Real-Time Patient and Staff Radiation Dose Monitoring in IR Practice

Optimizing the hemodynamics of hand injections in neuroangiography

PURPOSE

Optimizing the preparation of a 10 ml syringe for manual injection of contrast media can help operators obtain easier and faster injections. This study aims to compare the flow rates of different contrast media injection methods.

METHODS

Different contrast media solutions were compared: 100% contrast (10 ml contrast), mixed contrast solution (8:2 contrast/saline), and layered contrast below saline ("Parfait") in different volumes. Contrast media were injected at room temperature (20°C) and after heating (37°C). Four operators injected 10 ml syringes filled with different mediums through 5-French angiographic catheters. The average flow rate was used to compare different contrast injection mediums. The Kruskal-Wallis test with post-hoc pairwise comparisons using Bonferroni correction or Mann-Whitney U-tests were employed depending on the type of comparison.

RESULTS

Compared to the 100% contrast solution, every Parfait media and mixed contrast solution demonstrated significantly higher flow rates (p < 0.001). The 5 ml saline Parfait had the highest flow rate among the Parfait solutions. The 5 ml saline Parfait and the mixed solution had comparable flow rates (p = 0.237). Higher flow rates were observed upon heating both 100% contrast (p < 0.001) and mixed contrast solutions (p < 0.001) in comparison to their flow rates at room temperature.

CONCLUSION

This study demonstrates the capability of the Parfait and mixed contrast injections to achieve higher flow rates than the 100% contrast solutions. Heating the contrast media to 37°C also proves to be a viable strategy for further enhancing the flow rates for 100% and mixed contrast solutions.

Intraoperative Ionizing Radiation Exposure Awareness and Associated Morbidity in Neurosurgery: A Nationwide Survey

BACKGROUND

Neurosurgeons often use radiation to visualize blood vessels and implants intraoperatively. However, high exposure to radiation increases one's cancer risk. This study aims to investigate intraoperative ionizing radiation exposure awareness and associated morbidity among neurosurgeons.

METHODS

An anonymized 30-question survey about their intraoperative radiation exposure, protective measures, radiation knowledge, and any conditions that can arise from protracted radiation exposure was disseminated to 3344 American Association of Neurological Surgeons members.

RESULTS

A total of 227 (6.8%) neurosurgeons completed the survey. Most neurosurgeons (61, 27%) performed 2-4 surgeries per week necessitating radiation (61, 27%), did not use a dosimeter (134, 59%), and wore a lead apron (89%) and a thyroid shield (75%). Only 7 (3%) of respondents could correctly identify the safety limit for occupational radiation. One hundred and thirty-four (59%) respondents correctly identified the relationship between distance and radiation dose reduction. Two hundred and thirteen (94%) neurosurgeons reported concern about occupational radiation exposure. No significant association was found between occupational radiation exposure and the rate of cataracts, combined cancer, and skin cancer. Multivariate logistic regression adjusting for age and cancer history found that the likelihood of developing leukemia (P = 0.02) and nonmalignant thyroid nodular disease (P = 0.01) is positively associated with increased total occupational radiation exposure.

CONCLUSIONS

There is a need for improved radiation safety awareness among neurosurgeons, especially in the context of rising usage of minimally invasive surgery. This can allow for a greater understanding of radiation-associated risks among neurosurgeons and guide the implementation of safer practices.

