Eye Lens Dosemeter Research Articles

Modification of algorithm for accurate estimation of Hp(3) based on response of head TLD badge calibrated using ISO cylindrical phantom.

In India, the prevailing approach to eye lens dosimetry is the placement of an existing dosemeter on the forehead region after slight modification serves as a dedicated Eye Lens Dosemeter. A methodology for estimating the eye lens dose in terms of the Hp(3) has been previously explored employing an algorithm based on the response characteristics of this dosemeter using ISO slab phantom. It was observed that the performance of the dosemeter in terms of Hp(3) using previous algorithm showed under response at higher angles of incidence and photon beams of energy < 200keV. Further, study was conducted to modify the algorithm following the latest ISO recommendations. This involved generation of data from the response of existing dosemeter on a cylindrical phantom. The results of this study revealed better performance of the newly established algorithm in estimating eye lens dose in terms of Hp(3) when compared to the earlier algorithm.

Basic characteristics of Vision badge and its performance as an eye lens dosimeter for endoscopists

Vision badge is an eye lens dosimeter to measure H p(3). This study aimed to evaluate the basic characteristics of the Vision badge and its performance as an eye lens dosimeter for endoscopists by phantom study. Energy dependence was evaluated by changing the tube voltage to 50 kV (effective energy of 27.9 keV), 80 kV (32.2 keV), and 120 kV (38.7 keV). Dose linearity was evaluated by changing the number of irradiation to 1, 5, and 40 times, which corresponded to 0.53, 5.32, and 21.4 mGy. Batch uniformity was evaluated by calculating the coefficient of variation of H p(3) obtained from 10 Vision badges. Angular dependence was evaluated at 0° (perpendicular to the incident direction of x-rays), 30°, 60°, 75°, and 90°. The Vision badge and optically stimulated luminescence (OSL) dosimeter were attached to the inside of the radioprotective glasses, worn on the endoscopist phantom, and the H p(3) obtained from both dosimeters were compared. The H p(3) obtained from the Vision badge with 38.7 keV was 3.8% higher than that with 27.9 keV. The Vision badge showed excellent linearity (R 2 = 1.00) with the air kerma up to 21.4 mGy. The coefficient of variation of the H p(3) for 10 Vision badges was 3.47%. The relative dose of the Vision badge decreased as the angle increased up to 75°, but increased at 90°. The H p(3) obtained by the OSL dosimeter and the Vision badge were decreased as the endoscopist phantom was turned away from the patient phantom. The H p(3) that was obtained by the Vision badge was 35.5%–55.0% less than that obtained by the nanoDot. In conclusion, the Vision badge showed specific angular dependence due to its shape, but satisfactory basic properties were exhibited for all characteristics. In phantom study, the Vision badge showed generally similar trends with the OSL dosimeter.

Influence of eye lens dosimeter positioning in a realistic dosimetric phantom in reference radiation beams

This paper presents a novel approach to dosimeter placement evaluation for personal eye lens dosimetry. A new assembly, known as the “Eye-Band”, and an anthropomorphic phantom containing two “Real Eye Dosimeters”, referred to as REDs, are proposed. The purpose of this study is to compare the energy and angular responses of the Eye-Band dosimeter assembly with those of an anthropomorphic dosimeter holder (RED-holder) placed inside a phantom. The objective is to analyze the maximum deviations between these measurements to determine the ideal placement of the holders from a metrological point of view. The commercially available BeOSL Eye Lens Dosimeters were also used for comparison, placed near each eye. BeO OSL EzClips were used as the sensitive elements in all three holders. Overall, except for 24 keV and 33 keV at 90° incidence, the differences between the dosimeters worn on the most exposed side of the head (Eye-Band or the standard commercial casings) and the estimated dose at the most exposed lens inside the anthropomorphic phantom were less than ∼20%. Results for the energy dependence of the central Eye-Band dosimeter at each angle of incidence (0°, 30°, 60° and 90°) showed that the deviation in dose to the most exposed eye (right eye) between RED and the central Eye-Band dosimeter ranged from 0% to ∼20% across all energies and angles from 0° to 90°. These results show that the angular dependence of the dosimeter on the most exposed side of the head is critical to ensure adequate results between the doses registered by the worn dosimeters at the side or center positions and the actual dose delivered to the most exposed eye. For the least exposed eye on the exit beam, the dosimeters worn on the left side (the left Eye-Band and the left standard commercial casing dosimeter worn near the left eye) are shown to be inadequate in representing the dose at the left eye position, even at a slight angle of incidence of 30°. This is due to partial shielding of the left dosimeters by the operator's head as the head rotates to the left. Anthropomorphic eye lens dosimeters have proven to be an invaluable tool for gaining a comprehensive understanding of the various factors influencing dose estimation in ocular lens dosimetry from a metrological perspective. This approach effectively bridges the gap between the controlled type testing conditions of dosimeters and real-world workplace conditions, while maintaining standard radiation beam conditions.

