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Background Purpose Methods Results Conclusion The increasing use of nuclear medicine and PET imaging has intensified scrutiny of radiotracer extravasation. To our knowledge, this topic is understudied but holds great potential for enhancing our understanding of extravasation in clinical PET imaging.This work aims to (1) quantify the absorbed doses from radiotracer extravasation in PET imaging, both locally at the site of extravasation and with the extravasation location as a source of exposure to bodily organs and (2) assess the biological ramifications within the injection site at the cellular level.A radiation dosimetry simulation was performed using a whole‐body 4D Extended Cardiac‐Torso (XCAT) phantom embedded in the GATE Monte Carlo platform. A 10‐mCi dose of 18F‐FDG was chosen to simulate a typical clinical PET scan scenario, with 10% of the activity extravasated in the antecubital fossa of the right arm of the phantom. The extravasation volume was modeled as a 5.5 mL rectangle in the hypodermal layer of skin. Absorbed dose contributions were calculated for the first two half‐lives, assuming biological clearance thereafter. Dose calculations were performed as absorbed doses at the organ and skin levels. Energy deposition was simulated both at the local extravasation site and in multiple organs of interest and converted to absorbed doses based on their respective masses. Each simulation was repeated ten times to estimate Monte Carlo uncertainties. Biological impacts on cells within the extravasated volume were evaluated by randomizing cells and exposing them to a uniform radiation source of 18F and 68Ga. Particle types, their energies, and direction cosines were recorded in phase space files using a separate Geant4 simulation to characterize their entry into the nucleus of the cellular volume. Subsequently, the phase space files were imported into the TOPAS‐nBio simulation to assess the extent of DNA damage, including double‐strand breaks (DSBs) and single‐strand breaks (SSBs).Organ‐level dosimetric estimations are presented for 18F and 68Ga radionuclides in various organs of interest. With 10% extravasation, the hypodermal layer of the skin received the highest absorbed dose of 1.32 ± 0.01 Gy for 18F and 0.99 ± 0.01 Gy for 68Ga. The epidermal and dermal layers received absorbed doses of 0.07 ± 0.01 Gy and 0.13 ± 0.01 Gy for 18F, and 0.14 ± 0.01 Gy and 0.29 ± 0.01 Gy for 68Ga, respectively. In the extravasated volume, 18F caused an average absorbed dose per nucleus of 0.17 ± 0.01 Gy, estimated to result in 10.58 ± 0.50 DSBs and 268.11 ± 12.43 SSBs per nucleus. For 68Ga, the absorbed dose per nucleus was 0.11 ± 0.01 Gy, leading to an estimated 6.49 ± 0.34 DSBs and 161.24 ± 8.12 SSBs per nucleus. Absorbed doses in other organs were on the order of micro‐gray (µGy).The likelihood of epidermal erythema resulting from extravasation during PET imaging is low, as the simulated absorbed doses to the epidermis remain below the thresholds that trigger such effects. Moreover, the organ‐level absorbed doses were found to be clinically insignificant across various simulated organs. The minimal DNA damage at the extravasation site suggests that long‐term harm, such as radiation‐induced carcinogenesis, is highly unlikely. [ABSTRACT FROM AUTHOR]

Background: Peptide receptor radionuclide therapy (PRRT) with [177Lu]Lu-DOTA-TATE has emerged as a promising treatment for gastroenteropancreatic neuroendocrine tumours (GEP-NETs). Its treatment protocol is currently standardised for all patients, resulting in different patient outcomes. This study investigates the variability of tumours and organs-at-risk (kidneys and red marrow) dosimetric parameters across treatment cycles in patients with pancreatic and intestinal NETs. Data from 37 patients enrolled in a prospective phase II study (LuMEn) were analysed. Treatment consisted of four cycles of [177Lu]Lu-DOTA-TATE administered 8–12 weeks apart. Three-time-point SPECT/CT imaging was performed after each treatment cycle, and dosimetry of tumours and organs-at-risk (kidneys and red marrow) was conducted following the medical internal radiation dose formalism. Coefficients of variation (CoV) assessed the variability of absorbed doses, activity concentrations on day 1, and effective half-lives. Linear mixed effect models (SAS software) were used to investigate the evolution of the dosimetric parameters over cycles, discerning between different primary NET types and grades of tumours. Results: There is an important variability in absorbed doses and activity concentrations among patients, particularly in tumours (CoV: ~50%). Tumour absorbed doses and activity concentrations decreased over treatment cycles in pancreatic NETs, although at a limited rate (~-13%/cycle). An opposite trend was observed for the kidneys (~ + 8%/cycle). Effective half-lives remained relatively constant across cycles for both organs-at-risk and tumours. The primary NET type significantly influenced effective half-lives in tumours, shorter in pancreatic NETs than intestinal NETs (77 h vs. 107 h, p < 0.0001). No significant effect of the grade was observed on either of the variables investigated. Conclusions: Our study revealed considerable variations in tumour absorbed doses among patients with NETs treated with a standardized protocol. These findings confirm the need for personalized dosimetry approaches in PRRT, considering patient and tumour characteristics. Trial registration: EudraCT Number: 2012-003666-41. Clinicaltrials.gov identifier: NCT01842165. Registered 25 April 2013, https://clinicaltrials.gov/ct2/show/NCT01842165. [ABSTRACT FROM AUTHOR]

• Radiation protection experiment conducted on the ISS. • A new polymer composite for protection against cosmic radiation has been developed. • 2 containers were made from a new material and sent into space. • The attenuation coefficients of the new composite were studied. • Studied the change in the properties of the composite after testing in space. The article presents the results of polymer composite testing on the Russian segment of the International Space Station (ISS) during 225 days. For the space experiment "Shielding Composite" two cylinder-shaped composite containers were manufactured. Inside the containers there were detectors for dose registration during the orbital space flight. Presents the results of research on the first container, which was lowered to Earth in 2022. As a result of the space experiment "Shielding Composite", it was found that the attenuation ratio of the absorbed dose of space ionizing radiation (Inner sensor value/Outdoor sensor value) with a shield wall thickness of 10 mm was 0.71 ± 0.02 for container No. 1. There is no induced radiation in the container after its descent to Earth. [ABSTRACT FROM AUTHOR]

Despite a rise in clinical use of radiopharmaceutical therapies, the biological effects of radionuclides and their relationship with absorbed radiation dose are poorly understood. Here, we set out to define this relationship for Auger electron emitters [99mTc]TcO 4 − and [123I]I− and β−-particle emitter [188Re]ReO 4 −. Studies were carried out using genetically modified cells that permitted direct radionuclide comparisons. Triple-negative MDA-MB-231 breast cancer cells expressing the human sodium iodide symporter (hNIS) and green fluorescent protein (GFP; MDA-MB-231.hNIS-GFP) were used. In vitro radiotoxicity of [99mTc]TcO 4 −, [123I]I−, and [188Re]ReO 4 − was determined using clonogenic assays. Radionuclide uptake, efflux, and subcellular location were used to calculate nuclear absorbed doses using the Medical Internal Radiation Dose (MIRD) formalism. In vivo studies were performed using female NSG mice bearing orthotopic MDA-MB-231.hNIS-GFP tumors and compared with X-ray–treated (12.6-15 Gy) and untreated cohorts. Absorbed dose per unit activity in tumors and sodium iodide symporter–expressing organs was extrapolated to reference human adult models using OLINDA/EXM. [99mTc]TcO 4 − and [123I]I− reduced the survival fraction only in hNIS-expressing cells, whereas [188Re]ReO 4 − reduced survival fraction in hNIS-expressing and parental cells. [123I]I− required 2.4- and 1.5-fold lower decays/cell to achieve 37% survival compared with [99mTc]TcO 4 − and [188Re]ReO 4 −, respectively, after 72 hours of incubation. Additionally, [99mTc]TcO 4 −, [123I]I−, and [188Re]ReO 4 − had superior cell killing effectiveness in vitro compared with X-rays. In vivo, X-ray led to a greater median survival compared with [188Re]ReO 4 − and [123I]I− (54 days vs 45 and 43 days, respectively). Unlike the X-ray cohort, no metastases were visualized in the radionuclide-treated cohorts. Extrapolated human absorbed doses of [188Re]ReO 4 − to a 1 g tumor were 13.8- and 11.2-fold greater than for [123I]I− in female and male models, respectively. This work reports reference dose-effect data using cell and tumor models for [99mTc]TcO 4 −, [123I]I−, and [188Re]ReO 4 − for the first time. We further demonstrate the tumor-controlling effects of [123I]I− and [188Re]ReO 4 − in comparison with external beam radiation therapy. [ABSTRACT FROM AUTHOR]