Measurement of Hp(10), Hp(3) and Hp(0.07) to medical staff in endoscopic retrograde cholangiopancreatography, using thermoluminescence dosimetry

Endoscopic retrograde cholangiopancreatography (ERCP) is widely used in the diagnosis and treatment of pancreatic and bile duct disorders. The procedure is performed under the guidance of fluoroscopy. This study aims to investigate the dose received by staff in the Endoscopy Department of AbuAli Sina Medicine and Organ Transplant Hospital in Shiraz. The dosimetry was performed using thermoluminescent dosemeters (TLD), type TLD-100. The values of Hp(10), Hp(3) and Hp(0.07) were estimated for the staff for 2 months. According to the results obtained in this study, the equivalent dose of the gastroenterologist's body, eye lenses and hands was 0.045 ± 0.001 mSv, 0.111 ± 0.014 mSv and 0.357 ± 0.034 $\mathrm{mSv}$, respectively. This study showed that the annual radiation exposure for ERCP department staff of Abu Ali Sinai Hospital is less than the annual dose limit. However, if the principles of proper radiation protection and individual dosimetry are followed, the dose to staff members can be reduced.

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.

FACTORS INFLUENCING FLUOROSCOPY TIME IN ENDOVASCULAR TREATMENT OF ABDOMINAL ANEURYSMS: A RETROSPECTIVE STUDY

Patients who undergo endovascular aortic aneurysm repair (EVAR) may require prolonged radiation exposure affected by several factors. The objectives of this study were to document fluoroscopy time (FT) during EVAR and identify possible factors that influence it. A retrospective analysis of a 180 patients' database with abdominal infrarenal aortic aneurysms submitted to EVAR during a 7-y period was performed. The FT is evaluated regarding risk factors and comorbidities, graft type and patient-related, clinical and technical parameters. FT's median (interquartile range) was 1011 (698-1500) s. Excluder and C3 Excluder were associated with significantly lower FT values when compared with other grafts. Hypertension, dyslipidemia, age ≥ 70 y, maximum aneurysm diameter ≥ 6 cm and procedure duration ≥2 h resulted in higher FT values. A significantly lower FT was found for the operations performed in the 7th y of the study's period compared with the previous 6 y, mainly because of the use of Excluder or C3 Excluder grafts. However, these grafts did not show any significant difference in FT values during the 7 y. A significant correlation between FT with age and procedure duration was found. Nevertheless, procedure duration is a poor FT predictor in linear and logistic regressions, although is significantly correlated with FT. Dyslipidemia, procedure duration and graft type are independent predictors of FT larger than the median, whereas only the procedure duration is a predictor for FT larger than the 75th percentile value. The identified factors regarding radiation protection issues should be considered when contemplating abdominal aortic aneurysm repair, however, without compromising the procedure's efficacy. Further work is necessary to identify more potential anatomical, clinical and technical factors affecting procedures' complexity and FT and patient radiation dose during EVAR interventions.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

ADVANCES IN KNOWLEDGE

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

Nursing care management in radiation protection in interventional radiology

OBJECTIVE

To reflect on the elements of nursing care management in radiological protection in interventional radiology.

METHODOLOGY

A reflection paper based on national and international articles and laws addressing the nursing care management issue and radiological protection in interventional radiology.

RESULTS

From the conceptions of nursing care management and professional practice, the following elements were perceived in this management: expertise and applicability of the radiological protection principles, biological effects of ionizing radiation, occupational dose monitoring, personal and collective protective equipment, patient safety, training in radiological protection, quality assurance program.

CONCLUSION

The management of nursing care in radiological protection in interventional radiology is implemented in an elementary way regarding care aimed at dose reduction, either for workers or patients. There is a need to recognize, understand and characterize the management of nursing care in this scenario.

ASSESSMENT OF OCCUPATIONAL EXPOSURE IN THE MAIN PAEDIATRIC INTERVENTIONAL RADIOLOGY PROCEDURES

The aim of this study is to evaluate the personal dose equivalent Hp(10) in the most frequent (non-cardiac) paediatric interventional radiology (PIR) procedures: central venous catheters (CVC), hepatic/biliary and sclerotherapy interventions. i2 active solid-state dosemeters placed over the lead apron were used to monitor the exposure of three interventional radiologists over 18 months. A database was created to register all procedures performed by each radiologist (including the type of procedure and the kerma-area product, PKA). The mean Hp(10) per procedure for CVC, sclerotherapy and hepatic/biliary interventions was respectively 0.01 ± 0.01 mSv, 0.18 ± 0.13 mSv and 0.12 ± 0.06 mSv (k = 2). A similar value of Hp(10)/PKA was found despite the type of procedure or the patient weight (~10 μSv/Gy·cm2). There was high variability among individual interventions, probably due to the variable level of complexity, which led to uncertainties in the measurements' mean higher than those associated with the dosemeter's angular and energy dependence. i2 therefore proved suitable for monitoring Hp(10) in PIR procedures.

