Annual Eye Lens Dose Research Articles

Dose rate conversion coefficients for ocular contamination in nuclear medicine: A Monte Carlo simulation with experimental validation.

Since 2011, the International Commission on Radiological Protection (ICRP) has recommended an annual eye lens dose limit of 20 mSv for radiation workers, averaged over 5 years, with no year exceeding 50 mSv. However, limited research has been conducted on dose rate conversion coefficients (DCCs) for direct contamination of the eye. This study aimed to accurately determine DCCs for the eye lens and cornea for ocular contamination with radionuclides used in nuclear medicine. DCCs for 37 radionuclides used in nuclear medicine were determined using two different methods. Method 1 involved conducting Monte Carlo (MC) simulations of an ICRU cylinder to determine the absorbed dose at a depth of 3mm resulting from a point source. The accuracy of this simulation approach was validated by experimental thermoluminescent dosimeter (TLD) measurements for 18F, 68Ga, 99mTc, and 177Lu. In method 2, average DCCs were calculated for the eye lens (complete and radiosensitive parts) and the cornea for both a point source and thin surface contamination centered on the cornea using MC simulations on the adult mesh-type reference computational phantom of the eye from the ICRP (MRCP). DCCs determined from TLD measurements showed excellent agreement (deviations: +1.4%, +4.7%, -3.1%, and -2.5% for 18F, 68Ga, 99mTc, and 177Lu, respectively) compared to MC simulations of the experimental set-up. For the 37 radionuclides, DCCs of the complete eye-lens for a point source ranged from 2.53×10-7 to 4.15×10-2 mGy MBq-1 s-1 for the adult MRCPs, being substantially smaller compared to DCCs determined via MC simulations of a ICRU cylinder. In general, point source and surface contamination showed comparable DCCs for the eye lens. Radionuclides emitting low-energy beta radiation or conversion electrons (e.g., 177Lu, 99mTc) showed low DCCs as the radiation does not penetrate to the depth of the eye lens, while radionuclides emitting high-energy beta radiation (e.g., 90Y) showed high DCCs. Overall, DCCs for the radiosensitive part of the eye lens were larger (up to a factor of 3) compared to the complete eye lens. DCCs for the cornea were larger than for the eye lens with a factor that strongly depended on the emitted radiation type. Especially alpha emitters (e.g., 211At, 223Ra) showed high DCCs for the cornea because of the short range of alpha radiation, leading to local maxima in the cornea and not reaching the eye lens. DCCs at a depth of 3mm in an ICRU cylinder and adult MRCP DCCs for both the complete and sensitive parts of the eye lens and cornea were determined for 37 radionuclides having applications in nuclear medicine. These DCCs are highly useful in radiation safety assessments and radiation dose calculations in ocular contamination incidents.

Eye lens dose assessment in interventional cardiology

Introduction: Medical professionals performing fluoroscopy guided interventional procedures in cardiology are exposed to a risk of radiation induced cataract, especially if the eye lens dose exceeds the annual dose limit of 20 mSv. Aim: The aim of the current study is to measure the eye lens exposure in three interventional cardiology departments, to analyze the relationship between patient dose and eye lens dose and to study the effectiveness of lead goggles without side protection. Material and methods: Measurements were performed in three departments with participation of 4 interventional cardiologists and 6 nurses. The exposure of the eye lens was measured with EYE-DTM (Radcard) passive dosimeters. Results: For nurses the annual eye lens dose varied from 1.6 mSv to 4.3 mSv. For the interventional cardiologists the results were between 3.2 mSv and 31.4 mSv. The dose reduction factor of the studied safety goggles without side protection is 1 and 1.1. Conclusions: There is a risk of exceeding the annual exposure limit of 20 mSv among interventional cardiologists The eye lens exposure depends on the workload and the clinical complexity of the procedures, as well as on the use of radiation protection devices. Due to the specifics of the procedures, the use of goggles with side protection is recommended. The eye lens dose for nurses is lower than the annual limit, which can be explained with the larger distance between the patient and the nurses and partial shielding by the main operator. Lead glasses without side shielding are not recommended because the exposure occurs from the side.

