OPtimising protection
Effectiveness of PPE
Effectiveness of PPE
2023
Radiation exposure in the cardiac catheterization laboratory (CCL) is an occupational hazard that predisposes health care workers to the development of adverse health effects such as cataracts, cancer, and orthopedic injury. To mitigate radiation exposure, personal protective shielding as well as permanently installed shields reduces these adverse effects. Yet, heavy protective lead aprons and poor ergonomics required for positioning movable shields remain barriers to a safer environment. Recent innovations to enhance personal protective equipment and revolutionize fixed shielding systems will permit the CCL team to work in a personal “lead-free” environment, markedly reducing occupational hazards. The purpose of this review is to update the status and future of radiation protection in the CCL.
Roguin A, Wu P, Cohoon T, et al. Update on Radiation Safety in the Cath Lab – Moving Toward a “Lead-Free” Environment. Journal of the Society for Cardiovascular Angiography & Interventions. 2023; 2: 101040.
Purpose
We utilized an anthropomorphic model made with a human skull to determine how different personal protective equipment influence operator intracranial radiation absorbed dose.
Materials and Methods
A custom anthropomorphic phantom made with a human skull coated with polyurethane rubber, mimicking superficial tissues, and was mounted onto a plastic thorax. To simulate scatter, an acrylic plastic scatter phantom was placed onto the fluoroscopic table with a 1.5 mm lead apron on top. Two Radcal radiation detectors were utilized; one inside of the skull and a second outside. Fluoroscopic exposures were performed with and without radiation protective equipment in AP, 45-degree RAO, and 45-degree LAO projections.
Results
The skull and soft tissues reduce intracranial radiation by 76% when compared to radiation outside the skull. LAO (308.95 μSv/min) and RAO projections (96.47μSv/min) result in significantly higher radiation exposure to the primary operator when compared to an AP projection (54 μSv/min). All tested radiation protection equipment demonstrated various reduction in intracranial radiation when compared to no protection. The hood (68% reduction in AP, 91% LAO, and 43% in RAO), full cover (53% reduction in AP, 76% in LAO, and 54% in RAO), and open top with ear coverage (43% reduction in AP, 77% reduction in LAO, and 22% in RAO) demonstrated the most reduction in intracranial radiation when compared to the control.
Conclusion
All tested equipment provided various degrees of additional intracranial protection. The skull and soft tissues attenuate a portion of intracranial radiation.
Qazi E, Ursani A, Patel N, et al. Operator Intracranial Dose Protection During Fluoroscopic-Guided Interventions. Cardiovasc Intervent Radiol. 2023; 46: 943-52.
Highlights
- The efficiency of novel equipment to protect the staff in interventional cardiology, and particularly the eye lens and the brain, was investigated.
- The dose reduction effectiveness of the caps, masks and drapes strongly depends on the design, exposure conditions and staff position.
- Independent testing of radioprotective devices in realistic conditions of use is recommended.
Purpose
To evaluate the effectiveness of currently available radioprotective (RP) devices in reducing the dose to interventional cardiology staff, especially to the eye lens and brain.
Methods
The performances of five RP devices (masks, caps, patient drapes, staff lead and lead-free aprons and Zero-Gravity (ZG) suspended radiation protection system) were assessed by means of Monte Carlo (MC) simulations. A geometry representative of an interventional cardiology setup was modelled and several configurations, including beam projections and staff distance from the source, were investigated. In addition, measurements on phantoms were performed for masks and drapes.
Results
An average dose reduction of 65% and 25% to the eyes and the brain respectively was obtained for the masks by MC simulations but a strong influence of the design was observed. The cap effectiveness for the brain ranges on average between 13% and 37%. Nevertheless, it was shown that only some upper parts of the brain were protected. There was no significant difference between the effectiveness of lead and lead-free aprons. Of all the devices, the ZG system offered the highest protection to the brain and eye lens and a protection level comparable to the apron for the organs normally covered.
Conclusion
All investigated devices showed potential for dose reduction to specific organs. However, for masks, caps and drapes, it strongly depends on the design, exposure conditions and staff position. Therefore, for a clinical use, it is recommended to evaluate their effectiveness in the planned conditions of use.
Huet C, Dabin J, Domienik-Andrzejewska J, et al. Effectiveness of staff radiation protection devices for interventional cardiology procedures. Phys Med. 2023; 107: 102543.
Purpose
To assess occupational eye lens dose based on clinical monitoring of interventional radiologists and to assess personal protective eyewear (PPE) efficacy through measurements with anthropomorphic phantom.
Methods
Two positions of the operator with respect to X-ray beam were simulated with phantom. Dose reduction factor (DRF) of four PPE was assessed, as well as correlation between eye lens and whole-body doses. Brain dose was also assessed. Five radiologists were monitored for one-year clinical procedures. All subjects were equipped with whole-body dosimeter placed over lead apron at the chest level and eye lens dosimeter placed over the left side of the PPE. Kerma-Area Product (KAP) of procedures performed during the monitoring period was recorded. The correlation of eye lens dose with whole-body dose and KAP was assessed.
Results
DRF was 4.3/2.4 for wraparound glasses, 4.8/1.9 for fitover glasses, 9.1/6.8 for full-face visor in radial/femoral geometries. DRF of half-face visor depended on how it is worn (range 1.0–4.9). Statistically significant correlation between dose value over the PPE and chest dose was observed, while there was no correlation between eye lens dose and chest dose. The results on clinical staff showed statistically significant correlation between dose values over the PPE and KAP.
Conclusions
All PPE showed significant DRF in all configurations, provided they were worn correctly. Single DRF value is not applicable to all clinical situations. KAP is a valuable tool for determining appropriate radiation protection measures.
D’Alessio A, Matheoud R, Cannillo B, et al. Evaluation of operator eye exposure and eye protective devices in interventional radiology: Results on clinical staff and phantom. Phys Med. 2023; 110: 102603.
Purpose
To evaluate the radiation protection offered by an exoskeleton-based radiation protection system (Stemrad MD) and to compare it with that offered by conventional lead aprons.
Methods
The experimental setup involved 2 anthropomorphic phantoms, an operator, a patient, and a C-arm as the x-ray radiation source. Thermoluminescent detectors were used to measure radiation doses to different radiosensitive body parts on the operator phantom both with the exoskeleton and a conventional lead apron at the left radial and right femoral positions. Detected radiation doses for the exoskeleton and lead apron for different body parts and positions were compared.
Results
At the left radial position, the mean radiation dose (mGy) reduction by the exoskeleton compared with that by the lead apron was >90% for the left eye lens (0.22 ± 0.13 vs 5.18 ± 0.08; P < .0001), right eye lens (0.23 ± 0.13 vs 4.98 ± 0.10; P < .0001), left head (0.11 ± 0.16 vs 3.53 ± 0.07; P < .0001), right head (0.27 ± 0.09 vs 3.12 ± 0.10; P < .0001), and left brain (0.04 ± 0.08 vs 0.46 ± 0.07; P < .0001). At the right femoral position, radiation reduction was >90% for the left eye lens (0.14 ± 0.10 vs 4.16 ± 0.09; P < .0001), right eye lens (0.06 ± 0.08 vs 1.90 ± 0.11; P < .0001), left head (0.10 ± 0.08 vs 4.39 ± 0.08; P < .0001), left brain (0.03 ± 0.07 vs 1.44 ± 0.08; P < .0001), right brain (0.00 ± 0.14 vs 0.11 ± 0.13; P = .06), and thyroid (0.04 ± 0.07 vs 0.27 ± 0.09; P < .0001). Protection of the torso was equivalent to that offered by conventional lead aprons.
Conclusions
The exoskeleton-based system provided superior radiation protection to the physician compared with that provided by conventional lead aprons. The effects are particularly impactful for the brain, eye lens, and head areas.
Katsarou M, Zwiebel B, Chowdhury RP, et al. Experimental Analysis of Radiation Protection Offered by a Novel Exoskeleton-Based Radiation Protection System versus Conventional Lead Aprons. J Vasc Interv Radiol. 2023; 34: 1345-52.
Objective
Long-term radiation exposure from fluoroscopically guided interventions (FGIs) can cause cataracts and brain tumors in the operator. We have previously demonstrated that leaded eyewear does not decrease the operator eye radiation dose unless lead shielding has been added to the lateral and inferior portions. Therefore, we have developed a disposable, lightweight, lead-equivalent shield that can be attached to the operator’s eyewear that conforms to the face and adheres to the surgical mask. In the present study, we evaluated the efficacy of our new prototype in lowering the operator brain and eye radiation dose when added to both leaded and nonleaded eyewear.
