Personal Dosimeters Research Articles

Characteristic testing (performance) of CaSO4: Dy thermoluminescent ring dosimeter according to the ISO 12794:2000

CaSO4: Dy thermoluminescent dosimeters (TLD) disc known as TLD-900 is widely used for personal dosimetry purposes. An optimum response dosimeter procedure can be determined from its characteristics. The equivalent dose limitation for hands and feet or skin Hp (0.07) of 500 mSv/year. Therefore, we need a device to measure the radiation dose to optimize the safety of radiation workers so do not exceed the limit detection. The research objective is to produce accurate dosimeters by testing the characteristics of personal dosimeters according to ISO 12794: 2000. Tests of 129 dosimeters were tested with dosage variations of 0.3, 0.5, 1, 3, and 5 mSv in the 90Sr beta, gamma 137Cs, and x-ray voltage 20-100 kV in Secondary Standard Dosimeter Laboratory (SSDL). The results of tests obtained the dosimeter’s dependence on angle variations is relatively small and has a high energy dependency. Obtaining a dosimeter limit for the detection of extremities for beta and photon radiation less than 1 mSv with the lowest sensitivity being at 80 keV of 24 µSv. The dosimeter response to extremity is good, evidenced by the reading values within the trumpet curve range set by the IAEA and EURADOS.

Re-Evaluation of Chromium Doped Alumina for Dosimetric Applications

Abstract Many medical examinations involve ionizing radiation. Although the range of available dosimeters is rather wide, their linearity and chemical stability are limited. Recently, there has been a growing interest in new, improved dosimetric materials for emerging applications in medicine and other fields, such as sterilisation of consumer goods and medical instruments, irradiation of seeds, chemical agents and others. One of the classical dosimeters is carbon-doped alumina (Al2O3:C) – a well-established and widely used material for personal and industrial dosimeter with a range of great properties, such as high sensitivity, wide linearity range and relative ease of production and handling. However, the demand for reliable dosimeters in a high-dose range is still only partially fulfilled, and alumina doped with chromium ions (Al2O3:Cr) can be a promising candidate. In this study, we explored alumina doped with chromium porous microparticles synthesized with a sol-gel method as a possible high dose dosimeter and evaluated its thermostimulated luminescence signal, dose response with two irradiation sources and measured long-time fading. It was found that although the TSL signal was quite complex (consisting of two main peaks above room temperature) and the long-term fading was significant (around 50 % in the span of 30 days), with sufficient optimisation the material could be used as a high-dose dosimeter for X-ray and beta irradiation. Wide high dose linearity range, physical and chemical characteristics, as well as low production costs and ease of synthesis make chromium (III) doped alumina a compelling candidate for applicability in various medical and industry fields.

Determination of the average daily natural background dose for individual monitoring of occupationally exposed workers in Switzerland

The average daily natural background dose was computed with a statistical approach from the dose records of personal dosemeters worn by professionally exposed workers in Switzerland. The values ranged between 1.3–3.0 μSv/day depending on the geographic location of the customers site. The highest values were found in the Lepontine Alps, the lowest in the Swiss Plateau. The results from measurements with control dosemeters at 31 customer sites were in agreement with the computed values. The geographic variation in the natural background and an inaccurate correction are likely to give rise to differences in dose records by up to 0.1 mSv/month. For quarterly surveillance periods up to 3% of the dose records are expected to be false positives or negatives.

Challenges in Occupational Dosimetry for Interventional Radiologists.

This review presents the challenges met by interventional radiologists in occupational dosimetry. The issues mentioned are derived from the recommendations of the International Commission on Radiological Protection, the CIRSE guidelines on "Occupational radiation protection in interventional radiology" and the requirements of the European directive on Basic Safety Standards. The criteria for a proper use of personal dosimeters and the need to introduce optimization actions in some cases are set out in this review. The pros and cons of the electronic real-time dosimeters are outlined and the potential pitfalls associated with the use of personal dosimeters summarized. The electronic dosimeters, together with the appropriate software, allow an active optimization of the interventional procedures.

