Management of Patient and Staff Radiation Dose in Interventional Radiology: Current Concepts

An investigation into the knowledge, attitudes, and practice of radiation protection in interventional radiology and cardiac catheter-laboratories

BACKGROUND

According to current literature, there is a lack of information regarding the radiation protection (RP) practices of interventional radiology (IR) and cardiology catheter laboratory (CCL) staff. This study aims to determine the RP practices of staff within IR and CCLs internationally and to suggest areas for improvement.

METHODS

A cross-sectional study in the form of an online questionnaire was developed. Participation was advertised via online platforms and through email. Participants were included if they were healthcare professionals currently working in IR and CCLs internationally. Questionnaire design included Section 1 demographic data, Section 2 assessed RP training and protocols, Section 3 surveyed the use of different types of RP lead shields, both personal and co-worker use and Section 4 assessed other methods of minimising radiation dose within practice. Questions were a mix of open and closed ended, descriptive statistics were used for closed questions and thematic analysis was employed for open ended responses.

RESULTS

A total of 178 responses to the questionnaire were recorded with 130 (73 %) suitable for analysis. Most respondents were female (n = 94, 72 %) and were radiographers (n = 97, 75 %). Only 68 (53 %) had received training, the majority receiving this in-house (n = 54, 79 %). 118 (98 %) of respondents had departmental protocols in place for RP. Radiology managers (n = 106, 82 %) were most likely to contribute to such protocols. Multiple methods of dose minimisation exist, these include low-dose fluoroscopy, staff rotation, radiation dose audits and minimal time in the controlled areas. Respondents reported that lead apron shields were wore personally by 99 % of respondents and by co-workers in 95 % of cases.

CONCLUSION

The practices of RP by IR and CCL staff in this survey was variable and can be improved. The unavailability of basic radiation protection tools and RP specific training courses/modules were some of the reasons for sub-optimal self-protection against ionising radiation reported by respondents.

Videourodynamics - role, benefits and optimal practice

Videourodynamics (VUDS) is an advanced diagnostic procedure that simultaneously combines functional and anatomical evaluation of the lower urinary tract. The goal of this synchronous assessment is to promote accurate diagnosis of the aetiology responsible for patient symptoms, improving therapeutic decision-making. Overall, high-quality VUDS is advocated when other tests such as traditional urodynamics might not provide sufficient data to guide therapy, particularly in patients with complex, persistent or recurrent dysfunctions of the lower urinary tract. Additionally, VUDS is often crucial in the follow-up monitoring of many patients with these dysfunctions. A VUDS study is frequently considered a gold standard in patients with neurogenic lower urinary tract dysfunction, female bladder outlet obstruction or congenital anomalies of the lower urinary tract. Nevertheless, this specialized test should be limited to patients in whom VUDS data add value. Particularly, reliable studies comparing the effect of diagnosis with and without imaging on management outcomes are lacking, and no standardized procedures for undertaking VUDS are available. Additionally, patients should be carefully selected for VUDS evaluation, considering the increased cost and risks associated with radiological imaging. In routine practice, clinicians should balance the additional value of synchronous imaging and the enhanced diagnostic precision of VUDS against the limitations of this approach, which mainly include an uncertain effect of VUDS on final treatment outcomes.

Understanding the factors that influence CT utilization for mild traumatic brain injury in a low resource setting - a qualitative study using the Theoretical Domains Framework

Introduction

In low resource settings (LRS), utilization of Computed Tomography scan (CTS) for mild traumatic brain injuries (mTBIs) presents unique challenges and considerations given the limited infrastructure, financial resources, and trained personnel. The Theoretical Domains Framework (TDF) offers a comprehensive theoretical lens to explore factors influencing the decision-making to order CTS for mTBI by imaging referrers (IRs).

Objectives

The primary objective was to explore IRs' beliefs about factors influencing CT utilization in mTBIs using TDF in Uganda.Differences in the factors influencing CTS ordering behavior across specialties, levels of experience, and hospital category were also explored.

Materials and Methods

In-depth semi-structured interviews guided by TDF were conducted among purposively selected IRs from 6 tertiary public and private hospitals with functional CTS services. A thematic analysis was performed with codes and emerging themes developed based on the TDF.

Results

Eleven IRs including medical officers, non-neurosurgeon specialists and neurosurgeons aged on average 42 years (SD+/-12.3 years) participated.Identified factors within skills domain involved IRs' clinical assessment and decision-making abilities, while beliefs about capabilities and consequences encompassed their confidence in diagnostic abilities and perceptions of CTS risks and benefits. The environmental context and resources domain addressed the availability of CT scanners and financial constraints. The knowledge domain elicited IRs' understanding of clinical guidelines and evidence-based practices while social influences considered peer influence and institutional culture. For memory, attention & decision processes domain, IRs adherence to guidelines and intentions to order CT scans were cited.

Conclusion

Using TDF, IRs identified several factors believed to influence decision making to order CTS in mTBI in a LRS. The findings can inform stakeholders to develop targeted strategies and evidence-based interventions to optimize CT utilization in mTBI such as; educational programs, workflow modifications, decision support tools, and infrastructure improvements, among others.