EURADOS IC2019exteye- a self-funded intercomparison for extremity and eye lens dosemeters organised by EURADOS working group 2.

The European Radiation Dosimetry Group (EURADOS) has been organising regular, self-funding, external dosimetry intercomparisons (ICs) since 2008. IC2019exteye, for extremity and eye lens dosemeters, attracted 113 systems (68 extremity and 45 eye lens) from 60 institutes with participants from 26 countries around the world. Irradiations were carried out in accredited European irradiation facilities in terms of Hp(0.07)/or Hp(3) in the ranges: photon energy: 16-662keV, beta mean energy 250-1000keV, dose: 0.5mSv to 1Sv, maximum angle of incidence: ±60°. This paper describes the IC2019exteye set-up, irradiation plan and coordination with an overview of the main conclusions. Out of the total of 113 systems, 57 reported results for photons only and 56 reported both photon and beta. In general, the participants showed very satisfactory performances with the medians of all Hp(0.07) and Hp(3) response values very close to unity.

Establishment of Hp(3) calibration system for eye dose monitoring in Taiwan.

In response to the ICRP's amending the occupational exposure limit for the eye lens, the Institute of Nuclear Energy Research (INER) established the Hp(3) calibration system for eye dose monitoring in Taiwan to accurately assess the dose received in the eye lens. INER employed the narrow-spectrum series radiation according to the ISO 4037 as the X-ray radiation qualities, and the measured half-value layer consistent with a 5% difference. The air kerma rate standard was determined by the self-made free air chamber, and through dose conversion coefficient referring to ISO 4037 to obtain the Hp(3) on an ISO cylinder phantom. Furthermore, the calibration system was provided as the characteristics tests for DOSIRIS headset dosemeters. Finally, the Hp(3) calibration system has been established in Taiwan, and it can be used to provide calibration services for eye lens dosemeters and be applied to the proficiency testing that will be held in 2023.

In Vivo Lens Dosimetry in a Case of En Face Electron Adjuvant Radiotherapy for Cutaneous Nasal Bridge Basal Cell Carcinoma: A Case Report

"Radiation therapy represents one of the main treatment modalities for basal cell carcinoma (BCC), the most common type of skin cancer. The proximity of organs at risk (OARs) increases the risk of side effects. Treatment planning system (TPS) estimates the absorbed dose, but the real value can be determined only by in vivo dosimetry. We measured the absorbed dose at the lenses’ level in a case who received electron irradiation for a resected BCC with positive microscopic margins, located at the bridge of the nose. The thermoluminescent eye lens dosimeters (TLD) were placed under the lead protections. We compared the measured dose with the values estimated by TPS. The treatment involved delivering 50 Gy in 25 fractions. A Monaco 5.11 Treatment Planning System (TPS) was used to plan treatment with a 9 MeV electron field and a 10x10 cm applicator at a 100 cm Source-to-Skin Distance (SSD). Customized lead layers and circular lead blocks were used for protection. The TPS estimated maximum doses of 5.87 Gy for the left lens, and 2.70 Gy for the right lens, respectively. After measuring the doses for the first three fractions by TLD, we calculated that maximum dose for the left lens would get to 0.55 Gy, and to 0.30 Gy for the right lens. In this case report we show that irradiation for a BCC localised at the bridge of the nose is possible with proper shielding and can be safely delivered, without exposing the patient to long- term side effects"

The energy and angular Hp(3,α) response of commercial eye-lens dosemeters to photon and beta particle radiation