Uso de radiaciones ionizantes en estudios de diagnóstico en una institución de salud de Ecuador

Objectives: The objective of this study was to evaluate the knowledge of professionals working in the radiology area of a public hospital in the city of Portoviejo, province of Manabí, Ecuador, on the application of ionizing radiation in diagnostic studies and their involvement in the use of protective measures. Methods: A questionnaire with closed questions was applied on the protection measures adopted by practitioners and the radiation doses they apply to patients, among others, to all occupationally exposed workers of the radiology service of the mentioned hospital. Results: The professionals surveyed show a moderate knowledge about the application of ionizing radiation, regardless of their years of experience and profession. Due to the type of radiological application, professionals only use shielding as a protection measure, but not personal dosimeters during operation with X-ray equipment. Conclusions: Professionals have received similar and adequate training; however, radiation update courses are required, particularly concerning radiation protection.

The Method for Estimation of Radiation Dose of Eye Lens Covered by Radiation Protection Glasses Using Personal Dosimeter for Trunk of the Body and X-ray Shielding Material

Radiation protection glasses is a useful tool for dose reduction of eye lens. However, the method to evaluate the dose of eye lens, which is covered with radiation protection glasses in actual radiation management situation, has not been established. We invented the easy-to-use procedure to estimate the dose of eye lens inside of radiation protection glasses for occupationally exposed person using an X-ray shielding material and an additional personal dosimeter for trunk of the body. The objective of this study was to evaluate the feasibility of the new method. The radiation field in interventional radiology (IR) was reconstructed. A personal dosimeter was set to the eye position and neck position of medical staff phantom. Each dosimeter was covered by radiation protection glasses or X-ray shielding material, and the 1 cm or 70 mm dose equivalent quantity in the neck position was compared to the 3 mm dose equivalent quantity in the eye position. The dose equivalent quantity measured inside of X-ray shielding material in the neck position was similar to that of inside radiation protection glasses. Thus, the X-ray attenuation by radiation protection glasses was able to be simulated using the X-ray shielding material. It was suggested that the dose of eye lens inside of radiation protection glasses could be easily estimated by covering the conventional personal dosimeter for trunk of the body with the X-ray shielding material.

Personal Dosimetry of Microwave Electromagnetic Radiation. Long-Term Experiments with a “MERA” Device

In this paper, we present the measurement results of the dynamics of the level of electromagnetic microwave radiation obtained using “MERA” personal dosimeters developed at the Kotelnikov Institute of Radioengineering and Electronics, Russian Academy of Sciences. The measurements were performed under various conditions: in Russia and foreign countries, in megacities and resort areas, day and night, and in public transport and airplanes. The data obtained based on direct long-term measurements allows assessing the real electromagnetic microwave load exerted by modern means of mobile communications on the environment surrounding a person.

Understanding the Basis of Radiation Protection for Endovascular Procedures: Occupational and Patients

IntroductionSome concepts of radiation protection are not well understood and must be refreshed periodically. The basic knowledge that a vascular surgeon must have about radiation protection for patients and staff is summarised.ReportDiagnostic reference levels are a form of investigation into the medical exposure of patients during diagnostic and endovascular procedures that help to optimise them. Radiological quantities such as dose area product, also known as kerma area product and cumulative dose, are the most relevant to the patient. Equivalent dose, in mSv, determines the dose limits for staff. The effective dose (related to absorbed dose), also in mSv, represents the global risk of cancer and hereditary effects. For patient protection, the most important factors are fluoroscopy time, collimation, magnification, keeping the patient as near as possible to the image detector and as far as possible away from the tube, and trying to work in fluoroscope mode. Regarding occupational protection, distance, shielding, and dosimetry are the most important.DiscussionWith the increased use of endovascular procedures, radiation protection is an issue that has grown in importance. Radiation protection is based on three principles: justification; optimisation; and dose limits. Every action focused on reducing a patient's radiation dose will also reduce the dose to staff. Basic principles such as “the further away the better”, “always use a lead apron, thyroid protector, and lead glasses”, and “do not forget to wear personal dosimeters” must be remembered at all times.

