ICRP Research Articles

Electron streaming dose measurements and calculations on a 1.5 T MR-Linac.

To evaluate the accuracy of different dosimeters and the treatment planning system (TPS) for assessing the skin dose due to the electron streaming effect (ESE) on a 1.5 T magnetic resonance (MR)-linac. Skin dose due to the ESE on an MR-linac (Unity, Elekta) was investigated using a solid water phantom rotated 45° in the x-y plane (IEC61217) and centered at the isocenter. The phantom was irradiated with 1 × 1, 3 × 3, 5 × 5, 10 × 10, and 22 × 22cm2 fields, gantry at 90°. Out-of-field doses (OFDs) deposited by electron streams generated at the entry and exit surface of the angled phantom were measured on the surface of solid water slabs placed±20.0cm from the isocenter along the x-direction. A high-resolution MOSkin™ detector served as a benchmark due to its shallower depth of measurement that matches the International Commission on Radiological Protection (ICRP) recommended depth for skin dose assessment (0.07mm). MOSkin™ doses were compared to EBT3 film, OSLDs, a diamond detector, and the TPS where the experimental setup was modeled using two separate calculation parameters settings: a 0.1cm dose grid with 0.2% statistical uncertainty (0.1cm, 0.2%) and a 0.2cm dose grid with 3.0% statistical uncertainty (0.2cm, 3.0%). OSLD, film, the 0.1cm, 0.2%, and 0.2cm, 3.0% TPS ESE doses, underestimated skin doses measured by the MOSkin™ by as much as -75.3%, -7.0%, -24.7%, and -41.9%, respectively. Film results were most similar to MOSkin™ skin dose measurements. These results show that electron streams can deposit significant doses outside the primary field and that dosimeter choice and TPS calculation settings greatly influence the reported readings. Due to the steep dose gradient of the ESE, EBT3 film remains the choice for accurate skin dose assessment in this challenging environment.

Determination of organ doses in thyroid treatments with radioactive iodine by Monte Carlo simulation

I-131 is a radioisotope widely used in nuclear medicine for the treatment of pathologies such as thyroid cancer or hyperthyroidism. When I-131 is ingested, it rapidly accumulates in the thyroid gland, emitting radiation that affects the targeted thyroid tissue while also impacting other organs. To ensure patients receive the appropriate dose for desired therapeutic outcomes while minimizing the risk of adverse effects, accurate estimations of absorbed doses after the treatment is crucial. This study focuses on evaluating organ doses following I-131 pill administration. It leverages the recent High-Resolution Anthropomorphic Computational Phantom distributed by the International Commission on Radiological Protection (ICRP), known as the Mesh Type Reference Computational Phantom. Additionally, a biokinetic analysis of iodine is conducted using a Matlab-developed tool based on the ICRP compartment model for oral iodine administration. Furthermore, Monte Carlo simulation techniques employing the MCNP6.2 code have been used to examine the radiation transport within the phantom at various time points. Consequently, the study provides dose data for each affected organ throughout the treatment, demonstrating the suitability of this simulation methodology for conducting dosimetric investigations in thyroid treatment.

Spécificités de la prise en charge diagnostique du cancer du sein chez la femme jeune

Breast cancer in women under the age of 40 is a rare diagnosis, but its course is generally less favourable than that of older women. It generally appears as a palpable mass, and its radiological presentation can sometimes be misleading, in the form of a falsely benign mass. The diagnostic work-up for breast cancer in young women should be complete, combining breast ultrasound and mammography, generally supplemented by breast MRI to look for additional lesions. In the specific case of pregnant or breast-feeding women, the Centre de référence des agents tératogènes (Crat), the American College of Radiology (ACR), the European Society of Urogenital Radiology (ESUR), the International Commission on Radiological Protection (ICRP) and the Société française de radiologie (SFR) have issued recommendations to ensure the safety of mother and child during complementary examinations.

