- point Likert scale. A statement was considered to be a key competency when the internal consistency was greater than alpha = 0.80 and at least 80% of the experts agreed (rating 4/5) or strongly agreed (rating 5/5) with the statement. Questionnaires were emailed to panel members using the Surveymonkey service.

RESULTS

Forty-one of 65 (63.1%) invited experts agreed to participate in the study. The response rates were 36 out of 41 (87.8%): overall 38 out of 41(92.6%) in the first round and 36 out of 38 (94.7%) in the second round. The 71 primary statements were supplemented with nine items suggested by the panel. The results showed excellent consensus among responders (Cronbach's alpha = 0.937 first round; 0.958 s round). Experts achieved a consensus that 30 of 33 knowledge skills (90.9%), 23 of 27 technical skills (82.1%), and 15 of 20 attitudes (75.0%) should be considered as key competencies.

CONCLUSIONS

A multispecialty European endovascular expert panel reached consensus about the key competencies in radiation protection. These results may serve to create practical and relevant radiation protection training courses in the future, enhancing radiation safety for both patients and the entire endovascular team.

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

PURPOSE

Radiation safety and protection are a key component of fluoroscopy-guided interventions. We hypothesize that providing weekly personal dose feedback will increase radiation awareness and ultimately will lead to optimized behavior. Therefore, we designed and implemented a personalized feedback of procedure and personal doses for medical staff involved in fluoroscopy-guided interventions.

MATERIALS AND METHODS

Medical staff (physicians and technicians, n = 27) involved in fluoroscopy-guided interventions were equipped with electronic personal dose meters (PDMs). Procedure dose data including the dose area product and effective doses from PDMs were prospectively monitored for each consecutive procedure over an 8-month period (n = 1082). A personalized feedback form was designed displaying for each staff individually the personal dose per procedure, as well as relative and cumulative doses. This study consisted of two phases: (1) 1-5th months: Staff did not receive feedback (n = 701) and (2) 6-8th months: Staff received weekly individual dose feedback (n = 381). An anonymous evaluation was performed on the feedback and occupational dose.

RESULTS

Personalized feedback was scored valuable by 76% of the staff and increased radiation dose awareness for 71%. 57 and 52% reported an increased feeling of occupational safety and changing their behavior because of personalized feedback, respectively. For technicians, the normalized dose was significantly lower in the feedback phase compared to the prefeedback phase: [median (IQR) normalized dose (phase 1) 0.12 (0.04-0.50) µSv/Gy cm2 versus (phase 2) 0.08 (0.02-0.24) µSv/Gy cm2, p = 0.002].

CONCLUSION

Personalized dose feedback increases radiation awareness and safety and can be provided to staff involved in fluoroscopy-guided interventions.

Assessment of the occupational eye lens dose for clinical staff in interventional radiology, cardiology and neuroradiology

In accordance with recommendations by the International Commission on Radiological Protection, the current European Basic Safety Standards has adopted a reduced occupational eye lens dose limit of 20 mSv yr^-1. The radiation safety implications of this dose limit is of concern for clinical staff that work with relatively high dose x-ray angiography and interventional radiology. Presented in this work is a thorough assessment of the occupational eye lens dose based on clinical measurements with active personal dosimeters worn by staff during various types of procedures in interventional radiology, cardiology and neuroradiology. Results are presented in terms of the estimated equivalent eye lens dose for various medical professions. In order to compare the risk of exceeding the regulatory annual eye lens dose limit for the widely different clinical situations investigated in this work, the different medical professions were separated into categories based on their distinct work pattern: staff that work (a) regularly beside the patient, (b) in proximity to the patient and (c) typically at a distance from the patient. The results demonstrate that the risk of exceeding the annual eye lens dose limit is of concern for staff category (a), i.e. mainly the primary radiologist/cardiologist. However, the results also demonstrate that the risk can be greatly mitigated if radiation protection shields are used in the clinical routine. The results presented in this work cover a wide range of clinical situations, and can be used as a first indication of the risk of exceeding the annual eye lens dose limit for staff at other medical centres.

EYE LENS DOSIMETRY FOR FLUOROSCOPICALLY GUIDED CLINICAL PROCEDURES: PRACTICAL APPROACHES TO PROTECTION AND DOSE MONITORING

Doses to the eye lenses of clinicians undertaking fluoroscopically guided procedures can exceed the dose annual limit of 20 mSv, so optimisation of radiation protection is essential. Ceiling-suspended shields and disposable radiation absorbing pads can reduce eye dose by factors of 2-7. Lead glasses that shield against exposures from the side can lower doses by 2.5-4.5 times. Training in effective use of protective devices is an essential element in achieving good protection and acceptable eye doses. Effective methods for dose monitoring are required to identify protection issues. Dosemeters worn adjacent to the eye provide the better option for interventional clinicians, but an unprotected dosemeter worn at the neck will give an indication of eye dose that is adequate for most interventional staff. Potential requirements for protective devices and dose monitoring can be determined from risk assessments using generic values for dose linked to examination workload.

OPTIMISATION OF OCCUPATIONAL RADIATION PROTECTION IN IMAGE-GUIDED INTERVENTIONS: EXPLORING VIDEO RECORDINGS AS A TOOL IN THE PROCESS

The overall purpose of this work was to explore how video recordings can contribute to the process of optimising occupational radiation protection in image-guided interventions. Video-recorded material from two image-guided interventions was produced and used to investigate to what extent it is conceivable to observe and assess dose-affecting actions in video recordings. Using the recorded material, it was to some extent possible to connect the choice of imaging techniques to the medical events during the procedure and, to a less extent, to connect these technical and medical issues to the occupational exposure. It was possible to identify a relationship between occupational exposure level to staff and positioning and use of shielding. However, detailed values of the dose rates were not possible to observe on the recordings, and the change in occupational exposure level from adjustments of exposure settings was not possible to identify. In conclusion, the use of video recordings is a promising tool to identify dose-affecting instances, allowing for a deeper knowledge of the interdependency between the management of the medical procedure, the applied imaging technology and the occupational exposure level. However, for a full information about the dose-affecting actions, the equipment used and the recording settings have to be thoroughly planned.