Radiation Exposure and Safety Considerations in Interventional Radiology: Comparison of a Twin Robotic X-ray System to a Conventional Angiography System

Background/Objectives: To evaluate radiation exposure in standard interventional radiology procedures using a twin robotic X-ray system compared to a state-of-the-art conventional angiography system. Methods: Standard interventional radiology procedures (port implantation, SIRT, and pelvic angiography) were simulated using an anthropomorphic Alderson RANDO phantom (Alderson Research Laboratories Inc. Stamford, CT, USA) on an above-the-table twin robotic X-ray scanner (Multitom Rax, Siemens Healthineers, Forchheim, Germany) and a conventional below-the-table angiography system (Artis Zeego, Siemens Healthineers, Forchheim, Germany). The phantom's radiation exposure (representing the potential patient on the procedure table) was measured with thermoluminescent dosimeters. Height-dependent dose curves were generated for examiners and radiation technologists in representative positions using a RaySafe X2 system (RaySafe, Billdal, Sweden). Results: For all scenarios, the device-specific dose distribution differs depending on the imaging chain, with specific advantages and disadvantages. Radiation exposure for the patient is significantly increased when using the Multitom Rax for pelvic angiography compared to the Artis Zeego, which is evident in the dose progression through the phantom's body as well as in the organ-related radiation exposure. In line with these findings, there is an increased radiation exposure for the performing proceduralist, especially at eye level, which can be significantly minimized by using protective equipment (p < 0.001). Conclusions: In this study, the state-of-the-art conventional below-the-table angiography system is associated with lower radiation dose exposures for both the patient and the interventional radiology physician compared to an above-the-table twin robotic X-ray system for pelvic angiographies. However, in other clinical scenarios (port implantation or SIRT), both devices are suitable options with acceptable radiation exposure.

Radiation dose to multidisciplinary staff members during complex interventional procedures

INTRODUCTION

Complex interventional radiology procedures involve extensive fluoroscopy and image acquisition while staff are in-room. Monitoring occupational radiation dose is crucial in optimization. The purpose was to determine radiation doses received by staff involved in complex interventional procedures performed in a dedicated vascular or neuro intervention room.

METHODS

Individual real-time radiation dose for all staff involved in vascular and neuro-interventional procedures in adult patients was recorded over a one-year period using wireless electronic dosimeters attached to the apron thyroid shield. A reference dosimeter was attached to the C-arm near the tube housing to measure scattered, unshielded radiation. Radiology staff carried shoulder thermo-luminescent dosimeters with monthly read-out to monitor dose over time.

RESULTS

Occupational radiation dose was measured in 99 interventional procedures. In many cases prostate artery embolization procedures exposed radiologists to high radiation doses with a median of 15.0 μSv and a very large spread, i.e. 0.2-152.5 μSv. In all procedures except uterine fibroid embolization radiographers were exposed to lower doses than those of radiologists, with endovascular aortic repair being the procedure with highest median exposure to assisting radiographers, i.e. 2.2 μSv ranging from 0.1 to 36.1 μSv. Median radiation dose for the reference dosimeter was 670 μGy while median staff dose for all procedures combined was 3.2 μGy.

CONCLUSION

Radiation doses for multiple staff were determined and the ratio between staff dose and reference dosimeter indicated proper use of shielding in general. Some high-dose procedures may need further optimization for certain staff members, especially those not primarily employed in radiology.

IMPLICATIONS FOR PRACTICE

The study provides benchmark doses that may be used widely in audits and in the ongoing effort to optimize radiation protection for staff in interventional radiology.

Digital Subtraction Angiography (DSA) Technical and Diagnostic Aspects in the Study of Lower Limb Arteries

Cardiovascular diseases represent one of the most frequent diseases worldwide; among these, lower limb ischemia is a threatening condition, which can lead to permanent disability if not promptly and correctly diagnosed and treated. A patient’s clinical evaluation and diagnostic imaging (e.g., color-Doppler ultrasound, computed tomography angiography (CTA), and magnetic resonance imaging (MRI)) are mandatory to carefully assess arterial lesion extension and severity. Digital subtraction angiography (DSA) is a minimally invasive technique that represents the gold standard for percutaneous revascularization treatment of symptomatic patients who are refractory to medical management. However, when dealing with patients with lower limb terminal ischemia, the correct interpretation of diagnostic DSA findings is mandatory for treatment re-planning and to effectively evaluate post-treatment results and complications. The purpose of this review is to provide interventional radiologists and endovascular practitioners with an up-to-date practical guide to diagnostic angiography of the lower limbs, which is mandatory to address correct treatment decisions and post-treatment evaluation.

THE EFFECTS OF CONE-BEAM COMPUTED TOMOGRAPHY IMAGING GUIDANCE ON PATIENT RADIATION EXPOSURES IN TRANS-ARTERIAL CHEMOEMBOLISATION FOR HEPATOCELLULAR CARCINOMA

This study investigated the effects of cone-beam computed tomography (CBCT) guidance in trans-arterial chemoembolisation (TACE) procedures on the number of digital subtraction angiography (DSA) runs acquired and total patient radiation exposure in patients with hepatocellular carcinoma (HCC). A retrospective, analytical cross-sectional, single institution, study was conducted. Dose data were compared across the control (DSA guidance alone) and study (DSA and CBCT guidance) groups. A total of 122 procedures were included within the study. There was a significant reduction in the number of DSA runs (3 vs 5, p < 0.001) and DSA air kerma-area product (PKA) (3077.3 vs 4276.6 μGym2, p = 0.042) for the study group when compared to the control group. Total procedural PKA and total procedural reference air kerma (Ka,r) were shown to be 50 and 73% higher, respectively, for the study group when compared to the control group. CBCT imaging guidance does reduce the number of DSA runs and DSA PKA required to complete the TACE procedure for patients diagnosed with HCC; however, a substantial increase in total procedural PKA is to be expected and it is thus important that this increased dose is carefully considered and justified.