In 2012, the International Commission on Radiological Protection recommended a reduction of the equivalent dose limit for the lens of the eye from 150 mSv to 50 mSv per year, with a maximum 5-year average of 100 mSv. This noticeable reduction imposes more demands on the performance on personnel eye-lens dosimetry. Regulatory authorities of various jurisdictions worldwide followed some or all, of the ICRP recommendations and implemented reduced occupational lens of eye dose limits in their legislation. Commercial dosimetry service providers have risen to the challenges by developing new dosemeter technologies, and some in-house dosimetry services have developed their own eye-lens dosemeters. The results of the energy and angular response, to photon and beta radiation, of three commercial dosemeters are reported here. Their performances are compared to those of the dosemeter developed, in-house, by Canadian Nuclear Laboratories. With some adjustments to their calibrations, the responses of all dosemeters, could be within the performance limits set by the ISO 14146 and the IEC 62387 standards for the conditions of the tests that were performed.

Evaluation of operator eye exposure and eye protective devices in interventional radiology: Results on clinical staff and phantom

PurposeTo 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. MethodsTwo 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. ResultsDRF 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. ConclusionsAll 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.

Evaluation of 3D Printed Anthropomorphic Head Phantom for Calibration of TLD in Eye Lens Dosimeter

Calibration of Thermo Luminescent Dosimetry (TLD) in eye lens dosimeter requires a standard phantom. The use of anthropomorphic phantoms in calibration needs evaluation. This study aimed to analyze the angular response of the TLD on the fabricated 3D anthropomorphic head phantom and Computerized Imaging Reference Systems (CIRS)- Computed Tomography (CT) dose phantom as a standard phantom irradiated with Cs-137 and to compare the absorbed dose and linear attenuation for both phantoms. Hp(3) analysis, conversion coefficient (hpK(3)), and calibration factor (CF) are also investigated. In this experimental study, the fabricated 3D printed anthropomorphic head phantom was analyzed using polylactic acid (PLA) with the skull and then filled with the artificial brain and cerebrospinal fluid (CSF) as a test phantom. TLD-700H and TLD Reader Harshaw 6600 plus were used to analyze the angular response of Cs-137 radiation and to determine the absorbed dose and linear attenuation coefficient of test and standard phantoms. The effect of the angle of radiation source towards TLD reading at the anthropomorphic head phantom has a similar value to the standard phantom with a calibration factor ranging from 0.82 to 1. The absorbed dose measurement and the linear attenuation coefficient of the anthropomorphic head phantom with the standard phantom have different values of 2.52 and 3.78%, respectively. The fabricated 3D printed anthropomorphic head phantom has good potential as an alternative to standard phantoms for TLD calibration in eye lens dosimeter.

Surgeon eye lens dose monitoring in interventional neuroradiology, cardiovascular and radiology procedures

PurposeThis study investigated the radiation dose to surgeon eye lens for single procedure and normalised to exposure parameters for eight selected neuroradiology, cardiovascular and radiology interventional procedures. MethodsThe procedures investigated were diagnostic study, Arteriovenous Malformations treatment (AVM) and aneurysm embolization for neuroradiology procedures, Coronary Angiography and Percutaneous Transluminal Coronary Angioplasty (CA-PTCA), Pacemaker and Implantable Cardioverter-Defibrillator implantation (PM-ICD), Endovascular Aortic Repair (EVAR) and Fenestrated Endovascular Aortic Repair (FEVAR) for cardiovascular and electrophysiology procedures. CT-guided lung biopsy was also monitored.All procedures were performed with table-mounted and ceiling-suspended shields (0.5 mm lead equivalent thickness), except for FEVAR and PM-ICD where only a table mounted shield was present, and CT-guided lung biopsy where no shield was used. Dose assessment was performed using a dosemeter positioned close to the most exposed eye of the surgeon, outside the protective eyewear. ResultsThe surgeon most exposed eye lens median Hp(3) equivalent dose for a single procedure, without protective eyewear contribution, was 18 μSv for neuroradiology diagnostic study, 62 μSv for AVM, 38 μSv for aneurysm embolization, 33 μSv for CA-PTCA, 39 μSv for PM-ICD, 49 μSv for EVAR, 2500 μSv for FEVAR, 153 μSv for CT-guided lung biopsy. ConclusionsIn interventional procedures, the 20 mSv/year dose limit for surgeon eye lens exposure might be exceeded if shields or protective eyewear are not used.Surgeon eye lens doses, normalised to single procedures and to exposure parameters, are a valuable tool for determining appropriate radiation protection measures and dedicated eye lens dosemeter assignment.

