Medical staff dose estimation during pediatric cardiac interventional procedures.

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

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

Vision badge is an eye lens dosimeter to measureHp(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 ofHp(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 theHp(3) obtained from both dosimeters were compared. TheHp(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 (R2= 1.00) with the air kerma up to 21.4 mGy. The coefficient of variation of theHp(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°. TheHp(3) obtained by the OSL dosimeter and the Vision badge were decreased as the endoscopist phantom was turned away from the patient phantom. TheHp(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.

Comparison of shielding effects of over-glasses-type and regular eyewear in terms of occupational eye dose reduction.

Given the new recommendations for occupational eye lens doses, various lead glasses have been used to reduce irradiation of interventional radiologists. However, the protection afforded by lead glasses over prescription glasses (thus over-glasses-type eyewear) has not been considered in detail. We used a phantom to compare the protective effects of such eyewear and regular eyewear of 0.07 mm lead-equivalent thickness. The shielding rates behind the eyewear and on the surface of the left eye of an anthropomorphic phantom were calculated. The left eye of the phantom was irradiated at various angles and the shielding effects were evaluated. We measured the radiation dose to the left side of the phantom using RPLDs attached to the left eye and to the surface/back of the left eyewear. Over-glasses-type eyewear afforded good protection against x-rays from the left and below; the average shielding rates on the surface of the left eye ranged from 0.70-0.72. In clinical settings, scattered radiation is incident on physicians' eyes from the left and below, and through any gap in lead glasses. Over-glasses-type eyewear afforded better protection than regular eyewear of the same lead-equivalent thickness at the irradiation angles of concern in clinical settings. Although clinical evaluation is needed, we suggest over-glasses-type Pb eyewear even for physicians who do not wear prescription glasses.

Radiation exposure in augmented fluoroscopic bronchoscopy procedures: a comprehensive analysis for patients and physicians.

Cancer is a major health challenge and causes millions of deaths worldwide each year, and the incidence of lung cancer has increased. Augmented fluoroscopic bronchoscopy (AFB) procedures, which combine bronchoscopy and fluoroscopy, are crucial for diagnosing and treating lung cancer. However, fluoroscopy exposes patients and physicians to radiation, and therefore, the procedure requires careful monitoring. The National Council on Radiation Protection and Measurement and the International Commission on Radiological Protection have emphasised the importance of monitoring patient doses and ensuring occupational radiation safety. The present study evaluated radiation doses during AFB procedures, focusing on patient skin doses, the effective dose, and the personal dose equivalent to the eye lens for physicians. Skin doses were measured using thermoluminescent dosimeters. Peak skin doses were observed on the sides of the patients' arms, particularly on the side closest to the x-ray tube. Differences in the procedures and experience of physicians between the two hospitals involved in this study were investigated. AFB procedures were conducted more efficiently at Hospital A than at Hospital B, resulting in lower effective doses. Cone-beam computed tomography (CT) contributes significantly to patient effective doses because it has higher radiographic parameters. Despite their higher radiographic parameters, AFB procedures resulted in smaller skin doses than did image-guided interventional and CT fluoroscopy procedures. The effective doses differed between the two hospitals of this study due to workflow differences, with cone-beam CT playing a dominant role. No significant differences in left and right eyeHp(3) values were observed between the hospitals. For both hospitals, theHp(3) values were below the recommended limits, indicating that radiation monitoring may not be required for AFB procedures. This study provides insights into radiation exposure during AFB procedures, concerning radiation dosimetry, and safety for patients and physicians.

Evaluation of radiation dose to the lens in interventional cardiology physicians before and after dose limit regulation changes.