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

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

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.

Impact of Different Measures of Body Size on the Radiation Dose During Coronary Angiography and Percutaneous Coronary Intervention: Results from a Large Single Center Cohort

Efforts to reduce and optimize the radiation exposure during coronary angiography and intervention have pointed at patients' body size as a major determinant of irradiation for the patients and operators. We aimed at comparing body weight and body mass index (BMI) among consecutive patients undergoing angiographic procedures (coronary angiography and/or interventions) in a single center. Patients were divided in normal weight (NW, BMI <25 Kg/m²) and overweight (OW, BMI ≥25 Kg/m²). Patients' dose exposure was evaluated as dose area product (DAP), time of exposure (fluoroscopy duration), and relative DAP (DAP/minutes of exposure). We included 748 patients, 61.6% undergoing percutaneous coronary interventions and 56.8% classified as OW. OW patients were more often men (P < .001), with history of hypertension (P < .001) and diabetes (P = .001). Mean DAP and relative DAP were significantly higher among OW compared with NW patients (P < .001). DAP and relative DAP were directly related with body weight (both r = .22, P < .001); a similar linear association was also described for BMI (r = .18, P < .001 and r = .19, P < .001, respectively). At multivariate analysis, however, body weight, but not BMI, independently predicted the DAP. Therefore, body weight should be considered as the preferred indicator of body size in the setting and optimization of radiation exposure during coronary diagnostic and intervention procedures.

Gestão do cuidado em enfermagem na proteção radiológica em radiologia intervencionista

RESUMO Objetivo: Refletir sobre os elementos da gestão do cuidado em enfermagem na proteção radiológica em radiologia intervencionista. Metodologia: Estudo reflexivo realizado a partir de artigos e legislação nacional e internacional abordando a temática da gestão do cuidado em enfermagem e proteção radiológica em radiologia intervencionista. Resultados: A partir das concepções de gestão do cuidado em enfermagem e atuação profissional na prática vislumbrou-se como elementos dessa gestão: conhecimentos e aplicabilidade dos princípios de proteção radiológica, efeitos biológicos da radiação ionizante, monitoramento de dose ocupacional, equipamentos de proteção individual e coletiva, segurança do paciente, educação em proteção radiológica, programa de garantia de qualidade. Conclusão: A gestão do cuidado em enfermagem em proteção radiológica em radiologia intervencionista é implementada de forma incipiente no que tange aos cuidados voltados para redução de dose, seja para trabalhadores ou paciente. Torna-se necessário reconhecer, compreender e caracterizar a gestão do cuidado em enfermagem nesse cenário.

Reduction of Radiation Exposure in Adrenal Vein Sampling: Impact of the Rapid Cortisol Assay

PURPOSE

 To determine radiation exposure associated with adrenal vein sampling and its reduction by implementing the rapid cortisol assay and modification of the sampling protocol.

MATERIALS AND METHODS

 A single-center retrospective study of adrenal vein sampling performed between August 2009 and March 2020 revealed data from 151 procedures. Three subgroups were determined. In group I, a sampling protocol including sampling from the renal veins without the rapid cortisol assay was applied. In group II, blood was sampled using the same protocol but applying the rapid cortisol assay. In group III, a modified sampling protocol was used, in which the additional sampling from the renal veins was dispensed with, while the rapid cortisol assay was retained. Primary endpoints were radiation exposure parameters with dose area product, fluoroscopy time, and effective dose. As secondary endpoints, procedural data including technical success, lateralization, the correlation between patient BMI and radiation exposure, and concordance of lateralization with cross-sectional imaging were investigated. Furthermore, the correlation of aldosterone-cortisol ratios between the adrenal and ipsilateral renal vein was calculated to assess the benefit of sampling from the renal veins.