MAPPING OF WORKPLACE RADIATION FIELDS IN DIAGNOSTIC RADIOLOGY FACILITIES USING PERSONNEL MONITORING TLD BADGES.

The radiation protection programme is aimed at safe usage of radiation at workplace, ensuring minimum possible dose to radiation workers, patients and members of the public. Verification of the adequacy of protective measures in actual workplace is important, especially for diagnostic radiology facilities, as a substantial number of suspected overexposures are reported from these facilities. To address this issue, a study was conducted for mapping workplace radiation field at various locations in nine Diagnostic Radiology Facilities of two hospitals in India. The cumulative doses were measured for a period of 1-3months, using personnel monitoring TLD badges. The dosemeters were placed at positions representative of two exposure situations: (1) probable locations of workers during procedures, leading to genuine exposure and (2) inappropriate storage locations of personal dosemeters at user end for probing claims of nongenuine exposures. The results indicate that the measured doses at locations (1) were just a fraction of the permissible dose, provided all safety practices are adhered to. However, the measured doses at certain locations (2) exceeded the investigation levels and indicate that any inadvertent storage of the dosemeters at such locations could lead to reporting of the overexposure from these radiology facilities. The outcome of the study will be useful for the investigation of such exposures and better understanding of the readout patterns of TLD badges in radiology workplaces.

APPLICABILITY OF A COMMERCIALLY AVAILABLE ACTIVE EXTREMITY DOSE-RATE METER TO EYE LENS DOSE MONITORING.

A commercially available active extremity dosemeter is a promising candidate for medical staff aid individual monitoring of the eye lens. We investigated the applicability of the newly developed active extremity dosemeter, which uses a low-energy photon probe, to eye lens dose monitoring by performing a complete characterization of the dosemeters. Performance tests revealed that the active extremity dosemeter would overestimate personal dose equivalent, Hp(3), when the probe is worn close to the lens of the eye of a medial worker without any improvement in the response. Introducing an appropriate filter into the probe for low-energy photon has proven to improve the response. The dosemeter then satisfies the criteria of the personal dosemeter for eye lens dosimetry and can be applicable to individual monitoring of eye lens dose. This article also discusses the applicability of the dosemeter to area monitoring for decision making regarding additional monitoring of the eye lens and the extremities.

OCCUPATIONAL EYE LENS DOSE OVER SIX YEARS IN THE STAFF OF A US HIGH-VOLUME CANCER CENTER.

This paper summarizes the dose to the eye lens of workers of Memorial Sloan Kettering Cancer Center, a high-volume US oncologic and associated diseases facility. The doses presented in this report were collected from personal dosemeter readings using optically stimulated luminescence badges to estimate Hp(3). Doses were collected for 5950 clinical and research workers between January 2012 and December 2017. The median eye lens dose for all monitored workers was 0.23 mSv y−1. Workers performing, or supporting, fluoroscopy procedures received the highest unprotected eye lens dose of all workers with a median eye dose of 10 mSv. The use of leaded glasses by this group reduced the actual doses to the lens. Nurses and technicians involved in positron emission tomography injections received median eye lens dose of 1.2 mSv.

A One-Month Monitoring of Exposure to Solar UV Radiation of a Group of Construction Workers in Tuscany

Solar radiation exposure at work is a relevant heath risk in the construction sector. Our objective was to monitor for a full month the individual solar ultraviolet radiation (UVR) exposure of a group of three construction workers active in Siena (latitude = 43°19′ N), a town in Tuscany (Italy). We used personal electronic dosimeters “X-2012-10” (Gigahertz, Turkenfeld, Germany) to register the UV irradiance in the UVA and UVB/C regions separately and we consulted a specific database to retrieve the corresponding ambient erythemal UVR dose (cloud-free conditions). In spring, construction workers from central Italy received a quite variable UVR dose, between 0.9 standard erythemal doses (SED) and 15.6 SED/day, 5.7 on average. Considering the proportion with respect to the potential environmental exposure, personal exposure resulted between 2.7% and 31.2% of the ambient erythemal dose, with a mean value of 12.5%. Cumulatively, the three construction workers received in one working month a UVR dose of more than 120 SED. In a year, we estimated that a construction worker from Tuscany region is exposed to about 750 SED. This data demonstrates that construction workers in Italy are exposed to extremely high levels of solar UVR, with a relevant risk of developing adverse health effects related to the potential accumulation of UVR-induced damage in susceptible biological tissues, such as the skin and the eyes.