Methods
The attenuating efficacy of leaded eyewear alone, leaded eyewear plus the prototype, and nonleaded eyewear plus the prototype were compared with no eyewear protection in both a simulated setting and clinical practice. In the simulation, optically stimulated, luminescent nanoDot detectors (Landauer, Inc, Glenwood, Ill) were placed inside the ocular, temporal lobe, and midbrain spaces of a head phantom (ATOM model-701; CIRS, Norfolk, Va). The phantom was positioned to represent a primary operator performing right femoral access. Fluorography was performed on a plastic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. In the clinical setting, nanoDots were placed below the operator’s eye both inside and outside the prototype during the FGIs. The median and interquartile ranges were calculated for the dose at each nanoDot location for the phantom and clinical studies. The average dose reduction was also recorded.
Results
Wearing standard leaded eyewear alone did not decrease the operator ocular or brain radiation dose. In the phantom experiment, the leaded glasses plus the prototype reduced the radiation dose to the lens, temporal lobe, and midbrain by 83% (P < .001), 78% (P < .001), and 75% (P < .001), respectively. The nonleaded glasses plus the prototype also reduced the dose to the lens, temporal lobe, and midbrain by 85% (P < .001), 81% (P < .001), and 71% (P < .001), respectively. A total of 15 FGIs were included in the clinical setting, with a median reference air kerma of 98.4 mGy. The use of our prototype led to an average operator eye dose reduction of 89% (P < .001).
Conclusions
Attaching our prototype to both leaded and nonleaded glasses significantly decreased the eye and brain radiation dose to the operator. This face shield attachment provided meaningful radiation protection and should be considered as either a replacement or an adjunct to routine eyewear.
Kirkwood ML, Klein A, Timaran C, et al. Disposable, lightweight shield decreases operator eye and brain radiation dose when attached to safety eyewear during fluoroscopically guided interventions. J Vasc Surg. 2022; 75: 2047-53.
2022
Aim – Advanced angiographic procedures in interventional radiology are becoming more important and are more frequently used, especially in the treatment of several acute life-threatening diseases like stroke or aortic injury. In recent years, technical advancement has led to a broader spectrum of interventions and complex procedures with longer fluoroscopy times. This involves the risk of higher dose exposures, which, in rare cases, may cause deterministic radiation effects, e.g. erythema in patients undergoing angiographic procedures. Against this background, these procedures recently also became subject to national and international regulations regarding radiation protection. At the same time, individual risk assessment of possible stochastic radiation effects for each patient must be weighed up against the anticipated benefits of the therapy itself. Harmful effects of the administered dose are not limited to the patient but can also affect the radiologist and the medical staff. In particular, the development of cataracts in interventionalists is a rising matter of concern. Furthermore, long-term effects of repeated and prolonged x-ray exposure have long been neglected by radiologists but have come into focus in the past years.
Conclusion – With all this in mind, this review discusses different efforts to reduce radiation exposition levels for patients and medical staff by means of technical, personal as well as organizational measures.
Kaatsch HL, Schneider J, Brockmann C, et al. Radiation exposure during angiographic interventions in interventional radiology – risk and fate of advanced procedures. Int J Radiat Biol. ahead-of-print: 1-8.
Aim – The efficiency of protective equipment for the brain has not been verified at the left anterior oblique (LAO) position, which is commonly used in clinical procedures. The purpose of this study was to investigate radiation exposure of the brain in interventional radiology (IR) and the shielding ability of a new protective flap.
Methods – We made a flap that combined a protective cap with a left lateral face shield. The flap was made of tungsten‐containing rubber (TCR). An anthropomorphic head phantom was placed at the physician’s position, and air kerma rates (μGy/min and μGy/15s) were measured by electronic dosimeter at three locations: the surface of the left side of the head, and the left and right temporal lobes with the protective cap and the flap in fluoroscopy and cine modes. The X‐ray tube was at the lower left side of the physician, and its angles were LAO60 and LAO60CAU40. The tube voltage (95–125 kV), tube current (4.7–732 mA), and air kerma rate (27.8–1078 mGy/min) were automatically adjusted by the X‐ray system. We obtained the cap and the flap shielding efficiencies.
Results = In cine mode at LAO60CAU40, the shielding efficiencies on the surface of the left side of the head and left temporal lobe with the cap were 92.6% and 5.1%, respectively, and the corresponding shielding efficiencies with the flap were 92.5% and 86.1%, respectively. The flap can reduce radiation exposure of the brain more than the cap alone.
Conclusions – At the left anterior oblique in interventional radiology, the flap can reduce exposure to the brain.
Hattori S, Monzen H, Tamura M, Kosaka H, Nakamura Y and Nishimura Y. Estimating radiation exposure of the brain of a physician with a protective flap in interventional radiology: A phantom study. J Appl Clin Med Phys. 2022; 23.
Interventional radiology (IVR) procedures are associated with increased radiation exposure
and injury risk. Furthermore, radiation eye injury (i.e., cataract) in IVR staff have also been reported.
It is crucial to protect the eyes of IVR physicians from X-ray radiation exposure. Many IVR physicians use protective Pb eyeglasses to reduce occupational eye exposure. However, the shielding effects of Pb eyeglasses are inadequate.
We developed a novel shield for the face (including eyes) of IVR physicians. The novel shield consists of a neck and face guard (0.25 mm Pb-equivalent rubber sheet, nonlead protective sheet). The face shield is positioned on the left side of the IVR physician.
We assessed the shielding effects of the novel shield using a phantom in the IVR X-ray system;
a radiophotoluminescence dosimeter was used to measure the radiation exposure. In this phantom
study, the effectiveness of the novel device for protecting against radiation was greater than 80% in almost all measurement situations, including in terms of eye lens exposure.
A large amount of scattered radiation reaches the left side of IVR physicians. The novel radiation shield effectively protects the left side of the physician from this scattered radiation. Thus, the device can be used to protect the face and eyes of IVR physicians from occupational radiation exposure.
The novel device will be useful for protecting the face (including eyes) of IVR physicians from radiation, and thus could reduce the rate of radiation injury. Based on the positive results of this phantom study, we plan to perform a clinical experiment to further test the utility of this novel radiation shield for IVR physicians.
Keywords: radiation protection and safety; fluoroscopy; interventional radiology (IVR); fluoroscopically guided interventional procedures; percutaneous coronary intervention (PCI); protective apron; face
shield; radiation dose; X-ray examination; disaster medicine
Sato T, Eguchi Y, Yamazaki C, Hino T, Saida T and Chida K. Development of a New Radiation Shield for the Face and Neck of IVR Physicians. Bioengineering (Basel). 2022; 9: 354.
Methods – Two sets of the protection system (set A and B) were equipped with 12 thermoluminiscence detectors (TLD). For simultaneous measurement of radiation exposure and dose-reduction, each six TLDs were fixed to the inner side and on the corresponding outer side of the protection system. Set A was used exclusively for general radiological interventions and set B exclusively for neuroradiological interventions. To compare the staff exposure in general radiology and neuroradiology, dose values were normalized to a DAP of 10 000 µGy∙m2.
Results – The sets were tested during 20 general radiological interventions and 32 neuroradiological interventions. In neuroradiology, the mean normalized radiation exposure was 13.44 ± 1.36 µSv/10 000 µGy∙m2 at the head protection and 22.27 ± 2.09 µSv/10 000 µGy∙m2 at the thyroid collar. In general radiology, the corresponding results were 29.91 ± 4.19 µSv/10 000 µGy∙m2 (head protection) and 68.07 ± 17.25 µSv/10 000 µGy∙m2 (thyroid collar). Thus, mean dose exposure was 2.5 times higher in general radiological interventions (p = 0.016). The use of the protection system resulted in a mean dose reduction of 81.2 ± 11.1 % (general radiology) and 92.1 ± 4.2 % (neuroradiology; p = 0.016).
Conclusion – Fluoroscopy-guided interventions lead to significant radiation exposure of the head area for the examiner. The novel protection system tested led to a significant dose reduction of 80–90%, depending on the type of intervention.
Bärenfänger F, Walbersloh J, El Mouden R, Goerg F, Block A and Rohde S. Clinical evaluation of a novel head protection system for interventional radiologists. Eur J Radiol. 2022; 147: 110114-.
Purpose: Fluoroscopy guided interventional procedures guarantee high benefits for patients, but are associated
with high levels of radiation exposure for the medical staff. Their increasing use and complexity results in even
higher radiation exposures, with a risk to exceed the annual dose limit of 20 mSv for the eye lens. The aim of the study was to evaluate the potential dose reduction of eye lens exposure for lead glasses and for two types of visors (half and full), used by physicians performing interventional procedures.
Methods: Eye lens dose measurements were carried out on an anthropomorphic phantom simulating a physician
performing a fluoroscopy guided interventional procedure. Dose reduction factors were calculated using high sensitivity thermoluminescent dosimeters. Moreover, a spatial dose distribution was generated for the two visors.
Results: The dose reduction coefficient was found to be 1.6 for the glasses, 1.2 for the half visor and 4.5 for the full
visor.
