Eye lens dosimetry in interventional cardiology: results of staff dose measurements and link to patient dose levels

Influence of Hospital Bed Count on the Positioning of Cardiovascular Interventional Radiology (IR) Nurses: Online Questionnaire Survey of Japanese IR-Specialized Radiological Technologists

BACKGROUND/OBJECTIVES

Interventional radiology (IR) utilizing X-rays can lead to occupational radiation exposure, posing health risks for medical personnel in the field. We previously conducted a survey on the occupational radiation exposure of IR nurses in three designated emergency hospitals in Japan. Our findings indicated that a hospital with 214 beds showed a higher lens-equivalent dose than hospitals with 678 and 1182 beds because the distance between the X-ray irradiation field and the IR nurse's position of the hospital with 214 beds was shorter than those of 678 and 1182 beds. Based on these observations, we hypothesized that the number of hospital beds affects the distance between the X-ray irradiation field and the IR nurse's position.

METHODS

To verify this hypothesis, we conducted a more extensive online questionnaire survey, focusing exclusively on hospitals that perform cardiovascular IR.

RESULTS

We analyzed data from 78 facilities. The results of this study confirmed our earlier findings, showing that both the number of physicians performing IR procedures and the distance from the X-ray irradiation field to the IR nurse's position are influenced by the number of hospital beds. Additionally, factors such as the type of hospital, emergency medical system, annual number of IR sessions, location of medical equipment, and the positioning of IR nurses appear to be associated with the number of hospital beds.

CONCLUSIONS

Understanding these relationships could enable the development of individualized and prioritized radiation exposure reduction measures for IR nurses in high-risk settings, provided that comprehensive occupational radiation risk assessments for cardiovascular IR consider the number of hospital beds and related factors. This study was not registered.

Medical staff dose estimation during pediatric cardiac interventional procedures

The purpose of this study is to evaluate the occupational doses (eye lens, extremities and whole body) in paediatric cardiac interventional and diagnostic catheterization procedures performed in a paediatric reference hospital located in Recife, Pernambuco. For eye lens dosimetry, the results show that the left eye receives a higher dose than the right eye, and there is a small difference between the doses received during diagnostic (D) and therapeutic (T) procedures. The extrapolated annual values for the most exposed eye are close to the annual limit. For doses to the hands, it was observed that in a significant number of procedures (37 out of 45 therapeutic procedures, or 82%) at least one hand of the physician was exposed to the primary beam. During diagnostic procedures, the physician's hand was in the radiation field in 11 of the 17 catheterization procedures (65%). This resulted in a 10-fold increase in dose to the hands. The results underscore the need for optimization of radiation safety and continued efforts to engage staff in a radiation safety culture.

A practical method for routine eye lens dosimetry of staff in interventional radiology

Hospital staff doing fluoroscopy-guided interventions receive the highest doses and are at risk of exceeding the new occupational eye lens dose limit of 20 mSv. Since the introduction of the new limit in the International Commission on Radiological Protection recommendations different eye lens dose monitoring techniques have been tested on phantoms. This study uses real-life dose data to assess the need for routine eye lens dose monitoring. The correlation of eye lens dose and Hp (10) measured with a whole-body dosemeter above the lead apron was investigated as an alternative to dedicated eye lens dosimetry. A survey taken among the medical personnel allowed to determine the preferred method for measuring eye lens doses in daily practice.

PATIENT AND STAFF DOSES FOR VARIOUS INTERVENTIONAL RADIOLOGY AND CARDIOLOGY EXAMINATIONS IN TURKEY

This study aims to determine the radiation doses of patients and staff during different interventional radiology and cardiology examinations. Dose measurements for interventional radiology examinations were performed in Ibn-i Sina Hospital of Ankara University using Siemens Artis-Zee medical imaging system. Patient dose measurement was carried out for interventional cardiology examinations in Cardiology Department of TOBB-ETU University, Medical Faculty Hospital using Philips Allura Centron interventional X-ray system. Patient doses were obtained in terms of kerma area product (KAP) and cumulative air kerma (CAK) from KAP meter attached to the angiography system. Performance tests of the angiography system were performed before patient dose measurements. Staff dose measurements were carried out with thermoluminescence dosimeters (TLD-100) placed in certain areas on the staff. Patient dose measurements were performed for 15 different interventional radiology examinations on a total of 431 patients and for four different cardiology examinations on a total of 299 patients. Monte Carlo based PCXMC 2.0 program was used to calculate patient effective doses. Lower extremity arteriography was the most common examination with a mean KAP value of 30 Gy cm2 and mean effective dose value of 1.2 mSv for total number of 194 patients. Mean KAP values calculated for coronary angiography, percutaneous coronary intervention, electrophysiological procedures and radiofrequency cardiac ablation examinations were 62.8, 162.8, 16.7 and 70.6 Gy cm2, respectively. Radiologist, nurse and technician effective dose normalised to the unit KAP of patient dose were 0.15, 0.11 and 0.14 μSv Gy-1 cm-2. Similarly, cardiologist, nurse and technician effective dose normalised to the unit KAP of patient dose were 0.22, 0.15 and 0.09 μSv Gy-1 cm-2. Measured KAP and CAK values vary depending on the type and complexity of the examination. The measured staff doses during cardiac examinations were higher when compared with that measured for interventional radiology as expected.