In response to the International Commission on Radiological Protection, which lowered the lens equivalent dose limit, Japan lowered the lens dose limit from 150 mSv y-1to 100 mSv/5 years and 50 mSv y-1, with this new rule taking effect on 1 April 2021. DOSIRIS®is a dosimeter that can accurately measure lens dose. Herein, we investigated lens dose in interventional cardiology physicians 1 year before and after the reduction of the lens dose limit using a neck dosimeter and lens dosimeter measurements. With an increase in the number of cases, both personal dose equivalent at 0.07 mm depth [Hp(0.07), neck dosimeter] and personal dose equivalent at 3 mm depth [Hp(3), lens dosimeter] increased for most of the physicians. The Hp(3) of the lens considering the shielding effect of the Pb glasses using lens dosimeter exceeded 20 mSv y-1for two of the 14 physicians. Protection from radiation dose will become even more important in the future, as these two physicians may experience radiation dose exceeding 100 mSv/5 years. The average dose per procedure increased, but not significantly. There was a strong correlation between the neck dosimeter and lens dosimeter scores, although there was no significant change before and after the lens dose limit was lowered. This correlation was particularly strong for physicians who primarily treated patients. As such, it is possible to infer accurate lens doses from neck doses in physicians who primarily perform diagnostics. However, it is desirable to use a dosimeter that can directly measure Hp(3) because of the high lens dose.

Evaluation of a New Real-Time Dosimeter Sensor for Interventional Radiology Staff.

In 2011, the International Commission on Radiological Protection (ICRP) recommended a significant reduction in the lens-equivalent radiation dose limit, thus from an average of 150 to 20 mSv/year over 5 years. In recent years, the occupational dose has been rising with the increased sophistication of interventional radiology (IVR); management of IVR staff radiation doses has become more important, making real-time radiation monitoring of such staff desirable. Recently, the i3 real-time occupational exposure monitoring system (based on RaySafeTM) has replaced the conventional i2 system. Here, we compared the i2 and i3 systems in terms of sensitivity (batch uniformity), tube-voltage dependency, dose linearity, dose-rate dependency, and angle dependency. The sensitivity difference (batch uniformity) was approximately 5%, and the tube-voltage dependency was <±20% between 50 and 110 kV. Dose linearity was good (R2 = 1.00); a slight dose-rate dependency (~20%) was evident at very high dose rates (250 mGy/h). The i3 dosimeter showed better performance for the lower radiation detection limit compared with the i2 system. The horizontal and vertical angle dependencies of i3 were superior to those of i2. Thus, i3 sensitivity was higher over a wider angle range compared with i2, aiding the measurement of scattered radiation. Unlike the i2 sensor, the influence of backscattered radiation (i.e., radiation from an angle of 180°) was negligible. Therefore, the i3 system may be more appropriate in areas affected by backscatter. In the future, i3 will facilitate real-time dosimetry and dose management during IVR and other applications.

Eye-lens dose rate conversion factors due to hot particles and surface contaminations on the cornea.

In 2012, the International Commission on Radiological Protection issued new recommendations, in publication 118, regarding the dose limits to the eye-lens. New analyses of historical exposure data had indicated that radiation-induced cataracts may appear at lower doses than previously assumed. This spurred largescale efforts in a variety of fields including dosimetry, radiation effects simulations, and the review of national regulatory limits. On the simulation side, much work led to the publication of dose rate conversion factors (DRCFs), to calculate the dose to the radiosensitive part of the eye-lens, and to the whole eye-lens as functions of the incident fluence of electron, photon, positron, and neutron radiation. The standard, ISO-15382 (2015Radiological Protection-Procedures for Monitoring the Dose to the Lens of the Eye, the Skin and the Extremities), from the International Organization for Standardization (ISO), stated that the direct contact of a hot radioactive particle on the eye-lens represents a special contamination condition that must be considered. The aim of this work was to produce tabulated data of eye-lens dose rates, per activity (MBq), for a variety of radionuclides. In this work, the dose to the eye-lens from contamination directly in contact with the cornea, expressed in terms of DRCFs for eye-lens, in units of Gy h-1MBq-1, are presented for 102 radionuclides of interest. These radionuclides were selected as they had been considered by the International Atomic Energy Agency of importance for skin dose. The method consisted of two steps. The first was the determination of the DRCFs for mono-energetic electrons and photons for a hot particle in contact with the eye-lens, followed by the folding of these quantities with the emissions of the radionuclides of interest. Contributions from spontaneous fission neutrons were considered separately. Exposure geometries for spherical hot particles of different dimensions, materials and locations on the cornea were considered. In addition, partial surface coverage of the cornea, consistent with an accidental exposure to a contaminated liquid, was also modelled. Resulting radionuclide DRCFs were verified, for a few specific geometries and radionuclides with dedicated Monte Carlo simulations. The final data are presented in several tables included in this paper.