Conclusions: Optimal radiation protection requires a combination of different radiation protection equipment.
Full visors that cover all the face of the operator are recommended, as they absorb scattered radiation reaching
the eyes from all directions. Full visors should be prioritized over radiation protection glasses for cases where other protective equipment such as ceiling shielding cannot be used.
Samara ET, Cester D, Furlan M, Pfammatter T, Frauenfelder T and Stüssi A. Efficiency evaluation of leaded glasses and visors for eye lens dose reduction during fluoroscopy guided interventional procedures. Phys Med. 2022; 100: 129-34.
A two centre clinical study was performed to analyse exposure levels of cardiac physicians performing electrophysiology and haemodynamic procedures with the use of state of the art Zero-Gravity™ radiation protective system (ZG). The effectiveness of ZG was compared against the commonly used ceiling suspended lead shield (CSS) in a haemodynamic lab. The operator’s exposure was assessed using thermoluminescent dosimeters (TLDs) during both ablation (radiofrequency ablation (RFA) and cryoablation (CRYA)) and angiography and angioplasty procedures (CA/PCI). The dosimeters were placed in multiple body regions: near the left eye, on the left side of the neck, waist and chest, on both hands and ankles during each measurement performed with the use of ZG.
In total 29 measurements were performed during 105 procedures. To compare the effectiveness of ZG against CSS an extra 80 measurements were performed with the standard lead apron, thyroid collar and ceiling suspended lead shield during CA/PCI procedures. For ZG, the upper values for the average eye lens and whole body doses per procedure were 4 µSv and 16 µSv for the left eye lens in electrophysiology lab (with additionally used CSS) and haemodynamic lab (without CSS), respectively, and about 10 µSv for the remaining body parts (neck, chest and waist) in both labs.
The skin doses to hands and ankles non-protected by the ZG were 5 µSv for the most exposed left finger and left ankle in electrophysiology lab, while in haemodynamic lab 150 µSv and 17 µSv, respectively. The ZG performance was 3 times (p < 0.05) and at least 15 times (p < 0.05) higher for the eye lenses and thoracic region, respectively, compared to CSS (with dosimeters on the apron/collar). However, when only ZG was used slightly higher normalised doses were observed for the left finger compared to CSS (5.88e − 2 Sv/Gym2 vs. 4.31 e − 2 Sv/Gym2, p = 0.016).
The study results indicate that ZG performance is superior to CSS. It can be simultaneously used with the ceiling suspended lead shield to ensure the protection to the hands as long as this is not obstructive for the work.
Domienik-Andrzejewska J, Mirowski M, Jastrzębski M, et al. Occupational exposure to physicians working with a Zero-Gravity™ protection system in haemodynamic and electrophysiology labs and the assessment of its performance against a standard ceiling suspended shield. Radiat Environ Biophys. 2022; 61: 293-300.
Interventional radiology represents subspecialty of radiology, which does not use imaging modalities only for diagnostics, but mostly for therapeutic purposes. Realisation of interventional procedures is done through X-rays, which replaces direct visual control done by interventional radiologist or cardiologist.
For the targeted reduction of the radiation exposure, the interventional radiology staff use personal protective equipment. Usually, aprons with lead-equivalent are used, which provide protection for 75% of the radiosensitive organs. As the eye lens and thyroid gland belong to the radiosensitive organs, lead eyeglasses and thyroid collar are commonly used for their protection.
Cap and gloves with lead-equivalent can be utilised as an additional personal protective equipment, that is commercially available. Innovative protection systems, such as mobile radiation protection cabin and suspended radiation protection, have been designed to ensure better radiation protection and safety. These systems provide the comfort for the interventional radiologists at work, while offering better protection against ionising radiation.
Budošová D, Horváthová M, Bárdyová Z and Balázs T. CURRENT TRENDS OF RADIATION PROTECTION EQUIPMENT IN INTERVENTIONAL RADIOLOGY. Radiation Protection Dosimetry. 2022; 198: 554-9.
2021
Aim – This study was conducted to investigate the relationship between the type of lead apron and radiation exposure to the backs of physicians and nurses while using C-arm fluoroscopy.
Methods – We compared radiation exposure to the back in the three groups: no lead apron (group C), front coverage type (group F) and wrap-around type (group W). The other wrap-around type apron was put on the bed instead of on a patient. We ran C-arm fluoroscopy 40 times for each measurement. We collected the air kerma (AK), exposure time (ET) and effective dose (ED) of the bedside table, upper part and lower part of apron. We measured these variables 30 times for each location.
Results – In group F, ED of the upper part was the highest (p < 0.001). ED of the lower part in group C and F was higher than that in group W (p = 0.012). The radiation exposure with a front coverage type apron is higher than that of the wrap-around type and even no apron at the neck or thyroid.
Conclusion – For reducing radiation exposure to the back of physician or nurse, the wrap-around type apron is recommended. This type of apron can reduce radiation to the back when the physician turns away from the patient or C-arm fluoroscopy.
Hong SW, Kim TW and Kim JH. Radiation Exposure to the back with different types of aprons. Radiation Protection Dosimetry. 2021; 193: 185-9.
Aim – This work was designed to study the effectiveness of radiation protection caps in lowering the dose to the brain and the eye lens during fluoroscopically guided interventions.
Methods – Two types of radiation protection caps were examined with regards to their capacity to lower the radiation dose. One cap is equipped with lateral flaps, the other one is not. These caps were fitted to the head of an anthropomorphic Alderson-Rando (A.-R.) phantom. The phantom was positioned aside an angiographic table simulating the position of the first operator during a peripheral arterial intervention. One of the brain slices and both eyes of the A.-R. phantom were equipped with thermoluminescence dosimeters (TLDs).
Results – The analysis of the data showed that the cap without lateral flaps reduced the dose to the brain by 11,5–27,5 percent depending on the position within the brain. The cap with lateral protection flaps achieved a shielding effect between 44,7 and 78,9 percent. When evaluating the dose to the eye, we did see an increase of dose reduction from 63,3 to 66,5 percent in the left eye and from 45,8 to 46,8 percent in the right eye for the cap without lateral protection. When wearing the cap with lateral protection we observed an increase of dose reduction from 63,4 to 67,2 percent in the left eye and from 45,8 to 50,0 percent in the right eye.
Conclusion – Radiation protection caps can be an effective tool to reduce the dose to the brain and the eyes.
Guni E, Hellmann I, Wucherer M, et al. Effectiveness of Radiation Protection Caps for Lowering dose to the Brain and the Eye Lenses. Cardiovasc Intervent Radiol. 2021; 44: 1260-5.
Aim – Evaluation and registration of patient and staff doses are mandatory under the current European legislation, and the occupational dose limits recommended by the ICRP have been adopted by most of the countries in the world.
Methods – Relevant documents and guidelines published by international organisations and interventional radiology societies are referred. Any potential reduction of patient and staff doses should be compatible with the clinical outcomes of the procedures.
Results – The review summarises the most common protective measures and the needed quality control for them, the criteria to select the appropriate protection devices, and how to avoid unnecessary occupational radiation exposures. Moreover, the current and future advancements in personnel radiation protection using medical simulation with virtual and augmented reality, robotics, and artificial intelligence (AI) are commented. A section on the personnel radiation protection in the era of COVID-19 is introduced, showing the expanding role of the interventional radiology during the pandemic.
Conclusion – The review is completed with a summary of the main factors to be considered in the selection of the appropriate radiation protection tools and practical advices to improve the protection of the staff.
Bartal G, Vano E and Paulo G. Get Protected! Recommendations for Staff in IR. Cardiovasc Intervent Radiol. 2021; 44: 871-6.
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.
Schueler BA and Fetterly KA. Eye protection in interventional procedures. Br J Radiol. 2021; 94: 20210436.
Aim – Long-term radiation exposure from fluoroscopically guided interventions (FGIs) can cause cataracts and brain tumors in the operator. We have previously demonstrated that leaded eyewear does not decrease the operator eye radiation dose unless lead shielding has been added to the lateral and inferior portions. Therefore, we have developed a disposable, lightweight, lead-equivalent shield that can be attached to the operator’s eyewear that conforms to the face and adheres to the surgical mask. In the present study, we evaluated the efficacy of our new prototype in lowering the operator brain and eye radiation dose when added to both leaded and nonleaded eyewear.
Methods – The attenuating efficacy of leaded eyewear alone, leaded eyewear plus the prototype, and nonleaded eyewear plus the prototype were compared with no eyewear protection in both a simulated setting and clinical practice. In the simulation, optically stimulated, luminescent nanoDot detectors (Landauer, Inc, Glenwood, Ill) were placed inside the ocular, temporal lobe, and midbrain spaces of a head phantom (ATOM model-701; CIRS, Norfolk, Va). The phantom was positioned to represent a primary operator performing right femoral access. Fluorography was performed on a plastic scatter phantom at 80 kVp for an exposure of 3 Gy reference air kerma. In the clinical setting, nanoDots were placed below the operator’s eye both inside and outside the prototype during the FGIs. The median and interquartile ranges were calculated for the dose at each nanoDot location for the phantom and clinical studies. The average dose reduction was also recorded.