Purpose: [177Lu]Lu-DOTATATE is an established somatostatin receptor (SSTR) agonist for the treatment of metastasized neuroendocrine neoplasms, while the SSTR antagonist [177Lu]Lu-DOTA-LM3 has only scarcely been employed in clinics. Impressive preclinical data obtained with [161Tb]Tb-DOTA-LM3 in tumor-bearing mice indicated the potential of terbium-161 as an alternative to lutetium-177. The aim of the present study was to compare the tolerability of 161Tb- and 177Lu-based DOTA-LM3 and DOTATATE in immunocompetent mice. Methods: Dosimetry calculations were performed based on biodistribution data of the radiopeptides in immunocompetent mice. Treatment-related effects on blood cell counts were assessed on Days 10, 28 and 56 after application of [161Tb]Tb-DOTA-LM3 or [161Tb]Tb-DOTATATE at 20 MBq per mouse. These radiopeptides were also applied at 100 MBq per mouse and the effects compared to those observed after application of the 177Lu-labeled counterparts. Bone marrow smears, blood plasma parameters and organ histology were assessed at the end of the study. Results: The absorbed organ dose was commonly higher for the SSTR antagonist than for the SSTR agonist and for terbium-161 over lutetium-177. Application of a therapeutic activity level of 20 MBq [161Tb]Tb-DOTA-LM3 or [161Tb]Tb-DOTATATE was well tolerated without major hematological changes. The injection of 100 MBq of the 161Tb- and 177Lu-based somatostatin analogues affected the blood cell counts, however. The lymphocytes were 40–50% lower in treated mice compared to the untreated controls on Day 10 irrespective of the radionuclide employed. At the same timepoint, thrombocyte and erythrocyte counts were 30–50% and 6–12% lower, respectively, after administration of the SSTR antagonist (p < 0.05) while changes were less pronounced in mice injected with the SSTR agonist. All blood cell counts were in the normal range on Day 56. Histological analyses revealed minimal abnormalities in the kidneys, liver and spleen of treated mice. No correlation was observed between the organ dose and frequency of the occurrence of abnormalities. Conclusion: Hematologic changes were more pronounced in mice treated with the SSTR antagonist than in those treated with the SSTR agonist. Despite the increased absorbed dose delivered by terbium-161 over lutetium-177, [161Tb]Tb-DOTA-LM3 and [161Tb]Tb-DOTATATE should be safe at activity levels that are recommended for their respective 177Lu-based analogues. [ABSTRACT FROM AUTHOR]

Background: The CQ$C_Q$ formalism proposed by Watson et al. allows users of the INTRABEAM (Carl Zeiss Medical AG, Jena, Germany) electronic brachytherapy system to accurately determine the absorbed dose to water, in the absence of a primary dosimetry standard. However, all published CQ$C_Q$ values are for PTW 34013 ionization chambers calibrated in a TW30 reference beam, traceable to PTB (Germany). For North American users, it would be advantageous to have CQ$C_Q$ data for chambers calibrated in a kV reference beam maintained by the National Institute of Standards and Technology (NIST). Purpose: In this work, we determine CQ$C_Q$ for a PTW 34013 chamber calibrated in three NIST‐traceable reference beams: M30, L40, and L50. Methods: Using available photon spectra data for M30, L40, and L50 reference beam qualities, Monte Carlo simulations using EGSnrc were performed to calculate the ratio of the absorbed dose to the PTW 34013 chamber air cavity to air‐kerma (Dgas/Ka$D_{\textrm {gas}}/K_a$) for these beams. From this ratio, CQ$C_Q$ as a function of depth in water was determined. The effect of the use of a buildup foil was also investigated. An uncertainty analysis considering both the Type A and Type B uncertainties in the calculation of CQ$C_Q$ was performed. Results: The largest difference in CQ$C_Q$ was found between L50 and TW30, with a relative decrease of 1.4% (no buildup) to 1.6% (buildup). For M30 and L40, the differences were minimal compared with measurement uncertainties. Conclusions: We report CQ$C_Q$ values for three NIST‐traceable kV reference beams. This study reinforces the feasibility of adapting the Watson et al. methodology using different kV reference beams, facilitating the use of INTRABEAM in North America and ensuring the continuity and accuracy of dosimetry standards in intraoperative radiation therapy. [ABSTRACT FROM AUTHOR]

Purpose: To study the adaptation of bacteria to the natural γ-background of mountains and anthropogenic emissions from nuclear power plants; to establish the main factors of variability and speciation of bacteria. Method: Analysis of materials on the radiation background and its impact on living organisms in the landscape of Armenia, calculation of the absorbed dose by microbes due to rock radiation. Results: The review shows the death, reproduction, radioresistance and speciation of bacteria in changing conditions of low variable natural and anthropogenic γ-background. Conclusion: We assume that γ-rays from rocks activate cellular epigenetic mechanisms that regulate genome expression, signaling and, ultimately, variability of bacteria. Some of them have already been studied, others require research. [ABSTRACT FROM AUTHOR]

Radiolysis of transplutonium elements and rare earths (REE)-containing solutions in radiochemical processes destroys complexing reagents and precipitates target products. We investigated the effect of the radiation-absorbed dose (AD) and acidity on the behavior of simulated DTPA and NTA REE-containing solutions to eliminate precipitation. We measured the AD by bichromate dosimetry. Without nitric acid, the AD = 0.12–0.24 MGy causes abundant precipitation of REEs. In the presence of HNO3 up to 2 mol L−1, no precipitation occurred up to 1.53 MGy. At HNO3 1 mol L−1 and AD = 1.02 MGy, DTPA is entirely decomposed. We have suggested a method to avoid precipitation. [ABSTRACT FROM AUTHOR]

The activity concentrations of 238U, 232Th, and 40K were determined at 56 sites along the East Coast of India, near the Bay of Bengal, with 31 sites in Odisha and 25 in Andhra Pradesh. In Odisha, average concentrations were 109 ± 13 Bq kg−1 for 238U, 296 ± 27 Bq kg−1 for 232Th, and 450 ± 33 Bq kg−1 for 40K, while in Andhra Pradesh, they were 51 ± 13 Bq kg−1, 149 ± 16 Bq kg−1, and 236 ± 21 Bq kg−1, respectively. Absorbed dose rates and annual effective doses were higher outdoors and indoors in Odisha compared to Andhra Pradesh. The calculated radiological parameters exhibited elevated values at certain sampling locations; however, overall, the values generally complied with regulatory standards. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a widely used biopolymer and is currently produced on a global scale. However, PLA has low melt strength, which limits its application. Poly(butylene adipate-co-terephthalate) (PBAT) is a fully biodegradable polymer and one of the most attractive polymers for hardening PLA. As PLA and PBAT are immiscible, they need to be compatibilized to improve the properties of the blend. In this context, the compatibilization of PLA/PBAT blends was investigated through an irradiation process. PLA was previously irradiated, at different absorbed doses, in a cobalt-60 source to assess the compatibility of its blends with PBAT. Differential scanning calorimetry showed a reduction in the glass transition, cold crystallization and melting temperatures, and a second melting peak was observed after polymer irradiation. Also, X-ray diffraction analyses revealed a slight increase in the crystalline fraction. Thermogravimetric analysis showed that as the absorbed dose increased, the thermal stability of PLA decreased. Fourier-transform infrared spectroscopy shows bands attributed to oxidized terminations of polymer chains with carbonyls attributed to the effect of irradiation exposure. For samples irradiated above 100 kGy, an increase in tensile strength and tensile modulus can be observed as the dose increases. Rheological measurements showed a decrease in the complex viscosity of irradiated PLA with increasing absorbed dose. The surface of the polymer blend with PLA irradiated with gamma rays at 150 kGy appears to be more homogeneous according to scanning electron analysis. The polymer blend with 150 kGy irradiated PLA showed improved interaction between the components. [ABSTRACT FROM AUTHOR]