Reduction of radiation exposure during transcatheter edge-to-edge mitral valve repair

BACKGROUND

Transcatheter mitral valve repair is an increasingly used therapy for mitral regurgitation which requires fluoroscopic guidance. Limiting radiation exposure during lengthy procedures is important for both patient and operator safety. This study aimed to investigate radiation dose during contemporary use of MitraClip implantation and the effects of a dose reduction program.

METHODS

A total of 115 patients who underwent MitraClip implantation were prospectively enrolled in a single-center observational study. During the inclusion period, our institution adopted a radiation dose reduction program, comprising lowering of fluoroscopy pulse rate and image target dose. The first 58 patients were treated with conventional fluoroscopy settings, while the following 57 patients underwent the procedure with the newly implemented low dose protocol.

RESULTS

Radiation dose area product significantly decreased after introduction of the low dose protocol (693 [366-1231] vs. 2265 [1517-3914] cGy·cm² , p < 0.001). After correcting for fluoroscopy time, gender and body mass index, the low dose protocol emerged as a strong negative predictor of radiation dose (p < 0.001), reducing dose area product by 64% (95% confidence interval [57-70]). Device time, device success, and procedural safety did not differ between the normal dose and low dose group. Furthermore, the low dose protocol was not associated with an increased incidence of a combined endpoint consisting of death, repeat intervention, or heart surgery during 12 months follow-up.

CONCLUSION

Reduction of radiation exposure during transcatheter mitral valve repair by 64% is feasible without affecting procedural success or safety.

Assessment of eye doses to staff involved in interventional cardiology procedures in Kuwait

In this study, which is the first of its kind in the gulf region, eye doses of interventional cardiologists and nurses were measured using active dosimeters for left and right eyes, in 60 percutaneous coronary interventions in three main hospitals in Kuwait. The dose given in terms of H_p(0.07) per procedure when ceiling suspended screens were used by main operators ranged from 18.5 to 30.3 µSv for the left eye and from 12.6 to 23.6 µSv for the right eye. Taking into account typical staff workload, the results show that the dose limit of 20 mSv/year to the eyes can be exceeded for interventional cardiologists in some situations, which demonstrates the need of using additional effective radiation protection tools, e.g. protective eye spectacles, in addition to the regular and proper use of ceiling suspended screens. With indications of increase in workload, the need for availability of a dedicated active dosimeter for the regular monitoring of eye doses is emphasized.

Eye protection in interventional procedures

Data suggest that radiation-induced cataracts may form without a threshold and at low-radiation doses. Staff involved in interventional radiology and cardiology fluoroscopy-guided procedures have the potential to be exposed to radiation levels that may lead to eye lens injury and the occurrence of opacifications have been reported. Estimates of lens dose for various fluoroscopy procedures and predicted annual dosages have been provided in numerous publications. Available tools for eye lens radiation protection include accessory shields, drapes and glasses. While some tools are valuable, others provide limited protection to the eye. Reducing patient radiation dose will also reduce occupational exposure. Significant variability in reported dose measurements indicate dose levels are highly dependent on individual actions and exposure reduction is possible. Further follow-up studies of staff lens opacification are recommended along with eye lens dose measurements under current clinical practice conditions.

Are X-ray Safety Glasses Alone Enough for Adequate Ocular Protection in Complex Radiological Interventions?

ABSTRACT

The maximum annual radiation ocular dose limit for medical staff has been reduced to 20 mSv in the current European directive 2013/59/Euratom. This multi-centric study aims at reporting the protected and unprotected eye lens doses in different fluoroscopically guided interventions and to evaluate any other factors that could influence the ocular dose. From July 2018 to July 2019, ocular radiation doses of six interventionists of four departments during complex interventions were recorded with a thermoluminescent dosimeter in front of and behind radiation protection glasses to measure the protected and unprotected doses. The position of personnel, intervention type, fluoroscopy time, total body dose and use of pre-installed protection devices like lead acrylic shields were also systematically recorded. Linear regression analysis was used to estimate the doses at 2 y and 5 y. The annual unprotected/protected ocular doses of six interventionists were 67/21, 32.7/3.3, 27.4/5.1, 7/0, 21.8/2.2, and 0/0 mSv, respectively. The unprotected dose crossed the 20-mSv annual limits for four interventionists and protected dose for one less experienced interventionist. The estimated 5-y protected ocular dose of this interventionist was 101.318 mSv (95%CI 96.066-106.57), also crossing the 5-y limit. The use of a lead acrylic shield was observed to have a significant effect in reducing ocular doses. The annual unprotected and protected ocular doses for interventionists dealing with complex interventions could cross the present permitted yearly limit. The measurement of significant protected ocular dose behind the radiation protection glasses emphasizes the additional indispensable role of pre-installed radiation protection devices and training in reducing radiation doses for complex procedures.

Report of IRPA task group on issues and actions taken in response to the change in eye lens dose limit

In 2018, the International Radiation Protection Association (IRPA) established its third task group (TG) on the implementation of the eye lens dose limit. To contribute to sharing experience and raising awareness within the radiation protection community about protection of workers in exposure of the lens of the eye, the TG conducted a questionnaire survey and analysed the responses. This paper provides an overview of the results of the questionnaire.