Assessment of Occupational Exposure to Eye Lens Dosimetry for Interventional Radiology Workers in China during 2017-2019.

The eye lens is a sensitive tissue to ionizing radiation and recently has been recognized as more radiosensitive than previously considered. The International Commission on Radiological Protection (ICRP) has recommended a considerable reduction in the equivalent dose limit of eye lens from 150 mSv y -1 to 20 mSv y -1 , averaged over a defined period of 5 y. In this paper, the eye lens dose of interventional radiology workers in China during 2017-2019 is analyzed to understand the current status of eye lens occupational exposure and to provide decision-making suggestions for health supervision departments using data obtained from the National Radiological Health Information Platform in China. A total of 3,026 eye lens dose records of interventional radiology workers were collected. The average annual eye lens dose (AAELD) for interventional radiology workers ranged from 1.07 to 1.51 mSv during 2017-2019 and was 1.44 mSv for all monitored interventional radiology workers, with 2,973 records (98.2%) lower than the public limit of 15 mSv and 33 records (1.1%) exceeding the newly revised occupational eye lens dose limit of 20 mSv y -1 . During the period of 2017-2019, the AAELDs of interventional radiologists (1.61 mSv) and of interventional cardiologists (1.59 mSv) were significantly higher than that of other interventional workers (0.62 mSv); the AAELD of doctors (1.50 mSv) was significantly higher than that of nurses (1.01 mSv); the AAELD of western China (2.00 mSv) was significantly higher than that of eastern (1.11 mSv) and central China (1.27 mSv); and the AAELD of males (1.59 mSv) was significantly higher than that of females (0.84 mSv). The eye lens dose of interventional radiology workers meets the Chinese standard limit of 150 mSv y -1 , while some cases exceed the one recommended by ICRP. The study shows that the interventional radiology workers' eye lens dosimetry data complied with the existing Chinese eye lens dose limits. However, education, training, and supervision of radiation protection also should be strengthened continuously for interventional radiology workers, especially for the interventional radiologists and interventional cardiologists. Significant attention should be paid to the radiation protection of underdeveloped regions in China in future works.

Occupational exposure evaluation and radiation protection optimization in coronary angiography procedures

Introduction The large number of coronary angiography procedures and inappropriate use of radiation protection equipment constitute a high occupational radiological risk for cardiologists generated by chronic exposure to low doses of radiation, in particular for parts of the body unprotected such as eyes and head. Materials and methods The eye lens dose was evaluated for seven cardiologists performing coronary angiography procedures over three months. The equivalent dose to the eye lens, Hp (3), was calculated from the equivalent dose to the skin, Hp (0.07), measured by an active dosimeter worn at the cardiologist's neck. The annual eye lens dose and the brain cancer risk were estimated. The correlation between the eye lens dose and the procedure parameters including the dose-area product, the fluoroscopy duration, and the number of fluography images was studied. Phantom-based measurements by a babyline 81 allowed to separate the contribution of the two modes, fluoroscopy and fluorography to the total dose and therefore, to propose another method of continuous lens dose monitoring. Finally, an optimization study was performed to reduce the eye lens dose and consequently the brain cancer risk. Results Two cardiologists have exceeded the annual lens dose limit (28mSv, 22mSv). A good correlation was found between Hp (3) and the fluoroscopy duration (R² = 0.89). The measurements showed that most of the exposure was in fluoroscopic mode (89%). The optimization study reduced the annual eye lens dose to 2.9 mSv and 2.3 mSv, respectively, for these two cardiologists. Thus, this decreased the brain cancer risk by a factor of ten. Conclusion The high eye lens annual doses recorded in this study are due to non-compliance with radiation protection rules. The proposed optimization process reduced the eye lens dose and the risk of brain cancer, at least, by a factor of ten.