Cardiologist's exposure to radiation in cath lab measured with InstadoseTMdosimeter.

INTRODUCTION: complex fluoroscopy-guided interventional procedures in cardiology are known to result in higher radiation doses for patients and staff. PURPOSE: to estimate the equivalent dose received in different regions of the cardiologist's body in catheterism (CATH) and percutaneous coronary intervention (PCI) procedures, as well as to evaluate the effectiveness of monitoring the doses in the catheritization laboratory (cath lab) using a direct ion storage dosimeter. MATERIALS AND METHODS: the InstadoseTMand the thermoluminescent dosimeters (TLD-100) were fixed simultaneously in the following regions of the cardiologist's body: near the eyes (left and right), the trunk region (over the lead apron) and the left ankle. Occupational doses were recorded during 86 procedures (60% CATH). RESULTS: catheterization procedures showed third quartile dose values near to the left eye region equal to 0.10 mSv (TLD-100) and 0.12 (InstadoseTM) and for intervention 0.15 mSv (TLD-100 and InstadoseTM). The doses measured in the trunk region, over the lead apron, were about 13% higher for catheterization procedures and 20% higher for intervention procedures compared to left eye region measurements. The Wilcoxon-Mann-Whitney test was applied for unpaired data for all body regions, comparing the data obtained between the TLD-100 and InstadoseTMdosimeters. For CATH and PCI, the responses of the TLD-100 and InstadoseTMdosimeters are considered equal for all analysed regions (p> 0.05) with the exception of the right eye region. CONCLUSION: the InstadoseTMpassive dosimeter can be useful as a complementary assessment in the monitoring of a cardiologist's personal occupational doses in the cath lab.

Eye lens dose for medical staff assisting patients during computed tomography: comparison of several types of radioprotective glasses.

Medical staff sometimes assists patients in the examination room during computed tomography (CT) scans for several purposes. This study aimed to investigate the dose reduction effects of four radioprotective glasses with different lead equivalents and lens shapes. A medical staff phantom was positioned assuming body movement restraint of the patient during chest CT, and Hp(3) at the eye surfaces of the medical staff phantom and inside the lens of the four types of radioprotective glasses were measured by changing the distance of the staff phantom from the gantry, eye height, and width of the nose pad. The Hp(3) at the right eye surface with glasses of 0.50-0.75 mmPb and 0.07 mmPb was approximately 83.5% and 58.0%, respectively, lower than that without radioprotective glasses. The dose reduction rates at left eye surface increased with over-glass type glasses by 14%-28% by increasing the distance from the CT gantry to the staff phantom from 25 to 65 cm. The dose reduction rates at the left eye surface decreased with over-glass type glasses by 26%-31% by increasing the height of the eye lens for the medical staff phantom from 130 to 170 cm. The Hp(3) on the left eye surface decreased by 46.9% with the widest nose pad width compared to the narrowest nose pad width for the glasses with adjustable nose pad width. The radioprotective glasses for staff assisting patients during CT examinations should have a high lead equivalent and no gap around the nose and under the front lens.

New operational quantities (RBE ×Dp lens/Φ) for eye lens neutron dosimetry as a function of energy and angle of incidence in the ICRU 95 formalism.