Scatter radiation reduction with a radiation-absorbing pad in interventional radiology examinations

PURPOSE

Radiation-absorbing pads are an additional possibility to reduce scattered radiation at its source. The goal of this study is to investigate the efficacy of a new reusable radiation-absorbing pad at its origin in an experimental setup.

MATERIAL AND METHODS

All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol, different C-arm angulations and an anthropomorphic torso phantom as a scattering body. An ionization chamber was used to measure the radiation exposure at five different heights of a simulated operator during a simulated transfemoral angiography intervention. Measurements were carried out with and without radiation-absorbing pads with lead equivalents of 0.25 and 0.5 mm placed onto the scattering body. For all measurements a mobile acrylic shield and an under-table lead curtain was used.

RESULTS

At all operator heights from 100 to 165 cm a significant radiation dose reduction of up to 80.6 % (p < 0.01) using the radiation-absorbing pad was measured, when compared to no radiation-absorbing pad. At the height of 165 cm the radiation-absorbing pad with a lead equivalence of 0.5 mm showed a significant radiation dose reduction (51.4 %, p < 0.01) in comparison to a lead equivalence of 0.25 mm.

CONCLUSION

The addition of a radiation-absorbing pad to the standard protection means results in a significant dose reduction for the operator, particularly for upper body parts.

Occupational eye dose to medical staff in various interventional cardiologic procedures: is the need for lead goggles the same in all groups of radiation workers?

Considering the increased use of interventional cardiologic procedures and concern about irradiation to the eyes, it is necessary to measure eye dose in radiation workers. The assessment of eye dose using collar dose is a routine but inaccurate method. Therefore this study was designed to measure eye dose in the radiation workers of various interventional cardiologic procedures. In this study eye dose was measured for left and right eyes in three groups of radiation workers in angiography ward of Afshar hospital in various procedures using TLD. Measurements were done separately for cardiologists, nurses and radio-technologists in 100 procedures. The nurses functioned as surgical assistants and were usually close to the table. The correlation of staff dose to exposure parameters was also investigated. Eye dose in physicians were higher than other staff in all procedures. Also the left eye dose was considerably higher than right one, especially for physicians. The median equivalent dose per procedure of left eye for physicians, nurses and radio-technologists were 7.4, 3.6, 1.4 µSv (PCI) and 3.2, 3.1, 1.3 µSv (Adhoc) and 3.2, 1.7, 1.1 µSv (CA), respectively. The annual left eye equivalent dose with (without) using lead goggles were 2.4 (15.3), 1.4 (2.2), 1.0 (1.1) mSv for physicians, nurses and radio-technologists, respectively. There were also a positive correlation between eye dose and KAP for procedures without lead goggles. The lead goggles showed lower protection effects for radio-technologists than other staff. Only 30% of physicians received a dose higher than 1/3 of the ICRP annual dose limit, therefor only physician eye dose should be monitored in catheterization labs.

OCCUPATIONAL EYE LENS DOSE ESTIMATED USING WHOLE-BODY DOSEMETER IN INTERVENTIONAL CARDIOLOGY AND RADIOLOGY: A MONTE CARLO STUDY

Medical personnel performing interventional procedures in cardiology and radiology is considered to be a professional group exposed to high doses of ionizing radiation. Reduction of the eye lens dose limit made its assessment in the interventional procedures one of the most challenging topics. The objective of this work is to assess eye lens doses based on the whole-body doses using methods of computational dosimetry. Assessment included different C-arm orientations (PA, LAO and RAO), tube voltages (80 -110 kV) and efficiency of different combinations of protective equipment used in interventional procedures. Center position at the height of the thyroid gives best estimate of eye lens dose, with spreads of 11% (13%), 13% (17%) and 14% (13%) for the left (right) eye lens. The conversion factors of 1.03 (0.83), 1.28 (1.06) and 1.36 (1.06) to convert whole body to eye lens dose were derived for positions of first operator, nurse and radiographer, respectively. The eye lens dose reduction factors for different combinations of applied protective equipment are 178, 5 and 6, respectively.

Protective Efficacy of Different Ocular Radiation Protection Devices: A Phantom Study

PURPOSE

The aim of this study was to investigate the efficacy of different designs and types of ocular radiation protection devices depending on simulated varied body heights in a phantom-simulated thoracic intervention.

MATERIALS AND METHODS

A clinical angiography system with a standardized fluoroscopy protocol with an anthropomorphic chest phantom as a scattering object and optically stimulated luminescence dosimeters for measuring radiation dose were used. The dosimeters were placed at the position of eyes of an anthropomorphic head phantom simulating the examiner. The head phantom was placed on a height-adjustable stand simulating the height of the examiner from 160 to 200 cm with 10 cm increments. The dose values were then measured with no radiation protection, a weightless-like radiation protection garment, radiation protection glasses and visors.

RESULTS

The average dose reduction using radiation protection devices varied between 57.7 and 83.4% (p < 0.05) in comparison with no radiation protection. Some radiation protection glasses and visors showed a significant dose reduction for the eye lenses when the height of the examiner increased. The right eye was partially less protected, especially if the distances between the simulated examiner's head and the scatter object were small.