RESULTS

 For all procedures performed in the study collective, the median dose area product was 60.01 Gy*cm² (5.71-789.31), the median fluoroscopy time was 14.90 min (3.27-80.90), and the calculated median effective dose was 12.60 mSv (1.20-165.76). Significant differences in radiation exposure parameters between the study subgroups could be revealed. Dose area product resulted in reductions of 57.94 % after implementation of the rapid cortisol assay and a further 40.44 % after revision of the sampling protocol. Fluoroscopy time was reduced by 40.48 % after integration of the rapid cortisol assay and a further 40.47 % after protocol refinement. Radiation doses were increased in cases of resampling (dose area product 51.31 vs. 118.11 Gy*cm², fluoroscopy time of 12.48 vs. 28.70 min). A strong correlation between patient BMI and procedural dose area product could be found. After the introduction of the rapid cortisol assay, successive improvement of the technical success rate could be found (33.33 % in group I, 90.22 % in group II and 92.11 % in group III). The correlation of aldosterone-cortisol ratios between adrenal and renal veins was poor.

CONCLUSION

 The introduction of the rapid cortisol assay significantly decreased the radiation exposure and increased the technical success rate. Renal vein sampling did not provide further benefit in the evaluation of primary aldosteronism subtype and its omission resulted in a further reduction of radiation dose.

KEY POINTS

· The rapid cortisol assay significantly reduces the procedure-related radiation dose in adrenal vein sampling and increases the procedural technical success.. · Since additional sampling from the renal veins offers no further diagnostic benefit, a refinement of the sampling protocol can enable a further reduction of radiation dose.. · Resampling, technical unsuccessful procedures, and higher patients' BMI are associated with higher radiation exposures..

CITATION FORMAT

· Augustin A, Dalla Torre G, Fuss CT et al. Reduction of Radiation Exposure in Adrenal Vein Sampling: Impact of the Rapid Cortisol Assay. Fortschr Röntgenstr 2021; 193: 1392 - 1402.

Managing occupational doses with smartphones in interventional radiology

Purpose

This study presents a prototype smartphone application for occupational dosimetry in interventional practices based on electronic personal dosimeters to assist in dose monitoring.

Methods

The prototype receives and records information from the occupational dose report containing the cumulative dose of electronic personal dosimeters worn over the apron at chest level and electronic area dosimeters located on C‐arms (reference dosimeters), for each fluoroscopy‐guided procedure. Using their smartphones, personnel involved in interventional practices can review and compare their occupational records with an investigation level, the dose limits, and their department colleagues (anonymously). The ratio between H_p(10) measured by the personal and the reference dosimeters at the C‐arm is presented as an indicator of consistent use of suspended operator shield. Some general results extracted from the first months of use are presented.

Results

The reference dosimeter located at the C‐arm (without lead protection and acting as an ambient dosimeter) recorded in one of the laboratories 217 mSv during 308 procedures over 5 months, showing an indication of the radiation risk present in an interventional laboratory. The ratio between the personal cumulative dose and the dose at a reference C‐arm dosimeter ranged from 0.2% to 1.67% (a factor of 8.5) for different interventionalists. These differences suggest different protection habits among interventional operators, as well as a target for dose reduction.

Conclusions

With this system, professionals have easy access to their occupational dosimetry records (including information on the workload) in the setting of their interventional departments, to thereby actively engage in the protection process.