Extrapolation of Monte Carlo–Derived Noble Gas Air-Submersion Effective Dose Rate Coefficients for Selected Occupational Settings to Other Geometries and Radionuclides

External exposures to airborne radioactivity at nuclear power sites are typically based on semi-infinite clouds with uniform concentrations and corresponding effective dose rate coefficients (EDRCs), along with the simplifying assumption that the radioactive clouds extend to infinity around the receptor of interest. The two regulatory models that are typically employed for finite-cloud adjustments to submersion doses, namely, Regulatory Guide 1.183 for hemispherical clouds and the International Commission on Radiological Protection (ICRP) document ICRP-30 for spherical clouds, were purposely oversimplified to facilitate their implementation. As a result, dose projections can be significantly underestimated under certain circumstances, particularly with radionuclides emitting low-energy photons and/or particles. In addition, these adjustments do not account for scatter radiation off surrounding walls, ceilings, and floors of typical occupational settings. In recognition of these limitations and for the mitigation thereof, Veinot et al. published an article [Rad. and Environ. Biophy., Vol. 56, p. 453 (2017)] that provided monoenergetic photon, electron, and positron EDRCs based on elaborate Monte Carlo computations for submersion in three typical occupational settings at nuclear facilities (namely, an office, a laboratory, and a warehouse). Included in the article were also EDRCs for exposure to 45 noble gases airborne within the said occupational settings. However, extrapolation of the results to other settings was limited due to geometry variations. Even so, as described in the present paper, the Veinot et al. article provided the basis for the definition of a straightforward model for extrapolation of the Monte Carlo–derived EDRCs to other occupational settings and radionuclides. The objective of the EDRC extrapolation model in this paper is to provide a simple but comprehensive approach to licensing-basis submersion dose calculations consistent with the recommendations in ICRP Publication 103. The model is reasonably accurate and applicable to submersion volumes that are smaller than an office and larger than a typical warehouse, as would be needed for control room habitability evaluations. It is emphasized that the model is only suitable for the external dose computation of airborne noble gases and particulates; dose contributions via the inhalation pathway and from direct shine from contaminated surfaces need to be evaluated separately. The EDRC extrapolation model was programmed into an Excel workbook (OccuSetEDRCs-R0.xlsx) that is available to interested parties; see Supplementary Data section for further details. The model can handle all 1252 radionuclides in ICRP-107 and submersion volumes ranging between about 40 and 4000 m3, with an upper estimated error of about 10% on average for large submersion volumes.

Radon exhalation and health hazard assessment for various ceramic tiles used in Bangladesh

Objective: Among various building materials, tiles are the most used decorative materials used worldwide. For the safe use of tiles at home and workplace it is required to select them properly based on radiation dose due to radon and gamma emission.
 Experiments: Among various tiles available in the market, 25 different types of tiles were collected for this experiment. Collected tiles are then ground and stored in sealed cans for secular equilibrium. To measure gamma activity due to the radionuclides 226Ra, 232Th, 40K, High Purity Germanium (HPGe) detector was used. To store radon gas emitting from tiles, a big box was used. The activity concentration was then measured by a radon detector (RadonEye) by placing it inside the box.
 Results and discussion: It was observed that 226Ra, 232Th, 40K activity varies from 45 – 89 Bq/Kg, 77 – 110 Bq/Kg, and 321 – 694 Bq/Kg. The radium equivalent activity varies from 198.32 – 280.46 Bq/Kg, less than the recommended value of 370 Bq/Kg set by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation). The activity concentration of radon varies from 31 – 71 Bq/m3. This is lower than the 300 Bq/m3 recommended by ICRP (International Commission on Radiological Protection). The radon exhalation rate varies from 0.179 – 0.409 Bqm−2h−1. To assess radiological hazards associated with the tiles samples air absorbed dose rate, internal and external hazard index, gamma index, annual indoor and outdoor effective dose rate, and dose due to radon were also calculated.
 Conclusion: Though the estimated values for external and internal hazards are below the recommended values, they may be safe for adults. As children have thinner skin and breathe more air due to high breathing frequency, they may receive more radiation than adults. Moreover, they are at a greater risk because of their developing bodies and long life expectancy post-exposure.