This paper is a continuation of a study published recently by the authors. It presents and discusses computed personal absorbed dose in the lens of the eye (Dp lens/Φ), and a relative biological effectiveness (RBE)-weighted absorbed dose (in terms of an newly proposed operational quantity RBE ×Dp lens/Φ), conversion coefficients for the lens of the eye for neutron exposure at incident energies from thermal to ∼20 MeV and at angles of incidence from 0°to 90°in 15° increments, at 180° and for rotational incidence irradiation geometry (from 0°to 360°in 5°increments). These conversion coefficients were obtained from a simulation model developed for this study that contains the stylised eye model, embedded in the adult UF-ORNL mathematical phantom, whereby the previously stated RBE-weighted absorbed dose was obtained using the proposed RBE versus neutron energy distribution compiled in a previous paper by the authors. The simulations carried out for this study using the Monte Carlo N-Particle transport code version 6.2, were conducted in a realistic human eye model, for the left and right sensitive and whole volume of the lens of the eye, considering the recent proposed redefinition of the operational quantities for external radiation exposure in International Commission on Radiation Units and Measurements (ICRU) report 95. A comprehensive set of tabulated data for neutron fluence-to-dose conversion coefficients (Dp lens/Φin pGy cm2) and RBE-weighted absorbed dose (RBE ×Dp lens/Φin pGy cm2) conversion coefficients is included in this paper as a function of incident neutron energy and angle of incidence. Data forDp lens/Φ(pGy cm2) are compared to similar data from the literature for validation of our model. Data for RBE ×Dp lens/Φ(in pGy cm2), were also compared to the equivalent operational quantityHp(3,α)/Φ(in pSv cm2) conversion coefficients calculated at 3 mm depth in a cylindrical phantom for different incident neutron energies and angles of incidence from 0°to 75°in 15°increments to demonstrate the relevance of this newly proposed operational quantity for doses resulting in tissue reactions (deterministic effects) which should be quoted in Gray (RBE-weighted absorbed dose, RBE ×D(Gy)), rather than Sievert (Sv) which is reserved for stochastic effects. The current neutron weighted absorbed dose (RBE ×Dp lens) is proposed for the tissue reactions in the eye-lens for neutron radiation as per National Council on Radiation Protection and Measurements report 180 and in line with the recent proposal for the review and revision of the System of Radiological Protection to Keeping the International Commission on Radiological Protection (ICRP) recommendations fit for purpose. This method would bring better alignment between the dose limits in ICRP 118 and the new operational quantity consistent with the units of the new eye-lens dose limits without being overly conservative. The utilization of the proposed new operational quantities, as outlined in ICRU 95, has the potential to address the ongoing challenge in enforcing regulatory limits for neutron eye dose, specifically the use of Gy instead of Sv. It should be noted that the applicability of this will vary from country to country as in many countries the legislation is likely to mandate the use ofHp(3) until the regulation is amended. This approach can serve as an interim solution while awaiting the issuance of the new ICRP general recommendations, which is expected to take several years. Implementing the new operational quantities can contribute to enhancing the accuracy and effectiveness of neutron eye dose limit enforcement.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Phylogenetic analysis of congenital rubella virus from Indonesia: a case report.

BACKGROUND: Rubella is a common inherited infection resulting in congenital cataracts and a significant cause of permanent vision loss in developing countries. In 2016, Indonesia had the highest number of congenital rubella syndrome (CRS) cases globally. Here, we report the first genotype of the rubella virus extracted from the eye lens from a child with congenital cataracts due to CRS. CASE PRESENTATION: A female neonate was delivered by an elective caesarean delivery with normal birth weight at term from a 24-year-old mother in the rural setting. The baby presented with bilateral congenital cataracts, small-moderate secundum atrial septal defect, severe supravalvular pulmonary stenosis, and profound bilateral hearing loss. She also had microcephaly and splenomegaly. The patient's serology showed persistent positive IgG for rubella virus at the age of four years and four months. Following extraction during cataract surgery, viral detection of the lenses identified the presence of rubella. Phylogenetic analysis confirmed that the virus was grouped into genotype 1E. CONCLUSIONS: Our study reports the first phylogenetic analysis of the rubella virus extracted from the eye lens of a child with CRS in Indonesia. The detection of the rubella virus from eye lenses is remarkably promising. Our findings also emphasize the importance of molecular epidemiology in tracking the origin of rubella infection toward achieving virus eradication.

Organ-based tube current modulation and bismuth eye shielding in pediatric head computed tomography.

BACKGROUND: Exposure of the eye lens to ionizing radiation results in cataract. Several dose optimization techniques to protect the lens are available for computed tomography (CT). OBJECTIVE: The radiation dose to the eye lens, volume CT dose index (CTDIvol) and image quality of various methods of dose optimization were evaluated for pediatric head CT: automated tube current modulation (ATCM), automated tube voltage selection (ATVS), organ-based tube current modulation (OBTCM) and bismuth shielding. MATERIALS AND METHODS: An anthropomorphic phantom of a 5-year-old child was scanned with nine protocols: no dose optimization technique and then adding different dose optimization techniques alone and in combination. Dose to the eye, thyroid and breast were estimated using metal oxide semiconductor field effect transistor (MOSFET) dosimetry. CTDIvol, influence of timing of shield placement, image noise and attenuation values in 13 regions of interest of the head and subjective image quality were compared. RESULTS: The eye shield significantly reduced the eye lens dose when used alone, to a similar degree as when using all software-based techniques together. When used in combination with software-based techniques, the shield reduced the eye lens dose by up to 45% compared to the no dose optimization technique. Noise was significantly increased by the shield, most pronounced in the anterior portion of the eye. CONCLUSION: The combination of ATCM, ATVS, OBTCM and a bismuth shield, with the shield placed after acquiring the localizer image, should be considered to reduce the radiation dose to the eye lens in pediatric head CT.