KERMA-AREA PRODUCT, ENTRANCE SURFACE DOSE AND EFFECTIVE DOSE IN ABDOMINAL ENDOVASCULAR ANEURYSM REPAIR

This study aims to evaluate patient radiation dose during fluoroscopically guided endovascular aneurysm repair (EVAR) procedures. Fluoroscopy time (FT) and kerma-area product (KAP) were recorded from 87 patients that underwent EVAR procedures with a mobile C-arm fluoroscopy system. Effective dose (ED) and organs' doses were calculated utilising appropriate conversion coefficients based on the recorded KAP values. Entrance surface dose (ESD) was calculated based on KAP values and technical parameters. The mean FT was 22.7 min (range 6.4-76.8 min), resulting in a mean KAP of 36.6 Gy cm2 (range 2.0-167.8 Gy cm2), a mean ED of 6.2 mSv (range 0.3-28.5 mSv) and a mean ESD of 458 mGy (range 26-2098 mGy). The corresponding median values were 17.4 min, 25.6 Gy cm2, 4.4 mSv and 320 mGy. The threshold of 2 Gy for skin erythema was exceeded in two procedures for a focus-to-skin distance (FSD) of 40 cm and six procedures when an FSD of 30 cm was considered. The highest doses absorbed by the adrenals, kidneys, spleen and pancreas and ranged between 3.7 and 313.3 mGy (average 66.8 mGy), 3.3 and 285.1 mGy (average 60.8 mGy), 1.3 and 111.1 mGy (average 23.7 mGy), 1.1 and 92.1 mGy (average 19.6 mGy), respectively. A wide range of patient doses was reported in the literature. The radiation dose received by the patients was comparative or lower than most of the previously reported values. However, higher doses can be revealed due to the X-ray system's non-optimum use and extended FTs, mainly affected by complex clinical conditions, patients' body habitus and vascular surgeon experience. The large variation of patient doses highlights the potential to optimise the EVAR procedure by considering the balance between the radiation dose and the required image quality. Additional studies need to be conducted in increasing the vascular surgeons' awareness regarding patient dose and radiation protection issues during EVAR procedures.

CIRSE Clinical Practice Manual

Background

Interventional radiology (IR) has come a long way to a nowadays UEMS-CESMA endorsed clinical specialty. Over the last decades IR became an essential part of modern medicine, delivering minimally invasive patient-focused care.

Purpose

To provide principles for delivering high quality of care in IR.

Methods

Systematic description of clinical skills, principles of practice, organizational standards and infrastructure needed for the provision of professional IR services.

Results

There are IR procedures for almost all body parts and organs, covering a broad range of medical conditions. In many cases IR procedures are the mainstay of therapy, e.g. in the treatment of hepatocellular carcinoma. In parallel the specialty moved from the delivery of a procedure towards taking care for a patient’s condition with the interventional radiologists taking ultimate responsibility for the patient’s outcomes.

Conclusions

The evolution from a technical specialty to a clinical specialty goes along with changing demands on how clinical care in IR is provided. The CIRSE Clinical Practice Manual provides interventional radiologist with a starting point for developing his or her IR practice as a clinician.

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.

Development of air pressure mirroring particle dispersion method for producing high-density tungsten medical radiation shielding film

Radiation shielding films used in medical institutions are manufactured by mixing polymer materials with eco-friendly shielding materials. However, it is not easy to distribute the shielding material particles uniformly during the process. The uniform distribution of the shielding material particles is key to the reproducibility of the shielding performance of the films. Therefore, in this study, an air pressure mirroring particle dispersion method was developed to maintain a uniform distribution of the shielding material by dispersing the shielding material on a curved reflector through an air nozzle. The particle distribution state, density, and shielding performance of the cross-section and surface of the shielding films developed using the single-sided dispersion, double-dispersion, and air pressure mirroring particle dispersion methods were evaluated. Compared to the conventional single-sided distribution method, the shielding film produced by the air pressure mirroring particle dispersion method increased the particle packing by 41.5%, density by 12.9%, shielding material content by 22.2%, and shielding performance by 21.4%. Thus, the proposed dispersion method enables better shielding performance through uniform dispersion of shielding material, which is the most important parameter in the manufacture of low-dose shielding films.