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The main goal of this study is to test the utility of calyculin A induced G2-PCC assay as a biodosimetry triage tool for assessing a wide range of low and acute high radiation dose exposures of photons. Towards this initiative, chromosome aberrations induced by low and high doses of x-rays were evaluated and characterized in G2-prematurely condensed chromosomes (G2-PCCs) by fluorescence in situ hybridization (FISH) using human centromere and telomere specific PNA (peptide nucleic acid) probes. A dose dependent increase in the frequency of dicentric chromosomes was observed in the G2-PCCs up to 20 Gy of x-rays. The combined yields of dicentrics and rings in the G2-PCCs showed a clear dose dependency up to 20 Gy from 0.02/cell for 0.1 Gy to 14.98/cell for 20 Gy. Centric rings were observed more frequently than acentric ring chromosomes in the G2-PCCs at all the radiation doses from 1 Gy to 20 Gy. A head-to-head comparison was also performed by FISH on the yields of chromosome aberrations induced by different doses of x-rays (0 Gy -7.5 Gy) in colcemid arrested metaphase chromosomes and calyculin A induced G2-PCCs. In general, the frequencies of dicentrics, rings and acentric fragments were slightly higher in G2-PCCs than in colcemid arrested metaphase chromosomes at all the radiation doses, but the differences were not statistically significant. To reduce the turnaround time for absorbed radiation dose estimation, attempt was made to obtain G2-PCCs by reducing the culture time to 36 hrs. The absorbed doses estimated in x-rays irradiated (0,1,2 and 4 Gy) G2-PCCs after 36 hrs of culture were grossly like that of G2-PCCs and colcemid arrested metaphase chromosomes prepared after 48 hrs of culture. Our study indicates that the shortened version of calyculin A induced G2-PCC assay coupled with the FISH staining technique can serve as an effective triage biodosimetry tool for large-scale radiological/nuclear incidents. [ABSTRACT FROM AUTHOR]

This study investigates the levels of natural and artificial radioactivity in rice samples collected from various local markets in Islamabad, Pakistan. The 226Ra, 232Th, and 40K activity concentrations were measured through gamma-ray spectrometry with a NaI(Tl) detector. The average activity concentrations were 1.67 ± 1.19 Bq kg−1 for 226Ra, 3.31 ± 1.83 Bq kg−1 for 232Th, and 88.51 ± 11.65 Bq kg−1 for 40K. Calculated radium equivalent (Raeq) values ranged from 7.35 to 18.08 Bq kg−1, with a mean value of 11.11 Bq kg−1, all below the permissible maximum of 370 Bq kg−1. The absorbed dose rates ranged from 6.85 to 16.39 nGy h−1, with an average of 10.64 nGy h−1, falling below the acceptable limit of 51 nGy h−1. The outdoor and indoor radiation hazard indices (Hex and Hin) had mean values of 0.03, both below the threshold value of one. The external and internal hazard indices (Iγ and Iα) were both 0.088, also below the critical value of one. The excess lifetime cancer risk (ELCR) ranged from 0.28 to 0.11, with a mean value of 0.18, which is less than the critical value of one. Overall, the radioactivity levels in the analyzed rice samples are within the acceptable limits set by the International Commission on Radiological Protection and are below global averages. These results offer important insights into the radiological safety of rice consumption in the study area. [ABSTRACT FROM AUTHOR]

A toxicokinetic model of the pyrethroid insecticide lambda-cyhalothrin (LCT) was developed to relate absorbed doses to urinary cis-3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylic acid (CFMP) metabolite levels used as a biomarker of exposure. The model then served to reconstruct absorbed doses in agricultural workers and their probability of exceeding the EFSA Acceptable occupational Exposure Level (AOEL). The toxicokinetic model was able to reproduce the temporal profiles of CFMP in the urine of operators spraying pesticides using the optimized model parameters (adjusted to human volunteer data). Modeling also showed that simulation of an inadvertent oral exposure mainly was the exposure scenario giving the best fit to CFMP urinary time-course data in applicators. With the dermal model parameters optimized from data in volunteers, simulation of a dermal exposure in applicators did not allow to reproduce the observed peak excretions and urinary metabolite levels; extremely high applied dermal doses would be required but still simulated dermal penetration rate would remain too slow. Simulation of an inhalation exposure allowed to reproduce the observed time-courses, but with unrealistic air concentrations. For applicators with the highest urinary concentrations, there was a probability of exceeding the AOEL at some points during the biomonitoring period [>50% probability of exceeding for 27% of 24-h samples]; for non-applicator workers the probability of exceeding the AOEL value was very low [corresponding value of 5%]. Furthermore, the median [95% CI] estimates of 10 000 Monte Carlo simulations led to a biological reference value corresponding to the AOEL of 116 [113–119] ng/kg bw/d and 7.5 [7.3–7.7] μg/L. Overall, 7% of applicators and 1% of workers performing weeding and strawberry picking had a probability of exceeding this biological reference value. As a next step, it would be interesting to apply these methods to multiple exposure to various contaminants. [ABSTRACT FROM AUTHOR]

To construct adult Japanese phantoms applicable to individual exposure dose assessments, we created adult Japanese polygon mesh-type male (JPM) and female (JPF) phantoms through modification of the adult Japanese voxel phantoms, JM-103 (male) and JF-103 (female). The body sizes and masses of organs, tissues, and organ contents in JPM and JPF were adjusted to the Japanese averages, except for those unimportant for radiation protection or risks. The JPM and JPF data were converted to tetrahedral mesh-type data and incorporated into the Particle and Heavy Ion Transport code System (PHITS) for dose calculations. The dosimetric characteristics of the JPM and JPF phantoms were validated by calculating their effective doses in the anterior–posterior geometry for the external irradiation of photons with energies of 0.01–20 MeV and compared with those of JM-103 and JF-103 or the reference values given in ICRP Publication 116. The results confirmed no problems applying JPM and JPF to dose assessments in adult Japanese subjects. Furthermore, it was found that JPM and JPF can also accurately calculate the absorbed doses for entire organs and high radiosensitive cell regions with thin, small, and complicated structures. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Size‐specific dose estimates (SSDE) are used to assess patient‐specific radiation exposure in Computed Tomography (CT), complementing the volume CT dose index (CTDIvol). This study compared SSDE calculated using patient's lateral size from scan projection radiograph (SPR) with SSDE calculated using water equivalent diameter (Dw) from tomographic images in adult chest high‐resolution CT (HRCT).In a single‐centre study, the CTDIvol and dose‐length product (DLP) were recorded from HRCT dose reports of adult patients. Lateral width (SLat), at the centre of the scan range, from the SPR was measured and the SSDE (SSDER) was calculated using conversion factors related to SLat. Average CT number, area of the slice, and lateral size of the patient (AxLat) were measured on the middle slice. The Dw and SSDE from Dw (SSDEW) were calculated. SSDER and SSDEW were compared using Wilcoxon signed rank test. Correlation between patient size and dosimetry parameters were investigated using Spearman Correlation test with statistical significance at P < 0.05. Bland–Altman plot was also used to test agreement between the two SSDE values.Median CTDIvol, DLP, SSDER and SSDEW were 11.0 mGy, 372 mGy.cm, 11.6 mGy and 12.9 mGy, respectively. Small but statistically significant differences (P < 0.03) were found between SLat and AxLat as well as between SSDER and SSDEW. Bland–Altman analysis resulted in borderline agreement between SSDE values. Moderate correlations were observed between dosimetry quantities and patient size measurements (ρ > 0.640; P < 0.001). SSDEw showed statistically significant correlation (ρ = 0.587 and P < 0.001) with SSDER.SSDER may be used to assess patients' absorbed radiation dose, before the scan, in adult chest HRCT. The median value of SSDER was about 10% lower than the median value SSDEW. However, the SSDEW should be used after the scan to establish effective dose and radiation risk to the patient. [ABSTRACT FROM AUTHOR]