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.

[Evaluation of an Experimental Production Wireless Dose Monitoring System for Radiation Exposure Management of Medical Staff]

Because of the more advanced and more complex procedures in interventional radiology, longer treatment times have become necessary. Therefore, it is important to determine the exposure doses received by operators and patients. The aim of our study was to evaluate an experimental production wireless dose monitoring system for pulse radiation in diagnostic X-ray. The energy, dose rate, and pulse fluoroscopy dependence were evaluated as the basic characteristics of this system for diagnostic X-ray using a fully digital fluoroscopy system. The error of 1 cm dose equivalent rate was less than 15% from 35.1 keV to 43.2 keV with energy correction using metal filter. It was possible to accurately measure the dose rate dependence of this system, which was highly linear until 100 μSv/h. This system showed a constant response to the pulse fluoroscopy. This system will become useful wireless dosimeter for the individual exposure management by improving the high dose rate and the energy characteristics.

Assessment of the occupational exposure in real time during interventional cardiology procedures

Interventional cardiology (IC) procedures can be complex, requiring the operators to work near the patient, during long exposure times. Owing to scattered radiation in the patient and the fluoroscopic equipment, the medical staff are exposed to a non-uniform radiation field and can receive high radiation doses. In this study, it is proposed to analyse staff doses obtained in real time, during IC procedures. A system for occupational dosimetry in real time was used. In order to identify some parameters that may affect the staff doses, Monte Carlo (MC) calculations, using MCNPX v.2.7.0 code and voxel phantoms, were performed. The data obtained from measurements, together with MC simulations, allowed the identification of actions and behaviours of the medical staff that could be considered a risk under routine working conditions. The implementation of this monitoring system for exposure of personnel may have a positive effect on optimisation of radiological protection in fluoroscopically guided cardiac procedures.

On the feasibility of utilizing active personal dosimeters worn on the chest to estimate occupational eye lens dose in x-ray angiography

The International Commission on Radiological Protection (ICRP) has recommended that the occupational dose limit to the eye lens be substantially reduced. To ensure compliance with these recommendations, monitoring of the occupational eye lens dose is essential in certain hospital work environments. For assessment of the eye lens dose it is recommended to use a supplementary dosimeter placed at a position adjacent to the eye(s). Wearing a dosimeter at eye level can, however, be impractical and distributing and managing additional dosimeters over long periods of time is cumbersome and costly for large clinical sites. An attractive alternative is to utilize active personal dosimeters (APDs), which are routinely used by clinical staff for real-time monitoring of the personal dose equivalent rate (H(p)(10)). In this work, a formalism for the determination of eye lens dose from the response of such APD's worn on the chest is proposed and evaluated. The evaluation is based on both phantom and clinical measurements performed in an x-ray angiography suite for interventional cardiology. The main results show that the eye lens dose to the primary operator and to the assisting clinical staff can be conservatively estimated from the APD response as D(eye)(conductor) = 2.0 APD chest and D(eye)(assisting) = 1.0 APD chest, respectively. However, care should be exercised for particularly short assisting staff and if radiation protection shields are misused. These concerns can be greatly mitigated if the clinical staff are provided with adequate radiation protection training.

Optimisation of occupational radiological protection in image-guided interventions: potential impact of dose rate measurements

The optimisation of occupational radiological protection is challenging and a variety of factors have to be considered. Physicians performing image-guided interventions are working in an environment with one of the highest radiation risk levels in healthcare. Appropriate knowledge about the radiation environment is a prerequisite for conducting the optimisation process. Information about the dose rate variation during the interventions could provide valuable input to this process. The overall purpose of this study was to explore the prerequisite and feasibility to measure dose rate in scattered radiation and to assess the usefulness of such data in the optimisation process.Using an active dosimeter system, the dose rate in the unshielded scattered radiation field was measured in a fixed point close to the patient undergoing an image-guided intervention. The measurements were performed with a time resolution of one second and the dose rate data was continuously timed in a data log. In two treatment rooms, data was collected during a 6 month time period, resulting in data from 380 image-guided interventions and vascular treatments in the abdomen, arms and legs. These procedures were categorised into eight types according to the purpose of the treatment and the anatomical region involved.The dose rate varied substantially between treatment types, both regarding the levels and the distribution during the procedure. The maximum dose rate for different types of interventions varied typically between 5 and 100 mSv h(-1), but substantially higher and lower dose rates were also registered. The average dose rate during a complete procedure was however substantially lower and varied typically between 0.05 and 1 mSv h(-1). An analysis of the distribution disclosed that for a large part of the treatment types, the major amount of the total accumulated dose for a procedure was delivered in less than 10% of the exposure time and in less than 1% of the total procedure time.The present study shows that systematic dose rate measurements are feasible. Such measurements can be used to give a general indication of the exposure level to the staff and could serve as a first risk assessment tool when introducing new treatment types or x-ray equipment in the clinic. For example, it could provide an indication for when detailed eye dose measurements are needed. It also gives input to risk management considerations and the development of efficient routines for other radiological protection measures.