Results – Wearing standard leaded eyewear alone did not decrease the operator ocular or brain radiation dose. In the phantom experiment, the leaded glasses plus the prototype reduced the radiation dose to the lens, temporal lobe, and midbrain by 83% (P < .001), 78% (P < .001), and 75% (P < .001), respectively. The nonleaded glasses plus the prototype also reduced the dose to the lens, temporal lobe, and midbrain by 85% (P < .001), 81% (P < .001), and 71% (P < .001), respectively. A total of 15 FGIs were included in the clinical setting, with a median reference air kerma of 98.4 mGy. The use of our prototype led to an average operator eye dose reduction of 89% (P < .001).
Conclusions – Attaching our prototype to both leaded and nonleaded glasses significantly decreased the eye and brain radiation dose to the operator. This face shield attachment provided meaningful radiation protection and should be considered as either a replacement or an adjunct to routine eyewear.
Kirkwood ML, Klein A, Timaran C, et al. Disposable, lightweight shield decreases operator eye and brain radiation dose when attached to safety eyewear during fluoroscopically guided interventions. J Vasc Surg. 2021.
Aim – This study sought to investigate the RADPAD No Brainer (Worldwide Innovation and Technologies, Overland Park, Kansas) efficiency in reducing brain exposure to scattered radiation.
Background – Cranial radioprotective caps such as the RADPAD No Brainer are being marketed as devices that significantly reduce operator’s brain exposure to scattered radiation. However, the efficiency of the RADPAD No Brainer in reducing brain exposure in clinical practice remains unknown to date.
Methods – Five electrophysiologists performing device implantations over a 2-month period wore the RADPAD cap with 2 strips of 11 thermoluminescent dosimeter pellets covering the front head above and under the shielded cap. Phantom measurements and Monte Carlo simulations were performed to further investigate brain dose distribution.
Results – Our study showed that the right half of the operators’ front head was the most exposed region during left subpectoral device implantation; the RADPAD cap attenuated the skin front-head exposure but provided no protection to the brain. The exposure of the anterior part of the brain was decreased by a factor of 4.5 compared with the front-head skin value thanks to the skull. The RADPAD cap worn as a protruding horizontal plane, however, reduced brain exposure by a factor of 1.7 (interquartile range: 1.3 to 1.9).
Conclusion – During device implantation, the RADPAD No Brainer decreased the skin front head exposure but had no impact on brain dose distribution. The RADPAD No Brainer worn as a horizontal plane worn around the neck reduces brain exposure and confirms that the exposure comes from upward scattered radiation.
Lemesre C, Graf D, Bisch L, et al. Efficiency of the RADPAD Surgical Cap in Reducing Brain Exposure During Pacemaker and Defibrillator Implantation. JACC Clinical electrophysiology. 2021; 7: 161-70.
2020
Lead barriers to reduce operator radiation exposure in the catheterization laboratory are effective. This study of a novel vertical radiation shield suggests significant reduction in operator radiation exposure when used in addition to standard protection methods. Although additional barriers may help reduce radiation exposure, further education and training of operators in radiation safety may be as effective and perhaps more effective than additional barriers.
Vincent, L. L., & Dean, L. S. (2020). Shading operators from the Gray: Are novel radiation barriers or changing physician behaviors the best next step?. Catheterization and cardiovascular interventions: official journal of the Society for Cardiac Angiography & Interventions.
Highlights
- Hybrid Angio-MRI imaging can be used to optimize stroke treatment.
- The MRI system can protect the operators from scattered radiation.
- Using an over-couch x-ray source will significantly increase patient eye lens dose.
- Correct positioning during irradiation can significantly reduce the dose of the operator.
This work investigates the patient eye lens dose and x-ray scatter to the operator expected for a proposed hybrid Angio-MR concept.
Two geometries were simulated for comparative assessment: a standard C-arm device for neuro-angiography applications and an innovative hybrid Angio-MR system concept, proposed by Siemens Healthineers. The latter concept is based on an over-couch x-ray tube and a detector inside an MRI system, with the aim of allowing combined, simultaneous MRI and x-ray imaging for procedures such as neurovascular interventions (including x-ray fluoroscopy and angiography imaging, 3D imaging, diffusion, and perfusion).
To calculate the scattered radiation dose to the physician, Monte Carlo simulations were performed. Dose estimates of simplified models of the brain and eyes of both the patient and the physician and of the physician’s torso and legs have been calculated. A number of parameters were varied in the simulation including x-ray spectrum, field of view (FOV), x-ray tube angulation, presence of shielding material and position of the physician. Additionally, 3D dose distributions were calculated in the vertical and horizontal planes in both setups. The patient eye lens dose was also calculated using a detailed voxel phantom and measured by means of thermoluminescent dosimeters (TLDs) to obtain a more accurate estimate.
Assuming the same number of x-rays and the same size of the irradiated area on the patient’s head, the results show a significant decrease in the scattered radiation to the physician for the Angio-MR system, while large increases, depending on setup, are expected to patient eye lens dose.
Dehairs M, Marshall NW, Bosmans H and Leghissa M. Radiation protection of operators and patients in a hybrid Angio-MR suite. Phys Med. 2020; 74: 143-54.
Radioprotection of the eye lens of medical staff involved in Surgical procedures is a subject of international debates since ICRP recommended, on 2011, a lower equivalent dose limit for the lens of the eye. In this work we address the effectiveness of different models of X-ray protective eyewear by relating actual dosimetry measurements to an ad hoc developed mathematical model, in order to disentangle the contribution of geometrical factors and shield capabilities.
Phantom irradiation was carried out in fixed exposure conditions in angiographic room: we found that measured Dose Reduction Factors (DRF) strongly depend on the ergonomics of the investigated eyewear. Actually a very poor DRF was observed in the case of a glass model in spite of its high nominal attenuation, whereas a protective tool with low shielding capabilities such a visor resulted much more effective as a consequence of is shape (i.e. extended geometric protection of the eye lens).
Our work highlights the need of the introduction of a specific parameter to quantify the effectiveness of the protection tools and able to predict their DRF by taking into account the geometry of the clinical condition of exposure. Aiming at making steps forward the standardization of the guidelines concerning the features of eye protective tools, we developed a simple mathematical model describing the eye lens irradiation geometry which allows the introduction, for each eyewear, of a comprehensive parameter, the Eye Protection Effectiveness (EPE), that, for any defined clinical irradiation condition and glass shielding capabilities and shape, defines the overall effective X-ray protection of the eyewear.
Doria S, Fedeli L, Redapi L, et al. Addressing the efficiency of X-ray protective eyewear: Proposal for the introduction of a new comprehensive parameter, the Eye Protection Effectiveness (EPE). Phys Med. 2020; 70: 216-23.
2019
Background – The increasing number of minimally invasive fluoroscopy-guided interventions is likely to result in higher radiation exposure for interventional radiologists and medical staff. Not only the number of procedures but also the complexity of these procedures and therefore the exposure time as well are growing. There are various radiation protection means for protecting medical staff against scatter radiation. This article will provide an overview of the different protection devices, their efficacy in terms of radiation protection and the corresponding dosimetry.
Method - The following key words were used to search the literature: radiation protection, eye lens dose, radiation exposure in interventional radiology, cataract, cancer risk, dosimetry in interventional radiology, radiation dosimetry.
Results and Conclusion - Optimal radiation protection always requires a combination of different radiation protection devices. Radiation protection and monitoring of the head and neck, especially of the eye lenses, is not yet sufficiently accepted and further development is needed in this field. To reduce the risk of cataract, new protection glasses with an integrated dosimeter are to be introduced in clinical routine practice.
Key Points – A combination of personal radiation protection devices and optimized dosimetry improves the safety of medical staff.
König AM, Etzel R, Thomas RP et al. Personal Radiation Protection and Corresponding Dosimetry in Interventional Radiology: An Overview and Future Developments. Fortschr Röntgenstr 2019; 191: 512 – 521
Highlights
- A BeOSL eye lens dosemeter for photon radiation is characterized.
- A TLD eye lens dosemeter for photon and beta radiation is introduced.
- Dosemeters are integrated in the frame of the glasses behind the lead shielding.
- A standardized mechanical interface between dosemeter and RP glasses was introduced.