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.

Calculations of backpatch factors and conversion coefficients for the personal dose equivalent for X-ray beams used in radiodiagnostic

The purpose of this study is to use the Monte Carlo N-Particle radiation transport code (MCNP) to calculate the conversion coefficients of air kerma for personal dose equivalent (Hp [Sv]) and Back Scattering Factors (BSF) for X-ray beams used in diagnostic radiography at potentials of 40, 50, 60, 70, 80, 90, 100, 120, and 150 kVp. Additionally, effective dose is determined using male and female anthropomorphic voxel-based simulators (REX and REGINA) as recommended by the International Commission on Radiological Protection (ICRP) Publication 110, along with tissue weight factors from ICRP Publication 103 to simulate whole-body irradiation. The results indicate that the relationship between operational metrics such as Hp and risk limitation metrics like effective dose varies from 0.14 to 0.71 for Radiation Qualities in Radiation (RQR) beams from the X-ray source assembly and up to 0.64 for Radiation Qualities based on a phantom with an added aluminium filter (RQA). When comparing the obtained values for air kerma conversion coefficients for personal dose equivalent with the value adopted by the National Commission for Nuclear Energy (CNEN) of 1.14 Sv/Gy for individual dose determination, it is observed that at low energies, the values are overestimated by up to 44%, while at high energies, the values are underestimated by up to 67%.

Characterization of Radiation Exposure at Aviation Flight Altitudes Using the Nowcast of Aerospace Ionizing Radiation System (NAIRAS)

AbstractExposure to ionizing radiation from galactic cosmic rays (GCR) and solar energetic particles (SEP) at aircraft flight altitudes can have an adverse effect on human health. Although airline crews are classified as radiation workers by the International Commission on Radiological Protection (ICRP), in most countries, their level of exposure is unquantified and undocumented throughout the duration of their career. As such, there is a need to assess pilot ionizing radiation exposure. The Nowcast of Aerospace Ionizing RAdiation System (NAIRAS), a real‐time, global, physics‐based model is used to assess such exposure. The Automated Radiation Measurements for Aerospace Safety (ARMAS) measurement data set consists of high latitude, high altitude, and long‐duration aircraft flights between 2013 and 2023. Here, we characterize radiation exposure at aviation flight altitudes using the NAIRAS model and compare with 45 flight trajectories from the recent ARMAS flight measurement inventory.

Assessment of variation of radon gas due to internal dwelling decorated materials in Amasaman District in Greater Accra Region, Ghana

Abstract This study investigates the influence and variation of indoor radon gas due to internally decorated materials in residential buildings within Amasaman District, Accra, using CR-39 techniques. Internal covering used for decorations are wallpaper, wall tiles, gypsum panels, epoxy paints, and oil paints. Statistical analysis of the obtained radon data revealed a positively skewed distribution, suggesting a log-normal distribution of indoor radon data. The indoor radon concentrations across the studied dwellings varied from 27.7 to 287.0 Bqm−3 with a mean value of 116.0 ± 4.4 Bqm−3. The majority of dwellings (54%) exceeded the WHO reference level of 100 Bq/m3, while 92% remained below the lower limit of the international commission on radiological protection (ICRP)-recommended range of 200–600 Bqm−3. These findings emphasize the need for vigilance and proper ventilation practices to mitigate potential health risks. The annual effective dose assessments ranged from 0.7 to 7.2 mSv/y, with an arithmetic mean (AM) of 2.9 ± 0.1 mSv/y which is about 2.6 times greater than the world average value of 1 mSv/y. The excess lifetime cancer risk estimated ranged from 2.4 to 24.9, with an AM of 10.1 ± 0.4. This study reveals variations in indoor radon concentrations, with dwellings having different internal covering materials.