A study on the use of modified extremity dosemeters for the measurement of Hp(3,α)

In most jurisdictions, the presently imposed annual eye-lens dose limits are 150 mSv for occupational and 15 mSv for the general public. These limits were based on a 1991 recommendations of the International Commission on Radiological Protection (ICRP), in its publication 60, and they were reiterated in 2007 in the ICRP publication 103. However, recent re-analyses of available epidemiological data appear to indicate that the onset of cataracts may occur at doses as low as 0.5 Gy. This led the ICRP to recommend, in the 2012 publication 118, the lowering of the annual dose limits to the lens of the eye of 20 mSv, averaged over 5 years, with no dose exceeding 50 mSv for any one year. The annual eye-lens dose limit for the general public remained at 15 mSv.The reduction of the eye-lens annual dose limit by nearly one order of magnitude led to large research efforts, including in the area of personal dose monitoring. This paper presents the results of a performance study of Hp(0.07) dosemeters which were modified to allow the measurement of Hp(3,α). The dosemeters were provided by four Canadian nuclear facilities, and one United States medical institution. Hence, five different technologies were tested for a variety of photon qualities and one standard beta field. The motivation to use Hp(0.07) dosemeters was to show that it is possible to leverage dosimetry technologies already in place at various institutions. It was found that, using a low atomic number filter of nominally 300 mg cm−2 in mass thickness, most of the dosemeters considered would provide acceptable performances for the measurement of Hp(3,α).

Radiation Exposure of Surgical Team During Endourological Procedures: International Atomic Energy Agency-South-Eastern European Group for Urolithiasis Research Study.

Introduction: Fluoroscopy-guided endourology procedures require proper radiation protection to minimize radiation risk. This multicenter study aimed at investigating radiation protection practice and related radiation exposure of operating team members. Materials and Methods: Six endourology centers from the South-Eastern European Group for Urolithiasis Research answered questionnaires and collected data of 315 procedures performed within a 3-months period, with simultaneous measurement of dose to staff and dose area product (DAP) to patient. A pair of calibrated personal dosimeters, one for body and one for eye-lens dose, was worn by all key staff members. Dosimeters were centrally calibrated, measured, and analyzed. Results: The annual workload ranged from 173 to 865 procedures per center. Practice of personal dose monitoring and use of radiation protection shielding was found to be inconsistent. Lead aprons and thyroid collars were used by all, whereas protective eyewear was used in only half of centers. Due to the regular use of protective aprons, the whole-body dose of all 44 monitored staff members was safely below the regulatory dose limits. Eye-lens dose of 17 (14 urologists and 3 assisting staff) was above the dosimeter detection level, and dose per procedure varied from <10 to 63 μSv. The highest annual eye-lens dose of 13.5 mSv was found for the surgeon in the busiest department by using an over-the-couch X-ray tube without a ceiling suspended screen. Working closer to patient body with no protection resulted in a six-time higher eye-lens dose per DAP for a surgeon compared with others in the same center. Lower eye-dose per procedure was associated with lower DAP to patient and with the use of an under-the-couch tube, lower fluoroscopy pulse rate, collimation, fluoroscopy time, and acquired images. Conclusions: The study results call for the need to establish standard protocols about use of fluoroscopy during endourology procedures and to increase radiation protection knowledge and awareness of surgical staff.

Eye Lens Dosimetry in Interventional Radiology: Assessment With Dedicated Hp(3) Dosimeters.

To quantify eye lens dose in interventional radiology and assess whether neck dosimeter is a good surrogate to evaluate eye lens dosimetry. Radiation exposure was prospectively measured in 9 interventional radiologists between May and October 2017. Standard Hp(0,07) thermoluminescent dosimeters (TLDs) were worn at the neck outside the lead apron, and 2 dedicated eye lens Hp(3) TLDs were placed just above the eyes, one midline and another at the outer edge of the left eye. Correlations between eye lens and neck TLD doses were assessed with Pearson coefficient, and linear regression was used to predict eye lens dose from neck TLD values. Eye lens dose without eye protection was 0.18 ± 0.11 (mean ± standard deviation; 0.08-0.41) mSv per workday and 35.3 ± 6.6 mSv (16.3-82.9) annually (200 workdays/year). Five (56%) radiologists exceeded the 20 mSv annual eye lens dose limit. Eye lens doses from left and central TLDs were 12.46 ± 3.02 and 9.29 ± 3.38 mSv, respectively (P = .027). Mean eye lens (left and central) and neck TLD doses were 10.87 ± 2.67 and 16.56 ± 5.67 mSv, respectively (P = .008). Pearson correlation coefficient between both eye lens TLD and between mean eye lens TLD and neck TLD doses were 0.91 and 0.92, respectively. Average of eye lens dose was 0.0179 + (0.5971 × neck dose). Full-time interventional radiologists are likely to suffer from deterministic radiation effects to the eye lens, especially on the left side. Neck TLD significantly overestimates eye lens dose. However, eye lens doses are highly correlated with neck doses and may be predicted from the neck TLD values.