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.

DIAGNOSTIC REFERENCE LEVELS BASED ON PATIENT BODY MASS INDEX FOR SELECT INTERVENTIONAL PROCEDURES IN MINAS GERAIS/BRAZIL

This work establishes local diagnostic reference levels (DRLs) in interventional radiology based on adult patient body mass index (BMI). The monitoring was carried out from 23 institutions and patient data from 3015 procedures were collected, being 907 Catheterism (CAT), 921 Percutaneous transluminal coronary angioplasty (PTCA) and 1187 CAT/PTCA and 6 BMI ranges were taken, going from under 18 up to 40 kg·m-2. It is presented that 18 initial DRL values to be used in the county of Minas Gerais. The overall 75th kerma-area product (KAP), commonly considered DRL, in Gy·cm2, is 94.6(SD 119)-CAT, 88.6(SD 121)-PTCA and 33.0(SD 47.6)-CAT/PTCA. In considering KAP-BMI individual values, one obtain the min-max ranges, in Gy·cm2, 3.2-BMI A to 101-BMI B for CAT, 65-BMI A to 102-BMI F for PTCA and 10.4-BMI A to 59.2-BMI E for CAT/PTCA. The KAP-BMI approach has shown to be feasible as a DRL optimization process.

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.

Radiation exposure during angiographic interventions in interventional radiology - risk and fate of advanced procedures

PURPOSE

Advanced angiographic procedures in interventional radiology are becoming more important and are more frequently used, especially in the treatment of several acute life-threatening diseases like stroke or aortic injury. In recent years, technical advancement has led to a broader spectrum of interventions and complex procedures with longer fluoroscopy times. This involves the risk of higher dose exposures, which, in rare cases, may cause deterministic radiation effects, e.g. erythema in patients undergoing angiographic procedures. Against this background, these procedures recently also became subject to national and international regulations regarding radiation protection. At the same time, individual risk assessment of possible stochastic radiation effects for each patient must be weighed up against the anticipated benefits of the therapy itself. Harmful effects of the administered dose are not limited to the patient but can also affect the radiologist and the medical staff. In particular, the development of cataracts in interventionalists is a rising matter of concern. Furthermore, long-term effects of repeated and prolonged x-ray exposure have long been neglected by radiologists but have come into focus in the past years.

CONCLUSIONS

With all this in mind, this review discusses different efforts to reduce radiation exposition levels for patients and medical staff by means of technical, personal as well as organizational measures.

First local diagnostic reference levels for fluoroscopically guided cardiac procedures in adult patients in Chile

The goal of this study was to generate the first values of local diagnostic reference levels for a range of fluoroscopically guided cardiac diagnostic and therapeutic procedures in adult patients in Chile and to compare radiation dose levels with others presented in the literature. The dosimetric data collection period was conducted over the whole of 2020. The local diagnostic reference levels were calculated as the 75th percentile of patient dose data distributions for kerma area-product values. The sample of collected clinical procedures (480) was divided into diagnostic and therapeutic procedures. The kerma area-product differences found between diagnostic and therapeutic procedures were statistically significant. The local diagnostic reference levels were 81.6 Gy cm2 and 166.9 Gycm2 for fluoroscopically guided cardiac diagnostic and therapeutic procedures, respectively. A comparison of our results with results found in the literature for the last 10 years, showed that there are no published papers for hospitals in Latin America and the Caribbean. It becomes urgent to be able to carry out more research of this type, given that the health reality between countries on different continents is very different. While in some the establishment of diagnostic reference levels is a legal obligation, in others it is a matter of good or bad will.

BRAIN AND EYE AS POTENTIAL TARGETS FOR IONIZING RADIATION IMPACT: PART II - RADIATION CEREBRO/OPHTALMIC EFFECTS IN CHILDREN, PERSONS EXPOSED IN UTERO, ASTRONAUTS AND INTERVENTIONAL RADIOLOGISTS

BACKGROUND

Ionizing radiation (IR) can affect the brain and the visual organ even at low doses, while provoking cognitive, emotional, behavioral, and visual disorders. We proposed to consider the brain and the visual organ as potential targets for the influence of IR with the definition of cerebro-ophthalmic relationships as the «eye-brain axis».

OBJECTIVE

The present work is a narrative review of current experimental, epidemiological and clinical data on radiation cerebro-ophthalmic effects in children, individuals exposed in utero, astronauts and interventional radiologists.

MATERIALS AND METHODS

The review was performed according to PRISMA guidelines by searching the abstract and scientometric databases PubMed/MEDLINE, Scopus, Web of Science, Embase, PsycINFO, Google Scholar, published from 1998 to 2021, as well as the results of manual search of peer-reviewed publications.

RESULTS

Epidemiological data on the effects of low doses of IR on neurodevelopment are quite contradictory, while data on clinical, neuropsychological and neurophysiological on cognitive and cerebral disorders, especially in the left, dominant hemisphere of the brain, are nore consistent. Cataracts (congenital - after in utero irradiation) and retinal angiopathy are more common in prenatally-exposed people and children. Astronauts, who carry out longterm space missions outside the protection of the Earth's magnetosphere, will be exposed to galactic cosmic radiation (heavy ions, protons), which leads to cerebro-ophthalmic disorders, primarily cognitive and behavioral disorders and cataracts. Interventional radiologists are a special risk group for cerebro-ophthalmic pathology - cognitivedeficits, mainly due to dysfunction of the dominant and more radiosensitive left hemisphere of the brain, andcataracts, as well as early atherosclerosis and accelerated aging.