Radon, Thoron and Polonium Concentrations Estimated in Building Materials Samples Collected from Al-Shatra, Dhi-Qar, Iraq

Radon, Thoron and their short-lived daughters have a high contribution to background radiation, as long-term exposure causes the risk of lung cancer. In current study, five types of building materials with a total 55 samples in Al-Shatra City, Dhi-Qar Governorate, Iraq collected to measure the radon and thoron concentration by using CR-39 solid state nuclear track detector. The results showed that the average radon concentrations in all samples were (103.53±55.94) Bqm−3, while the average thoron concentration was (53.20±44.69) Bqm−3. On the other hand, the annual effective dose of radon ranged between (0.85-6.46) msvy−1, with an average of 2.61msvy−1. While, for thoron concentration was ranged between (0.12-3.28) msvy−1, with an average of 1.49 msvy−1. The annual effective dose was found acceptable limit (3-10 msvy−1) recommended by the International Commission on Radiological Protection (ICRP). On the other side, the average Polonium concentrations (218Po, 214Po) have been found to be 2.053 KBqm−3, 0.866 KBqm−3, respectively.

Investigation on Individual Variation of Organ Doses for Photon External Exposures: A Monte Carlo Simulation Study

Background: The reference dose coefficients (DCs) of the International Commission on Radiological Protection (ICRP) have been widely used to estimate organ doses of individuals for risk assessments. This approach has been well accepted because individual anatomy data are usually unavailable, although dosimetric uncertainty exists due to the anatomical difference between the reference phantoms and the individuals. We attempted to quantify the individual variation of organ doses for photon external exposures by calculating and comparing organ DCs for 30 individuals against the ICRP reference DCs.Materials and Methods: We acquired computed tomography images from 30 patients in which eight organs (brain, breasts, liver, lungs, skeleton, skin, stomach, and urinary bladder) were segmented using the ImageJ software to create voxel phantoms. The phantoms were implemented into the Monte Carlo N-Particle 6 (MCNP6) code and then irradiated by broad parallel photon beams (10 keV to 10 MeV) at four directions (antero-posterior, postero-anterior, left-lateral, right-lateral) to calculate organ DCsResults and Discussion: There was significant variation in organ doses due to the difference in anatomy among the individuals, especially in the kilovoltage region (e.g., <100 keV). For example, the red bone marrow doses at 0.01 MeV varied from 3 to 7 orders of the magnitude depending on the irradiation geometry. In contrast, in the megavoltage region (1–10 MeV), the individual variation of the organ doses was found to be negligibly small (differences <10%). It was also interesting to observe that the organ doses of the ICRP reference phantoms showed good agreement with the mean values of the organ doses among the patients in many casesConclusion: The results of this study would be informative to improve insights in individualspecific dosimetry. It should be extended to further studies in terms of many different aspects (e.g., other particles such as neutrons, other exposures such as internal exposures, and a larger number of individuals/patients) in the future.

Pediatric phantom library constructed from ICRP mesh-type reference computational phantoms (MRCPs)

International Commission on Radiological Protection (ICRP) recently developed the adult and pediatric mesh-type reference computational phantoms (MRCPs) in high-quality/fidelity mesh format, featuring high deformability into various body sizes and poses. Utilizing this feature, the adult MRCPs-based body-size-dependent phantom library was developed for individualized dosimetry. To complete the full phantom library set, the present study produced the pediatric-MRCPs-based body-size-dependent pediatric phantom library. The library comprises a total of 637 phantoms (356 males and 281 females) with varying standing heights and body weights, covering a wide range of body sizes (i.e., including from 1st to 99th percentile height and weight values) for infants, children, and adolescents, offering a realistic representation of body shapes by reflecting ten secondary anthropometric parameters. The phantoms were automatically constructed utilizing automatic deformation program. The dosimetric impact of the library was investigated by calculating organ doses for external exposures to broad parallel photon beams in anterior-posterior direction. Compared with the values of the pediatric MRCPs, significant differences were observed at energies <0.05 MeV, showing larger values for underweight phantom and smaller values for obese phantom. The results highlight the importance of using the pediatric phantom library for accurate dose estimates of individual children with various body sizes.