ELECTRON EYE-LENS OPERATIONAL DOSE COEFFICIENTS.

In 2012, the International Commission on Radiological Protection issued a recommendation for a reduced annual eye-lens dose limit in the face of mounting evidence of the risk of cataract induction. This led to worldwide research efforts in various areas including the dose simulation in realistic eye-models, the production of dosimeters and the elaboration of protection and operation fluence to eye-lens dose coefficients. In this last case, much efforts have been expanded with regards to photon operational coefficients for Hp (3) but much less for electron radiation. In this work, Hp (3) coefficients for electrons are presented following simulations using MCNP and compared to those that are available in the literature. It is found that, at energies of 1MeV and less, Hp (3) coefficients depend strongly on the selected electron transport options and on the dose tally volume. The effect of these differences is demonstrated for two beta emitters.

Assessment of the Annual Eye Lens Dose for Cardiologists During Interventional Procedures Using Anthropomorphic Phantoms and mEyeDose_X Tool

ObjectivesIn this study, eye lens dose measurements were performed using two anthropomorphic phantoms simulating the cardiologist and patient during interventional procedures. BackgroundInterventional procedures known as areas with high potential risk and the cardiologists can receive relatively high doses to their eyes. MethodsThis study was comprised of both phantom and computer simulations. Thermoluminescent dosimeters (TLDs) and mEyeDose_X tool were used to measure and calculate eye lens doses for the cardiologist. 144 TLDs measurements were performed using cardiac protocol for three angiographic projections: anterior-posterior (AP), left anterior oblique 90° (LAO90) and left anterior oblique 45° with cranial 30° (spider) angulations. All cine and fluoroscopy modes including the projections used in this study performed with and without protection tools. ResultsThe annual equivalent doses with protective tools using mEyeDose_X were found to be 1.831 and 1.424 mSv/year, whereas the values using phantom were found to be 2.204 and 1.802 mSv/year for the lens of lift and right eye respectively. ConclusionThe annual doses reported in this study are almost comparable to other studies performed on interventional cardiology (IC) procedures. The highest dose rate in the lens was 20.21 ± 0.015 mSv/h without protective tools in cine mode for spider projection. Cardiologists may therefore easily exceed the lens dose limit if protective tools are not used.

New Eye Lens Dose Limit: Status of Knowledge in Campania Hospitals.

The International Commission on Radiation Protection (ICRP) in 2011 recommended the lowering of the annual eye lens dose limit from 150 mSv/year to 20 mSv/year in order to reduce the risk of X-ray-induced lens opacity in medical staff. The purpose of this study was to assess the status of knowledge of the new eye lens dose limit and of the radioprotection culture among operators. To this end, a questionnaire was administered to physicians, X-ray technicians, and nurses working in five hospitals of the Campania region, Italy. A total of 64 questionnaires were collected in the hospital departments in which procedures involving ionizing radiation were routinely performed. The data analyzed yielded the following results: 12 operators affirmed to know the new eye lens dose limit, 53 operators routinely wore lead aprons, and 23 operators used lead glasses. Four workers performed eye lens dosimetry through specific dosimeters. A significant lack of knowledge of the reduced eye lens dose limit suggests the need to implement radioprotection-training programs aimed at raising awareness about the importance of health care in the workplace and at reducing the risk of radio-induced effects to the eye lens.