Objective. 177Lu-based targeted radionuclide therapy (TRT) has become an important cancer treatment option in recent years, in particular in the treatment of advanced prostate cancer and metastasized neuroendocrine tumors. Although it is known from conventional radiotherapy that the temporal dynamics of the dose-rate can be of relevance for tumor cell survival, the analysis of TRT efficacy usually considers only the absorbed dose. Thus, the aim of this theoretical analysis is to shed light on the possible effects of the pattern of dose-rate in TRT on tumor control probability (TCP). Approach. For this purpose, TCP is studied numerically in a typical four-cycle treatment regime based on the mechanistic lethal-potentially lethal model and the Zaider–Minerbo model for TCP including repopulation of tumor cells. Main results. It is shown that the dose-rate pattern in TRT can have a substantial effect on TCP even though the absorbed dose in the tumor lesion is unchanged. These dose-rate effects are particularly evident when repair of potentially lethal lesions is slow. Significance. The results indicate that in some situations in the analysis of the efficacy of TRT it is necessary to consider the full dose-rate pattern instead of the absorbed dose alone. This can be highly relevant for optimization and further development of TRTs. In particular, it could be of relevancy in studying the efficacy of newly emerging treatment concepts that combine the use of TRT and drugs that inhibit DNA damage repair. [ABSTRACT FROM AUTHOR]

This article presents the results of a study of the influence of radionuclide and chemical pollution on the morphological and anatomical parameters of Calamagróstis epigéjos plants growing in the territory of "Degelen" at the Semipalatinsk Test Site (STS). Quantitative data of morphological and anatomical parameters are given, and the content of radionuclides and toxic elements in samples of plants obtained. Statistical processing of the obtained data was conducted. The results revealed that elevated concentrations of radionuclides 137Cs and 90Sr, and the calculated absorbed dose, do not have effects on plants. Changes in the anatomical parameters of leaves and stems were observed at elevated concentrations of the elements: for leaves—Al, Pb, Sr, U, Ni, Rb, Sm; for stems—Al, Cr, Cd, U, Cu, Be, Ni, Sm, Fe. The mesophyll of the leaves and the epidermis of the stems were the most exposed to toxic elements. The data of the anatomical parameters are recommended to be used as indicative parameters of plants grown in chemically contaminated areas. [ABSTRACT FROM AUTHOR]

The assessment of potential radiation hazards in accumulated sediments in aquatic ecosystems is vital for the management and disposal of sediments. Furthermore, preemptive management of radionuclides in terrestrial ecosystems is critical for marine ecosystem conservation. We analyzed the activity concentrations of natural radionuclides (226Ra,232Th, 238U, and 40K) in the surface sediments of major river watersheds in Korea and evaluated the radiation hazards stemming from these activity concentrations. The mean activity concentrations of 226Ra and 238U were lower than the global average, whereas those of 232Th and 40K were higher. The mean values of radium equivalent activity, external hazard index, and internal hazard index calculated from these activity concentrations did not exceed the recommended maximum values. The mean values of absorbed gamma dose rate in air and annual outdoor effective dose rate (AEDRout) were higher than the global average by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) but remarkably lower than the recommended and background values by the International Commission on Radiological Protection (ICRP) and the Korea Institute of Nuclear Safety (KINS). The contribution of 40K and 232Th to the AEDRout mean value was predominant. In conclusion, the surface sediments of major river watersheds in Korea are associated with negligible radiation hazards. These findings provide fundamental data for the management and treatment of sediments in terrestrial and marine ecosystems. [ABSTRACT FROM AUTHOR]

This study analyzes the concentration of radioactive material in the soil near the Maanshan nuclear power plant (NPP). Out of the thirty samples, only one sample was found to have 137Cs radioactivity measuring 2.58 Bq/kg. The activity concentrations were 77.2–517.7 Bq/kg, 3.9–31.6 Bq/Kg, and 5.3–39.1 Bq/kg, respectively, with mean values of 344.4 Bq/kg, 18.6 Bq/kg, and 26.5 Bq/kg for 40K, 226Ra, and 232Th, respectively. These levels are lower than the global average of soil activity concentrations. The activity concentrations varied, with the highest levels being 7–8 times greater than the lowest levels. Clay content had a positive correlation and sand content had a negative correlation with 40K, 226Ra, and 232Th activity concentrations. The activity concentrations followed a normal distribution for 40K, 226Ra, and 232Th. The activity ratios for 232Th/226Ra, 40K/232Th, and 40K/226Ra were 1.43 ± 0.22, 13.1 ± 1.9, and 18.8 ± 4.1, respectively, and ratios show light minerals in the soils. The average values for external hazard indices (Hex) and radium equivalent activity (Raeq) were 0.22 Bq/kg and 83.0 Bq/kg, respectively, both of which are below the recommended limit values of 1.0 Bq/kg and 370 Bq/kg, respectively. The outdoor absorbed dose rate (DRex) and annual effective dose equivalent (AEDex) were 39.0 nGy/h and 47.8 μSv/y, respectively, both of which are lower than the global soil average of 59 nGy/h and 70 μSv/y, respectively. These results indicate that local residents and tourists are not at significant risk of radiological hazards from the soil. The soil activity concentrations can serve as a baseline for continuous monitoring, even after the Maanshan NPP is decommissioned in 2025. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusion In carbon ion radiotherapy, accurate measurement of the three‐dimensional (3D) absorbed dose distribution is critical for effectively targeting tumors. Although micellar gel dosimeters exhibit considerable potential for measuring 3D absorbed dose distributions, few studies have focused on radiotherapy using carbon ion beams.This study investigated the applicability of the surfactant hydrogel dosimeter (SHD), a micellar gel dosimeter, to measuring a 3D dose absorbed through carbon ion beam irradiation.A cubic target region of 34 mm per side was established at a depth of 46 mm below the upper surface of an SHD specimen. Scanning irradiation was performed using a pencil beam of carbon ions at the Ion‐beam Radiation Oncology Center in Kanagawa (“i‐ROCK”), Japan, under irradiation conditions set by the treatment planning system (“Monaco for Carbon”, Ver. 5.20, Elekta AB, Sweden) to create a spread‐out Bragg peak within the target. The physical dose was set to 10 Gy at the isocenter, situated at the center of the target. The SHD responsiveness was measured twice using optical computed tomography (CT) (“Vista 15”, Modus Medical Devices, Canada) for three irradiated specimens, and six types of measured optical attenuation coefficient (OAC) were obtained. To assess whether the OAC represented the absorbed dose expected in the treatment plan, we compared the relative distribution of the OAC and that of the absorbed dose. Relative fraction (RF) was used to measure the difference between the relative value of the OAC and that of the absorbed dose. Moreover, the distribution of OH radical (•OH) concentration obtained by Monte Carlo simulation (“PHITS” ver. 3.24 JAEA, Japan) and that of the OAC were compared.In the direction of beam travel, the relative distribution of the OAC was lower than that of the absorbed dose. This discrepancy could be attributed to a decrease in the concentration of •OH produced by irradiation owing to the recombination reaction, which does not accurately reflect the absorbed dose. By contrast, the distributions in the plane perpendicular to the beam travel were consistent. The RF increased from ± 3% to ± 13% along the beam travel direction. The small RF in the plane perpendicular to the beam travel could be attributed to the constant distribution of linear energy transfer, regardless of the irradiation position, and the generation of radicals proportionally to the absorbed dose. The increase in RF along the beam travel direction was ascribed to ring artifacts in the irradiated region.The measurement of the absorbed dose distribution in the beam travel direction should be improved. The observed discrepancy is attributed to the reduced reactivity of the SHD due to a high liner energy transfer near the Bragg peak. However, the absorbed dose distribution can be effectively evaluated in the plane perpendicular to the direction of beam travel. [ABSTRACT FROM AUTHOR]

Background: Boron neutron capture therapy (BNCT) is a tumor-selective particle radiotherapy that combines preferential boron accumulation in tumors and neutron irradiation. Based on previous studies in tumor-bearing mice, this study evaluated the biodistribution of the sodium salt of cobaltabis(dicarbollide) (Na[3,3′-Co(C2B9H11)2], abbreviated as Na[o-COSAN]) in the hamster cheek pouch oral cancer model and the Na[o-COSAN]/BNCT therapeutic effect on tumors and induced radiotoxicity. The synthesis and comprehensive characterization of 10B-enriched trimethylammonium salt of nido-[7,8-C210B9H12]−o-carborane, along with the cesium and sodium salts of [o-10COSAN] cobaltabis(dicarbollide) are reported here for the first time. Methods: Hamsters bearing tumors were injected with Na[o-COSAN] (7.5 mg B/kg) and euthanized at different time-points after injection (30 min, 2, 3, 5, and 18 h post-administration) to evaluate boron uptake in different tissues/organs. Based on these results, tumor-bearing animals were treated with Na[10B-o-COSAN]/BNCT (7.5 mg B/kg b.w., 3 h), prescribing 5 Gy total in absorbed dose to the precancerous tissue surrounding tumors, i.e., the dose-limiting tissue. Results: Na[o-10COSAN] exhibited no toxicity. Although biodistribution studies employing Na[o-COSAN] have shown low absolute boron concentration in the tumor (approx. 11 ppm), Na[o-10COSAN]/BNCT induced a high and significant therapeutic effect on tumors versus the control group (cancerized, untreated animals). Moreover, only half of the animals exhibited severe mucositis in the precancerous dose-limiting tissue after BNCT, which resolved completely at 21 days after irradiation. Conclusions: Na[o-10COSAN] would be potentially useful to treat head and neck cancer with BNCT. [ABSTRACT FROM AUTHOR]