Radionuclides distribution and radiation hazards assessment of black sand separation plant’s minerals: a case study

This study assessed the radioactivity levels and associated risks in the black sand-separated products obtained from the black sand separation plant in Delta, Egypt. A total of sixteen samples were taken from hot spots during and after the separation process. These include water samples and other samples that represent monazite, rutile, zircon, granite, ilmenite, and silica products. The hot spots included the area where the ore was stored. The activity concentrations of 232Th\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{232}Th$$\\end{document}, 226Ra\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{226}Ra$$\\end{document}, and 40K\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{40}K$$\\end{document} were determined in these samples using a p-type HPGe detector. Based on gamma spectrometric analysis, samples of rutile, zircon, and monazite had the highest amounts of radioactivity because they contained the highest NORM’s activity concentrations. In addition, it indicated that the radiological hazard indices of the collected samples were higher than the average world limits for sand texture. These findings suggest that the black sand separation process reveals potential risks to human health and the environment, and therefore, appropriate measures need to be taken to mitigate these risks, especially for the safety of the workers on-site. Reducing the risk associated with those sites should be controlled by implementing the recommendations declared for the series of International Basic Safety Standards of the International Atomic Energy Agency (GSR) Part 3, as affirmed in Document No. 103 of 2007 by the International Commission on Radiological Protection (ICRP) as will be presented in the paper body.

National-level Dental Radiological Dose Management

There is growing public concern about patients' radiation exposure from recent medical imaging using ion-izing radiation. While medical radiation exposure has inevitable aspects, efforts to optimize doses in line with the principles of justification and optimization are necessary to maximize diagnostic value with the minimumradiation dose. Diagnostic reference levels have been proposed as a means to achieve optimization, in accordance with ICRP (International Commission on Radiological Protection) publications 60 and 73, as well as EC (European Commission) Directive 97/43/Euratom. According to Requirement 34 of the 'InternationalBasic Safety Standards' published by the IAEA in 2014, governments are recommended to establish national diagnostic reference levels. According to ICRP Publication 135, issued in 2017, national diagnostic reference levels should be revised regularly, preferably every 3-5 years, and more frequently in the case of technologicaladvancements, such as in the case of CBCT. In South Korea, diagnostic reference levels for various imagingmodalities have been established since 2007. In the field of dentistry, diagnostic reference levels for intraoral and panoramic radiography were established in 2009, and in 2018, diagnostic reference levels for dental CBCT were introduced for the first time. The purpose of this report is to discuss the current national-level patient radia-tion dose management in South Korea and explore its applications

Radioiodine internal dose coefficients specific for Koreans

This study developed internal dose coefficients for radioiodine, tailored to the Korean population, by incorporating the Korean biokinetic model along with the Korean S values. The observed differences in dose coefficients for Koreans compared to the International Commission on Radiological Protection (ICRP) reference values noticeably varied depending on physical half-lives of iodine isotopes. For longer-lived isotopes such as I-125 and I-129, significant differences in thyroid dose coefficients were observed, with ratios (Korean/ICRP) from 0.30 to 0.55, indicating that actual doses for Koreans can be considerably lower than those evaluated based on the ICRP data. However, for short-lived iodine isotopes, such as I-131, the thyroid dose coefficients were comparable to the ICRP reference values (ratio = 0.95–0.98). These comparable dose coefficients resulted from the lower thyroidal iodine uptake in the Korean model being almost entirely offset by the higher thyroid self-absorption S values in the Korean phantoms. Additionally, this study delves into the substantial differences in absorbed dose coefficients for non-thyroidal regions and effective dose coefficients, which arose not only from physiological/anatomical variability but also technical differences in phantom design. The use of Korean-specific dose coefficients is advisable particularly in scenarios predicting elevated doses, yielding a more precise and clinically relevant dose assessment.

