A comparative analysis of deep learning and hybrid iterative reconstruction algorithms with contrast-enhancement-boost post-processing on the image quality of indirect computed tomography venography of the lower extremities.

PURPOSE: To examine whether there is a significant difference in image quality between the deep learning reconstruction (DLR [AiCE, Advanced Intelligent Clear-IQ Engine]) and hybrid iterative reconstruction (HIR [AIDR 3D, adaptive iterative dose reduction three dimensional]) algorithms on the conventional enhanced and CE-boost (contrast-enhancement-boost) images of indirect computed tomography venography (CTV) of lower extremities. MATERIALS AND METHODS: In this retrospective study, seventy patients who underwent CTV from June 2021 to October 2022 to assess deep vein thrombosis and varicose veins were included. Unenhanced and enhanced images were reconstructed for AIDR 3D and AiCE, AIDR 3D-boost and AiCE-boost images were obtained using subtraction software. Objective and subjective image qualities were assessed, and radiation doses were recorded. RESULTS: The CT values of the inferior vena cava (IVC), femoral vein ( FV), and popliteal vein (PV) in the CE-boost images were approximately 1.3 (1.31-1.36) times higher than in those of the enhanced images. There were no significant differences in mean CT values of IVC, FV, and PV between AIDR 3D and AiCE, AIDR 3D-boost and AiCE-boost images. Noise in AiCE, AiCE-boost images was significantly lower than in AIDR 3D and AIDR 3D-boost images ( P < 0.05). The SNR (signal-to-noise ratio), CNR (contrast-to-noise ratio), and subjective scores of AiCE-boost images were the highest among 4 groups, surpassing AiCE, AIDR 3D, and AIDR 3D-boost images (all P < 0.05). CONCLUSION: In indirect CTV of the lower extremities images, DLR with the CE-boost technique could decrease the image noise and improve the CT values, SNR, CNR, and subjective image scores. AiCE-boost images received the highest subjective image quality score and were more readily accepted by radiologists.

Monitoring of surgical staff x-ray exposure in the operating room with DosiBadge.

Surgical procedures involving the use of x-rays in the operating room (OR) have increased in recent years, thereby increasing the exposure of OR staff to ionizing radiation. An individual dosimeter makes it possible to record the radiation exposure to which these personnel are exposed, but there is a lack of compliance in the wearing of these dosimeters for several practical reasons. This makes the dose results obtained unreliable. To try to improve the rate of dosimeter wearing in the OR, the Dosibadge project studied the association of the individual dosimeter with the hospital access badge, forming the Dosibadge. Through a study performed at the Tours University Hospital in eight different ORs for two consecutive periods of 3 months. The results show a significant increase in the systematic use of the dosimeter thanks to the Dosibadge, which improves the reliability of the doses obtained on the dosimeters and the monitoring of personnel. The increase is especially marked with clinicians. Following these results and the very positive feedback to this first single-centre study, we are then planning a second multicentre study to validate our proof of concept on different sites, with the three brands of individual dosimeters used in France i.e. dosimeters supplied by Dosilab; Landauer and IRSN.

Evaluation of low-dose pediatric chest CT examination using in-house developed various age-size pediatric chest phantoms.

PURPOSE: This study aims to develop Various Age-size Pediatric Chest Phantoms (VAPC) to evaluate low-dose protocol that approximates clinical conditions achieved by low organ-specific doses and optimal image quality among the challenges of pediatric size variations. METHODS: Three original pediatric data aged 1, 4, and 7 years were used as a reference for developing VAPC phantoms. Six protocols, namely standard dose (STD) and low dose (low mA and low kV) reconstructed using Filtered Back Projection (FBP) and iterative reconstruction (IR) algorithms, were investigated. This study directly measured the lungs, heart, and spinal cord dose using LD-V1 film. Linearity, Modulation Transfer Function (MTF), Contrast to Noise Ratio (CNR), and Noise Power Spectrum (NPS) were evaluated to assess the CT image quality of the VAPC phantom. RESULTS: This study found that the mean organ-specific dose was higher than CTDIvol. A Comparison of mean lung doses showed VAPC phantom 1 (y.o.) received 74.8% and 137.2% more doses than 4 (y.o.) and 7 (y.o.), respectively. Low kV produces a lower organ dose than low mA. The linearity of CT numbers is not biased at low doses. Differences in age measures significantly influenced organ-specific dose, MTF, CNR, and NPS. CONCLUSION: Smaller pediatrics are still exposed to higher doses at low-dose examinations, whereas larger pediatrics have lower contrast resolution and increased image noise. CT number linearity is unbiased. The combination of low kV with FBP produces higher spatial resolution, while low mA with IR effectively reduces noise to detect low-contrast objects better.