The influence of absorbed dose (up to 90 kGy) and the initial concentrations of ethylene glycol and glycerol (from 30 to 250 mg/L) on their degradation in aqueous solutions under a 3-MeV electron beam has been studied. Aeration of the solutions during irradiation decreased the yield of degradation. In the absence of aeration, the observed initial yields of degradation were about 0.23 µmol/J for ethylene glycol and about 0.14 µmol/J for glycerol. Degradation products formed in aqueous solutions are more resistant to ionizing radiation compared to the parent alcohols. A simultaneous reduction in alcohol concentration and chemical oxygen demand (COD) to standard values was achieved in solutions with an initial concentration of 30–40 mg/L at a dose of no higher than 2–3 kGy. [ABSTRACT FROM AUTHOR]

Lithium tetraborate (Li2B4O7) was synthesized using the precipitation-aided high-temperature solid state technique followed by heating at various sintering temperatures. Then, Li2B4O7 was doped with Mn using several concentrations to find the optimum composition. Manganese-doped lithium tetraborate (Li2B4O7: Mn) was characterized using XRD, SEM, and TL techniques. Li2B4O7: Mn was irradiated using Sr-90 at several irradiation doses to investigate how the material responded to the β radiation. Based on this experiment, the TL dose response is linear for the absorbed dose from 10 to 30 mGy. Such a feature makes this synthesized material a promising material for dosimetry applications. [ABSTRACT FROM AUTHOR]

This study assessed radionuclide concentration in Murree's natural spring water and the variation of soil mass-attenuation coefficient. Water samples from 20 springs and soil from 15 sites were analyzed. Radium-226, Thorium-232, and Potassium-40 activity concentrations averaged 0.43 ± 0.09, 0.52 ± 0.08, and 1.52 ± 0.19 Bq/L, respectively. Radiation hazard indices, including Radium equivalent, External and Internal hazard indices, External and internal absorbed and equivalent doses, and lifetime cancer risk, were quantified but found non-alarming. Mass-attenuation coefficients for various energies were measured experimentally and theoretically. Various radiation shielding parameters were calculated. Murree's soil demonstrated lower attenuation properties compared to cement, tiles, concrete, and Egyptian soil. [ABSTRACT FROM AUTHOR]

Treated tritium-containing water is stored in tanks at the Fukushima Daiichi Nuclear Power Plant until ocean discharge is completed; however, the risk of leakage and contamination remains. We propose the combination of a superabsorbent polymer and an anion-supporting hydrogel for the safe and long-term storage of this water. The external radiation resistance of these materials in the presence of water was investigated, and their water absorption and Cs+ and I retention capacities following irradiation to a cumulative absorbed dose of up to 40 Gy were determined. The superabsorbent polymer demonstrated good water retention and Cs+ adsorption capability. The saturated I adsorption capacity of the hydrogel was 575 ± 28 mg/g, and maintained up to an absorbed dose of 100 Gy. The proposed method can be implemented until the planned completion of water processing even if the storage location has a dose rate of 100 µGy/h. [ABSTRACT FROM AUTHOR]

In the present study, the specific activities of 238U, 232Th, and 40K of 54 soil samples collected from 18 village surroundings of the Narora Atomic Power Plant, Narora are measured by utilizing a high Purity Germanium (HPGe) detector. The mean values of 226Ra, 232Th, and 40K 67.21 ± 11.88 Bqkg−1, 77.06 ± 9.94 Bqkg−1, and 843.72 ± 156.34 Bqkg−1 respectively. The absorbed gamma dose rate with standard deviation for outdoor and indoor environment is found 142.56 ± 20.07 nGyh−1 and 214.09 ± 29.01 nGyh−1. The specific activities of 226Ra, 232Th, and 40K in the soil samples are higher than the prescribed limit set by UNSCEAR. The radon mass exhalation rate also has been measured by SRM (Smart Radon Monitor) and found in the range of 28.90 to 81.90 in the unit of mBqkg−1 h−1 with the mean value of 58.78 ± 14.59 mBqkg−1 h−1. The radon emanation factor has fallen in the range of 0.07 to 0.18 with mean value as 0.12 ± 0.04. [ABSTRACT FROM AUTHOR]

One of the main problems associated with the implementation of neutron capture therapy in clinical practice, requiring a solution, is the determination of absorbed dose. The only method that directly allows measuring the absorbed does is gamma spectrometry based on the detection of gamma rays with an energy of 478 keV. This article considers the possibility of using a xenon gamma spectrometer, which has high radiation resistance to neutron fluxes. The GEANT4 software package was used to study the neutron capture therapy process and conduct corresponding calculations. [ABSTRACT FROM AUTHOR]

In recent years, prostate-specific membrane antigen (PSMA), a transmembrane glycoprotein, has emerged as a promising biomarker for theranostics, integrating diagnosis and therapy. PSMA's overexpression in various tumors, including brain metastases and high-grade gliomas, suggests its potential in neuro-oncology. Pruis et al. conducted a proof-of-concept study comparing intra-arterial (IA) and intravenous (IV) administration of 68Ga-PSMA-11 in brain tumor patients, aiming to enhance radioligand therapy (RLT) outcomes. Ten patients underwent IV and super-selective IA (ssIA) tracer administration, showing higher tumor uptake and more favorable biodistribution after ssIA administration on positron emission tomography (PET). Dosimetry modeling on the basis of PET data resulted in median absorbed radiation doses per tumor per cycle notably higher with ssIA with respect to IV administration, indicating its potential for RLT optimization. Challenges persist, notably in penetrating intact blood–brain barriers and targeting tumor cells effectively. To overcome these limitations, novel approaches like convection-enhanced delivery and focused ultrasound warrant exploration. Safety concerns, though minimal in this study, underscore the need for larger trials and AI-assisted procedures. PSMA's role in neuro-oncological theranostics is promising, but future research must address specificity and compare it with emerging targets. [ABSTRACT FROM AUTHOR]

This investigation aimed to optimize gradient positioning for radiochromic film calibration to facilitate a uniform distribution of calibration points. The study investigated the influence of various parameters on gradient dose profiles generated by a physical wedge, assessing their impact on the field's dose dynamic range, a scalar quantity representing the span of absorbed doses. Numerical parameterization of the physical wedge profile was used to visualize and quantify the impact of field size, depth, and energy on the dynamic range of dose gradients. This concept enabled the optimization of the gradient positioning and estimation of the necessary number of exposures for the desired calibration dose range. An optimization algorithm based on histogram bin height minimization was developed and presented. The maximum dynamic range was achieved with a 20 ×$\times$ 20 cm2$\textrm {cm}^{2}$ field size at 5 cm depth. Optimization of wedge gradient positioning yielded the most uniform dose distribution with 7 exposures for the [1,10] Gy range and 8 exposures for the [1,20] Gy range. Film calibration using gradients centered at 1.6, 3, 3.5, and 7 Gy central axis (CAX), obtained through optimized gradient positioning, was showcased. The presented work demonstrates the potential for an improved film calibration process, with efficient material utilization and enhanced dosimetric accuracy for clinical applications. While the method was described for the use of a physical wedge, the methodology can be easily extended to the use of a more convenient dynamic wedge. [ABSTRACT FROM AUTHOR]