CONCLUSIONS

Results of current studies indicate the high radiosensitivity of the brain and eye in different contingents of irradiated persons. Further research is needed to clarify the nature of cerebro-ophthalmic disorders in different exposure scenarios, to determine the molecular biological mechanisms of these disorders, reliable dosimetric support and taking into account the influence of non-radiation risk factors.

Investigation of Radiation Dose Estimates and Image Quality Between Commercially Available Interventional Fluoroscopy Systems for Fluoroscopically Guided Interventional Procedures

RATIONALE AND OBJECTIVES

To investigate differences in radiation dose and image quality for single-plane flat-panel-detector based interventional fluoroscopy systems from two vendors using phantom study and clinical procedures.

MATERIALS AND METHODS

AlluraClarityIQ (Philips) and Artis Q (Siemens-Healthineers) interventional fluoroscopy systems were evaluated. Phantom study included comparison of system-reported air-kerma rates (AKR) for clinical protocols with simulated patient thicknesses (20-40 cm). Differences in system-reported radiation dose estimates, cumulative-air-kerma (CAK) and kerma-area-product (KAP), for different clinical procedures were investigated. Subset analysis investigated differences in CAK, KAP and other factors affecting radiation dose when the same patients underwent repeat embolization procedures performed by the same physician on the two different fluoroscopy systems. Two blinded interventional radiologists reviewed image-quality for these procedures using a five-point scale (1-5; 5-best) for five parameters.

RESULTS

Phantom study revealed that air-kerma rates was significantly higher for Artis Q system for 30-40cm of simulated patient thicknesses (p < 0.05). Overall data analysis from 4381 clinical cases revealed significant differences in CAK and KAP for certain procedures (p < 0.05); with significantly lower values for AlluraClarityIQ systems (median CAK lower by: 29%-58%). Subset analysis with 40 patients undergoing repeat embolization procedures on both systems revealed that median CAK and KAP were significantly lower for AlluraClarityIQ systems (p < 0.02) by 45% and 31%, respectively. Image quality scores for AlluraClarityIQ systems were significantly greater (mean difference range for five parameters: 1.3-1.6; p < 0.005).

CONCLUSION

Radiation dose and image quality differences were observed between AlluraClarityIQ and Artis Q systems. AlluraClarityIQ systems showed lower radiation utilization and an increase in subjective perception of image quality.

A critical appraisal of the quality of guidelines for radiation protection in interventional radiology using the AGREE II tool: A EuroAIM initiative

PURPOSE

To systematically review and assess the methodological quality of guidelines for radiation protection in interventional radiology.

MATERIALS AND METHODS

On April 15^th, 2021, a systematic search for guidelines on radiation protection in interventional radiology was performed using MEDLINE, EMBASE, National Guideline Clearinghouse, and National Institute for Health and Clinical Excellence databases. Among retrieved guidelines, we then excluded those not primarily focused on radiation protection or on interventional radiology. Authors' professional role and year of publication were recorded for each included guideline. Guideline quality evaluation was performed independently by three authors using the six-domain tool "AGREE II", with an overall guideline quality score divided into three classes: low (<60%), acceptable (60-80%), and good quality (>80%).

RESULTS

Our literature search identified 106 citations: after applying exclusion criteria, 11 guidelines published between 2009 and 2018 were included, most of their authors being interventional radiologists (168/224, 75%). Overall quality of included guidelines was acceptable (median 72%, interquartile range 64-83%), with only one guideline (9%) with overall low quality and four guidelines (36%) with overall good quality. Among AGREE II domains, "Scope and Purpose", "Clarity of Presentations", and "Editorial Independence" had the best results (87%, 76%, and 75% respectively), while "Applicability", "Rigor of Development", and "Stakeholder Involvement" the worst (46%, 49%, and 52% respectively).

CONCLUSION

Considering all guidelines, the overall methodological quality was acceptable with one third of them reaching the highest score class. The "Applicability" domain had the lowest median score, highlighting a practical implementation gap to be addressed by future guidelines.

Personal dosimeter utilisation among South African interventionalists

Ionising radiation (IR) is increasingly being used in diagnostic and therapeutic procedures and offers increased benefits to patients but poses an increased occupational health risk to operators. The consistent use and monitoring of radiation health care workers' dosimeters is an important part of the process for ensuring adequate monitoring and control of IR in the workplace. There is however often inconsistent dosimeter utilisation among these workers. The aim of this study was to report on the dosimeter utilisation and dosimetry practices in South African interventionalists. We conducted a survey and did in-depth and group interviews to evaluate dosimetry practices and the factors influencing these practices. We used STATA 15 to do a descriptive analysis of the quantitative data. A thematic analysis of the qualitative data was done using a deductive and inductive approach. There were 108 respondents (35 radiologists, 41 adult cardiologists, 32 paediatric cardiologists). The majority overall (65.8%), and in each category were males. The median age was 44 (interquartile range (IQR) 31-66)) and the median years worked with fluoroscopy was 10 years (IQR 1-32). Overall interventionalists (55%) ranked their perceived occupation risk as 2/10. Thirteen per cent of all interventionalists reported never using a personal dosimeter (PD), 58% reported wearing it >70% of the time. Inconsistent and inappropriate use of PDs emerged strongly from the qualitative data. There was poor dosimeter utilisation in this study. Participants were not aware of the role of medical physics departments. Evaluation of dosimetry practices as a means of monitoring and improving radiation safety in the catheterisation laboratory must be improved to create an improved culture of radiation safety and protection.