Evaluation of the performance of digital x-ray systems in pelvis radiography.

The aim of this study was to investigate the performance of eight digital radiography systems and to optimise the dose-image quality relationship for digital pelvis radiography. The study involved eight digital radiography systems used for general examinations at Vilnius University Hospital Santaros Klinikos. An anthropomorphic pelvic phantom (CIRS, US) was used to simulate a patient undergoing clinical pelvis radiography. Dose quantities entrance surface dose, dose area product (DAP) and exposure parameters (kVp, mA, mAs) were measured and the effects on the images were evaluated, considering physical contrast to noise ratio (CNR) and observer-based evaluations as image quality metrics. Increasing the tube voltage by 5 kVp from standard protocol led to a reduction in radiation dose (DAP) by 12%-20% with a slight impact on image quality (CNR decreases by 2%-10%). There was an inter-observer variability in image rating across different equipment (kappa value between 0 and 0.3); however, both observers agreed that increasing kVp up to 85-90 kV had no effect on perceived image quality. The results indicate that optimisation strategies should be tailored specifically for each x-ray system since significant performance differences and wide variations in radiation dose exist across various digital radiography systems used in clinical settings. The use of high kVp can be used for dose optimisation in digital pelvis radiography without compromising image diagnostic accuracy.

G0-PCC-FISH derived multi-parametric biodosimetry methodology for accidental high dose and partial body exposures.

High dose radiation exposures are rare. However, medical management of such incidents is crucial due to mortality and tissue injury risks. Rapid radiation biodosimetry of high dose accidental exposures is highly challenging, considering that they usually involve non uniform fields leading to partial body exposures. The gold standard, dicentric assay and other conventional methods have limited application in such scenarios. As an alternative, we propose Premature Chromosome Condensation combined with Fluorescent In-situ Hybridization (G0-PCC-FISH) as a promising tool for partial body exposure biodosimetry. In the present study, partial body exposures were simulated ex-vivo by mixing of uniformly exposed blood with unexposed blood in varying proportions. After G0-PCC-FISH, Dolphin's approach with background correction was used to provide partial body exposure dose estimates and these were compared with those obtained from conventional dicentric assay and G0-PCC-Fragment assay (conventional G0-PCC). Dispersion analysis of aberrations from partial body exposures was carried out and compared with that of whole-body exposures. The latter was inferred from a multi-donor, wide dose range calibration curve, a-priori established for whole-body exposures. With the dispersion analysis, novel multi-parametric methodology for discerning the partial body exposure from whole body exposure and accurate dose estimation has been formulated and elucidated with the help of an example. Dose and proportion dependent reduction in sensitivity and dose estimation accuracy was observed for Dicentric assay, but not in the two PCC methods. G0-PCC-FISH was found to be most accurate for the dose estimation. G0-PCC-FISH has potential to overcome the shortcomings of current available methods and can provide rapid, accurate dose estimation of partial body and high dose accidental exposures. Biological dose estimation can be useful to predict progression of disease manifestation and can help in pre-planning of appropriate & timely medical intervention.

Efficacy of radiation attenuating caps in reducing radiation doses received at the cerebral level in interventional physicians: a systematic review.

Background.Anecdotal reports are appearing in the scientific literature about cases of brain tumors in interventional physicians who are exposed to ionizing radiation. In response to this alarm, several designs of leaded caps have been made commercially available. However, the results reported on their efficacy are discordant.Objective.To synthesize, by means of a systematic review of the literature, the capacity of decreasing radiation levels conferred by radiation attenuating devices (RADs) at the cerebral level of interventional physicians.Methodology.A systematic review was performed including the following databases: MEDLINE, SCOPUS, EBSCO, Science Direct, Cochrane Controlled Trials Register (CENTRAL), WOS, WHO International Clinical Trials Register, Scielo and Google Scholar, considering original studies that evaluated the efficacy of RAD in experimental or clinical contexts from January 1990 to May 2023. Data selection and extraction were performed in triplicate, with a fourth author resolving discrepancies.Results.Twenty articles were included in the review from a total of 373 studies initially selected from the databases. From these, twelve studies were performed under clinical conditions encompassing 3801 fluoroscopically guided procedures, ten studies were performed under experimental conditions with phantoms, with a total of 88 procedures, four studies were performed using numerical calculations with a total of 63 procedures. The attenuation and effectiveness of provided by the caps analyzed in the present review varying from 12.3% to 99.9%, and 4.9% to 91% respectively.Conclusion.RAD were found to potentially provide radiation protection, but a high heterogeneity in the shielding afforded was found. This indicates the need for local assessment of cap efficiency according to the practice.