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 99m Tc, 123 I, and 18 F 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 99m Tc and 123 I radionuclides. Measured dose equivalents of exposure significantly differed between the body and eye lens dosimeters with respect to 18 F. 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.

Current status of eye-lens dosimetry in Canada.

For occupational exposures in planned exposure situations International Commission on Radiological Protection (ICRP) publication 118 recommends an equivalent dose limit for the lens of the eye of 20 mSv yr-1averaged over five years with no single year exceeding 50 mSv. This constitutes a reduction from the previous limit of 150 mSv yr-1. The Canadian nuclear regulator, the Canadian Nuclear Safety Commission, responded to the ICRP recommendation by initiating amendments to theRadiation Protection Regulationsthrough a discussion paper which was published for comment by interested stakeholders in 2013. The revised equivalent dose limit of 50 mSv in a one-year dosimetry period for nuclear energy workers came into effect in January 2021. This paper presents the outcome of discussions with Canadian stakeholders in diverse fields of radiological work which focused on the implementation of the reduced occupational equivalent dose limit for the lens of the eye in their respective workplaces. These exchanges highlighted the existing practices for monitoring doses to the lens of the eye and identified current technological gaps. The exchanges also identified that, in many cases, the lens of the eye dose is anticipated to be well within the new dose limit despite some of the gaps in technology. The paper also presents the monitoring and eye-lens dose assessment solutions that are available based on different methods for eye-lens monitoring; presented together with criteria for their use.

An investigation into potential improvements in the design of lead glasses for protecting the eyes of interventional cardiologists.

The lens of the eye can be damaged by ionising radiation, so individuals whose eyes are exposed to radiation during their work may need to protect their eyes from exposure. Lead glasses are widely available, but there are questions about their efficiency in providing eye protection. In this study, Monte Carlo simulations are used to assess the efficiency of lead glasses in protecting the sensitive volume of the eye lens. Two designs currently available for interventional cardiologists are a wraparound (WA) style and ones with flat frontal lenses with side shielding. These designs were considered together with four modifications that would impact upon their efficiency: changing the lead equivalent thickness, adding lead to the frames, elongating the frontal lenses, and adding a closing shield to the bottom rim. For the eye closest to the source, standard models of lead glasses only decrease the radiation reaching the most sensitive region of the eye lens by 22% or less. Varying the lead thickness between 0.4 mm and 0.75 mm had little influence on the protection provided in the simulation of clinical use, neither did adding lead to the frames. Improved shielding was obtained by elongating the frontal lens, which could reduce radiation reaching the eye lens by up to 76%. Glasses with lenses that had a rim at the base, extending towards the face of the user, also provided better shielding than current models, decreasing the dose by up to 80%. In conclusion, elongating the frontal lens of lead glasses, especially of the WA design, could provide a three-fold increase in shielding efficiency and this is still valid for lenses with 0.4 mm lead equivalence.

Practical guidelines for personal monitoring and estimation of effective dose and dose to the lens of the eye in interventional procedures.

Estimation of effective dose and dose to the lens of the eye for workers involved in interventional procedures is challenging. The interventional procedures in question involve high doses and, due to this, workers need to wear protective garments. As a result, various methodologies have been developed to assess the effective dose and dose to the lens of the eye. In the present study, measurements from four European dosimetry services, over and under protective garments, have been collected and analysed in order to provide practical guidelines based on the routine use of personal dosemeters from staff in interventional workplaces. The advantages and limitations of using one or two dosemeters are discussed.

Uncertainties in occupational eye lens doses from dosimeters over the apron in interventional practices.