Helping to know if you are properly protected while working in interventional cardiology

Occupational protection is still a challenge for interventional cardiology. One of the main problems is the occasional improper use of the ceiling suspended screen. We present a methodology to audit the correct use of the shielding using active electronic dosimeters. To improve the protection, we suggest the use of an alert based on the ratio between the occupational dose per procedure, measured by a personal electronic dosimeter over the lead apron, and the dose measured by an unshielded dosimeter, located at the C-arm. The new electronic dosimeters and the automatic dose management systems allow processing the dosimetric data for individual procedures and for the radiation events, sending the values (wireless) to a central database. We selected six interventional cardiologists and analysed 385 interventional procedures involving about 30 000 radiation events. Our results suggest that for individual procedures, standard values of the ratio between operator dose and the C-arm reference dose, should be between 1%–2% for a proper use of the shielding. Percentage values ≥5%–10% for individual procedures, require an analysis of the different radiation events to identify the lack of occupational protection and suggest corrective actions. In our sample, half of the operators should improve the use of the shielding in around 20% of the procedures. Using this ratio as an alert to operators allows optimising occupational radiation protection and discriminating between high occupational doses derived from complex procedures and high doses due to the improper use of the protective screen.

Experimentally determined and Monte Carlo–calculated energy dependence of NaCl pellets read by optically stimulated luminescence for photon beams in the energy range 30 keV to 1.25 MeV

Ordinary salt, NaCl, has many properties suitable for dosimetry and has been suggested for both retrospective and prospective optically stimulated luminescence (OSL) dosimetry. Lately, the focus has been on NaCl that is compressed into solid pellets, as this improves both its handling and dosimetric properties. In this project, the energy dependence of NaCl pellets produced in-house was investigated for photon energies between 30 and 1.25 MeV. The NaCl pellets were first exposed to free-in-air conditions, and the estimated absorbed dose to the NaCl pellets was compared to the air kerma, K air, at the point of exposure. Second, a backscatter medium of polymethyl methacrylate (PMMA) was added, and NaCl pellets were exposed when positioned on a ISO slab phantom to relate the response in the NaCl to the personal dose equivalent, H p(10). The results show a significant energy dependence for exposure to low-energy photons with a peak over-response compared to K air and H p(10) of up to 18. Comparisons with Monte Carlo simulations show good agreement, even though the simulations cannot account for properties related to the intrinsic luminescence effects of the NaCl pellets or the readout and calibration process. The finite thickness of the NaCl pellet makes it an imperfect Bragg-Grey cavity, which complicates the behaviour of the energy dependence. The results presented here may serve as an important basis for further experimental and theoretical modelling of a build-up layer and filters in efforts to develop a passive personal dosemeter based on NaCl.

A distributed and interconnected network of sensors for environmental radiological monitoring

The W-MON project aims to improve and automatize the control of the presence of radioactive material in conventional waste containers at CERN using a distributed network of interconnected low-power radiation sensors. The key development is the integration of a lightweight but sensitive radiation sensor in a powerful network that allows continuous data recording, transfer and storage in a database for alarm triggering and subsequent data analysis. The Chiyoda D-shuttle personal dosimeter was used as proof-of-concept. Extensive tests performed with the commercial version of the D-shuttle showed that its robustness, stability under variable thermal conditions, high sensitivity and hourly dose logging capabilities make it a strong candidate for the project. To comply with the requirements of remote operation and wireless data transmission to a central server, a customized version of the D-shuttle has been developed. Two additional radiation sensors are also currently being considered. The sensors have been coupled to a custom-made communication board allowing for long-range low-power LoRa wireless data transmission. A centralized IoT (Internet of Things) end-to-end data architecture has been developed for real-time monitoring and visualization of the radiation level in waste containers before the final integration into REMUS, the overall CERN Radiation and Environment Monitoring Unified Supervision service.