Evaluating spectral performance for quantitative contrast-enhanced breast CT with a GaAs based photon counting detector: a simulation approach.

Quantitative contrast-enhanced breast computed tomography (CT) has the potential to improve the diagnosis and management of breast cancer. Traditional CT methods using energy-integrated detectors and dual-exposure images with different incident spectra for material discrimination can increase patient radiation dose and be susceptible to motion artifacts and spectral resolution loss. Photon Counting Detectors (PCDs) offer a promising alternative approach, enabling acquisition of multiple energy levels in a single exposure and potentially better energy resolution. Gallium arsenide (GaAs) is particularly promising for breast PCD-CT due to its high quantum efficiency and reduction of fluorescence x-rays escaping the pixel within the breast imaging energy range. In this study, the spectral performance of a GaAs PCD for quantitative iodine contrast-enhanced breast CT was evaluated. A GaAs detector with a pixel size of 100µm, a thickness of 500µm was simulated. Simulations were performed using cylindrical phantoms of varying diameters (10 cm, 12 cm, and 16 cm) with different concentrations and locations of iodine inserts, using incident spectra of 50, 55, and 60 kVp with 2 mm of added aluminum filtration and and a mean glandular dose of 10 mGy. We accounted for the effects of beam hardening and energy detector response using TIGRE CT open-source software and the publicly available Photon Counting Toolkit (PcTK). Material-specific images of the breast phantom were produced using both projection and image-based material decomposition methods, and iodine component images were used to estimate iodine intake. Accuracy and precision of the proposed methods for estimating iodine concentration in breast CT images were assessed for different material decomposition methods, incident spectra, and breast phantom thicknesses. The results showed that both the beam hardening effect and imperfection in the detector response had a significant impact on performance in terms of Root Mean Squared Error (RMSE), precision, and accuracy of estimating iodine intake in the breast. Furthermore, the study demonstrated the effectiveness of both material decomposition methods in making accurate and precise iodine concentration predictions using a GaAs-based photon counting breast CT system, with better performance when applying the projection-based material decomposition approach. The study highlights the potential of GaAs-based photon counting breast CT systems as viable alternatives to traditional imaging methods in terms of material decomposition and iodine concentration estimation, and proposes phantoms and figures of merit to assess their performance.

Assessment and mitigation of radiation hazard for individuals engaged in reconnaissance survey in uranium exploration in Jharkhand, India.

The present study attempts to obtain an a priori estimate of the absorbed dose received by an individual engaged in the reconnaissance survey in Uranium exploration using a predictive mathematical regression analysis. Other radiation safety parameters such as excess lifetime cancer risk are also calculated. Study reflects that the proper handling of naturally occurring radioactive materials accounts for an absorbed dose significantly less than the prescribed limit.

Methodology for shielding design and evaluation for container scanners.

There has been an increase in the use of high energy photon beam for container scanners in many countries for multi purposes such as detecting high atomic number materials which might be nuclear materials, drugs, high explosive materials and other contrabands etc. High energy photon beams generally 6 and 9 MV can be used for scanning such materials. However, it is important to ensure that radiation level beyond the container scanner installation is within the permissible dose limit specified by the national competent authority for the protection of public and radiation workers. In this paper, challenges in the biological shielding during the installation of high energy X-ray system for scanning vehicles containing suspected materials are discussed. The purpose of the present study is to develop a methodology for shielding design and evaluation for container scanner installations. The basic concept pertaining to shielding evaluation of radiotherapy installations provided in National Council on Radiation Protection and Measurements (NCRP)/International Atomic Energy Agency (IAEA) reports are referred, and appropriately used to calculate optimized shielding thicknesses requirements for container scanner installation. Workload is estimated based on number of containers scanned, machine ON time and dose rate at 1 m. The shielding evaluation includes use of beam stopper in the primary beam, scattering by heterogeneous metallic scrap materials or any other suspected materials contained in the vehicle and their impact on the thickness of shielding walls. A model lay out plan to be used for installation of container scanner is developed. A methodology for shielding evaluation for various protective walls and ceiling of this model is also discussed. The study provides basic requirement for designing a structural room for installing 9MV container scanner from radiological safety view point.