Investigation of the effectiveness of ECOLAB ’Drape ArmourTM’ Radiation Protection in limiting eye-lens doses of healthcare personnel exposed to ionizing radiation during gastroenterology - interventional radiology procedures

Objectives: To investigate the efficiency of the ECOLAB “Drape ArmourTM” device in limiting the eye-lens doses absorbed by healthcare personnel exposed to ionizing radiation, in a four-month trial during gastroenterology interventional radiology procedures. Methods: Eyelens doses measured with eye-lens dosimeters calibrated in terms of equivalent dose at 3 mm depth ( Hp(3) ) were collected and analyzed since 2016 along with the irradiation parameters (Dose Area Product - DAP). The eye-lens doses received during the four-month trial, have been compared with doses normally received, in the same conditions of irradiation, in the absence of the protection drape. Results: During the period of use of Drape ArmourTM, the average dose to the eye lens was estimated to be 0.73 mSv (St.dev = 0.40 mSv). The average dose to the eye lens, measured in the same four-month period, across different years from 2017 to 2021, was equal to 1.30 mSv (st. dev = 0.35 mSv). Conclusions: Results suggest the effectiveness of Drape ArmourTM in containing the doses to the eye lens. Keypoint: Limiting eye-lens doses to a maximum value of 20 mSv/year is a real challenge, especially in interventional radiologic facilities. The use of suitable radio-opaque drapes may help healthcare workers involved in such facilities. The aim of the work is to evaluate the efficiency of the ECOLAB “Drape ArmourTM” sterile mono-use drape.

COMPARISON OF TWO TYPES EYE LENS DOSEMETERS USED IN INTERVENTIONAL CARDIOLOGY AND RADIOLOGY.

The aim of this contribution is to provide an overview of comparison of two types of eye lens dosemeter systems. The comparison was performed at the Department of Intravenous Cardiology using patient and physician phantoms and supplemented by dose simulation using the Monte Carlo method. The tests were performed in several specific geometries and in addition to eye lens dosemeters the value of a personal dosemeter located at the reference point was also monitored. The value of Hp(3) and Hp(10) was monitored. It is clear from the results that film dosemeters achieve more correct results in most cases. It is probably due to a better correction for the angle of exposure. This assumption must be verified by more detailed measurements in laboratory conditions.

MONITORING OF EYE LENS DOSE HP(3) CATHLAB STAFF USING SOCA DOSIMETER

MONITORING OF EYE LENS DOSE HP(3) CATHLAB STAFF USING SOCA DOSIMETER. The International Commission on Radiological Protection (ICRP) reduced the cataract threshold dose from 2‒5 Gy to 0.5 Gy, followed by a decrease in the dose limit value (NBD) of the radiation worker's eye lens to 20 mSv/year. Cathlab staff is one of the workers vulnerable to receiving high doses of eye lenses because they work near radiation sources, so staff's eye lens doses need to be monitored. Monitoring is carried out to analyze the dose of eye lenses received by workers and ensure workers are well protected. Eye lens measurement is carried out at Hp(3) or a depth of 3 mm because the lens is sensitive to radiation. Monitoring was carried out for one week on 14 staff (doctors, nurses, and radiographers) and four procedures with an eyepiece dosimeter (SOCA Dosimeter). The eye lens dose obtained for a week ranged from 0.108 – 1.642 mSv, and monitoring per procedure was 0.033 – 0.393 mSv. The annual dose received by workers is based on estimates mostly exceeding the NBD, so tracking with an eye lens dosimeter needs to be done, and eye protection equipment needs to be used to reduce the eye lens dose received. Keywords: Cathlab staff, eye lens dose Hp(3), SOCA dosimeter

Determination of a reliable assessment for occupational eye lens dose in nuclear medicine.