Radiation Awareness for Endovascular Abdominal Aortic Aneurysm Repair in the Hybrid Operating Room: An Instant Operator Risk Chart for Daily Practice

Introduction:

While the operator radiation dose rates are correlated to patient radiation dose rates, discrepancies may exist in the effect size of each individual radiation dose predictors. An operator dose rate prediction model was developed, compared with the patient dose rate prediction model, and converted to an instant operator risk chart.

Materials and Methods:

The radiation dose rates (DR_operator for the operator and DR_patient for the patient) from 12,865 abdomen X-ray acquisitions were selected from 50 unique patients undergoing standard or complex endovascular aortic repair (EVAR) in the hybrid operating room with a fixed C-arm. The radiation dose rates were analyzed using a log-linear multivariable mixed model (with the patient as the random effect) and incorporated varying (patient and C-arm) radiation dose predictors combined with the vascular access site. The operator dose rate models were used to predict the expected radiation exposure duration until an operator may be at risk to reach the 20 mSv year dose limit. The dose rate prediction models were translated into an instant operator radiation risk chart.

Results:

In the multivariate patient and operator fluoroscopy dose rate models, lower DR_operator than DR_patient effect size was found for radiation protocol (2.06 for patient vs 1.4 for operator changing from low to medium protocol) and C-arm angulation. Comparable effect sizes for both DR_operator and DR_patient were found for body mass index (1.25 for patient and 1.27 for the operator) and irradiated field. A higher effect size for the DR_operator than DR_patient was found for C-arm rotation (1.24 for the patient vs 1.69 for the operator) and exchanging from femoral access site to brachial access (1.05 for patient vs 2.5 for the operator). Operators may reach their yearly 20 mSv year dose limit after 941 minutes from the femoral access vs 358 minutes of digital subtraction angiography radiation from the brachial access.

Conclusion:

The operator dose rates were correlated to patient dose rate; however, C-arm angulation and changing from femoral to brachial vascular access site may disproportionally increase the operator radiation risk compared with the patient radiation risk. An instant risk chart may improve operator dose awareness during EVAR.

Get Protected! Recommendations for Staff in IR

Purpose

Evaluation and registration of patient and staff doses are mandatory under the current European legislation, and the occupational dose limits recommended by the ICRP have been adopted by most of the countries in the world.

Methods

Relevant documents and guidelines published by international organisations and interventional radiology societies are referred. Any potential reduction of patient and staff doses should be compatible with the clinical outcomes of the procedures.

Results

The review summarises the most common protective measures and the needed quality control for them, the criteria to select the appropriate protection devices, and how to avoid unnecessary occupational radiation exposures. Moreover, the current and future advancements in personnel radiation protection using medical simulation with virtual and augmented reality, robotics, and artificial intelligence (AI) are commented. A section on the personnel radiation protection in the era of COVID-19 is introduced, showing the expanding role of the interventional radiology during the pandemic.

Conclusion

The review is completed with a summary of the main factors to be considered in the selection of the appropriate radiation protection tools and practical advices to improve the protection of the staff.

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.

Registration Techniques for Clinical Applications of Three-Dimensional Augmented Reality Devices

Many clinical procedures would benefit from direct and intuitive real-time visualization of anatomy, surgical plans, or other information crucial to the procedure. Three-dimensional augmented reality (3D-AR) is an emerging technology that has the potential to assist physicians with spatial reasoning during clinical interventions. The most intriguing applications of 3D-AR involve visualizations of anatomy or surgical plans that appear directly on the patient. However, commercially available 3D-AR devices have spatial localization errors that are too large for many clinical procedures. For this reason, a variety of approaches for improving 3D-AR registration accuracy have been explored. The focus of this review is on the methods, accuracy, and clinical applications of registering 3D-AR devices with the clinical environment. The works cited represent a variety of approaches for registering holograms to patients, including manual registration, computer vision-based registration, and registrations that incorporate external tracking systems. Evaluations of user accuracy when performing clinically relevant tasks suggest that accuracies of approximately 2 mm are feasible. 3D-AR device limitations due to the vergence-accommodation conflict or other factors attributable to the headset hardware add on the order of 1.5 mm of error compared to conventional guidance. Continued improvements to 3D-AR hardware will decrease these sources of error.

High-Dose Fluoroscopically Guided Procedures in Patients: Radiation Management Recommendations for Interventionalists

The article is part of the series of articles on radiation protection. You can find further articles in the special section of the CVIR issue. In addition to the risks from fluoroscopic-guided interventional procedures of tissue injuries, recent studies have drawn attention to the risk of stochastic effects. Guidelines exist for preprocedural planning and radiation management during the procedure. The concept of a substantial radiation dose level (SRDL) is helpful for patient follow-up for tissue injury. The uncommon nature of tissue injuries requires the interventionalist to be responsible for follow-up of patients who receive substantial radiation doses. Dose management systems for recognizing and avoiding higher patient exposures have been introduced. The European Directive provides a legal framework and requirements for equipment, training, dose monitoring, recording and optimization that are helpful in radiation risk management.

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.

Radiation Dose of Patients in Fluoroscopically Guided Interventions: an Update

The benefits of fluoroscopically guided interventional procedures are significant and have established new standards in the clinical management of many diseases. Despite the benefits, it is known that they come with known risks, such as the exposure to ionizing radiation. To minimize such risks, it is crucial that the health professionals involved in the procedures have a common understanding of the concepts related to radiation protection, such as dose descriptors, diagnostic reference levels and typical dose values. An update about these concepts will be presented with the objective to raise awareness amongst health professionals and contribute to the increase in knowledge, skills and competences in radiation protection in fluoroscopically guided interventional procedures.