Surgeon eye lens dose monitoring in catheterization lab: A multi-center survey: Invited for ECMP 2018 Focus Issue

PurposeTo perform a multi-centre survey on the eye lens equivalent dose absorbed by primary interventionalist during catheterization procedures, using a personal dosimeter placed close to the eye lens. Methods15 different cardiologists working in 3 different centers, for a total of 5 operating rooms were enrolled. All of them were provided with a single thermoluminescent dosimeter positioned on the inner side of the temples of eyeglasses. The dose monitoring, performed on a two-months basis, started in 2016 and is still running. All dose measurements were performed by a ISO 17025 standard accredited dosimetry service thus providing certified uncertainties as well. Correlation of eye lens and wrist dose with KAP was also investigated. ResultsA total number of 101 eye lens measurements were performed. Annual eye lens dose estimation was obtained for all 15 surgeons (mean, mode, range, standard deviation: 10.8, 8, 4.9–27.3, 5.6 mSv, respectively). Uncertainties on annual eye lens dose estimations ranged between 10% and 20%. No significant correlation was found between eye lens dose and KAP. ConclusionsCardiologists involved in catheterization procedures may receive annual eye lens doses close to the ICRP 118 dose limit and thus individual monitoring with a dedicated dosimeter should be carried out. Uncertainty assessment play a relevant role in eye lens equivalent dose estimation to ensure not to exceed dose limit.

A PHANTOM STUDY TO DETERMINE THE OPTIMAL PLACEMENT OF EYE DOSEMETERS ON INTERVENTIONAL CARDIOLOGY STAFF.

The International Commission on Radiological Protection has substantially reduced the recommended maximum annual eye lens dose for workers. Use of a dedicated eye dosemeter is one method for accurate dose monitoring. The main aim of this study was to yield recommendations for optimal placement of eye dosemeters to estimate the eye dose to interventional cardiology physicians and nurses. A phantom measurement was conducted to simulate typical interventional cardiology procedures. Considering eight X-ray tube angulations, the left side of the head position provide good estimates for physician, and the forehead position provide good estimates for nurse.

Studies on pelletised lithium magnesium borate TL material for eye lens dosimetry

Recent epidemiological studies in various cohorts confirm that radiation induced cataract may occur at a threshold dose as low as 0.5 Gy. ICRP has recognised the higher radiosensitivity of eye lens and recommended to reduce annual eye lens dose limit from 150 to 20 mSv. Present dosimetry for eye lens is largely based on LiF based dosimeters. The present work is an attempt towards using near tissue equivalent lithium borate material namely lithium magnesium borate doped with terbium (LMB:Tb) in eye lens dosimetry. The material in powder form was synthesised using solid state sintering method and pelletised using poly tetra fluoro ethylene (PTFE) as binding agent. It was observed that 130 mg of 1 mm thick LMB:Tb pellet bound with PTFE showed stable glow curve structure and attractive dosimetric features in terms of sensitivity, fading, linearity, reusability etc. A proposal of 1.5 mm Teflon encapsulation corresponding to tissue equivalent thickness of 3 mm was put forward for an ideal dosimeter for the measurement in terms of Hp(3). Energy and angular dependence studies based on FLUKA simulations suggest a flat response for the prototype design. In addition to PTFE, various tissue equivalent encapsulations such as polyimide, polyamide 6 and PMMA were also evaluated using FLUKA code.

RADIATION DOSES TO ANAESTHETISTS DURING PROSTATIC ARTERY EMBOLIZATION INTERVENTIONAL PROCEDURES.

The objective of this study was to assess the radiation doses received by anaesthetists from prostatic artery embolization (PAE) procedures. Ten PAE procedures conducted in a reference hospital in the city of Recife, Brazil were investigated. Occupational dosimetry was performed using thermoluminescent dosemeters which were located next to the eyes, close to the thyroid (over the shielding), on the thorax (under the apron), on the wrist and on the feet of the physician's body. The results showed that the anaesthetist's feet received the highest doses followed by the eyes and the hands. In some complex PAE procedures the doses received by anaesthetists on the lens of the eyes and the effective dose were higher than those received by the main operator due to the anaesthetist's close position to the patient's table and the use of oblique projections. The personal dose equivalent Hp(3) per procedure for the anaesthetist's right eyebrow ranged from 20.2 μSv to 568.3 μSv. This result shows that anaesthetists assisting PAE procedures can exceeds the annual eye lens dose limit of 20 mSv recommended by the ICRP with only one procedure per week if radiation protection measures are not implemented during procedures.