With the annual dose limit for the lens of the eye being lowered to 20 mSv from 2019, both new efforts to improve radiation protection for this part of the body and new approved dosemeters for official dose monitoring are required. The individual monitoring services at the Helmholtz Zentrum München and Dosilab AG, together with MAVIG, have developed a mechanical interface to integrate eye lens dosemeters into radiation protection glasses. MAVIG has designed a new type of radiation protection glasses featuring this dosemeter interface. The two individual monitoring services have independently developed two new types of eye lens dosemeters for the interface. The Munich solution for the eye lens dosemeter is a BeOSL dosemeter for photon radiation with a new detector element introduced by Dosimetrics GmbH in 2018. The Dosilab approach is based on a TLD dosemeter for photon and beta radiation. This work describes the concepts for radiation protection glasses and interface, the new dosemeters, and presents the performance characteristics of the dosemeters in accordance with IEC requirements.
Hoedlmoser, H., Greiter, M., Bandalo, V., Mende, E., Brönner, J., Kleinau, P., … Figel, M. (2019). New eye lens dosemeters for integration in radiation protection glasses. Radiation Measurements, 125, 106–115. https://doi.org/10.1016/j.radmeas.2019.05.002
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.
Sailer, A., Paulis, L., Vergoossen, L., Wildberger, J., & Jeukens, C. (2019). Optimizing Staff Dose in Fluoroscopy-Guided Interventions by Comparing Clinical Data with Phantom Experiments. Journal of Vascular and Interventional Radiology, 30(5), 701–708.e1. https://doi.org/10.1016/j.jvir.2018.11.019
Objective – Transfemoral Transcatheter Aortic Valve Implantation (TAVI) has become a standard therapy for patients with aortic valve stenosis. Fluoroscopic imaging is essential for TAVI with the anesthesiologist’s workplace close to patient’s head side. While the use of lead-caps has been shown to be useful for interventional cardiologists, data are lacking for anesthesiologists.
Methods – A protective cap with a 0.35 lead-equivalent was worn on 15 working days by one anesthesiologist. Six detectors (three outside, three inside) were analyzed to determine the reduction of radiation. Literature search was conducted between April and October 2018.
Results – In the observational period, 32 TAVI procedures were conducted. A maximum radiation dose of 0.55 mSv was detected by the dosimeters at the outside of the cap. The dosimeters inside the cap, in contrast, displayed a constant radiation dose of 0.08 mSv.
Conclusion – The anesthesiologist’s head is exposed to significant radiation during TAVI and it can be protected by wearing a lead-cap.
Patrick Mayr, N., Wiesner, G., Kretschmer, A., Brönner, J., Hoedlmoser, H., Husser, O., … Tassani-Prell, P. (2019). Assessing the level of radiation experienced by anesthesiologists during transfemoral transcatheter aortic valve implantation and protection by a lead cap. PLoS ONE, 14(1), e0210872. https://doi.org/10.1371/journal.pone.0210872
Objective – Transfemoral Transcatheter Aortic Valve Implantation (TAVI) has become a standard therapy for patients with aortic valve stenosis. Fluoroscopic imaging is essential for TAVI with the anesthesiologist’s workplace close to patient’s head side. While the use of lead-caps has been shown to be useful for interventional cardiologists, data are lacking for anesthesiologists.
Methods – A protective cap with a 0.35 lead-equivalent was worn on 15 working days by one anesthesiologist. Six detectors (three outside, three inside) were analyzed to determine the reduction of radiation. Literature search was conducted between April and October 2018.
Results – In the observational period, 32 TAVI procedures were conducted. A maximum radiation dose of 0.55 mSv was detected by the dosimeters at the outside of the cap. The dosimeters inside the cap, in contrast, displayed a constant radiation dose of 0.08 mSv.
Conclusion – The anesthesiologist’s head is exposed to significant radiation during TAVI and it can be protected by wearing a lead-cap.
Aim – Cataract formation is a tissue reaction effected by radiation exposure. The purpose of this study was to evaluate the occupational exposure to the lens of the eye of interventional radiologists (IR’s) and interventional radiology staff, with and without lead glasses.
Methods – Ethical approval was provided by the hospital research and ethics committee. A prospective cohort study was performed over 1 year, doses recorded, lifetime dose (estimated at working 5 days in angiography, for 30 years) was estimated and dose compared to current guidelines. Thermoluminescent dosimeters (TLDs; Landauer, Glenwood, USA) Hp(3) were placed on both the exterior and interior side of the personal lead glasses worn by three interventional radiologists and two radiographers. They were monitored during all procedures performed within 1 year. Lead glasses (AttenuTech® Microlite®, Florida, USA) with specifications were 0.75 mm lead equivalent front shield, and Side shield 0.3 mm Pb equivalent. A control TLD was placed in the storage location of the lead glasses when not in use. Yearly dose was measured and lifetime dose was calculated from the data obtained. Calculation of dose received per day(s) spent performing procedures for both annual and lifetime exposure was performed. In addition a record of occurrence of splashes on glasses was made after each case.
Results – Eye doses without protection were double the recommended limits for both annual and lifetime dose. For interventional radiologists working between 3 and 4 or more days in the lab per week, annual dose thresholds would be exceeded (20 mSv/year averaged over 5 years, no more than 50 mSv in 1 year). If interventional radiologists worked between 3 and 4 or more days in the lab, lifetime dose thresholds would be exceeded (500 mSv lifetime dose). Lead glasses reduced radiation exposure by an average of 79%. If lead glasses were worn no interventional radiologists would exceed annual or lifetime dose thresholds to the eyes even if working 5 days per week as the primary operator. Radiographers would not exceed annual or lifetime dose thresholds even without lead glasses. Splash incidents occurred for all interventional radiologists and one radiographer.
Conclusion – The use of lead glasses even in this small study resulted in a decreased dose of radiation to the lens of the eye. Regular use of radiation protection eyewear will reduce eye dose for primary proceduralists to well below yearly and lifetime thresholds.
Moriarty HK, Clements W, Phan T, Wang S and Goh GS. Occupational radiation exposure to the lens of the eye in interventional radiology. J Med Imaging Radiat Oncol.2022; 66: 34-40.
Purpose – Cardiac resynchronization therapy (CRT) often requires a long fluoroscopic time and protection from scatter radiation. This study reports on scatter radiation levels during CRT, with and without additional shielding, and using standard or low pulse rate fluoroscopy.
Materials and methods – Additional lead-shielding drape (0.35-mm lead equivalent) was used on the left side of the table and pulsed fluoroscopy was performed at rates of 10 pulses/s (usual rate) and 7.5 pulses/s (low pulse rate). Fluoroscopy scatter radiation was measured for both pulse rates using an acrylic phantom with a radiation survey meter, both with and without the additional lead-shielding drape.
Results – With the additional lead-shielding drape, the fluoroscopy scatter radiation was reduced by 74.3% at 10 pulses/s and 78.6% at 7.5 pulses/s. If the fluoroscopy was changed from 10 pulses/s to 7.5 pulses/s, the scattered radiation at the primary physician’s position was reduced by 24.0%. The combined use of additional shielding drape and low pulse rate fluoroscopy reduced scatter radiation by over 80%.
Conclusion – Additional lead-shielding drape and low pulse rate fluoroscopy are effective in reducing the scattered radiation dose to physicians and nurses during CRT.
Morishima, Y., Chida, K., & Katahira, Y. (2019). The effectiveness of additional lead-shielding drape and low pulse rate fluoroscopy in protecting staff from scatter radiation during cardiac resynchronization therapy (CRT). Japanese Journal of Radiology, 37(1), 95–101. https://doi.org/10.1007/s11604-018-0783-7
2018
Medical staff should not be exposed to the primary X-ray beam during fluoroscopy-guided interventional procedures (FGIP). The main source of staff exposure is scatter radiation from the patient, which can be significant. Although many aspects of X-ray exposure to the patient as well as occupational exposure to interventional radiologists and other staff are strongly regulated and monitored in most countries, it is surprising how loosely the labeling and testing of the protective aprons is regulated.
Interventional radiologists (IRs) have to be experts in interventional radiology as well as in basic facts regarding ways to provide a satisfactory level of protection from occupational exposure. IRs, however, are not familiar with the apron testing methods. The accompanying documents provided with aprons by manufacturers may not be informative enough. Vendors often report apron effectiveness at a single beam quality and attenuation. The vendor reports repeatedly disagree with independent reports, which clearly show that the attenuation of these garments at other important unreported energies may be lower than expected. Better trust no one and check your protective garment yourself, or, better yet, consult a medical physicist when making purchasing decisions related to protective garments.
Each interventionist should choose garments that are appropriately protective for that individual’s practice. Review of past personal dosimetry results and consultation with a medical physicist can help the IR make the best decision.
This article will help the reader to understand why all protective garments are not created equally, and provides some practical tools that will allow safe and healthy practice in FGIP.