The most recent statement published by the International Commission on Radiological Protection describes a reduction in the maximum allowable occupational eye lens dose from 150 to 20 mSv/year (averaged over 5‐year periods). Exposing the eye lens to radiation is a concern for nuclear medicine staff who handle radionuclide tracers with various levels of photon energy. This study aimed to define the optimal dosimeter and means of measuring the amount of exposure to which the eye lens is exposed during a routine nuclear medicine practice. A RANDO human phantom attached to Glass Badge and Luminess Badge for body or neck, DOSIRIS and VISION for eyes, and nanoDot for body, neck, and eyes was exposed to 99mTc, 123I, and 18F radionuclides. Sealed syringe sources of each radionuclide were positioned 30 cm from the abdomen of the phantom. Estimated exposure based on measurement conditions (i.e., air kerma rate constants, conversion coefficient, distance, activity, and exposure time) was compared measured dose equivalent of each dosimeter. Differences in body, neck, and eye lens dosimeters were statistically analyzed. The 10‐mm dose equivalent significantly differed between the Glass Badge and Luminess Badge for the neck, but these were almost equivalent at the body. The 0.07‐mm dose equivalent for the nanoDot dosimeters was greatly overestimated compared to the estimated exposure of 99mTc and 123I radionuclides. Measured dose equivalents of exposure significantly differed between the body and eye lens dosimeters with respect to 18F. Although accurately measuring radiation exposure to the eye lenses of nuclear medicine staff is conventionally monitored using dosimeters worn on the chest or abdomen, eye lens dosimeters that provide a 3‐mm dose equivalent near the eye would be a more reliable means of assessing radiation doses in the mixed radiation environment of nuclear medicine.

Protected and Unprotected Radiation Exposure to the Eye Lens During Endovascular Procedures in Hybrid Operating Rooms

Radiation cataract has been observed at lower doses than previously thought, therefore the annual limit for equivalent dose to the eye lens has been reduced from 150 to 20 mSv. This study evaluated radiation exposure to the eye lens of operators working in a hybrid operating room before and after implementation of a dose reduction program. From April to October 2019, radiation exposure to the first operator was measured during all consecutive endovascular procedures performed in the hybrid operating room using BeOSL Hp(3) eye lens dosimeters placed both outside and behind the lead glasses (0.75 mm lead equivalent). Measured values were compared with data from a historic control group from the same hospital before implementation of the dose reduction program. A total of 181 consecutive patients underwent an endovascular procedure in the hybrid operating room. The median unprotected eye lens dose (outside lead glasses) of the main operator was 0.049 mSv for endovascular aortic repair (EVAR) (n= 30), 0.042 mSv for thoracic endovascular aortic repair (TEVAR) (n= 23), 0.175 mSv for complex aortic fenestrated or branched endovascular procedures (F/BEVAR; n= 15), and 0.042 mSv for peripheral interventions (n= 80). Compared with the control period, EVAR had 75% lower, TEVAR 79% lower, and F/BEVAR 55% lower radiation exposure to the unprotected eye lens of the first operator. The lead glasses led to a median reduction in the exposure to the eye lens by a factor of 3.4. The implementation of a dose reduction program led to a relevant reduction in radiation exposure to the head and eye lens of the first operator in endovascular procedures. With optimum radiation protection measures, including a ceiling mounted shield and lead glasses, more than 440 EVARs, 280 TEVARs, or 128 FEVARs could be performed per year before the dose limit for the eye lens of 20 mSv was reached.

The Impact of Implementing a Radiation-Sparing Protocol for Percutaneous Kyphoplasty-A Prospective Dosemetric Study.