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

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

P111] Eye lens exposure to ionising radiation in personnel of a nuclear medicine department.

Purpose The aim of the study was to estimate equivalent doses in the eye lens in employees of the Nuclear Medicine Department of the Pomeranian Medical University (PMU) in Szczecin. The European Directive 2013/59 limited the annual eye lens dose to 20 mSv, which stimulated the need to estimate equivalent doses in clinical laboratories using ionising radiation in diagnostic and therapeutic procedures. Methods 10 employees (2 doctors, 5 technicians and 3 nurses) used personal eye dosimeters for a total time of 3 months. Dosimeters were supplied by and analysed for their indications by the Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN) in Krakow. Technicians and nurses in the Nuclear Medicine Department PMU prepared radioisotopes for patients in a hot laboratory in a rotation system. Results Personnel preparing and administering radiopharmaceuticals with iodine I-131 to patients (2 doctors and 1 technician) received an average equivalent dose of 11.63 μ Sv per GBq of activity. Technicians preparing radiopharmaceuticals labelled with technetium Tc99m were exposed to an equivalent dose of 0.002 μ Sv/GBq. Nurses preparing and administering radiopharmaceuticals labelled with technetium Tc99m were exposed on average to an equivalent dose of 0.006 μ Sv/GBq. Doses registered during 3-month personal eye dosimetry ranged from max. 0.42 mSv to min. 0.20 mSv. The estimated maximum annual eye lens dose per employee in the NMD department was not higher than 2.5 mSv. Conclusions Personnel of the Nuclear Medicine Department PMU do not require personal eye dose monitoring while performing their routine duties. Personnel preparing and administering radiopharmaceuticals to patients may use leaded eyewear for protection.

P101] Are occupational doses of medical staff incurred in interventional procedures related to patient exposure

Purpose We wished to evaluate the range of occupational exposures of medical personnel accrued within interventional cardiology procedures. The aim of this was also to determine if, and to what extent, actual exposure of the medical personnel, operators in particular, would exceed the recently proposed annual eye lens dose limits. We also sought to establish possible correlations between values of measured individual personnel exposures with patient PKA values and finally between different measured occupational dose quantities to determine whether the accrued eye-lens exposures could be correlated with finger or whole-body exposures. Methods Patient kerma-area product PKA, cumulative kerma in the air KIRP, fluoroscopic time t, personal dose equivalent (in terms of Hp(10), Hp(0.07) and Hp(3)) for most common interventional cardiology procedures were measured. PKA and KIRP measurements were used for patients and thermoluminescent dosimetry for the personnel. Dosemeters for personal doses measurements containing MCP-N (LiF: Mg, Cu, P) type thermoluminescence detectors (TLDs), were read out at the Institute of Nuclear Physics Polish Academy of Science (IFJ PAN) dosimetry service. Results The mean values of total kerma-area product (PKA) were 22.7 (7.3–50.9) Gy · cm2 for coronary angiography (CA) and 43.1 (3.2–86.4) Gy · cm2 for percutaneous coronary intervention (PCI). In general, doses received by the staff performing PCI procedures were found to be systematically higher than those after CA procedures, by some 30% or more. Within the medical team, operators always received the highest doses, followed by nurses and technicians. Maximum eye lens doses, skin doses and whole body doses were 165 μ Sv, 962 μ Sv and 30 μ Sv per procedure, respectively. Annual eye lens doses received by the operators, especially in PCI procedures, may well exceed the value of the recently recommended annual dose limit of 20 mSv and should be monitored. No meaningful correlation could be established between occupational doses and patient exposure, however some degree of correlation was observed between values of dose to the eye lens and whole body dose. Conclusions The findings of this study clearly indicate the necessity of radiation protection measures in interventional cardiology. Our results show that personal doses per procedure vary markedly.