Absorbed dose coefficients for pediatric differentiated thyroid cancer patients undergoing radioiodine therapy

The escalating incidence of differentiated thyroid cancer (DTC) in pediatric patients and the resultant growing use of radioactive iodine (RAI) reinforce the need to evaluate radiation exposure to normal tissues and radiation-induced health risks in pediatric patients undergoing RAI therapy. In the current study, we calculated absorbed dose coefficients (i.e. absorbed dose per unit activity administered, mGy MBq−1) specific for pediatric patients with localized DTC undergoing RAI therapy following total thyroidectomy for use in epidemiological studies. We first modified previously-published biokinetic models for adult thyroid cancer patients to achieve a reasonable agreement with iodine biokinetics observed in pediatric patients or design principles addressed in the International Commission on Radiological Protection (ICRP) reference age-specific biokinetic models. We then combined the biokinetic models in conjunction with S values derived from ICRP reference pediatric voxel phantoms. The absorbed dose coefficients for pediatric patients were overall greater than those for adults with a ratio (pediatric/adult) up to 11.6 and rapidly decreased with increasing age. The sensitivity analysis showed that the renal clearance rate and S values may have the greatest impact on the absorbed dose coefficients with the rank correlation coefficients ranging from −0.53 to −0.82 (negative correlations) and from 0.51 to 0.80 (positive correlations), respectively. The results of the current study may be utilized in clinical or epidemiological studies to estimate organ-specific radiation absorbed doses and radiation-associated health risks among pediatric thyroid cancer patients.

Radiation Exposure Characteristics among Healthcare Workers: Before and After Japan's Ordinance Revision.

Radioactive materials and ionizing radiation have both medical value and disease risks, necessitating radiation dose measurement and risk reduction strategies. The International Commission on Radiological Protection (ICRP) lowered the lens of the eye exposure limit, leading to Japan's revised "Ionizing Radiation Ordinance." However, the effects on radiation exposure in medical settings and compliance feasibility remain unclear. To examine the impact of the revision to the "Ionizing Radiation Ordinance" and use it for measures to reduce exposure to radiation, a comprehensive analysis was conducted on data collected from Nagasaki University Hospital, Hiroshima University Hospital, and Fukushima Medical University Hospital in 2018, 2020, and April to September 2021. This included information on age, sex, occupation, department, and monthly radiation doses of workers, aiming to assess the impact of the revision to the "Ionizing Radiation Ordinance" on radiation exposure before and after its enforcement. Out of 9,076 cases studied, 7,963 (87.7%) had radiation doses below the measurable limit throughout the year. Only 292 cases (3.2%) exceeded 1 mSv y -1 , with 9 doctors and 2 radiological technologists surpassing 5 mSv y -1 . Radiological technologists showed significantly higher doses compared to doctors, dentists, and nurses (p < 0.01), while male subjects had significantly higher exposure doses than females (p < 0.01). No significant changes in radiation exposure were observed before and after the revision of the Ionizing Radiation Ordinance; however, variations in radiation exposure control were noted, particularly among nurses and radiological technologists, suggesting the impact of the revision and the need for tailored countermeasures to reduce radiation dose in each group.

Estimates of Inhaled and Deposited Doses following Exposure to Humidifier Disinfectant Containing Polyhexamethylene Guanidine (PHMG)

We estimated the inhaled and deposited dose in humans using the International Commission on Radiological Protection (ICRP) and multiple-path particle dosimetry (MPPD) models following exposure to humidifier disinfectant containing polyhexamethylene guanidine (PHMG). The disinfectant has caused at least 1,810 deaths, with an odds ratio of lung injury of 47.3 (95% confidence interval: 6.1–369.7), because of its application in Korea. In this study, the Oxy product, which is regarded as the causative agent of most lung diseases, was sprayed into a cleanroom at normal (6.5 ppm in solution) and worst case (65 ppm in solution) dilutions; the airborne aerosol was monitored with direct reading instruments. Areas of deposition were divided into the head airway, tracheobronchial, and alveolar regions. Four dose scenarios were considered in this study: adults and children in both daily average and sleep conditions. Most PHMG aerosols were smaller than PM1 (96%). Number-based concentration analysis showed that &lt;100 nm nanoparticles comprised 81% and 69% of the aerosol when the 6.5 and 65 ppm solutions were used, respectively. In all scenarios, the number-based deposited dose increased in the order of alveolar, tracheobronchial, and head airway regions; the mass-based deposited dose increased in the order of the head airway, alveolar, and tracheobronchial regions. The deposited dose per unit body weight was higher in children than in adults in terms of both number- and mass-based concentrations. When the humidifier was sprayed, the highest number-based concentration was found at a particle size of 15.4 nm; the highest deposition fraction or dose by PM1 was observed in the pulmonary and head airways in both models.