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.

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

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

Percutaneous structural cardiology: are anaesthesiologists properly protected from ionising radiation?

During transcatheter aortic valve implantations (TAVI) and other percutaneous structural procedures, some patients may need close anesthesiological care, thus exposing the anaesthesiologist to x-rays. This work aims to investigate the radiation dose received by anaesthesiologists during these specific procedures in order to improve their radiological protection. Occupational radiation doses were measured prospectively during percutaneous structural procedures in several health professionals using electronic dosimeters worn over the apron at chest level. A sample of 49 procedures were recorded, where the anaesthesiologists' average dose per procedure resulted 13 times higher than that of interventional cardiologists. The average dose per procedure received over the protection apron during TAVIs by the anaesthesiologist was 0.13 mSv, with a maximum value of 0.69 mSv. Taking these figures as a conservative estimation of the eye lens dose, an anaesthesiologist could participate in around 150 procedures before reaching the regulatory annual dose limit for the lens of the eye in Europe (20 mSv). In those clinical procedures where patients need close anesthesiological care, the anaesthesiologists might receive high radiation doses increasing the risk for cataracts and the risk of stochastic radiation effects. The proper use of occupational dosimeters will help identify these situations. It is recommended to use a mobile shielding barrier to reduce radiation exposure to acceptable levels in these situations.

Radiation dose reduction capabilities of a new C-arm system with optimized hard- and software

PURPOSE

To assess the radiation dose reduction capabilities and the image quality of a new C-arm system in comparison to a standard C-arm system.

METHOD

Prospective, randomized, IRB approved two-arm trial design. 49 consecutive patients with primary or secondary liver cancer were treated with transarterial chemoembolization (TACE) on two different angiography units. 28 patients were treated on a conventional angiography unit B, 21 patients on unit A which provides improved hardware and optimized image processing algorithms. Dose area product (DAP) and fluoroscopy time were recorded. DSA image quality of all procedures was assessed on a four-rank-scale by two independent and blinded readers.

RESULTS

Both cohorts showed no significant differences with regard to patient characteristics, tumor burden and fluoroscopy time. The new system resulted in a statistically significant reduction of cumulative DAP of 72% compared to the old platform (median 76 vs. 269 Gy*cm2). Individually, Fluoro-DAP and DSA-DAP decreased by 48% and 77% (p = 0.012 and p < 0.01), respectively. No statistically significant differences in DSA image quality were found between the two imaging platforms.

CONCLUSIONS

The new C-arm system significantly reduced radiation exposure for TACE procedures without increased radiation time or negative impact on DSA image quality. The combination of optimized hardware and software yields the highest radiation dose reduction and is of utmost importance for patients and interventionalists.

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.

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.

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.

Is trans-radial approach related to an increased risk of radiation exposure in patients who underwent diagnostic coronary angiography or percutaneous coronary intervention? (The SAKARYA study)

OBJECTIVE

It is still debatable whether diagnostic coronary angiography (CA) or percutaneous coronary interventions (PCIs) increase radiation exposure when performed via radial approach as compared to femoral approach. This question was investigated in this study by comparison of dose-area product (DAP), reference air kerma (RAK), and fluoroscopy time (FT) among radial and femoral approaches.

METHODS

All coronary procedures between November 2015 and November 2017 were assessed; and 4215 coronary procedures were enrolled in the study. Patients with bifurcation, chronic total occlusion, cardiogenic shock, or prior coronary artery bypass surgery were excluded. These 4215 procedures were evaluated for three different categories: diagnostic CA (Group I), PCI in patients with stable angina (Group II), and PCI in patients with ACS (Group III).