CONCLUSION

All the investigated protection devices showed a significant reduction in radiation exposure to the simulated examiner. For some devices, the radiation dose increased with decreasing distance to the scattering object, especially for the right eye lens.

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

AIMS

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

DESIGN

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

METHODS

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

RESULTS

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

CONCLUSION

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

IMPACT

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

OCCUPATIONAL DOSES FOR THE FIRST AND SECOND OPERATORS IN LEBANESE INTERVENTIONAL CARDIOLOGY SUITES

The study monitored occupational dose for 12 interventional cardiologists (first operators) and 10 technicians (second operators), from 10 different Lebanese hospitals performing coronary angiography and precutaneous coronary interventions exclusively on adult patients. Each individual wore dosemeters under and over the lead apron at chest and collar level, respectively, on the wrist and next to the left eye. The total follow-up period for each first/second operator varied between two to six bimonthly monitoring periods. For the first operator, the mean (range) effective, hand and eye lens doses were of 6 (1-41), 112 (10-356) and 15 (5-47) μSv/procedure, respectively. These were of 2.3 (0.1-8), 16 (2-109) and 7 (2-14) μSv/procedure for the second operator. Extrapolated annual eye lens doses revealed that both first and second operators may exceed 3/10th of the annual eye lens dose permissible limit thus supporting the need for dedicated eye lens monitoring.

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

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

Eye lens dose levels in interventional rooms using simple phantom simulation, dose management software and Monte Carlo method of uncertainty assessment

This paper presents a fast method to estimate the annual eye lens dose levels for interventional practitioners applying the Monte Carlo method of uncertainty assessment. The estimation was performed by placing an anthropomorphic phantom in the typical working position, and applying the habitually employed protocol. No radiation protection devices were considered in the simulation. The results were compatible with the measurements performed during interventions by placing dosimeters in the vicinity of the eyes of two paediatric interventional cardiologists working with a fluoroscopic biplane system.

Effectiveness of a new radiation protection system in the interventional radiology setting

OBJECTIVES

The goal of this study was to examine a new weightless-like radiation protection garment regarding its radiation protection efficacy and to compare it to a conventional two-piece apron suit plus thyroid collar and standard ancillary shields.

MATERIAL AND METHODS

All measurements were carried out using a clinical angiography system with a standardized fluoroscopy protocol for different C-arm angulations. An anthropomorphic torso phantom served as a scattering body. In addition, an ionization chamber was used to measure the radiation exposure on five different representative heights and at two different positions of an examiner during a typical fluoroscopic-guided intervention.

RESULTS

The new weightless-like radiation protection garment and the conventional protection concept showed a mean dose reduction of 98.1% (p < 0.01) and 90.1% (p < 0.01) when compared to no shielding, respectively. By adding ancillary shields to both systems, an average reduction of 99.0% (p < 0.01) and 98.2% (p < 0.01) was found. In addition, the efficacy of both systems varied depending on the height, the C-arm angulation and position of the examiner.

CONCLUSION

Combined with ancillary shields as an overall protection system, the recently introduced weightless-like radiation protection garment showed a significant better radiation protection efficacy when compared to conventional radiation protection measures.

A COMPARISON OF OCCUPATIONAL DOSES IN CONVENTIONAL AND INTERVENTIONAL RADIOLOGY IN IRAN

Occupational exposures in conventional and interventional radiology were investigated over a period of 10 years for all radiation workers. The statistical analysis carried out on the refined data showed that the average annual effective doses in conventional and interventional radiology were 0.28 and 0.59 mSv for measurably exposed workers and 0.18 and 0.52 mSv for all monitored workers in 2014. More than 99.9 and 82.8% of radiation workers in conventional and interventional radiology received annual doses less than the public dose limit (1 mSv) in 2014. Comparing the occupational dose levels of different countries (including Iran) in conventional as well as interventional radiology showed a poor comparability among them. Regarding the doses above the investigation level, the analysis showed that majority of them were due to improper use of personal dosimeters (false doses) and only 0.01 and 0.12% of the dose records actually crossed the level in conventional and interventional radiology in 2014.

EYE LENS DOSIMETRY WITHIN THE CARDIAC CATHETERISATION LABORATORY-ARE ANCILLARY STAFF BEING FORGOTTEN?

Eye lens doses have been widely explored for interventional clinicians, however, data for ancillary staff is limited. Eye doses have been measured using a headband technique for clinicians, specialist registrars, nurses and radiographers working in a cardiac catheterisation laboratory in a UK hospital. Workload was found to be significantly higher for ancillary staff, and consequently, despite the absolute monthly collar doses and other indicators such as eye dose/KAP and eye dose/procedure being highest for clinicians, our study found there was no significant difference in the monthly eye dose readings between the clinicians and nurses (p = 0.82), and clinicians and radiographers (p = 0.72). The average eye dose/collar dose ratios were 0.71 and 0.61 for cardiologists and SPRs, but ratios above one were found for nurses and radiographers. This work expands on the eye dose data available for ancillary staff and demonstrates that eye dosimetry for these workers should not be overlooked.