Radiation protection practice of medical doctors of surgical and interventional specialties in Saudi Arabia

This study aimed to evaluate the radiation protection practices of medical doctors of surgical and interventional specialties in different healthcare sectors of Saudi Arabia. A cross-sectional study of medical doctors in Saudi Arabia who utilize radiation to perform interventional procedures and surgical operations was conducted. Data were gathered about the basic demographic background of the respondents, their daily application of radiation protection, and variations among different specialties and institutions regarding radiation protection practices. A total of 182 responses were received from different specialties, including interventional radiology (22%), interventional cardiology (16.5%), orthopedic surgery (14.8%), urology (14.3%), and diagnostic radiology (12.1%). Responses were received from different healthcare sectors, including the Ministry of Health (47%), private sector (26%), and university hospitals (18%). Only 59% of the respondents reported applying the As Low As Reasonably Achievable (ALARA) principle of radiation protection. The specialties with the highest reported lack of the ALARA principle application were orthopedic surgery (89%), urology (69%) and endoscopy (57%). The highest reported non-adherence to the ALARA principle was in the Ministry of Defense hospitals (50%), private hospitals (44%) and Ministry of Health hospitals (43%). The use of a personal dosimeter was reported by 58% of the respondents and only 42% reported having training in radiation protection. The respondents reported a lack of regular checking of x-ray machines (28%) and protection aprons (40%), non-availability of radiation protection guidelines (48%), and a lack of policies for radiation dose monitoring (27%) in their institutions. It was concluded that the compliance with radiation protection practices was variable and generally poor among different specialties and healthcare sectors in Saudi Arabia. Similar poor practices were reported in the international literature of different countries. The concerned authorities worldwide are advised to take further actions in this regard.

Radiocesium levels in contaminated forests has remained stable, even after heavy rains due to typhoons and localized downpours

In recent years, Japan has suffered serious damage due to natural disasters such as earthquakes, heavy rains due to tropical storms (typhoons) and localized downpours. To assess the chronological changes in the attenuation of external exposure doses and environmental radiation contamination due to the rainfall associated with typhoons and heavy rains during October to December 2019 in Fukushima, we measured environmental radiation levels in forest areas along the Mt Okura hiking trail in Tomioka Town, Fukushima Prefecture, near the Fukushima Daiichi Nuclear Power Station. We confirmed that (1) current ambient dose rates of 0.38–0.95 μSv/h in most forest areas were 79.9–84.7% higher than in residential areas; (2) the number of sites along the hiking trail where 137Cs was detected was limited (1.1–4.7%); and (3) individual dose rates of 0.21–0.34 μSv/h were lower than ambient dose rates. These findings suggest that radiocesium has remained stable in natural forests that have not been decontaminated even though current levels are low, despite the occurrence of heavy rainfall associated with Super Typhoon Hagibis in 2019 and localized downpours. Hiking while managing exposure to environmental contamination using a personal dosimeter may be the safest model for spending time of leisure activities.

Mobile apps for environmental and health monitoring after a nuclear accident: Towards a better resilience with involvement of citizen science and general public