Assessment of radiation dose due to 210Po in water and food samples of Chamarajanagar district, Karnataka, India.

Groundwater is in direct contact with the soil and rocks that dissolve many compounds and minerals including uranium and its daughter products. 210Po is one of the decay products of 238U series that cause internal radiation dose in humans when consumed in the form of water and food, including sea food. Therefore, activities of 210Po have been studied in ground and surface water, and in food samples that are commonly used in Chamarajanagar region of Karnataka, India. The average 210Po concentration in bore well water samples and surface water samples are 3.21 and 1.85 mBq L-1, respectively. In raw rice and wheat, the average values of 210Po are 96 and 41 mBq kg-1, respectively. In millets and pulses, the average activity of 210Po is 157 and 79 mBq kg-1, respectively. Among food items, the highest activity of 1.3 kBq kg-1 is observed in marine crabs and the lowest activity of 2.6 mBq kg-1 is found in milk samples. The average ingestion dose due to 210Po in ground and surface water are 2.8 and 1.62 µSv y-1, respectively. The ingestion dose due to various food samples to the population is also calculated. Total ingestion dose due to 210Po to pure vegetarian population and general population are 38.09 and 590.80 µSv y-1, respectively. The concentration of 210Po in water samples and food samples of this region are in a comparable range with the world and Indian average values and lies well below the recommended guideline level.

Determination of uranium isotopes in ground water by alpha spectrometry and associated age-dependent ingestion dose.

Determination of uranium isotopes in ground water plays a key role in assessment of geochemical condition of ground water and for estimating ingestion dose received by the general public because of uranium intake through drinking water. An attempt has been made in the present study to estimate isotopic composition and activity ratios (AR) of uranium isotopes by analysing the ground water samples using alpha spectrometry. Associated age-dependent ingestion dose was also calculated for the public of different age groups. 238U, 235U and 234U activity concentration was found to vary in the ranges of 5.85 ± 1.19 to 76.67 ± 4.16, < 0.90 to 3.15 ± 0.84 and 6.52 ± 1.25 to 107.02 ± 4.92 mBq/L, respectively. 235U/238U AR varies from 0.038 to 0.068 with an average of 0.047 which is close to 0.046 implies that uranium in the ground water is from natural origin. Uranium concentration was found to vary in the range of 0.47 ± 0.10 µg/L to 6.20 ± 0.34 µg/L with a mean value of 3.01 ± 0.23 µg/L, which is much lower than national as well as international recommendation value. Annual ingestion dose to the public of all age groups for uranium intake through drinking water ranges from 0.60 ± 0.11 to 19.50 ± 1.03 µSv/y.

Assessment of indoor radon concentration in the dwellings of the industrial areas of Kannur District, Kerala.

All organisms on the earth-crest are exposed to natural background radiation since the evolution of the earth, as many environmental matrices such as soil, air, water bodies, vegetation, etc., act as the sources of natural radioactivity. The present study deals with the evaluation of indoor concentration of 222Rn (radon) in different dwellings with various construction materials used for the roof and floor in the industrial sites of Kannur district, Kerala. A pinhole-based dosemeter coupled with LR-115 Solid State Nuclear Track Detector and Direct Radon Progeny Sensor (DRPS) were respectively used for the measurement of indoor radon concentration and equilibrium equivalent concentration of radon. The indoor radon concentrations were found to vary from 102.30 Bqm-3 to 184.75 Bqm-3 and the values were within the recommended limits provided by International Commission on Radiological Protection (ICRP). The annual effective doses and excess lifetime cancer risks were observed in the range of 2.58-4.66 mSvy-1 and 7.68 × 10-3-15.60 × 10-3, respectively, and both exceed the world average values recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000. The study shows that, the houses with marble floors and concrete roofs have comparatively higher values of radon concentration, which indicates the significant contribution of construction materials to the enhanced radiation levels inside the dwellings.