Prospective cohort study. The purpose of this prospective study was to evaluate a protocol for radiation-sparing kyphoplasty by assessing dosemetrically recorded radiation exposures to both patient and surgeon. This prospective clinical study examines the radiation exposure to patient and surgeon during single-level kyphoplasty in 32 thoracolumbar osteoporotic vertebral body fractures (12 OF 2, 9 OF 3, 11 OF 4 types) using a radiation aware surgical protocol between May 2017 and November 2019. The radiation exposure was measured at different locations using film, eye lens and ring dosemeters. Dose values are reported under consideration of lower detection limits of each dosemeter type. A high proportion of dosemeter readings was below the lower detection limits, especially for the surgeon (>90%). Radiation exposure to the surgeon was highest at the unprotected thyroid gland (0.053 ± 0.047 mSv), however only slightly above the lower detection limit of dosemeters (0.044 mSv). Radiation exposure to the patient was highest at the chest (0.349 ± 0.414 mSv) and the gonad (0.186 ± 0.262 mSv). Fluoroscopy time, dose area product and number of fluoroscopic images were 46.0 ± 17.9 sec, 124 ± 109 cGy×cm2, and 35 ± 13 per kyphoplasty, respectively. Back pain significantly improved from 6.8 ± 1.6 to 2.5 ± 1.7 on the numeric rating scale on the first postoperative day (P < 0.0001). The implementation of a strict intraoperative radiation protection protocol allows for safely performed kyphoplasty with ultra-low radiation exposure for the patient and surgeon without exceeding the annual occupational dose limits. The study was registered in the German Clinical Trials Register (DRKS00011908, registration date 16/05/2017).

PERFORMANCE TESTING OF EYE LENS DOSEMETER AND EVALUATION OF PERSONAL RADIOLOGICAL EXPOSITION AT DOUERA ORTHOPEDIC INTERVENTIONAL SERVICE

The radiological monitoring of the eye in the workplace depends on the type of dosemeter used and its performance. The dosimetric performances of Nuclear Research Center of Algiers (CRNA) developed eye lens dosemeter (Larabi-Harfouche etal. Characterization and qualification of a CRNA eye dosemeter. Perspect Sci. 12, 100402 (2019)) are investigated in this work in order to assess its ability to measure the operational quantity Hp(3) in photon fields and to check its compliance with the International Commission on Radiological Protection recommendations for professionally exposed people (ICRP. ICRP statement on tissue reactions/early and late effects of radiation in normal tissues and organs - threshold doses for tissue reactions in a radiation protection context. ICRP Publication 118. Ann. ICRP 41(1/2) (2012)). Some key performance indicators including the relative response of the nonlinearity, coefficient of variation, and photon energy and angular dependence are assessed before the use of this dosemeter for eye lens monitoring of orthopedic staff in the operating room at Douera hospital. The monitoring results of this first pilot study are presented and discussed in view of supporting the recommendations of the International Organization for Standardization 15382: 2015 concerning the monitoring of the dose at lens.

Occupational eye lens dose in endoscopic retrograde cholangiopancreatography using a dedicated eye lens dosimeter

Increased x-ray exposure to physicians’ eye lenses during radiology procedures is a significant concern. In this study, x-ray exposure to the eye was measured using an anthropomorphic head phantom, with and without radiation-protective devices, to examine the dose of x-ray radiation that physicians are exposed to during endoscopic retrograde cholangiopancreatography (ERCP). X-ray exposure of the eye was measured using novel dedicated direct eye lens dosimeters that could specifically measure H p(3) during the ERCP procedure. The spatial dose in the height direction of the physician was measured using an ionization chamber dosimeter. Eye dosimeters were attached inside and outside the lead (Pb) glasses attached to the head of the human phantom to demonstrate its protective effect. Irradiation from the system lasted for 30 min. When the overcouch x-ray tube system is used, the cumulative radiation dose over the 30 min x-ray fluoroscopy time, without the use of radiation-protective devices, to the left and right eyes was 3.7 and 1.5 mSv, respectively. This dose was estimated to be the dose to the lens per therapeutic ERCP examination. With radiation-protective glasses, the dose reduced to 1.8 and 1.0 mSv for the left and right eye, respectively. The results of our study indicated that radiation exposure to the eye was reduced by up to 80.0% using Pb glasses and by 96.8% using radiation-protective curtains. Our study indicates that a physician’s maximum radiation exposure to the eyes during an ERCP procedure may be above the level recommended by the International Commission on Radiological Protection when the physician does not use radiation-protective devices. The eyewear, which is larger and fitted more closely to the face, provided a better protection effect even with a low lead equivalence, demonstrating that the shape of eyewear is important for protective function.