Hair relaxers have been suggested as a source of exposure to parabens and phthalates. However, dermally absorbed doses of these chemicals resulting from consumer use of hair relaxers have yet to be quantified, and results from epidemiological studies have consistently demonstrated that there is no increased risk for hormone-sensitive, reproductive cancers associated with use of hair relaxers among Black women. Therefore, dermal absorption of parabens and phthalates associated with hair relaxer use for several commercially available hair relaxer kits was modeled using IH SkinPerm™. The chemicals detected in the hair relaxer kits included methylparaben (MP), ethylparaben (EP), butylparaben (BP), diethyl phthalate (DEP), bis(2-ethylhexyl) phthalate (DEHP), and the phthalate substitute bis(2-ethylhexyl) adipate (DEHA). The daily absorbed dose ranges (mg/kg/day), standardized over a year of product use, were as follows: 8.64 × 10−5-0.00116 MP, 2.30 × 10−8-3.07 × 10−6 EP, 3.24 × 10−8-4.33 × 10−6 BP, 8.65 × 10−9-1.15 × 10−6 DEP, and 8.94 × 10−7-0.000119 DEHP for Kit #1; 8.44 × 10−5-0.00113 MP and 7.91 × 10−5-0.00106 DEP for Kit #2; and 2.49 × 10−6-3.33 × 10−5 MP, 1.52 × 10−8-2.03 × 10−6 EP, 3.29 × 10−9-4.39 × 10−7 DEP, and 3.11 × 10−6-4.14 × 10−5 DEHA for Kit #3. These absorbed doses were well below applicable health-based guidance values, indicating consumer exposure from product use is not expected to pose a health risk. These results provide valuable information for health risk evaluations for hair relaxer use. [ABSTRACT FROM AUTHOR]

The study assessed the concentration of natural radionuclides in soil samples from the Bambasi district in Ethiopia's Benishangul Gumuz region using a gamma‐ray spectrometer equipped with a high‐purity germanium (HPGe) detector. The measured activity concentrations of 238U, 232Th, and 40K in soil samples varied from 46.2 ± 2.25 to 88.49 ± 5.73 Bq/kg, 73.4 ± 4.12 to 119.65 ± 8.45 Bq/kg, and 176.78 ± 8.63 to 396.71 ± 25.39 Bq/kg, respectively. The average concentration of 238U and 232Th exceeded the recommended worldwide population weighted average values of 32.0 and 45.0 Bq/kg, respectively, while the average concentration of 40K was below the recommended value of 420.0 Bq/kg. The mean absorbed dose rate was calculated to be 91.6 ± 5.1 nGy/h, which is above the recommended safe value of 59 nGy/h. The average annual effective dose equivalents for indoor and outdoor exposure were determined to be 2.65 ± 0.14 mSv/y and 0.66 ± 0.1 mSv/y, respectively. The calculated mean values of the internal hazard index, external hazard index, and gamma index across all soil samples were 0.72 ± 0.05, 0.55 ± 0.02, and 0.72 ± 0.02, respectively, all below the recommended safe threshold of one. These findings suggest that the activity concentrations observed in the soil samples exceed safe levels, indicating the necessity for further investigation into radioactivity levels and epidemiological studies regarding potential hazards from high background radiation. [ABSTRACT FROM AUTHOR]

This work aims to develop and validate a framework for the multiscale simulation of the biological response to ionizing radiation in a population of cells forming a tissue. We present TOPAS-Tissue, a framework to allow coupling two Monte Carlo (MC) codes: TOPAS with the TOPAS-nBio extension, capable of handling the track-structure simulation and subsequent chemistry, and CompuCell3D, an agent-based model simulator for biological and environmental behavior of a population of cells. We verified the implementation by simulating the experimental conditions for a clonogenic survival assay of a 2-D PC-3 cell culture model (10 cells in 10,000 µm2) irradiated by MV X-rays at several absorbed dose values from 0–8 Gy. The simulation considered cell growth and division, irradiation, DSB induction, DNA repair, and cellular response. The survival was obtained by counting the number of colonies, defined as a surviving primary (or seeded) cell with progeny, at 2.7 simulated days after irradiation. DNA repair was simulated with an MC implementation of the two-lesion kinetic model and the cell response with a p53 protein-pulse model. The simulated survival curve followed the theoretical linear–quadratic response with dose. The fitted coefficients α = 0.280 ± 0.025/Gy and β = 0.042 ± 0.006/Gy2 agreed with published experimental data within two standard deviations. TOPAS-Tissue extends previous works by simulating in an end-to-end way the effects of radiation in a cell population, from irradiation and DNA damage leading to the cell fate. In conclusion, TOPAS-Tissue offers an extensible all-in-one simulation framework that successfully couples Compucell3D and TOPAS for multiscale simulation of the biological response to radiation. [ABSTRACT FROM AUTHOR]

The objective of the study is to evaluate natural radioactivity and its radiological impact on the health of the populace within Cape Coast North. Soil and water samples were taken and analysed using a high purity germanium (HPGe) detector. Results for the average activity concentrations of 226Ra, 232Th, and 40K in soil samples range from 15.0 to 60.8 Bq/kg with a mean of 20.9 ± 7.2 Bq/kg, 16.3 to 97.2 Bq/kg with a mean of 43.8 ± 2.4 Bq/kg, and 4.7 to 411.4 Bq/kg with an average of 140.6 ± 4.2 Bq/kg, respectively. The absorbed dose rate in air and outdoor annual effective dose to the public were estimated to be 46.6 nGyh−1 and 0.1 mSv, respectively, which fell below the recommended average. The average activity concentrations of 226Ra, 232Th, and 40K in water samples were 1.4, 0.4, and 1.2 Bq/L, respectively. The annual effective dose is 0.4 mSv, which is greater than the WHO recommended level of 0.1 mSv/y. [ABSTRACT FROM AUTHOR]

The benefits of a cardiac resynchronization therapy (CRT) implantation are known in severe heart failure and its implantation may also be considered during pregnancy to ensure safe pregnancy and delivery for both the mother and the fetus. This study on a patient case aimed to estimate the absorbed dose (AD) to the fetus during the CRT implantation of 21st week of the pregnant woman. AD measurement was done using anthropomorphic phantom, radiophotoluminescence dosemeters and Monte Carlo simulation utilizing kerma area product (KAP) of the procedures. The measured AD for a phantom's uterus and heart was 0.116 and 14.7 mGy with total KAP of 27.9 Gycm2. The estimated actual AD to the fetus and the mother's heart was 0.004 and 1.2 mGy, with total KAP of 1.5 Gycm2. The dose to the fetus can be minimized with the optimized procedure. [ABSTRACT FROM AUTHOR]

Introduction Methods Results Conclusion Improvements in computed tomography (CT) technology in terms of image quality and reduction in absorbed dose have increased its applications in medical imaging. Diagnostic reference levels (DRLs) help to identify high radiation doses that are unusually delivered to patients undergoing exposure to ionising radiation. The aim of this review was to provide an overview of published studies by African researchers towards establishing paediatric CT DRLs in Africa.The search for articles was conducted using some relevant literature search engines including PubMed, Scopus, Science Direct, Google Scholar and Web of Science. Two reviewers were involved in the article selection process which involved a three‐stage screening process of identifying; article titles, abstracts and full‐test reading.One hundred and seventy‐four articles were identified from the database, PubMed (30), Scopus (21), Google Scholar (53), Web of Science (25) and Science Direct (45). Fifty duplicated articles were excluded before screening. Twelve peer‐reviewed articles were included in this study based on the inclusion criteria. DRL values in terms of computed tomography dose index volume of head for the age groupings 0–1, 1–5, 5–10 and 10–15 were 27, 36.6, 39.5 and 47.5 mGy while the dose length product values were 461.6, 664, 872 and 978 mGy.cm respectively. The DRLs were calculated as 75th percentile of the local DRLs reported by the 12 articles included in this review.This review has shown that only few of the African countries (19%) have published studies on paediatric CT DRLs. There were variations in the DRLs published by the various authors which indicate that harmonisation and standardisation of paediatric CT protocols is essential for the optimisation of paediatric doses. [ABSTRACT FROM AUTHOR]