Technologies for retrospective radiation dosimetry.

Radiation dosimetry is an important task for assessing the biological damages created in human being due to ionising radiation exposure. Ionising radiation being invisible and beyond the perception of human natural sensors, the dosimetry equipments/systems are the utmost requirement for its measurement. Retrospective measurement of radiation doses is a challenging task as conventional radiation dosemeters are not available at the exposure site. The material/s in close proximity of exposed individual or individuals' biological samples may be used as retrospective radiation sensor for dosimetry purpose. Environment materials such as sand, bricks, ceramics, sand stones, quartz, feldspar, glasses and electronic chips have been utilised using TL (Thermoluminescence) techniques for retrospective gamma dose (min 10 cGy) measurement. Electron Spin Resonance techniques have been employed to human biological samples such as tooth enamel, bones, nails, hair, etc. and reported for dosimetry for ~20 cGy min dose measurement. Some commercial glasses have been found sensitive enough to measure the minimum gamma doses of the order of 100 cGy using TL techniques. For internal retrospective dosimetry, the radioactivity contamination assessment in food items, water, other edible product and ambient air are the prerequisites. The radioactivity concentration vis-à-vis their consumption rate may help in controlling the internal contamination and estimation of dose absorption in human body. Defence Laboratory, Jodhpur has been working extensively on the dosimetry techniques for external dose measurement using environmental material and developed portable contamination monitoring systems for food and water radioactivity measurement in the range of 50 Bq kg-1 to 1000 kBq kg-1 in 60 s measurement time. The recent research and development in the methodologies, equipments and systems undertaken towards capacity building and self-reliance in retrospective radiation dosimetry is reported in this paper.

Monitoring of terrestrial gamma dose rate from the Kumaun Himalayan region of the Bageshwar district in Uttarakhand, India.

The present study is carried out in 42 sampling sites for the measurement of background gamma dose rate in six tehsils of the Bageshwar district that comes under the Kumaun Himalaya, Uttarakhand. The annual effective dose in the pre-monsoon and post-monsoon seasons was estimated from the measured values of the Gamma dose rate. It is found that the minimum and maximum values ranged between 0.01-0.39 mSv per y (Arithmetic Mean = 0.19 mSv per y) in the pre-monsoon and 0.11-0.42 mSv per y (Arithmetic Mean = 0.20 mSv per y) in the post-monsoon season of the year. The finding of the present study shows that the annual effective dose equivalent is higher than the worldwide average value recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation.

Gamma-ray shielding characteristics of concrete containing different percentage of ceramics for different energies.

To shield people from dangerous gamma radiation, it is imperative to fabricate inexpensive and environmentally friendly materials. In the present work, suitability of concrete with various % concentrations of ceramics as gamma-ray shielding material has been studied. In this regard, concrete mixture using M-sand and cement with ceramic as filler in different concentrations has been prepared. The mass attenuation coefficients of the prepared samples were measured for different concentrations of ceramics such as 15, 30, 45 and 60%. The mass attenuation coefficients, half value layer (HVL) and tenth vale layer (TVL) of the prepared samples were determined using gamma-ray spectrometer with NaI(Tl) detector at 511, 661.6, 1173, 1332 keV gamma energies. Experimentally obtained mass attenuation coefficients varied from 0.080 to 0.090, 0.074 to 0.086, 0.056 to 0.072 and 0.054 to 0.055 cm2 g-1 at 511, 662, 1173 and 1332 keV, respectively. Therefore concrete mixture with ceramics filler could be a promising shielding material than the bare concrete.

Radiation dose due to uranium in groundwater to the population of Chamarajanagar district, Karnataka, India.

This paper presents the concentration of uranium in 67 groundwater samples of Chamarajanagar district, Karnataka, India, estimated using an LED fluorimeter. The age-dependent ingestion dose to the population of the district is also studied. The concentration of uranium in groundwater varied from 0.20 to 57.50 µg L-1 with an average of 4.40 µg L-1. The annual ingestion dose due to uranium varies from 0.18 to 142.68 µSv y-1, with an average of 7.11 µSv y-1. The ingestion dose received by the population in the study area is less than the recommended level of 100 µSv y-1 by the World Health Organization (2011).

Measurement of indoor radioactivity and dose derived from 222Rn, 220Rn and EECs by using SSNTD based technique.