RESULTS

Age was significantly higher in the femoral arm of all groups. Among patients in the radial arm of Groups I and II, males were over-represented. Therefore, a multiple linear regression analysis with stepwise method was performed. After adjusting these clinical confounders, there was no significant difference with regard to DAP, RAK, and FT between femoral and radial access in Group I. In contrast, PCI via radial access was significantly associated with increased DAP, RAK, and FT in Groups II and III.

CONCLUSION

In spite of an increased experience with trans-radial approach, PCI of coronary lesions via radial route was associated with a relatively small but significant radiation exposure in our study. Compared to femoral access, diagnostic CA via radial access was not related to an increased radiation exposure.

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.

Strategies to optimise occupational radiation protection in interventional cardiology using simultaneous registration of patient and staff doses

The International Commission on Radiological Protection recommends that occupational protection and patient protection be managed in an integrated approach. This paper describes the experience and the initial results of a system able to register and to process simultaneously staff and patient doses in interventional cardiology and the practical use of this system in the optimisation of occupational exposure. The system used simultaneously collects and manages patient and staff doses for all radiation events. The personal electronic dosimeters worn over the protective apron of health professionals working inside catheterisation laboratories can send (wireless) doses and dose rate values to an X-hub and provide the operators inside the catheterisation rooms with real-time information. Individual and global reports for all the health professionals may be periodically obtained from the system to help with the optimisation. The results for eight cardiologists, one fellow and four nurses for a total of 2468 interventional cardiology procedures and 3207 occupational dose values collected over one year are presented here. Annual doses Hp(10) measured over the apron for cardiologists ranged from 0.3 to 6.3 mSv. For the cardiologist, the ratio between occupational doses (over the apron) and patient doses ranged from 0.05 to 0.23 μSv Gy^-1 cm^-2, with a mean value of 0.12 μSv Gy^-1 cm^-2. The system allows defining optimisation strategies by comparing the results between the different operators while considering the workload and complexity of the procedures (based on the total Kerma Area Product managed by the different operators). The registration of the date and time of the occupational radiation doses allows auditing the use of the personal dosimeters worn by the various operators.

Radiation Doses to Operators in Hepatobiliary Interventional Procedures

PURPOSE

The primary aim of this study is to provide a summary of operators' radiation doses during hepatobiliary fluoroscopic guided procedures. In addition, patient dose in these procedures was also documented.

MATERIALS AND METHODS

A total of 283 transarterial chemoembolisation (TACE) and 302 biliary procedures, including 52 percutaneous transhepatic cholangiogram (PTC), 36 bilioplasty and 214 biliary catheter changes (BCC) performed over 14 months, were included. Electronic personal dosimeters were used to measure operator radiation doses. Effective dose (E) was calculated using modified Niklason algorithm. Patient dose was measured as dose area product (DAP) and fluoroscopy time (FT).

RESULTS

For TACE, E for radiologist ranged between 0 and 9.96 µSv, for radiographer 0-0.99 µSv and for nurse 0-4.65 µSv. The patient DAP and FT ranged between 1.5 and 421.9 Gy cm² and 1.91-67.25 min. For PTC, E for the radiologist ranged between 0.33 and 55.89 µSv, for radiographer 0-38.61 µSv and for nurse 0-3.18 µSv. Patient DAP and FT ranged between 1.7 and 218.4 Gy cm² and 2.07-71.53 min. For bilioplasty, E ranged between 0.09 and 9.24 µSv for radiologist, 0-0.84 µSv for radiographer and 0-1.38 µSv for nurse. The patients' DAP and FT ranged from 0.7 to 52.54 Gy cm² and 1.13-24.47 min. For BCC, E ranged from 0 to 12.78 µSv for radiologist, 0-8.43 µSv for radiographer and 0-4.05 µSv for nurse. Patient DAP and FT ranged between 0.12 and 117.3 Gy cm² and 0.57-15.83 min.

CONCLUSIONS

This study shows that doses to all operators performing hepatobiliary interventional procedures can be very low.