Background/Aim: One of the lessons learned from nuclear accidents is the need to increase stakeholder engagement in accident preparedness and response, including data collection by citizens (and citizen scientists). In particular, the use of personal dosimeters, including sensors connected to mobile phones, was widely used after the Fukushima accident, leading to the collection and sharing of many ambient radioactivity measurements, dedicated web-platforms for exchanging questions and advice, as well as attempts to initiate participative epidemiological studies. Methods: The SHAMISEN-SINGS European project combined 3 approaches: 1) review and testing of existing mobile apps for dose measurements; 2) review of relevant mobile apps on health & welfare that could be used after a nuclear accident, and 3) on-line anonymous survey & group discussions on awareness, experiences and willingness to use mobile apps for dose and health monitoring.Results: A Tool-kit for using apps for dose measurements has been developed, summarised in infographics for the general public, and described together with recommendations on developing and use of mobile apps for health monitoring in a booklet. A brief cost-benefit analysis based on data collected by citizens was performed to complement those existing from official sources. A data management plan was proposed, in which data from the apps can be used with benefits at the individual and societal level. Ethical issues related to apps development, data collection and sharing were explored. Conclusions: The Recommendations and Tool-kits for use and development of mobile apps for dose and health monitoring after a nuclear accident, as developed by the SHAMISEN SINGS project, are directed toward the general public, apps developers and relevant professional stakeholders. If implemented in collaboration with stakeholders and citizen scientists, they should provide individual and societal benefits, and may contribute to national and regional monitoring networks for radiation and health surveillance programs in post-accidental situations.

Light-provoked skin symptoms on the hands of erythropoietic protoporphyria patients related to personal dosimeter measurements, skin symptoms, light protection and priming

Erythropoietic protoporphyria (EPP) is characterised by accumulation of protoporphyrin IX (PpIX) in erythrocytes. Upon illumination PpIX is released to the skin. Activation of the photoactive substance PpIX causes painful skin symptoms. This study aimed to objectively quantify individual light exposure of EPP patients in their everyday lives through spring and summer. We further aimed to establish the associations between daily symptoms and light exposure dose to photoprimed and non-photoprimed skin, use of gloves, and erythrocyte PpIX concentration. 14 Danish EPP patients participated from April through June, the period when symptoms are most frequent. Light exposure was measured using personal electronic dosimeters with sensor sensitivity comparable to the absorption spectrum of PpIX, measuring the biological effect of the light in this disease. Concurrently participants reported symptoms and use of protective gloves in a diary. Patients had a blood sample analysed for erythrocyte PpIX. The median patient was exposed to an average daily PpIX-weighted light dose of 3.8 J/cm2 corresponding to approximately 15 min in the midday sun during summer in Denmark. The median patient reported symptoms on 29% and wore gloves on 11% of study days. There was a significant positive correlation between erythrocyte PpIX concentration and percentage of days wearing gloves (r = 0.65, p = 0.011), and a significant negative correlation between erythrocyte PpIX concentration and mean daily light dose on days not wearing gloves (r = −0.53, p = 0.049). Photosensitivity was strongly dependent on photopriming.

"Beach Lifeguards' Sun Exposure and Sun Protection in Spain".

BackgroundSunburn is the main avoidable cause of skin cancer. Beach lifeguards spend many hours exposed to the effects of solar radiation during their work day, precisely at times of the year when levels of solar irradiation are highest. The aim of this study is to quantify the risk to beach lifeguards of sun exposure.MethodsA descriptive cross-sectional study was carried out in the Western Costa del Sol, southern Spain, during the summer of 2018. The research subjects were recruited during a skin cancer prevention course for beach lifeguards. All participants were invited to complete a questionnaire on their habits, attitudes, and knowledge related to sun exposure. In addition, ten were specially monitored using personal dosimeters for three consecutive days, and the results were recorded in a photoprotection diary. A descriptive analysis (mean and standard deviation for the quantitative variables) was performed, and inter-group differences were evaluated using the Mann–Whitney U test.ResultsTwo hundred fifteen lifeguards completed the questionnaire, and 109 met the criteria for inclusion in this analysis. The mean age was 23.8 years (SD: 5.1), 78.0% were male, 71.5% were phototype III or IV (Fitzpatrick's phototype), and 77.1% had experienced at least one painful sunburn during the previous summer. The mean daily personal ultraviolet exposure per day, the minimal erythema dose, and the standard erythema dose, in J/m2, were 634.7 [standard deviation (SD): 356.2], 2.5 (SD: 1.4) and 6.35 (SD: 3.6), respectively.ConclusionBeach lifeguards receive very high doses of solar radiation during the work day and experience correspondingly high rates of sunburn. Intervention strategies to modify their sun exposure behavior and working environment are necessary to reduce the risk of skin cancer for these workers and to promote early diagnosis of the disease.