Off the pedal: Fluoroless transseptal puncture in pediatric supraventricular tachycardia ablation

BACKGROUND

Fluoroless transseptal (TS) puncture may represent the final step toward elimination of fluoroscopy in pediatric supraventricular tachycardia ablation in normal hearts. We aimed to demonstrate the safety and feasibility of fluoroless TS puncture in pediatric patients and compare procedural timing with the fluoroscopic approach.

METHODS

We performed a retrospective cohort analysis of all TS procedures performed without fluoroscopy at our institution; fluoroless TS procedures were performed under intracardiac echocardiography (ICE) guidance after the creation of a 3D electroanatomic map and identification of fossa ovalis (FO) on 3D map. TS procedure times reported are the time from sheath insertion (8.5F short sheath for ICE catheter and SL-1 for TS needle) to the time of confirmed left atrial access. Prior TS procedures performed by the same operator utilizing a combination of ICE and fluoroscopy and by a second operator utilizing fluoroscopic guidance alone were used for comparison.

RESULTS

Fluoroless TS puncture was performed in nine patients (mean age 13.8 years); the site of TS puncture was within 2 mm of the FO identified on the EA map. The mean TS procedure time was 22.2 minutes (range 10-45). There was no significant difference in TS procedure times between the three groups. There were no complications related to any TS procedure.

CONCLUSION

Fluoroless TS procedures utilizing ICE can safely be performed in pediatric patients without adding substantial procedural times compared with those utilizing fluoroscopic guidance.

The current status of eye lens dose measurement in interventional cardiology personnel in Thailand

Workers involved in interventional cardiology procedures receive high eye lens doses if radiation protection tools are not properly utilized. Currently, there is no suitable method for routine measurement of eye dose. In Thailand, the eye lens equivalent doses in terms of Hp(3) of the interventional cardiologists, nurses, and radiographers participating in interventional cardiology procedures have been measured at 12 centers since 2015 in the pilot study. The optically stimulated luminescence (OSL) dosimeter was used for measurement of the occupational exposure and the eye lens dose of 42 interventional cardiology personnel at King Chulalongkorn Memorial Hospital as one of the pilot centers. For all personnel, it is recommended that a first In Light OSL badge is placed at waist level and under the lead apron for determination of Hp(10); a second badge is placed at the collar for determination of Hp(0.07) and estimation of Hp(3). Nano Dots OSL dosimeter has been used as an eye lens dosimeter for 16 interventional cardiology personnel, both with and without lead-glass eyewear. The mean effective dose at the body, equivalent dose at the collar, and estimated eye lens dose were 0.801, 5.88, and 5.70 mSv per year, respectively. The mean eye lens dose measured by the Nano Dots dosimeter was 8.059 mSv per year on the left eye and 3.552 mSv per year on the right eye. Two of 16 interventional cardiologists received annual eye lens doses on the left side without lead glass that were higher than 20 mSv per year, the new eye lens dose limit as recommended by ICRP with the risk of eye lens opacity and cataract.

Shielding Effect of Lead Glasses on Radiologists' Eye Lens Exposure in Interventional Procedures

To study the shielding effect of radiologists' eye lens with lead glasses of different equivalent thicknesses and sizes in interventional radiology procedures. Using the human voxel phantom with a more accurate model of the eye and MCNPX software, eye lens doses of the radiologists who wearing different kinds of lead glasses were simulated, different beam projections were taken into consideration during the simulation. Measurements were also performed with the physical model to verify simulation results. Simulation results showed that the eye lens doses were reduced by a factor from 3 to 9 when wearing a 20 cm2-sized lead glasses with the equivalent thickness ranging from 0.1 to 1.0 mm Pb. The increase of dose reduction factor (DRF) was not significant whenever increase the lead equivalent of glasses of which larger than 0.35 mm. Furthermore, the DRF was proportional to the size of glass lens from 6 to 30 cm2 with the same lead equivalent. The simulation results were in well agreements with the measured ones. For more reasonable and effective protection of the eye lens of interventional radiologists, a pair of glasses with a lead equivalent of 0.5 mm Pb and large-sized (at least 27 cm2 per glass) lens are recommended.

Eye lens dose correlations with personal dose equivalent and patient exposure in paediatric interventional cardiology performed with a fluoroscopic biplane system

PURPOSE

To analyse the correlations between the eye lens dose estimates performed with dosimeters placed next to the eyes of paediatric interventional cardiologists working with a biplane system, the personal dose equivalent measured on the thorax and the patient dose.

METHODS

The eye lens dose was estimated in terms of H_p(0.07) on a monthly basis, placing optically stimulated luminescence dosimeters (OSLDs) on goggles. The H_p(0.07) personal dose equivalent was measured over aprons with whole-body OSLDs. Data on patient dose as recorded by the kerma-area product (P_KA) were collected using an automatic dose management system. The 2 paediatric cardiologists working in the facility were involved in the study, and 222 interventions in a 1-year period were evaluated. The ceiling-suspended screen was often disregarded during interventions.