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 (Ka,r). Ka,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 Ka,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 Ka,r (mGy) were evaluated.

RESULTS

There were 260 (0.3%) fluoroscopically-guided procedures with Ka,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 Ka,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 Ka,r (7,799 mGy), followed by neurosurgery (7452 mGy), vascular surgery (6849 mGy), and interventional radiology (6109 mGy). The mean Ka,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.

Radiation Safety Performance is More than Simply Measuring Doses! Development of a Radiation Safety Rating Scale

PURPOSE

Radiation safety performance is often evaluated using dose parameters measured by personal dosimeters and/or the C-arm, which provide limited information about teams' actual radiation safety behaviors. This study aimed to develop a rating scale to evaluate team radiation safety behaviors more accurately and investigate its reliability.

MATERIALS AND METHODS

A modified Delphi consensus was organized involving European vascular surgeons (VS), interventional radiologists, and interventional cardiologists. Initial items and anchors were drafted a priori and rated using five-point Likert scales. Participants could suggest additional items or adjustments. Consensus was defined as ≥ 80% agreement (rating ≥ 4) with Cronbach's alpha ≥ .80. Two VS with expertise in radiation safety evaluated 15 video-recorded endovascular repairs of infrarenal aortic aneurysms (EVAR) to assess usability, inter and intrarater reliability.

RESULTS

Thirty-one of 46 invited specialists completed three rating rounds to generate the final rating scale. Five items underwent major adjustments. In the final round, consensus was achieved for all items (alpha = .804; agreement > 87%): 'Pre-procedural planning', 'Preparation in angiosuite/operating room', 'Shielding equipment', 'Personal protective equipment', 'Position of operator/team', 'Radiation usage awareness', 'C-arm handling', 'Adjusting image quality', 'Additional dose reducing functions', 'Communication/leadership', and 'Overall radiation performance and ALARA principle'. All EVARs were rated, yielding excellent Cronbach's alpha (.877) with acceptable interrater and excellent intrarater reliability (ICC = .782; ICC = .963, respectively).

CONCLUSION

A reliable framework was developed to assess radiation safety behaviors in endovascular practice and provide teams with formative feedback. The final scale is provided in this publication.

Radiation protection in the cardiac catheterization laboratory

The trend towards more minimally invasive procedures in the past few decades has resulted in an exponential growth in fluoroscopy-guided catheter-based cardiology procedures. As these techniques are becoming more commonly used and developed, the adverse effects of radiation exposure to the patient, operator, and ancillary staff have been a subject of concern. Although occupational radiation dose limits are being monitored and seldom reached, exposure to chronic, low dose radiation has been shown to have harmful biological effects that are not readily apparent until years after. Given this, it is imperative that reducing radiation dose exposure in the cardiac catheterization laboratory remains a priority. Staff education and training, radiation dose monitoring, ensuring use of proper personal protective equipment, employment of shields, and various procedural techniques in minimizing radiation must always be diligently employed. Special care and consideration should be extended to pregnant women working in the cardiac catheterization laboratory. This review article presents a practical approach to radiation dose management and discusses best practice recommendations in the cardiac catheterization laboratory.

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.

Integrative Medicine in Interventional Oncology: A Virtuous Alliance

This review aimed to identify the potential role of integrative medicine in interventional oncology. The music therapy; stress management techniques; guided imagery, including virtual reality; clinical hypnosis; and digital sedation may all be efficient on anxiety and pain during procedures performed in interventional oncology. Beyond pharmacological sedation, the implementation of integrative medicine to interventional oncology may, therefore, improve the support and care of cancer patients, which may further create a virtuous alliance.

Sedation and analgesia in interventional radiology: Where do we stand, where are we heading and why does it matter?

The aims of this review were to describe the rationale and the techniques of sedation in interventional radiology, and to compile the safety and efficacy results available so far in the literature. A systematic MEDLINE/PubMed literature search was performed. Preliminary results from several studies demonstrated the feasibility, the efficacy and the safety of using sedative techniques in interventional radiology. Beyond pharmacological sedation and clinical hypnosis, digital sedation could reduce the anxiety and pain associated with interventional radiology procedures.

An Investigation of Procedural Radiation Dose Level Awareness and Personal Training Experience in Communicating Ionizing Radiation Examinations Benefits and Risks to Patients in Two European Cardiac Centers

PURPOSE

Cardiac interventional practitioners need to be appropriately informed regarding radiation dose quantities and risks. Communicating benefit-risk information to patients requires attention as specified in Basic Safety Standards Directive 2013/59/Eurotom. This study investigated the awareness of procedural radiation dose levels and the impact of personal training experience in communicating ionizing radiation benefit-risks to patients.

METHODOLOGY

A questionnaire, consisting of 28 questions, was distributed directly to adult and pediatric interventional cardiology specialists at specialized cardiovascular imaging centers in Dublin, Ireland and Milan, Italy.

RESULTS

A total of 18 interventional cardiologists (senior registrar to consultant grades with between 2 y to over 21 y experience in cardiac imaging) participated. The majority of participants (n = 17) stated that parents of pediatric and adult patients should be informed of the potential benefits and risk. All participants indicated they had radiation safety training; however, 50% had not received training in radiation examination benefit-risk communication. Despite this, 77.8% (n = 14) participants indicated a high confidence level in successfully explaining risks and/or benefits of cardiac imaging procedures. When asked to estimate effective dose (ED) values for common cardiac imaging procedures less than 50% identified appropriate dose ranges. All participants underestimated procedural dose values based on recent European data. 50% (n = 9) participants answered all questions correctly for a number of true or false radiation risk statements.