An Addendum to the AAPM's TG‐51 protocol for the determination of absorbed dose to water is presented for electron beams with energies between 4 MeV and 22 MeV (1.70cm≤R50≤8.70cm$1.70\nobreakspace {\rm cm} \le R_{\text{50}} \le 8.70\nobreakspace {\rm cm}$). This updated formalism allows simplified calibration procedures, including the use of calibrated cylindrical ionization chambers in all electron beams without the use of a gradient correction. New kQ$k_{Q}$ data are provided for electron beams based on Monte Carlo simulations. Implementation guidance is provided. Components of the uncertainty budget in determining absorbed dose to water at the reference depth are discussed. Specifications for a reference‐class chamber in electron beams include chamber stability, settling, ion recombination behavior, and polarity dependence. Progress in electron beam reference dosimetry is reviewed. Although this report introduces some major changes (e.g., gradient corrections are implicitly included in the electron beam quality conversion factors), they serve to simplify the calibration procedure. Results for absorbed dose per linac monitor unit are expected to be up to approximately 2 % higher using this Addendum compared to using the original TG‐51 protocol. [ABSTRACT FROM AUTHOR]

Background: In radiotherapy, it is essential to deliver prescribed doses to tumors while minimizing damage to surrounding healthy tissue. Accurate measurements of absorbed dose are required for this purpose. Gafchromic® external beam therapy (EBT) radiochromic films have been widely used in radiotherapy. While the dosimetric characteristics of the EBT3 model film have been extensively studied for photon and charged particle beams (protons, electrons, and carbon ions), little research has been done on α$\alpha$‐particle dosimetry. α$\alpha$‐emitting radionuclides have gained popularity in cancer treatment due to their high linear energy transfer, short range in tissue, and ability to spare surrounding organs at risk, thereby delivering a more localized dose distribution to the tumor. Therefore, a dose‐calibration film protocol for α$\alpha$‐particles is required. Purpose: This study aimed to develop a dose‐calibration protocol for the α$\alpha$‐particle emitting radionuclide 241Am, using Monte Carlo (MC) simulations and measurements with unlaminated EBT3 films. Methods: In this study, a MC‐based user code was developed using the Geant4 simulation toolkit to model and simulate an 241Am source and an unlaminated EBT3 film. Two simulations were performed: one with voxelized geometries of the EBT3 active volume composition and the other using water. The dose rate was calculated within a region of interest in the voxelized geometries. Unlaminated EBT3 film pieces were irradiated with the 241Am source at various exposure times inside a black box. Film irradiations were compared to a 6‐MV photon beam from a Varian TrueBeam machine. The simulated dose rate was used to convert the exposure times into absorbed doses to water, describing a radiochromic‐film‐based reference dosimetry protocol for α$\alpha$‐particles. The irradiated films were scanned and through an in‐house Python script, the normalized pixel values from the green‐color channel of scanned film images were analyzed. Results: The 241Am energy spectra obtained from the simulations were in good agreement with IAEA and NIST databases, having differences <$<$0.516% for the emitted γ$\gamma$‐rays and produced characteristic x‐rays and <$<$0.006% for the α$\alpha$‐particles. Due to the short range of α$\alpha$‐particles, there was no energy deposition in the voxels outside the active 241Am source region projected onto the film surface. Thus, the total dose rate within the voxels covering the source was 0.847 ±$\pm$ 0.003 Gy/min within the sensitive layer of the film (LiPCDA) and 0.847 ±$\pm$ 0.004 Gy/min in water, indicating that the active volume can be considered water equivalent for the 241Am beam quality. A novel approach was employed in α$\alpha$‐film dosimetry using an exponential fit for the green channel, which showed promising results by reducing the uncertainty in dose estimation within 5%. Although the statistical analysis did not reveal significant differences between the 6‐MV photon beam and the α$\alpha$ calibration curves, the dose–response curves exhibited the expected behavior. Conclusions: The developed MC user code simulated the experimental setup for α$\alpha$‐dosimetry using radiochromic film with acceptable uncertainty. Unlaminated EBT3 film is suitable for the dosimetry of α$\alpha$‐radiation at low doses and can be used in conjunction with other unlaminated GafChromic® films for quality assurance and research purposes. [ABSTRACT FROM AUTHOR]

Background: Stereotactic body radiation therapy (SBRT) is known to modulate the immune system and contribute to the generation of anti‐tumor T cells and stimulate T cell infiltration into tumors. Radiation‐induced immune suppression (RIIS) is a side effect of radiation therapy that can decrease immunological function by killing naive T cells as well as SBRT‐induced newly created effector T cells, suppressing the immune response to tumors and increasing susceptibility to infections. Purpose: RIIS varies substantially among patients and it is currently unclear what drives this variability. Models that can accurately predict RIIS in near real time based on treatment plan characteristics would allow treatment planners to maintain current protocol specific dosimetric criteria while minimizing immune suppression. In this paper, we present an algorithm to predict RIIS based on a model of circulating blood using early stage lung cancer patients treated with SBRT. Methods: This Python‐based algorithm uses DICOM data for radiation therapy treatment plans, dose maps, patient CT data sets, and organ delineations to stochastically simulate blood flow and predict the doses absorbed by circulating lymphocytes. These absorbed doses are used to predict the fraction of lymphocytes killed by a given treatment plan. Finally, the time dependence of absolute lymphocyte count (ALC) following SBRT is modeled using longitudinal blood data up to a year after treatment. This model was developed and evaluated on a cohort of 64 patients with 10‐fold cross validation. Results: Our algorithm predicted post‐treatment ALC with an average error of 0.24±0.21×109$0.24 \pm 0.21 \times {10}^9$ cells/L with 89% of the patients having a prediction error below 0.5 × 109 cells/L. The accuracy was consistent across a wide range of clinical and treatment variables. Our model is able to predict post‐treatment ALC < 0.8 (grade 2 lymphopenia), with a sensitivity of 81% and a specificity of 98%. This model has a ∼38‐s end‐to‐end prediction time of post treatment ALC. Conclusion: Our model performed well in predicting RIIS in patients treated using lung SBRT. With near‐real time model prediction time, it has the capability to be interfaced with treatment planning systems to prospectively reduce immune cell toxicity while maintaining national SBRT conformity and plan quality criteria. [ABSTRACT FROM AUTHOR]

Background: Following yttrium‐90 radioembolization (90Y‐RE), 90Y‐PET/CT and 90Y‐SPECT/CT imaging provide the means to calculate the voxelized absorbed dose distribution. Given the widespread use of the two imaging modalities and lack of well‐established standardized dosimetry protocols for 90Y‐RE, there is a clinical need to systematically investigate and evaluate differences in the performance of voxel‐based dosimetry between 90Y‐PET/CT and 90Y‐SPECT/CT. Purpose: To quantitatively analyze and compare 90Y‐PET/CT and 90Y‐SPECT/CT‐based dosimetry following 90Y‐RE. Methods: 90Y‐PET/CT and 90Y‐SPECT/CT imaging was acquired for 35 patients following 90Y‐RE with TheraSphere for the treatment of unresectable hepatocellular carcinoma. Dosimetry was performed using the local deposition method with known activity and the mean dose (Dmean) was calculated for perfused liver volumes (PV), tumors (T), and perfused normal livers (NL). Additionally, the absorbed dose to x% of the volume (Dx, x ∈$ \in $ [5%, 10%, ..., 90%, 95%]) and the volume receiving y Gy (Vy, y ∈$ \in $ [10 Gy, 20 Gy, ..., 190 Gy, 200 Gy]) were calculated for T and NL, respectively. Dose metrics were compared using linear regression, Bland‐Altman analysis, and statistical testing. Results: Both 90Y‐SPECT/CT and 90Y‐PET/CT‐based tumor Dmean were strongly correlated (R2 ≥ 0.90) with Dx, excluding metrics on the extrema. Intra‐modality comparisons of various Dx and Vy metrics yielded statistically significant differences (ANOVA, p < 0.001) for both90Y‐PET/CT and 90Y‐SPECT/CT. Based on statistical testing, only Dx metrics separated by greater than 20%–30% coverage, and only Vy metrics separated by greater than 40–70 Gy, reported significant differences. For PV, there was a strong correlation (R2 ≥ 0.99) between Dmean derived separately from 90Y‐PET/CT and 90Y‐SPECT/CT imaging. The strength of the correlation was slightly reduced for T and NL with R2 = 0.91 and R2 = 0.95, respectively. For PV, the mean bias ± standard error (SE) and 95% limits of agreement (LOA) between Dmean from the two modalities was effectively zero with ‐0.8 ± 0.4% (± 2.5%). For T and NL, the mean bias ± SE (± LOA) was ‐14.5 ± 3.7% (± 24%) and 9.4 ± 4.7% (± 27%), respectively. Conclusion: The strong correlation between Dmean and Dx suggests information from multiple dose metrics (e.g., D70 and Dmean) is largely redundant when establishing dose‐response relationships in 90Y‐RE. Dmean is highly correlated between 90Y‐PET/CT and 90Y‐SPECT/CT‐based dosimetry, for all liver VOIs. Relative to 90Y‐SPECT/CT, 90Y‐PET/CT, on average, yielded higher Dmean to tumors (14%) and lower Dmean to perfused normal livers (9%). Absorbed dose differences for perfused liver volumes between 90Y‐SPECT/CT and 90Y‐PET/CT were negligible. [ABSTRACT FROM AUTHOR]