Bartal, G., Sailer, A., & Vano, E. (2018). Should We Keep the Lead in the Aprons? Techniques in Vascular and Interventional Radiology, 21(1), 2–6. https://doi.org/10.1053/j.tvir.2017.12.002
Aims – This study aimed to evaluate the effectiveness of ceiling suspended screens, lead glasses and lead caps in reducing radiation doses to the brains of interventional cardiologists.
Methods and Results – Interventional procedures where the thorax of the patient is irradiated with different beam projections were modelled. The dose reduction in the white matter and hippocampus of the Zubal head phantom was studied for two sizes of ceiling suspended screens, two types of lead glasses and lead caps of surgical and hood models, which cover different regions of the head. Ceiling screens were the most effective, reducing the dose to brain tissue by 74% or even as much as 94%. The dose reduction provided by lead glasses varies between 10% and 17%. For the lead caps, it strongly depends on the model, varying from 6% (surgical) up to 68% (hood that also covered lower parts of the head).
Conclusions – The dose to the brain can be reduced by using appropriate radiation protection devices. This study has shown that lead caps are less protective than previously described and that the best protection is given by ceiling suspended screens, which are widely available in interventional theatres.
Honorio Da Silva, E., Vanhavere, F., Struelens, L., Covens, P., & Buls, N. (2018). Effect of protective devices on the radiation dose received by the brains of interventional cardiologists. EuroIntervention : Journal of EuroPCR in Collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, 13(15), e1778–e1784. https://doi.org/10.4244/EIJ-D-17-00759
This article is focused on occupational radiogenic brain tumors and some radioprotective techniques used to manage this risk. Published case reports have stimulated concern among operators. The anatomical pattern of tumor locations is not consistent with measured radiation dose distributions at operators’ heads. In addition, the lack of statistically positive findings in these reports, and a recently published survey on radiologist’s mortality both indicate that the current level of fluoroscopists’ radiation safety practices is likely to be adequate. This presumes that the rules of dose-management, time, distance, and shielding continue to be followed. These are briefly reviewed in this article. The use of radioprotective surgical caps is a current fashion. In clinical practice, these caps provide minimal reductions in brain dose and might induce operators to neglect applying the practical rules mentioned above. Appropriate management of personal, staff, and patient risk should always be on the radiologists’ mind.
Balter, S. (2018). Always on My Mind. Techniques in Vascular and Interventional Radiology, 21(1), 26–31. https://doi.org/10.1053/j.tvir.2017.12.006
As the number of interventional fluoroscopic procedures increases each year, numerous devices and techniques claiming improved radiation protection for the operator have emerged in response to increased concerns about radiation exposure. These are typically marketed toward interventionalists and often in a sensationalistic manner, including anecdotes of the harm that will likely befall the interventionalist who does not use the product. The purpose of this article is to provide a framework for evaluating the efficacy of personal radiation-protective devices used during fluoroscopy-guided interventional procedures. An analysis of existing products is used to highlight current discrepancies between science-based evidence and fear-based hype.
This article focuses on three products marketed as radiation protective devices: lead (or lead-equivalent) surgical caps, surgical pads, and radiation protection creams. It includes discussions within the context of decreased risk and associated economic burden. Risk estimates are based on converting the reported doses to effective dose and applying a 5%/Sv risk for developing a radiation-induced fatal cancer
Marsh, R., Balter, S., & Mahesh, M. (2018). Personal Protective Equipment in Interventional Fluoroscopy: Distinguishing Evidence From Hype. Journal of the American College of Radiology, 15(2), 322–324.
consequatur.
The effect of the ceiling-mounted radiation shielding on the amount of the scatter radiation was assessed under conditions simulating obese patients for clinically relevant exposure parameters. Measurements were performed in different projections and with different positions of the ceiling-mounted shielding: without shielding; shielding closest to the patient; and shielding closest to the physician performing the procedure. The protection provided by the shielding was assessed for cardiology when the femoral access is used and for radiology when the physician performs the procedure in the abdominal area. The results show that the use of the ceiling-mounted shielding can decrease the dose from the scatter radiation by 95% at the position of the performing physician. In cardiology, the impact is more pronounced when the left oblique projection is used. In radiology, a large decrease was observed for right oblique projections, compared to cardiology. The ceiling-mounted shielding should be placed as close to the physician as possible. The idea of creating the largest radiation shadow by placing the radiation shielding as close to the patient as possible does not provide as effective radiation protection of the operator as it might be thought.
Sukupova, L., Hlavacek, O., & Vedlich, D. (2018). Impact of the Ceiling-Mounted Radiation Shielding Position on the Physician’s Dose from Scatter Radiation during Interventional Procedures. Radiology Research and Practice, 2018, 7. https://doi.org/10.1155/2018/4287973
Introduction – Decreasing radiation exposure of the cardiac catheterization laboratory staff is critical for minimizing radiation-related adverse outcomes and can be accomplished by decreasing patient dose and by shielding.
Areas covered – protection from ionizing radiation can be achieved with architectural, equipment-mounted, and disposable shields, as well as with personal protective equipment.
Expert commentary – Radiation protective aprons are the most commonly used personal protective equipment and provide robust radiation protection but can cause musculoskeletal strain. Use of a thyroid collar is recommended, as is use of ‘shin guards’, lead glasses and radioprotective caps, although the efficacy of the latter is being debated. Alternatives to lead aprons include shielding suspended from the ceiling and robotic percutaneous coronary intervention. Radiation protective gloves and cream can be used to protect the hands, but the best protection is to not directly expose them to the radiation beam. Devices that provide real time operator radiation dose monitoring can enable real time adjustments in positioning and shield placement, reducing radiation dose. Shielding can be achieved with architectural, equipment-mounted, and disposable shields. Equipment-mounted shielding includes ceiling-suspended shields, table-suspended drapes, and radioabsorbent drapes. Personal protective equipment and shielding should be consistently and judiciously utilized by all catheterization laboratory personnel.
Karatasakis, A., & Brilakis, E. (2018). Shields and garb for decreasing radiation exposure in the cath lab. Expert Review of Medical Devices, 15(9), 683–688. https://doi.org/10.1080/17434440.2018.1510771
Aim – The aim of this study was to evaluate the effectiveness and shielding performance of a novel recently developed non-lead radiation-shielding fabric containing bismuth oxide (BO-fabric).
Methods – BO-fabric was fabricated using urethane resin and bismuth nanopowder. A dose-measurement method was employed to evaluate the radiation-attenuation characteristics of the shielding fabric in accordance with the Korean Standards standard. The shielding performances (%) were calculated by measuring the radiation doses after lamination with increasing layers of fabric (1–10 layers). The physical performance of the fabric in terms of flexural and abrasion resistances was evaluated by the Korea Apparel Testing and Research Institute (KATRI).
Results – The radiation-attenuation capabilities of one layer of BO-fabric were 58.5, 49.9, and 43.0% at tube voltages of 60, 80, and 100 kVp, respectively. The radiation-shielding performance upon lamination of BO-fabric gradually increased as the number of layers increased. Excellent flexural and abrasion resistances were observed in the KATRI evaluation.
Conclusions – A non-lead radiation-shielding fabric based on urethane resin and bismuth was fabricated and examined, revealing an excellent shielding performance. Owing to the flexibility and simple operation of the fabric, it can be employed for various designs of clothing and protective apparel with many purposes.
Kang JH, Oh SH, Oh J-I, Kim S-H, Choi Y-S and Hwang E-H. Protection evaluation of non-lead radiation-shielding fabric: preliminary exposure-dose study. Oral radiology. 2018; 35: 224-9.
Background – Accessory lead shields that protect physicians from scatter radiation are standard in many catheterization laboratories, yet similar shielding for staff members is not commonplace.
Methods – Real-time radiation exposure data were prospectively collected among nurses and technologists during 764 consecutive catheterizations. The study had 2 phases: in phase I (n = 401), standard radiation protection measures were used, and in phase II (n = 363), standard radiation protection measures were combined with an accessory lead shield placed between the staff member and patient. Radiation exposure was reported as the effective dose normalized to dose-area product (EDAP).
Results – Use of an accessory lead shield in phase II was associated with a 62.5% lower EDAP per case among technologists (phase I: 2.4 [4.3] μSv/[mGy × cm2] × 10−5; phase II: 0.9 [2.8] μSv/[mGy × cm2] × 10−5; p < 0.001) and a 63.6% lower EDAP per case among nurses (phase I: 1.1 [3.1] μSv/[mGy × cm2] × 10−5; phase II: 0.4 [1.8] μSv/[mGy × cm2] × 10−5; p < 0.001). By multivariate analysis, accessory shielding remained independently associated with a lower EDAP among both technologists (34.2% reduction; 95% confidence interval: 20.1% to 45.8%; p < 0.001) and nurses (36.4% reduction; 95% confidence interval: 19.7% to 49.6%; p < 0.001).