CONCLUSION

Benefit-risk communication training deficits and inaccurate understanding of radiation dose levels was identified. Further research and training to support clinicians using radiation on a daily basis is required.

SURVEY OF KEY RADIATION SAFETY PRACTICES IN INTERVENTIONAL RADIOLOGY: AN IRISH AND ENGLISH STUDY

Interventional radiology is a rapidly evolving speciality with potential to deliver high patient radiation doses, as a result high standards of radiation safety practice are imperative. IR radiation safety practice must be considered before during and after procedures through appropriate patient consent, dose monitoring and patient follow-up. This questionnaire-based study surveyed fixed IR departments across Ireland and England to establish clinical practice in relation to radiation safety. Pre-procedure IR patient consent includes all radiation effects in 11% of cases. The patient skin dose surrogate parameter of Kerma to air at a reference point (Kar) is under-reported. Only 39% of respondents use a substantial radiation dose level and inform patients after these have been reached. Poor compliance with unambiguous, readily available best practice guidance was observed throughout highlighting patient communication, patient dose quantification and subsequent patient dose management concerns.

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.

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.

A Phantom Menace to Medical Personnel During Endovascular Treatment of Cerebral Aneurysms: Real-Time Measurement of Radiation Exposure During Procedures

BACKGROUND

The number of endovascular treatment procedures performed for cerebral aneurysms has markedly increased. However, little is known about the annual effective radiation dose to medical staff in neurointervention fields. We performed a retrospective observational study to investigate the real-time radiation dose to surgeons, nurses, anesthesiologists, and radiologic technologists during endovascular treatment of intracranial aneurysms.

METHODS

We measured the real-time radiation doses for 2 weeks using standard and reinforced protection, during which 28 procedures were performed, including 23 coil embolizations for unruptured intracranial aneurysms. Four procedures were excluded because of an inadequately equipped sensor, which resulted in inappropriate data collection. The procedure time was defined from intubation to extubation. Five RaySafe i2 detectors were installed at the chest level of the operator, attending nurse, radiologic technologist, and anesthesiologist and just inside the front door of the hybrid operating room.

RESULTS

The median doses per session with standard protection to the operator, attending nurse, anesthesiologist, and radiologic technologist were 11.16, 2.60, 4.76, and 1.93 μSv, respectively. The dose to the operator, attending nurse, and anesthesiologist had decreased to 6.63, 0.39, and 1.52 μSv under reinforced protection, respectively. However, the session dose for the radiologic technologist had increased to 3.12 μSv.

CONCLUSIONS

We confirmed the differences in the amount of radiation exposure for different roles. An additional lead screen, which provided more effective protection on the operator side, was proved effective for attenuating radiation exposure during endovascular treatment. All personnel involved in the hybrid operating room were exposed to acceptable effective doses.

Cytogenetic status of interventional radiology unit workers occupationally exposed to low-dose ionising radiation: A pilot study

Interventional radiology unit workers represent one of the occupationally most exposed populations to low-dose ionizing radiation. Since there are many uncertainties in research of doses below 100 mSv, this study attempted to evaluate DNA damage levels in chronically exposed personnel. The study group consisted of 24 subjects matched with a control population by the number of participants, age, gender ratio, active smoking status, the period of blood sampling, and residence. Based on regular dosimetry using thermoluminiscent dosimeters, our study group occupationally received a dose of 1.82 ± 3.60 mSv over the last year. The results of the cytokinesis-block micronucleus assay and the comet assay showed a higher nuclear buds frequency (4.09 ± 1.88) and tail length (15.46 ± 1.47 μm) than in the control group (2.96 ± 1.67, 14.05 ± 1.36 μm, respectively). Differences in other descriptors from both tests did not reach statistical significance. Further investigations are needed to develop algorithms for improving personal dosimetry and those that would engage larger biomonitoring study groups.

Navigation and visualisation with HoloLens in endovascular aortic repair

Introduction

Endovascular aortic repair (EVAR) is a minimal-invasive technique that prevents life-threatening rupture in patients with aortic pathologies by implantation of an endoluminal stent graft. During the endovascular procedure, device navigation is currently performed by fluoroscopy in combination with digital subtraction angiography. This study presents the current iterative process of biomedical engineering within the disruptive interdisciplinary project Nav EVAR, which includes advanced navigation, image techniques and augmented reality with the aim of reducing side effects (namely radiation exposure and contrast agent administration) and optimising visualisation during EVAR procedures. This article describes the current prototype developed in this project and the experiments conducted to evaluate it.

Methods

The current approach of the Nav EVAR project is guiding EVAR interventions in real-time with an electromagnetic tracking system after attaching a sensor on the catheter tip and displaying this information on Microsoft HoloLens glasses. This augmented reality technology enables the visualisation of virtual objects superimposed on the real environment. These virtual objects include three-dimensional (3D) objects (namely 3D models of the skin and vascular structures) and two-dimensional (2D) objects [namely orthogonal views of computed tomography (CT) angiograms, 2D images of 3D vascular models, and 2D images of a new virtual angioscopy whose appearance of the vessel wall follows that shown in ex vivo and in vivo angioscopies]. Specific external markers were designed to be used as landmarks in the registration process to map the tracking data and radiological data into a common space. In addition, the use of real-time 3D ultrasound (US) is also under evaluation in the Nav EVAR project for guiding endovascular tools and updating navigation with intraoperative imaging. US volumes are streamed from the US system to HoloLens and visualised at a certain distance from the probe by tracking augmented reality markers. A human model torso that includes a 3D printed patient-specific aortic model was built to provide a realistic test environment for evaluation of technical components in the Nav EVAR project. The solutions presented in this study were tested by using an US training model and the aortic-aneurysm phantom.