RESULTS

The annual eye lens doses estimated on goggles were 4.13±0.93 and 4.98±1.28mSv. Over the aprons, the doses obtained were 10.83±0.99 and 11.97±1.44mSv. The correlation between the goggles and the apron dose was R²=0.89, with a ratio of 0.38. The correlation with the patient dose was R²=0.40, with a ratio of 1.79μSvGy^-1cm^-2. The dose per procedure obtained over the aprons was 102±16μSv, and on goggles 40±9μSv. The eye lens dose normalized to P_KA was 2.21±0.58μSvGy^-1cm^-2.

CONCLUSIONS

Measurements of personal dose equivalent over the paediatric cardiologist's apron are useful to estimate eye lens dose levels if no radiation protection devices are typically used.

Design of a head phantom produced on a 3D rapid prototyping printer and comparison with a RANDO and 3M lucite head phantom in eye dosimetry applications

An anthropomorphic head phantom including eye inserts allowing placement of TLDs 3 mm below the cornea has been produced on a 3D printer using a photo-cured acrylic resin to best allow tissue equivalence. Thus H_p(3) can be determined in radiological and interventional photon radiation fields. Eye doses and doses to the forehead have been compared to an Alderson RANDO head and a 3M Lucite skull phantom in terms of surface dose per incident air kerma for frontal irradiation since the commercial phantoms do not allow placement of TLDs 3 mm below the corneal surface. A comparison of dose reduction factors (DRFs) of a common lead glasses model has also been performed. Eye dose per incident air kerma were comparable between all three phantoms (printed phantom: 1.40, standard error (SE) 0.04; RANDO: 1.36, SE 0.03; 3M: 1.37, SE 0.03). Doses to the forehead were identical to eye surface doses for the printed phantom and the RANDO head (ratio 1.00 SE 0.04, and 0.99 SE 0.03, respectively). In the 3M Lucite skull phantom dose on the forehead was 15% lower than dose to the eyes attributable to phantom properties. DRF of a sport frame style leaded glasses model with 0.75 mm lead equivalence measured were 6.8 SE 0.5, 9.3 SE 0.4 and 10.5 SE 0.5 for the RANDO head, the printed phantom, and the 3M Lucite head phantom, respectively, for frontal irradiation. A comparison of doses measured in 3 mm depth and on the surface of the eyes in the printed phantom revealed no difference larger than standard errors from TLD dosimetry. 3D printing offers an interesting opportunity for phantom design with increasing potential as printers allowing combinations of tissue substitutes will become available. Variations between phantoms may provide a useful indication of uncertainty budgets when using phantom measurements to estimate individual personnel doses.

Radiobiology in Cardiovascular Imaging

The introduction of ionizing radiation in medicine revolutionized the diagnosis and treatment of disease and dramatically improved and continues to improve the quality of health care. Cardiovascular imaging and medical imaging in general, however, are associated with a range of radiobiologic effects, including, in rare instances, moderate to severe skin damage resulting from cardiac fluoroscopy. For the dose range associated with diagnostic imaging (corresponding to effective doses on the order of 10 mSv [1 rem]), the possible effects are stochastic in nature and largely theoretical. The most notable of these effects, of course, is the possible increase in cancer risk. The current review addresses radiobiology relevant to cardiovascular imaging, with particular emphasis on radiation induction of cancer, including consideration of the linear nonthreshold dose-response model and of alternative models such as radiation hormesis.

EYE LENS EXPOSURE TO MEDICAL STAFF PERFORMING ELECTROPHYSIOLOGY PROCEDURES: DOSE ASSESSMENT AND CORRELATION TO PATIENT DOSE

The purpose of this study was to assess the patient exposure and staff eye dose levels during implantation procedures for all types of pacemaker therapy devices performed under fluoroscopic guidance and to investigate potential correlation between patients and staff dose levels. The mean eye dose during pacemaker/defibrillator implementation was 12 µSv for the first operator, 8.7 µSv for the second operator/nurse and 0.50 µSv for radiographer. Corresponding values for cardiac resynchronisation therapy procedures were 30, 26 and 2.0 µSv, respectively. Significant (p < 0.01) correlation between the eye dose and the kerma-area product was found for the first operator and radiographers, but not for other staff categories. The study revealed eye dose per procedure and eye dose normalised to patient dose indices for different staff categories and provided an input for radiation protection in electrophysiology procedures.

Personnel real time dosimetry in interventional radiology

Interventional radiology and hemodynamic procedures have rapidly grown in number in the past decade, increasing the importance of personnel dosimetry not only for patients but also for medical staff. The optimization of the absorbed dose during operations is one of the goals that fostered the development of real-time dosimetric systems. Indeed, introducing proper procedure optimization, like correlating dose rate measurements with medical staff position inside the operating room, the absorbed dose could be reduced. Real-time dose measurements would greatly facilitate this task through real-time monitoring and automatic data recording. Besides real-time dose monitoring could allow automatic data recording. In this work, we will describe the calibration and validation of a wireless real-time prototype dosimeter based on a new sensor device (CMOS imager). The validation measurement campaign in clinical conditions has demonstrated the prototype capability of measuring dose-rates with a frequency in the range of few Hz, and an uncertainty smaller than 10%.