Conclusion – The relatively simple approach of using accessory lead shields to protect staff members during cardiac catheterization was associated with a nearly two-thirds reduction in radiation exposure among nurses and technologists.
Madder, R., Lacombe, A., Vanoosterhout, S., Mulder, A., Elmore, M., Parker, J., … Wohns, D. (2018). Radiation Exposure Among Scrub Technologists and Nurse Circulators During Cardiac Catheterization. JACC: Cardiovascular Interventions, 11(2), 206–212.
2017
Objectives – The first aim of this study was to assess the magnitude of radiation dose to tissues of the head and neck of physicians performing x-ray-guided interventional procedures. The second aim was to assess protection of tissues of the head offered by select wearable radiation safety devices.
Background – Radiation dose to tissues of the head and neck is of significant interest to practicing interventional physicians. However, methods to estimate radiation dose are not generally available, and furthermore, some of the available research relating to protection of these tissues is misleading.
Methods – Using a single representative geometry, scatter radiation dose to a humanoid phantom was measured using radiochromic film and normalized by the radiation dose to the left collar of the radioprotective thorax apron. Radiation protection offered by leaded glasses and by a radioabsorbent surgical cap was measured.
Results – In the test geometry, average radiation doses to the unprotected brain, carotid arteries, and ocular lenses were 8.4%, 17%, and 50% of the dose measured at the left collar, respectively. Two representative types of leaded glasses reduced dose to the ocular lens on the side of the physician from which the scatter originates by 27% to 62% but offered no protection to the contralateral eye. The radioabsorbent surgical cap reduced brain dose by only 3.3%.
Conclusions – A method by which interventional physicians can estimate dose to head and neck tissues on the basis of their personal dosimeter readings is described. Radiation protection of the ocular lenses by leaded glasses may be incomplete, and protection of the brain by a radioabsorbent surgical cap was minimal.
Fetterly, K., Schueler, B., Grams, M., Sturchio, G., Bell, M., & Gulati, R. (2017). Head and Neck Radiation Dose and Radiation Safety for Interventional Physicians. JACC: Cardiovascular Interventions, 10(5), 520–528. https://doi.org/10.1016/j.jcin.2016.11.026
Aim – The aim of this study was to evaluate the effectiveness of UltraBLOX™ radiation attenuating hand cream during lengthy cardiac catheterization procedures in children.
Background – The hands of interventional cardiologists receive high doses of radiation due to their proximity to the X-ray beam. Radiation attenuating gloves have about a 26% attenuation rate, but reduce dexterity and tactile sensation. The UltraBLOX™ cream is a new FDA-approved X-ray attenuating cream that can be applied to the operator’s hands for radio-protection.
Methods – Two nanoDot™ dosimeters were secured side by side on the dorsum of the operator’s (n = 2) left hand close to the wrist. One dosimeter and the rest of the hand were covered with 0.2 mm layer of the cream. The other dosimeter was unshielded. Procedures were performed using 110 kVp fluoroscopy at 15 pulses/sec. The measurements were categorized into four groups dependent on the duration of the procedure. The patients in all four groups were well matched for age and size.
Results – Procedural and cumulative hand radiation doses were higher with longer procedural duration. The overall % attenuation by the cream was 39.7% (28.6–51.5) and was unaffected by the length of the procedure (median: 40.9% at 30 min and 41.4% at 180 min; P = 0.66) or the dose of radiation. The kappa statistic for interobserver agreement for good tactile sensitivity was 0.82.
Conclusion – UltraBLOX™ cream provides a new option for radio-protection for the hands of interventional cardiologists without impairing tactile sensitivity. There was no decrease in attenuation up to 180 min.
Aim – Radiation to the interventionalist’s brain during fluoroscopically guided interventions (FGIs) may increase the incidence of cerebral neoplasms. Lead equivalent surgical caps claim to reduce radiation brain doses by 50% to 95%. We sought to determine the efficacy of the RADPAD (Worldwide Innovations & Technologies, Lenexa, Kan) No Brainer surgical cap (0.06 mm lead equivalent at 90 kVp) in reducing radiation dose to the surgeon’s and trainee’s head during FGIs and to a phantom to determine relative brain dose reductions.
Methods – Optically stimulated, luminescent nanoDot detectors (Landauer, Glenwood, Ill) inside and outside of the cap at the left temporal position were used to measure cap attenuation during FGIs. To check relative brain doses, nanoDot detectors were placed in 15 positions within an anthropomorphic head phantom (ATOM model 701; CIRS, Norfolk, Va). The phantom was positioned to represent a primary operator performing femoral access. Fluorography was performed on a plastic scatter phantom at 80 kVp for an exposure of 5 Gy reference air kerma with or without the hat. For each brain location, the percentage dose reduction with the hat was calculated. Means and standard errors were calculated using a pooled linear mixed model with repeated measurements. Anatomically similar locations were combined into five groups: upper brain, upper skull, midbrain, eyes, and left temporal position.
Results – This was a prospective, single-center study that included 29 endovascular aortic aneurysm procedures. The average procedure reference air kerma was 2.6 Gy. The hat attenuation at the temporal position for the attending physician and fellow was 60% ± 20% and 33% ± 36%, respectively. The equivalent phantom measurements demonstrated an attenuation of 71% ± 2.0% (P < .0001). In the interior phantom locations, attenuation was statistically significant for the skull (6% ± 1.4%) and upper brain (7.2% ± 1.0%; P < .0001) but not for the middle brain (1.4% ± 1.0%; P = .15) or the eyes (−1.5% ± 1.4%; P = .28).
Conclusions – The No Brainer surgical cap attenuates direct X rays at the superficial temporal location; however, the majority of radiation to an interventionalist’s brain originates from scatter radiation from angles not shadowed by the cap as demonstrated by the trivial percentage brain dose reductions measured in the phantom. Radiation protective caps have minimal clinical relevance.
Kirkwood ML, Arbique GM, Guild JB, et al. Radiation brain dose to vascular surgeons during fluoroscopically guided interventions is not effectively reduced by wearing lead equivalent surgical caps. J Vasc Surg. 2018; 68: 567-71.
2016
Background – Protection of the head and eyes of the neurointerventional radiologist is a growing concern, especially after recent reports on the incidence of brain cancer among these personnel, and the revision of dose limits to the eye lens. The goal of this study was to determine typical occupational dose levels and to evaluate the efficiency of non-routine radiation protective gear (protective eyewear and cap). Experimental correlations between the dosimetric records of each measurement point and kerma area product (KAP), and between whole body doses and eye lens doses were investigated.
Methods – Measurements were taken using thermoluminescent dosimeters placed in plastic bags and worn by the staff at different places. To evaluate the effective dose, whole body dosimeters (over and under the lead apron) were used.
Results – The mean annual effective dose was estimated at 0.4 mSv. Annual eye lens exposure was estimated at 17 mSv when using a ceiling shield but without protective glasses. The protective glasses reduced the eye lens dose by a factor of 2.73. The mean annual dose to the brain was 12 mSv; no major reduction was observed when using the cap. The higher correlation coefficients with KAP were found for the dosimeters positioned between the eyes (R2=0.84) and above the apron, and between the eye lens (R2=0.85) and the whole body.
Conclusions – Under the specific conditions of this study, the limits currently applicable were respected. If a new eye lens dose limit is introduced, our results indicate it could be difficult to comply with, without introducing additional protective eyewear.
Sans Merce, M., Korchi, A., Kobzeva, L., Damet, J., Erceg, G., Marcos Gonzalez, A., … Mendes Pereira, V. (2016). The value of protective head cap and glasses in neurointerventional radiology. Journal of NeuroInterventional Surgery, 8(7), 736–740. https://doi.org/10.1136/neurintsurg-2015-011703
Dave JK. Why Is the X-Ray Tube Usually Located Underneath the Patient Instead of Above the Patient for Interventional Fluoroscopic Procedures? AJR American journal of roentgenology. 2016;207(3):W24.
2015
2014
Background –Radiation exposure to patients and personnel remains a major concern in the practice of interventional radiology, with minimal literature available on exposure to the forehead and cranium.
Aim – In this study, we measured cranial radiation exposure to the patient, operating interventional neuroradiologist, and circulating nurse during neuroangiographic procedures. We also report the effectiveness of wearing a 0.5 mm lead equivalent cap as protection against radiation scatter.
Methods – 24 consecutive adult interventional neuroradiology procedures (six interventional, 18 diagnostic) were prospectively studied for cranial radiation exposures in the patient and personnel. Data were collected using electronic detectors and thermoluminescent dosimeters.
Results – Mean fluoroscopy time for diagnostic and interventional procedures was 8.48 (SD 2.79) min and 26.80 (SD 6.57) min, respectively. Mean radiation exposure to the operator’s head was 0.08 mSv, as measured on the outside of the 0.5 mm lead equivalent protective headgear. This amounts to around 150 mSv/year, far exceeding the current deterministic threshold for the lens of the eye (ie, 20 mSv/year) in high volume centers performing up to five procedures a day. When compared with doses measured on the inside of the protective skullcap, there was a statistically significant reduction in the amount of radiation received by the operator’s skull.