Results

During the navigation of the catheter tip in the US training model, the 3D models of the phantom surface and vessels were visualised on HoloLens. In addition, a virtual angioscopy was also built from a CT scan of the aortic-aneurysm phantom. The external markers designed for this study were visible in the CT scan and the electromagnetically tracked pointer fitted in each marker hole. US volumes of the US training model were sent from the US system to HoloLens in order to display them, showing a latency of 259±86 ms (mean±standard deviation).

Conclusion

The Nav EVAR project tackles the problem of radiation exposure and contrast agent administration during EVAR interventions by using a multidisciplinary approach to guide the endovascular tools. Its current state presents several limitations such as the rigid alignment between preoperative data and the simulated patient. Nevertheless, the techniques shown in this study in combination with fibre Bragg gratings and optical coherence tomography are a promising approach to overcome the problems of EVAR interventions.

Optimizing imaging and reducing radiation exposure during complex aortic endovascular procedures

Improvements in endovascular technologies and development of custom-made fenestrated and branched endografts currently allow clinicians to treat complex aortic lesions such as thoraco-abdominal and aortic arch aneurysms once treatable with open repair only. These advances are leading to an increase in the complexity of endovascular procedures which can cause long operation times and high levels of radiation exposure. This in turn places pressure on the vascular surgery community to display more superior interventional skills and radiological practices. Advanced imaging technology in this context represents a strong pillar in the treatment toolbox for delivering the best care at the lowest risk level. Delivering the best patient care while managing the radiation and iodine contrast media risks, especially in frail and renal impaired populations, is the challenge aortic surgeons are facing. Modern hybrid rooms are equipped with a wide range of new imaging applications such as fusion imaging and cone-beam computed tomography (CBCT). If these technologies contribute to reducing radiation, they can be complex and intimidating to master. The aim of this review is to discuss the fundamentals of good radiological practices and to describe the various imaging tools available to the aortic surgeon, both those available today and those we anticipate will be available in the near future, from equipment to software, to perform safe and efficient complex endovascular procedures.

Location of Disease on Imaging may Predict Radiation Exposure During Endoscopic Retrograde Cholangiopancreatography

Endoscopic retrograde cholangiopancreatography (ERCP) is performed for various diseases. The aim of this study is to evaluate the difference of dose-area product (DAP) during the ERCP procedures according to location of the lesion. We performed a retrospective study of consecutive 217 therapeutic ERCP examinations performed between November 2014 and April 2015 at a tertiary care center. ERCP procedures divided into two groups according to location of the lesion identified on imaging: lesions in the common hepatic duct (CHD) or the common bile duct (CBD) and lesions in the hepatic hilum or the intrahepatic duct (IHD). The mean DAP of the hilum-IHD group (48.7 Gy cm2) was significantly higher than that of the CBD-CHD group (34.9 Gy cm2) (P = 0.003). Radiation exposure during ERCP was significantly different according to location of bile duct lesion.

The Eyes Have It

The ocular lens is one of the most susceptible structures in the body to radiation damage. Unfortunately, much of the traditional academic and regulatory thinking on thresholds to develop radiation-induced opacities or cataracts has proven to be false. Individual vulnerability to the effects of radiation is extremely variable, largely because each individual is variably genetically equipped to repair the damage caused by radiation. Therefore many people, including some unsuspecting interventional radiologists may have no, or almost no, threshold at all for cataract development after radiation injury. For most others, if there is a threshold it is a fraction of what was previously thought. These new data have become apparent during the same time period when unprecedented numbers of physicians and medical staff have been exposed to unprecedented doses of scatter radiation as the number and complexity of fluoroscopic guided procedures has exploded. Increased rates of radiation lens damage have already been documented in physicians and support staff working in interventional medicine. As there is a latency period of years to decades for lens injury to fully evolve it is quite possible the true incidence will not be known for some time. Strategies to minimize the potential risks encountered in interventional medicine include radiation safety best practices, passive and personal barrier protection, and philosophical approach to interventional radiology practice. Ignore this article at your peril.

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.

Radiation-Induced Skin Injuries to Patients: What the Interventional Radiologist Needs to Know

For a long time, radiation-induced skin injuries were only encountered in patients undergoing radiation therapy. In diagnostic radiology, radiation exposures of patients causing skin injuries were extremely rare. The introduction of fast multislice CT scanners and fluoroscopically guided interventions (FGI) changed the situation. Both methods carry the risk of excessive high doses to the skin of patients resulting in skin injuries. In the early nineties, several reports of epilation and skin injuries following CT brain perfusion studies were published. During the same time, several papers reported skin injuries following FGI, especially after percutaneous coronary interventions and neuroembolisations. Thus, CT and FGI are of major concern regarding radiation safety since both methods can apply doses to patients exceeding 5 Gy (National Council on Radiation Protection and Measurements threshold for substantial radiation dose level). This paper reviews the problem of skin injuries observed after FGI. Also, some practical advices are given how to effectively avoid skin injuries. In addition, guidelines are discussed how to deal with patients who were exposed to a potentially dangerous radiation skin dose during medically justified interventional procedures.