Radiological landscape of natural resources and mining: Unveiling the environmental impact of naturally occurring radioactive materials in Ghana's mining areas

This study provides a general observation of the status of naturally occurring radioactive materials (NORMs) distribution in mining and industrial areas of Ghana in order to establish regional and national data on NORMs. The study includes data on radioactivity concentrations of U-238, Th-232, and K-40 in soils and for water concentrations of Ra-226, Th-228, and K-40 from various mining, oil, and gas communities, as well as water sources used for crop farming and farmlands. The average activity concentrations of U-238, Th-232, and K-40 in the soil samples were found to be 59 ± 16 Bq/kg, 48 ± 15 Bq/kg, and 286 ± 57 Bq/kg, respectively. The average concentration of Ra-226, Th-228, and K-40 in the water samples were found to be 1.62 ± 0.33 Bq/L, 2.08 ± 0.53 Bq/L, and 22.36 ± 3.44 Bq/L, respectively. The estimated average annual effective doses from external and internal exposure pathways in soil and water samples were 0.09 mSv/y and 0.54 mSv/y, respectively. The total annual effective dose resulting from both exposure pathways was calculated to be 0.63 mSv/y, which is below the 1 mSv/y dose limit recommended by the International Commission on Radiological Protection (ICRP) for controlling public radiation exposure. Based on the radiological hazard indices, the majority of the soil samples were found to be suitable as building materials as their respective indices were below the limits except for two sample locations and the sludge and scale samples. The average Excess Lifetime Cancer Risk (ELCR) value of the water samples was 1.6 times greater than the recommended value of 1.16 × 10−3, presenting a relatively higher risk to the public of developing cancer. No significant regional differences in the levels of radioactive elements. The regression models demonstrate strong interrelationships between the studied elements, with high R-squared values suggesting a predictable nature of one element’s concentration based on others.

National survey to update the diagnostic reference levels in interventional radiology procedures in Italy: working methodology.

Interventional Radiology (IR) deals with the diagnosis and treatment of various diseases through medically guided imaging. It provides unquestionable benefits to patients, but requires, in many cases, the use of high doses of ionizing radiation with a high impact on radiation risks to patients and to overall dose to the population. The International Commission on Radiological Protection introduced Diagnostic reference levels (DRLs) as an effective tool to facilitate dose verification and optimize protection for patients undergoing radiological procedures. In addition, EURATOM Council Directive 2013/59 and its Italian transposition (Legislative Decree 101/2020) have reiterated that DRLs must be established for many common radiological diagnostic procedures to compare the radiation dose delivered for the same diagnostic examination. Within this framework, Istituto Superiore di Sanità-Italian National Institute of Health (ISS)-, in collaboration with relevant Italian Scientific Societies, has provided documents on DRLs in radiological practices such as diagnostic and IR and diagnostic nuclear medicine. These reference documents enable National Hospitals to comply national regulation. The implementation of DRLs in IR is a difficult task because of the wide distribution of doses to patients even within the same procedure. Some studies have revealed that the amount of radiation in IR procedures is influenced more by the complexity of the procedure than by the weight of the patient, so complexity should be included in the definition of DRLs. For this reason, ISS promoted a survey among a sample of Italian Centers update national DRL in IR procedures with related complexity factors than can be useful for other radiological centers and to standardize the DRLs values. In the present paper the procedural methodology developed by ISS and used for the survey will be illustrated.