Conclusions – Our study suggests that a modern neurointerventional suite is safe when equipped with proper protective shields and personal gear. However, cranial exposure is not completely eliminated with existing protective devices and the addition of a protective skullcap eliminates this exposure to both the operator and support staff.
Chohan MO, Sandoval D, Buchan A, Murray-Krezan C and Taylor CL. Cranial radiation exposure during cerebral catheter angiography. J Neurointerv Surg. 2014; 6: 633-6.
2013
Aim – Radiation exposure to interventionalists is increasing. The currently available standard radiation protection devices are heavy and do not protect the head of the operator. The aim of this study was to evaluate the effectiveness and comfort of caps and thyroid collars made of a disposable, light-weight, lead-free material (XPF) for occupational radiation protection in a clinical setting.
Methods – Up to two interventional operators were randomized to wear a XPF or standard 0.5-mm lead-equivalent thyroid collars in 60 consecutive endovascular procedures requiring fluoroscopy. Simultaneously a XPF cap was worn by all operators. Radiation doses were measured using dosimeters placed outside and underneath the caps and thyroid collars. Wearing comfort was assessed at the end of each procedure on a visual analog scale (0–100 [100 = optimal]).
Results – Patient and procedure data did not differ between the XPF and standard protection groups. The cumulative radiation dose measured outside the cap was 15,700 μSv and outside the thyroid collars 21,240 μSv. Measured radiation attenuation provided by the XPF caps (n = 70), XPF thyroid collars (n = 40), and standard thyroid collars (n = 38) was 85.4% ± 25.6%, 79.7% ± 25.8% and 71.9% ± 34.2%, respectively (mean difference XPF vs standard thyroid collars, 7.8% [95% CI, −5.9% to 21.6%]; p = 0.258). The median XPF cap weight was 144 g (interquartile range, 128–170 g), and the XPF thyroid collars were 27% lighter than the standard thyroid collars (p < 0.0001). Operators rated the comfort of all devices as high (mean scores for XPF caps and XPF thyroid collars 83.4 ± 12.7 (SD) and 88.5 ± 14.6, respectively; mean scores for standard thyroid collars 89.6 ± 9.9) (p = 0.648).
Conclusion – Light-weight disposable caps and thyroid collars made of XPF were assessed as being comfortable to wear, and they provide radiation protection similar to that of standard 0.5-mm lead-equivalent thyroid collars.
Uthoff H, Peña C, West J, Contreras F, Benenati JF and Katzen BT. Evaluation of novel disposable, light-weight radiation protection devices in an interventional radiology setting: A randomized controlled trial. American journal of roentgenology (1976). 2013; 200: 915-20.
2011
During interventional procedures, the vast majority of scatter radiation originates from the patient and table and travels in all directions in straight lines. Because the operator’s head is much higher than the patient and at an angle upward and to the side of the patient (not directly above), the scatter received by the operator’s head is projected in an upward angle. Thus a face shield could potentially be lower than the object it is shielding, e.g., below the eyes. This principle may be used as an advantage to design the lowest shield that effectively protects the head while providing optimum vision, appearance, acoustics, low weight, and sense of openness. A flat acrylic plate shield, 0.5 mm Pb equivalence, was suspended vertically in front of a 451P dosimeter. A phantom patient created scatter in an interventional suite while the dosimeter was placed at the level of the crowns of different operators’ heads. Many different configurations were tested to determine which ones would provide effective shielding. The results confirmed that the top of the shield may reside several centimeters below the vertical height of the dosimeter (operator’s crown), allowing line of sight to monitor above the shield, and still provide effective shielding equivalent to when the dosimeter is positioned directly behind the center of the shield. The image receptor functioned as an effective shield against scatter. Factors increasing the minimum height of effective shielding included shorter operator, opposite oblique projection of image receptor, and shield closer to the face (in horizontal direction).
Prater, S., Rees, C., Bruner, A., & Savage, C. (2011). Determination of Minimum Effective Height of Transparent Radiation Face Shielding for Fluoroscopy. Health Physics, 101(5), S135–S141.
2003
Background – Occupational head exposure to radiation in cardiologists may cause radiation induced cataracts and an increased risk of brain cancer. Objective: To determine the effectiveness of 0.5 mm lead equivalent caps, not previously used in invasive cardiology, in comparison with a 1.0 mm lead equivalent ceiling mounted lead glass screen.
Design – An anthropomorphic Alderson-Rando phantom was used to represent the patient. Scatter entrance skin air kerma to the operator position (S-ESAK-O) was measured during fluoroscopy for all standard angulations and the S-ESAK-O per dose–area product (DAP) calculated, as applied to the phantom.
Results – Measured mean (SD) left/right anterior oblique angulation ratios of S-ESAK-O without lead devices were 23.1 (10.1), and varied as a function of tube angulation, body height, and angle of incidence. S-ESAK-O/DAP decreased with incremental operator body height by 10 (3)% per 10 cm. A 1.0 mm lead glass shield reduced mean S-ESAK-O/DAP originating from coronary angiography from 1089 (764) to 54 (29) nSv/Gy × cm2 . A 0.5 mm lead cap was effective in lowering measured levels to 1.8 (1.1) nSv/Gy × cm2 . Both devices together enabled attenuation to 0.5 (0.1) nSv/Gy × cm2 . The most advantageous line of vision for protection of the operator’s eyes was > 60° rightward.
Conclusions – Use of 0.5 mm lead caps proved highly effective, attenuating S-ESAK-O to 2.7 (2.0) × 10−3 of baseline, and to 1.2 (1.4) × 10−3 of baseline where there was an additional 1.0 mm lead glass shield. These results could vary according to the x ray systems used, catheterisation protocols, and correct use of radiation protection devices.
Kuon, E., Birkel, J., Schmitt, M., & Dahm, J. (2003). Radiation exposure benefit of a lead cap in invasive cardiology. Heart, 89(10), 1205–12010. https://doi.org/10.1136/heart.89.10.1205
Aim – This study was conducted to investigate the relationship between the type of lead apron and radiation exposure to the backs of physicians and nurses while using C-arm fluoroscopy.
Methods – We compared radiation exposure to the back in the three groups: no lead apron (group C), front coverage type (group F) and wrap-around type (group W). The other wrap-around type apron was put on the bed instead of on a patient. We ran C-arm fluoroscopy 40 times for each measurement. We collected the air kerma (AK), exposure time (ET) and effective dose (ED) of the bedside table, upper part and lower part of apron. We measured these variables 30 times for each location.
Results – In group F, ED of the upper part was the highest (p < 0.001). ED of the lower part in group C and F was higher than that in group W (p = 0.012). The radiation exposure with a front coverage type apron is higher than that of the wrap-around type and even no apron at the neck or thyroid.
Conclusion – For reducing radiation exposure to the back of physician or nurse, the wrap-around type apron is recommended. This type of apron can reduce radiation to the back when the physician turns away from the patient or C-arm fluoroscopy.
Hong SW, Kim TW and Kim JH. Radiation Exposure to the back with different types of aprons. Radiation Protection Dosimetry. 2021; 193: 185-9.
Aim – This work was designed to study the effectiveness of radiation protection caps in lowering the dose to the brain and the eye lens during fluoroscopically guided interventions.
Methods – Two types of radiation protection caps were examined with regards to their capacity to lower the radiation dose. One cap is equipped with lateral flaps, the other one is not. These caps were fitted to the head of an anthropomorphic Alderson-Rando (A.-R.) phantom. The phantom was positioned aside an angiographic table simulating the position of the first operator during a peripheral arterial intervention. One of the brain slices and both eyes of the A.-R. phantom were equipped with thermoluminescence dosimeters (TLDs).
Results – The analysis of the data showed that the cap without lateral flaps reduced the dose to the brain by 11,5–27,5 percent depending on the position within the brain. The cap with lateral protection flaps achieved a shielding effect between 44,7 and 78,9 percent. When evaluating the dose to the eye, we did see an increase of dose reduction from 63,3 to 66,5 percent in the left eye and from 45,8 to 46,8 percent in the right eye for the cap without lateral protection. When wearing the cap with lateral protection we observed an increase of dose reduction from 63,4 to 67,2 percent in the left eye and from 45,8 to 50,0 percent in the right eye.
Conclusion – Radiation protection caps can be an effective tool to reduce the dose to the brain and the eyes.
Guni E, Hellmann I, Wucherer M, et al. Effectiveness of Radiation Protection Caps for Lowering dose to the Brain and the Eye Lenses. Cardiovasc Intervent Radiol. 2021; 44: 1260-5.