InterCardioRisk: a novel online tool for estimating doses of ionising radiation to occupationally-exposed medical staff and their associated health risks

Those working in interventional cardiology and related medical procedures are potentially subject to considerable exposure to x-rays. Two types of tissue of particular concern that may receive considerable doses during such procedures are the lens of the eye and the brain. Ocular radiation exposure results in lens changes that, with time, may progress to partial or total lens opacification (cataracts). In the early stages, such opacities do not result in visual disability; the severity of such changes tends to increase progressively with dose and time until vision is impaired and cataract surgery is required. Scattered radiation doses to the eye lens of an interventional cardiologist in typical working conditions can exceed 34 μGy min^-1 in high-dose fluoroscopy modes and 3 μGy per image during image acquisition (instantaneous rate values) when radiation protection tools are not used. A causal relation between exposure to ionising radiation and increased risk of brain and central nervous system tumours has been shown in a number of studies. Although absorbed doses to the brain in interventional cardiology procedures are lower than those to the eye lens by a factor between 3.40 and 8.08 according to our simulations, doses to both tissues are among the highest occupational radiation doses documented for medical staff whose work involves exposures to x-rays. We present InterCardioRisk, a tool featuring an easy-to-use web interface that provides a general estimation of both cumulated absorbed doses experienced by medical staff exposed in the interventional cardiology setting and their estimated associated health risks. The tool is available at http://intercardiorisk.creal.cat.

Ionizing Radiation Doses Detected at the Eye Level of the Primary Surgeon During Orthopaedic Procedures

OBJECTIVES

To evaluate the ionizing radiation dose received by the eyes of orthopaedic surgeons during various orthopaedic procedures. Secondary objective was to compare the ionizing radiation dose received between differing experience level.

DESIGN

Prospective comparative study between January 2013 and May 2014.

SETTING

Westmead Hospital, a Level 1 Trauma Centre for Greater Western Sydney.

PARTICIPANTS

A total of 26 surgeons volunteered to participate within the study.

INTERVENTION

Experience level, procedure performed, fluoroscopy time, dose area product, total air kerma, and eye dose received was recorded. Participants were evaluated on procedure and experience level.

MAIN OUTCOME MEASUREMENTS

Radiation dose received at eye level by the primary surgeon during an orthopaedic procedure.

RESULTS

Data from a total of 131 cases was recorded and included for analysis. The mean radiation dose detected at the eye level of the primary surgeon was 0.02 mSv (SD = 0.05 mSv) per procedure. Radiation at eye level was only detected in 31 of the 131 cases. The highest registered dose for a single procedure was 0.31 mSv. Femoral nails and pelvic fixation procedures had a significantly higher mean dose received than other procedure groups (0.04 mSv (SD = 0.07 mSv) and 0.04 mSv (SD = 0.06 mSv), respectively). Comparing the eye doses received by orthopaedic consultants and trainees, there was no significant difference between the 2 groups.

CONCLUSIONS

The risk of harmful levels of radiation exposure at eye level to orthopaedic surgeons is low. This risk is greatest during insertion of femoral intramedullary nails and pelvic fixation, and it is recommended that in these situations, surgeons take all reasonable precautions to minimize radiation dose. The orthopaedic trainees in this study were not subjected to higher doses of radiation than their consultant trainers. On the basis of these results, most of the orthopaedic surgeons remain well below the yearly radiation dose of 20 mSv as recommended by the International Commission on Radiological Protection.

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

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

The effectiveness of lead glasses in reducing the doses to eye lenses during cardiac implantation procedures performed using x-ray tubes above the patient table

The dose reduction factors (DRF) for different types of lead glasses and C-arm units with x-ray tubes placed above the patient table were calculated from the results of measurements by loose thermoluminescent dosimeters (TLDs) and EYE-D dosimeters using a Rando phantom. The DRF values were analysed for different positions of routine dosimeters worn outside lead eyewear and confronted with DRFs calculated as the ratio of the dose equivalent to the eye measured with and without the eyewear. Moreover, for eye lens dosimeters designed to be worn behind lead glasses, multiplicative factors for various positions of dosimeter were derived in order to account for the differences between the doses measured on the inner side of the glasses and the dose equivalent to the eye lens. The DRFs calculated for the position of a routine dosimeter worn outside lead glasses on the band near the left eye lens are 5.6 and 5.7 for goggles and metallic glasses, respectively, while the DRFs calculated as the ratio of doses to the eyes measured with and without the eyewear are 10.2 and 9.9, respectively. Therefore, for dosimeters routinely used outside lead eyewear, the DRF calculated for the position of the dosimeter should be used. Otherwise, we can anticipate an almost two-fold underestimation of the doses. When the dosimeter is worn behind lead glasses, up to two-fold differences between the dose equivalent to the eye lens and the dose measured at the inner side of the glasses were observed depending on the dosimeter position.