OA219] Eye lens dose monitoring in interventional radiology

Purpose The new limit established for the eye lens has increased the interest for lens dose monitoring. This work aims to: • Estimate the lens doses for the staff of the Interventional Radiology department at Vicenza Hospital; • Establish relationships between the eye lens dose and the dose measured with personal dosimeters; • Verify the feasibility of using commercial Hp(3) dosimeters; • Investigate a possible relationships between the lens dose and the air Kerma–Area product (KAP). Methods Measurements have been carried out both in vivo (4 radiologists and 5 nurses) during 87 different abdominal procedures performed with a Multistar (Siemens, Germany), and in anthropomorphic-phantom using a single 180° projection at 59 kV and 125 kV. The evaluations included: Hp(10) and Hp(0.07) measurements performed at the chest level over the apron (Hp,chest); Hp(0.07) measurements performed on the external and inferior sides of the left eye using Hp(0.07) detectors specifically modified for this purpose (Hp,eye); Hp(3) performed with dedicated dosimeters positioned over the left arm of the protective glasses (Hp,glasses). Additional Hp(0.07) measurement were performed directly at the phantom eye lens level (Hp,lens). Transmission factors of the lead glasses were also estimated. Results The main results are: • Hp,eye/Hp,chest: 0.6 ± 0.6 (in vivo); 0.4 ± 0.2 (in phantom) • Hp,eye/Hp,glasses: 1.1 ± 1.2 (in vivo); 0.5 ± 0.5 (in phantom) • Hp,chest/KAP: 2.5 ± 3.6 μSv Gy−1 cm−2 (in vivo); 5.8 ± 2.0 μSv Gy−1 cm−2 (in phantom) In vivo and phantom results are consistent within the large uncertainties due to low dose levels and irradiations variability. Therefore phantom measurements allowed estimating Hp,lens/Hp,eye in 0.20 when glasses are used. Using this factor, the projected annual eye lens dose, considering the workload, resulted 4 mSv for the personnel using lead glasses and 15 mSv for the others. The ratio between eye lens dose with and without glasses is higher than expected based on transmission factors. Conclusions According to our results, traditional monitoring methods with proper corrections could be used to estimate lens dose in place of expensive Hp(3) dosimeters. Missing glasses-skin contact could explain eye doses higher than expected.

Risk of Radiation-Induced Cataracts: Investigation of Radiation Exposure to the Eye Lens During Endourologic Procedures.

Due to new radiobiologic data, the International Commission on Radiological Protection recommends a dose limit of 20 mSv per year to the eye lens. Therefore, the IAEA International Basic Safety Standard and the European council directive 2013/59/EURATOM require a reduction of the annual dose limit from 150 to 20 mSv. Urologists are exposed to an elevated radiation exposure in the head region during fluoroscopic interventions, due to the commonly used overtable X-ray tubes and the rarely used radiation protection for the head. Aim of the study was to analyze real radiation exposure to the eye lens of the urologist during various interventions, during which the patient is in the lithotomy position. The partial body doses (forehead and apron collar) of the urologists and surgical staff were measured over a period of 2 months. 95 interventions were performed on Uroskop Omnia Max workplaces (Siemens Healthineers, Erlangen, Germany). Interventions were class-divided in less (stage I) and more complex (stage II) interventions. Two dosimeter-types were applied, well-calibrated electronic personal dosimeter Mk2 and self-calibrated thermoluminescent dosimeter-100H (both Thermo Fisher Scientific, Waltham, MA). The radiation exposure parameters were documented using the dose area product (DAP) and the fluoroscopy time. The correlation between DAP and the apron dose of the urologist was in average 0.07 μSv per 1 μGym2. The more experienced urologists yielded a mean DAP of 166 μGym2 for stage I and 415 μGym2 for stage II procedures. The interventionist was exposed with 10 μSv in mean outside the lead apron collar. The mean dose value of the eye lenses per intervention was ascertained to 20 μSv (mean DAP: 233 μGym2). The study setup allows a differentiated and time-resolved measurement of the radiation exposure, which was found heterogeneous depending on intervention and surgeon. In this setting, ∼1000 interventions can be performed until the annual eye lens dose limit is achieved.

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

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