Alpha flux radiated from 222Rn, 220Rn and progeny is the primary contributor of natural radioactivity to the inhabitants in the ambient atmosphere. The annual indoor 222Rn and 220Rn concentrations were found to be 85 ± 43 and 84 ± 36 Bq m-3, respectively. The estimated annual indoor 222Rn and 220Rn concentration is below to reference value of 100 Bq m-3 suggested by WHO. The calculated annual inhalation dose due to exposure to the alpha flux of 222Rn, 220Rn and their progeny is well below the recommended reference level given by UNSCEAR and ICRP. The data were further checked for normalisation and found that 222Rn and Effective Equilibrium Radon Concentration (EERC) data are not normally distributed.

Neutron spectrum measurements near KAMINI reactor south beam vault door using nested neutron spectrometer.

KAlpakkam MINI reactor (KAMINI) is a 233U fuelled research reactor has various neutron irradiation locations for experimental purposes. The pit at the south beam end of KAMINI reactor is being extensively utilised for neutron attenuation experiments in prospective shielding materials as well as for neutron radiography. During reactor operation, it will be closed by a movable shield. A vault door is located above the shield and the movable shield is used to attenuate streaming neutrons and gamma-rays during reactor operation. Even with the shield, there exists significant dose because of streaming neutrons and gamma rays. Its variation depends on the power of the reactor. The neutron and gamma dose rates close to the south beam vault door have recently been found to be 275-300 µSv/h and 175-200 µSv/h, respectively, when the reactor is operating at 10 kW. In order to characterise the streaming neutron spectra of vault door place for the first time, measurements are done using the Nested Neutron Spectrometer. Along with the neutron flux, neutron mean energy and ambient dose-equivalent rate are also measured and compared with earlier measurements carried out inside the south beam pit. It is observed that the presence of paraffin shield reduces the neutron average energy from 370 to 178 keV. Apart from energy reduction, 10 kW normalised neutron flux of south beam pit is also attenuated by the shield by 25 000 times and it is found that the neutron spectrum of the measured location is also more thermalized. Neutron reference data of the location are generated.

60Co gamma radiation effects on NPN transistor at cryogenic temperature.

The 60Co gamma radiation effects on the DC electrical characteristics of silicon NPN transistor were studied in the dose range of 100 krad to 6 Mrad at room temperature (300 K) and cryogenic temperature (77 K). The measurements were carried out at both 300 and 77 K temperature. The electrical characteristics such as Gummel characteristics, excess base current (ΔIB), current gain (hFE), transconductance (gm) and output characteristics were studied in situ as a function of total dose. The results show that there is a considerable degradation in the electrical parameters of the device irradiated both at 300 and 77 K as a consequence of increase in excess base current (ΔIB) because of the formation of generation and recombination centers in the emitter-base spacer oxide (SiO2). At cryogenic temperature irradiation, the degradation in electrical characteristics is less because of the physical phenomena such as carrier freezeout effect, decreased recombination rate, reduced charge yield, decreased electron mobility, etc.

Measurements of radon exhalations and radiological doses using LR-115 (II) nuclear track detectors in Tiru region of the Naga Schuppen Belt, India.

In this present study, the nuclear track detector LR-115 (II) was employed to assess radon (222Rn) exhalation rate, effective radium (226Ra) content, and the annual effective dose from coal and soil samples collected in and around the coal mining area of Tiru region of Nagaland, India. The 222Rn mass and surface exhalation rates and 226Ra contents were found to be in the ranges of 7.3-17.3 mBq kg-1 h-1, 242.9-573.6 mBq m-2 h-1 and 1.0-2.3 Bq kg-1, respectively, for coal and 15.8-22.0 mBq kg-1 h-1, 523.8-730.4 mBq m-2 h-1 and 2.1-2.9 Bq kg-1, respectively, for soil. The 222Rn exhalation rates and 226Ra contents in soils were found to be higher than in coal. The estimated annual effective doses for coal and soils were found to be in the ranges of 17.6-41.6 and 38.0-53.0 µSv y-1, respectively. This study is an important contribution to the understanding of radiation exposure in the coal mining area of the thrust-bound sedimentary sequence of the Naga Schuppen Belt, and it would have potential impact on further human health studies. However, the measured values for all the samples were found to be within the globally recognised permissible range.