Assessment of radiation protection of patients and staff in interventional procedures in four Algerian hospitals

This study was aimed to assess patient dosimetry in interventional cardiology (IC) and radiology (IR) and radiation safety of the medical operating staff. For this purpose, four major Algerian hospitals were investigated. The data collected cover radiation protection tools assigned to the operating staff and measured radiation doses to some selected patient populations. The analysis revealed that lead aprons are systematically worn by the staff but not lead eye glasses, and only a single personal monitoring badge is assigned to the operating staff. Measured doses to patients exhibited large variations in the maximum skin dose (MSD) and in the dose area product (DAP). The mean MSD registered values are as follows: 0.20, 0.14 and 1.28 Gy in endoscopic retrograde cholangiopancreatography (ERCP), coronary angiography (CA) and percutaneous transluminal coronary angioplasty (PTCA) procedures, respectively. In PTCA, doses to 3 out of 22 patients (13.6 %) had even reached the threshold value of 2 Gy. The mean DAP recorded values are as follows: 21.6, 60.1 and 126 Gy cm(2) in ERCP, CA and PTCA procedures, respectively. Mean fluoroscopic times are 2.5, 5 and 15 min in ERCP, CA and PTCA procedures, respectively. The correlation between DAP and MSD is fair in CA (r = 0.62) and poor in PTCA (r = 0.28). Fluoroscopic time was moderately correlated with DAP in CA (r = 0.55) and PTCA (r = 0.61) procedures. Local diagnostic reference levels (DRLs) in CA and PTCA procedures have been proposed. In conclusion, this study stresses the need for a continuous patient dose monitoring in interventional procedures with a special emphasis in IC procedures. Common strategies must be undertaken to substantially reduce radiation doses to both patients and medical staff.

Eye lens monitoring for interventional radiology personnel: dosemeters, calibration and practical aspects of H p (3) monitoring. A 2015 review

A thorough literature review about the current situation on the implementation of eye lens monitoring has been performed in order to provide recommendations regarding dosemeter types, calibration procedures and practical aspects of eye lens monitoring for interventional radiology personnel. Most relevant data and recommendations from about 100 papers have been analysed and classified in the following topics: challenges of today in eye lens monitoring; conversion coefficients, phantoms and calibration procedures for eye lens dose evaluation; correction factors and dosemeters for eye lens dose measurements; dosemeter position and influence of protective devices. The major findings of the review can be summarised as follows: the recommended operational quantity for the eye lens monitoring is H p (3). At present, several dosemeters are available for eye lens monitoring and calibration procedures are being developed. However, in practice, very often, alternative methods are used to assess the dose to the eye lens. A summary of correction factors found in the literature for the assessment of the eye lens dose is provided. These factors can give an estimation of the eye lens dose when alternative methods, such as the use of a whole body dosemeter, are used. A wide range of values is found, thus indicating the large uncertainty associated with these simplified methods. Reduction factors from most common protective devices obtained experimentally and using Monte Carlo calculations are presented. The paper concludes that the use of a dosemeter placed at collar level outside the lead apron can provide a useful first estimate of the eye lens exposure. However, for workplaces with estimated annual equivalent dose to the eye lens close to the dose limit, specific eye lens monitoring should be performed. Finally, training of the involved medical staff on the risks of ionising radiation for the eye lens and on the correct use of protective systems is strongly recommended.

Radiation exposure to patients and medical staff in hepatic chemoembolisation interventional procedures in Recife, Brazil

The purpose of this study was to evaluate patient and medical staff absorbed doses received from transarterial chemoembolisation of hepatocellular carcinoma, which is the most common primary liver tumour worldwide. The study was performed in three hospitals in Recife, capital of the state of Pernambuco, located in the Brazilian Northeastern region. Two are public hospitals (A and B), and one is private (C). For each procedure, the number of images, irradiation parameters (kV, mA and fluoroscopy time), the air kerma-area product (PKA) and the cumulative air kerma (Ka,r) at the reference point were registered. The maximum skin dose (MSD) of the patient was estimated using radiochromic film. For the medical staff dosimetry, thermoluminescence dosemeters (TLD-100) were attached next to the eyes, close to the thyroid (above the shielding), on the thorax under the apron, on the wrist and on the feet. The effective dose to the staff was estimated using the algorithm of von Boetticher. The results showed that the mean value of the total PKA was 267.49, 403.83 and 479.74 Gy cm(2) for Hospitals A, B and C, respectively. With regard to the physicians, the average effective dose per procedure was 17 µSv, and the minimum and maximum values recorded were 1 and 41 µSy, respectively. The results showed that the feet received the highest doses followed by the hands and lens of the eye, since the physicians did not use leaded glasses and the equipment had no lead curtain.

Assessment of eye and body dose for interventional radiologists, cardiologists, and other interventional staff

A dose limit for the eye of 20 mSv, as proposed by the ICRP, could be exceeded by interventional clinicians. Data on eye dose levels for interventional radiologists and cardiologists provided by medical physicists from hospitals around the UK have been collated. The results indicate that most hospitals would require one or more interventional clinicians to be classified and several would have exceeded a 20 mSv limit. Dose data in the literature have been reviewed to derive factors that might be used to predict eye dose levels based on dose per procedure or kerma-area product workload. These could be used in prior risk assessments to establish monitoring practice. An alternative approach to personnel dose monitoring in radiology applications using a collar dosimeter worn outside the lead apron as the first dosimeter is proposed. The collar dosimeter would provide an assessment of eye dose in terms of Hp(3) and body dose in terms of Hp(10), which could be divided by ten to provide an assessment of effective dose. If Hp(3) exceeded 1 mSv per month, regular monitoring with a head dosimeter would be recommended, and if Hp(10) exceeded 2 mSv per month, then an under-apron dosimeter should also be worn.