It is relevant to estimate the uncertainties in the measurement of eye lens doses from a personal dosimeter over the protective apron without using additional dosimetry near the eyes. Additional dosimetry for interventionists represents a difficulty for routine clinical practice. This study analyses the estimated eye doses from dosimeter values taken at chest level over the apron and their uncertainties. Measurements ofHp(0.07) using optically stimulated luminescence dosimeters located on the chest over the apron and on the glasses (in the inner and outer part of the protection) were taken from ten interventionalists in a university hospital, in the period 2018-2019 during standard clinical practice. For a total sample of 133 interventional procedures included in our study, the ratio between theHp(0.07) on the glasses (left-outer side) and on the chest over the apron had an average of 0.74, with quartiles of 0.47, 0.64, 0.88. Statistically significant differences were found among operators using the U-Mann-Whitney test. The average transmission factor for the glasses was 0.30, with quartiles of 0.21, 0.25, and 0.32. Different complexity in the procedures, in the quality of the scatter radiation and in the individual operational practices, involve a relevant dispersion in the results for lens dose estimations from the over apron dosimeter. Lens doses may be between a 64% and an 88% of the over apron dosimeter values (using median or 3rd quartile). The use of 88% may be a conservative approach.

On the operational quantity for eye lens neutron dosimetry considering ICRU 95 report.

For planned occupational exposure situations, the International Commission on Radiological Protection (ICRP) publication 118 recommends an equivalent dose limit for the lens of the eye of 20 mSv yr-1averaged over 5 yr with no single year exceeding 50 mSv. 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. As compliance with the eye-lens dose limit will be based on the summation of doses received from all types of radiation, applicable to a variety of workplaces, the contribution of neutrons to eye lens dose will be important where it contributes a significant fraction of the total dose to the eye lens. This work presents and discusses computed personal absorbed dose (Dlens/Φ), and personal dose equivalent (Hp(3)/Φ) as well as a newly proposed relative biological effectiveness (RBE)-weighted absorbed dose (RBE ×Dlens/Φ) conversion coefficients for the lens of the eye for neutron exposure at incident energies from thermal to ∼20 MeV. TheDlens/Φ coefficients were obtained from a simulation model developed for this study that contains the stylised eye model embedded in the adult UF-ORNL mathematical phantom. The modelling techniques used in these simulations were also used to calculateHp(3)/Φ for the International Commission on Radiation Units and Measurements (ICRU) slab and cylinder phantoms. All simulations carried out for this study utilised the Monte Carlo N-Particle (MCNP) series of codes. The results are compared with the related published data. The issue of compliance with the current equivalent dose limit for the lens of the eye is addressed from a neutron perspective considering the recent proposed redefinition of the operational quantities for external radiation exposure in ICRU report 95. The use of a radiation weighted absorbed dose (RBE ×Dlens, in Gy) is proposed for the tissue reactions in the eye-lens for neutron radiation as per the National Council on Radiation Protection and Measurements report 180, and in line with the recent review and revision of the System of Radiological Protection To Keeping the ICRP Recommendations Fit for Purpose, which states that RBE weighted dose should be used for high-Linear energy transfer (LET) radiations such as neutrons. This confirms the earlier statement in ICRP publication 92, paragraph 297 and reiterated in the Executive summary, paragraph (q) of ICRP publication 118. The proposed approach would provide an operational quantity consistent with the units of the new eye-lens dose limits without being overly conservative.

Radiation exposure to the lens of the eye for Japanese nuclear power plant workers.

In Japan, the radiation-dose limit for the lens of the eye was revised in April 2021. Consequently, for workers, the numerical values of the equivalent dose to the lens of the eye are equal to those of the effective dose. Radiation workers, radiation safety officers and licensees must comply with regulations related to radiation protection and optimize protection. The new guidelines on dose monitoring of the lens of the eye developed by the Japan Health Physics Society recommend for the dose to be estimated near the eye for accurate estimation, when the dose to the lens approaches or exceeds the management criteria. However, there is limited information regarding the non-uniform exposure of nuclear power plant workers. In this study, the dose equivalents of high-dose-rate workplaces and the personal doses of 88 workers were estimated at four Japanese commercial nuclear power plant sites (RWR: 3 units and BWR: 3 units) and the dose to the lens of the eye and the exposure situations of the workers were analyzed.