Room staff radiation dose in a vascular surgery hybrid operating room and evaluation of a real-time radiation dosimeter

Abstract Objective Real-time radiation dosimeter have been shown to decrease radiation exposure of the staff. This effect is mainly explained by increased awareness of the radiation due to direct radiation exposure feedback to the operator. We aimed to measure the radiation exposure of all staff members working in a hybrid operating room and wanted to compare the equivalent doses of real-time radiation dosimeters with thermoluminescence dosimeters. Methods Prospective non-randomized comparative trial. From April – October 2019, all staff members working in a hybrid operating room were equipped with real-time radiation dosimeters (Unfors RaySafe i3). The table positions of all staff members were documented. In addition, the first operator was equipped with a thermoluminescence Hp(3) eye lens dosimeter (TLD) placed outside the lead glasses to validate the real-time radiation dosimeter. Results The median dose of the operator / the first assistant was 73.6 µSv / 21.8 µSv for EVAR (n = 30); 57.25 µSv / 18.2 µSv for TEVAR (n = 23); 207.0 µSv / 76.65 µSv for more complex aortic procedures (f/bEVAR etc.; n = 15); 14.85 µSv / 8.5 µSv for occlusive disease of the iliac arteries (n = 27) and 6.1 µSv / 3.4 µSv for occlusive disease of the peripheral arteries (n = 53). The anesthesiologist’s median dose was 0.3 µSv, with highest values in f/bEVAR (3.9µSv). The scrub nurse’s median dose was 2 µSv with highest values in f/bEVAR (24 µSv). The position of any staff member at the left arm for transbrachial cannulation in f/bEVAR was associated with higher median equivalent radiation doses compared to the right femoral position (272.5 vs. 207 µSv for the operator (p=ns), 175.3 vs. 27.8 µSv for the first assistant (p = 0.027) and 45.55 vs. 8.0 µSv for the scrub nurse (p = 0.14)). The equivalent doses of the TLD and RaySafe did not correlate well using simple lineal regression analysis (r2 0.1713, p = 0.0014). Conclusion With the RaySafe real-time radiation dosimeter, table positions with increased radiation exposure can be identified. This allows for improvement in shielding at these positions, possibly leading to lower radiation exposure of the staff.

Protected and unprotected radiation exposure to the eye lens of vascular surgeons during endovascular procedures in hybrid operating rooms

Abstract Objective Radiation induced cataract has been observed at lower threshold doses than expected. Therefore, the annual limit for equivalent dose to the eye lens has been reduced from 150 to 20 mSv. We aimed to evaluate radiation exposure to the eye lens of vascular surgeons working in a hybrid operating room before and after a dose reduction program was established. Methods Prospective non-randomized trial with a historic control group. From April – October 2019, radiation exposure to the operator was measured during all endovascular procedures performed in the hybrid operating room using BeOSL Hp(3) eye lens dosimeters placed outside the 0.75mm lead equivalent glasses on the side of the radiation source and behind the lead glasses. Measured values were compared to data from a prospective study performed at the same center in the years of 2012 and 2013 before a dose reduction program had been implemented. Results A total of 181 consecutive patients underwent an endovascular procedure in the hybrid operating room. The mean unprotected eye lens dose of the main operator was 0.119 mSv for EVAR (n = 30), 0.118 mSv for TEVAR (n = 23), 0.312 mSv for more complex aortic procedures (F/BrEVAR; n = 15) and 0.046 mSv for peripheral interventions. Compared to the control period, EVAR had 75% lower, TEVAR 79% lower and more complex aortic procedures 55% lower radiation exposure unprotected eye lens of the operator. The 0.75 mm lead equivalent glasses led to a median reduction of the exposure to the eye lens by the factor 3.43. Behind the lead glasses at the level of the eye lens, radiation exposure exceeding the detection limit of 0.042 mSv was measured only in 22 of 181 cases. There was a significant correlation between DAP between both protected and unprotected eye lens dose (p &amp;lt; 0.0001, r2 = 0.512 and 0.282). DAP correlated significantly with patients’ body mass index, operating time, fluoroscopy time and digital subtraction angiography time. Conclusion The dose reduction program at our institution has led to a relevant reduction of the radiation dose to the head and the eye lens of the main operator in endovascular procedures. With optimum radiation protection measures including a ceiling-mounted shield and 0.75 mm lead equivalent glasses, more than 440 EVARs, 280 TEVARs or 128 FEVARs could be performed per year until the dose limit for the eye lens of 20 mSv would be reached.