Background: Yttrium‐90 (90Y) positron emission tomography (PET)/computed tomography (CT) imaging is increasingly being used to perform tumor (T) and normal liver (NL) voxel dosimetry after 90Y‐radioembolization (90Y‐RE). Yet, the accuracy of in vivo 90Y‐PET/CT imaging, subject to motion blur and co‐registration inaccuracies, and 90Y‐PET/CT dose quantification, subject to availability of different voxel dosimetry algorithms, are not well understood. Purpose: The purpose of this study was to investigate the accuracy of 90Y‐PET/CT‐based activity estimates following 90Y‐RE and characterize differences between 90Y‐PET/CT‐based voxel dosimetry algorithms. Methods: Thirty‐five patients underwent 90Y‐PET/CT imaging after 90Y‐RE with TheraSphere. The net administered 90Y activity (Aadmin) was determined using a dose calibrator and pre‐ and post‐procedure exposure rate measurements. The summation of image‐based activity (Aimage) was extracted from perfused volume (PV) and 3D‐isotropically 2‐cm expanded PV contour (PV+2 cm). Absorbed doses were calculated using voxel S‐value (VSV), local deposition method (LDM), and LDM with known activity (LDMKA) dosimetry algorithms. Linear regression and Bland‐Altman analysis quantified the relationship between Aimage and Aadmin and between mean dose estimates (DLDM, DVSV, DLDM‐KA) for PV, T, and perfused NL volumes. Results: While Aadmin and Aimage in PV were highly correlated (R2 > 0.95), the mean bias ± standard error (SE) and (95% limits of agreement, LOA) was significantly non‐zero with −22.7 ± 4.7% (± 28.4%). In PV+2 cm, the mean bias ± SE (± LOA) decreased to 1.3 ± 3.4% (± 18.0%) consistent with zero mean error. DLDM and DVSV were highly correlated (R2 > 0.99) for all volumes of interest (VOIs) and the mean bias ± SE (± LOA) was 2.2 ± 0.2% (± 1.0%), 0.7 ± 0.4% (± 2.8%), and 3.2 ± 0.5% (± 2.8%) for PV, T, and NL, respectively. DLDM‐KA and DVSV were correlated with R2 = 0.86, 0.80, and 0.86 for PV, T, and NL, respectively. The mean bias ± SE (± LOA) between DLDM‐KA and DVSV was significantly non‐zero with −19.6 ± 5.1% (± 31.0%), −20.8 ± 4.4% (± 29.0%), and −18.1 ± 5.3% (± 31.1%) for PV, T, and NL, respectively. Conclusions: The summation of Aimage in PV was underestimated relative to Aadmin. Only by accounting for respiratory motion, limited spatial resolution, and PET/CT co‐registration errors through VOI expansion was Aimage, on average, equal to Aadmin. The differences between DLDM and DVSV were not clinically relevant, though DLDM‐KA was approximately 20% greater than DVSV. Given the high quantitative accuracy of dose calibrators and challenges associated with accurate 90Y‐PET/CT quantification, LDMKA is the preferred algorithm for accurate 90Y‐PET/CT‐based dosimetry following 90Y‐RE. [ABSTRACT FROM AUTHOR]

Natural radioactivity and trace elements content of two brands of shaving power that are commonly used by men were determined, in order to evaluate their radiological effect and health risk. The activity concentrations of the radionuclides were measured using gamma spectrometer equipped with calibrated NaI(Tl) detector system while the trace metals were measured using atomic absorption spectrophotometric (AAS) and energy dispersive x-ray fluorescence (ED-XRF) techniques. The averaged activity concentrations of 238U, 232Th and 40K were 2445.97 ± 9.29 Bq kg-1, 315.16 ± 17.72 Bq kg-1 and 50.45 ± 1.79 Bq kg-1 for 40K, 232Th and 238U, respectively. The equivalent dose had a mean value of 2.94 mSv year-1. The results of the trace elements analysis from both AAS and ED-XRF showed that iron had the highest concentration while selenium had the least concentration. ED-XRF showed a better recovery of the trace elements than AAS. The levels of the radionuclides identified were above the normal background for humans and the average concentrations of most of the trace metals were also above the permissible exposure limits, which can constitute health hazard to users of the shaving power. [ABSTRACT FROM AUTHOR]

Conventional X-ray therapy (XRT) is commonly applied to suppress cancerous tumors; however, it often inflicts collateral damage to nearby healthy tissue. In order to provide a better conformity of the dose distribution in the irradiated tumor, proton therapy (PT) is increasingly being used to treat solid tumors. Furthermore, radiosensitization with gold nanoparticles (GNPs) has been extensively studied to increase the therapeutic ratio. The mechanism of radiosensitization is assumed to be connected to an enhancement of the absorbed dose due to huge photoelectric cross-sections with gold. Nevertheless, numerous theoretical studies, mostly based on Monte Carlo (MC) simulations, did not provide a consistent and thorough picture of dose enhancement and, therefore, the radiosensitization effect. Radiosensitization by nanoparticles in PT is even less studied than in XRT. Therefore, we investigate the physics picture of GNP-enhanced RT using an MC simulation with Geant4 equipped with the most recent physics models, taking into account a wide range of physics processes relevant for realistic PT and XRT. Namely, we measured dose enhancement factors in the vicinity of GNP, with diameters ranging from 10 nm to 80 nm. The dose enhancement in the vicinity of GNP reaches high values for XRT, while it is very modest for PT. The macroscopic dose enhancement factors for realistic therapeutic GNP concentrations are rather low for all RT scenarios; therefore, other physico-chemical and biological mechanisms should be additionally invoked for an explanation of the radiosensitization effect observed in many experiments. [ABSTRACT FROM AUTHOR]

Background and objective: Treatment planning through the diagnostic dimension of theranostics provides insights into predicting the absorbed dose of RPT, with the potential to individualize radiation doses for enhancing treatment efficacy. However, existing studies focusing on dose prediction from diagnostic data often rely on organ-level estimations, overlooking intra-organ variations. This study aims to characterize the intra-organ theranostic heterogeneity and utilize artificial intelligence techniques to localize them, i.e. to predict voxel-wise absorbed dose map based on pre-therapy PET. Methods: 23 patients with metastatic castration-resistant prostate cancer treated with [177Lu]Lu-PSMA I&T RPT were retrospectively included. 48 treatment cycles with pre-treatment PET imaging and at least 3 post-therapeutic SPECT/CT imaging were selected. The distribution of PET tracer and RPT dose was compared for kidney, liver and spleen, characterizing intra-organ heterogeneity differences. Pharmacokinetic simulations were performed to enhance the understanding of the correlation. Two strategies were explored for pre-therapy voxel-wise dosimetry prediction: (1) organ-dose guided direct projection; (2) deep learning (DL)-based distribution prediction. Physical metrics, dose volume histogram (DVH) analysis, and identity plots were applied to investigate the predicted absorbed dose map. Results: Inconsistent intra-organ patterns emerged between PET imaging and dose map, with moderate correlations existing in the kidney (r = 0.77), liver (r = 0.5), and spleen (r = 0.58) (P < 0.025). Simulation results indicated the intra-organ pharmacokinetic heterogeneity might explain this inconsistency. The DL-based method achieved a lower average voxel-wise normalized root mean squared error of 0.79 ± 0.27%, regarding to ground-truth dose map, outperforming the organ-dose guided projection (1.11 ± 0.57%) (P < 0.05). DVH analysis demonstrated good prediction accuracy (R2 = 0.92 for kidney). The DL model improved the mean slope of fitting lines in identity plots (199% for liver), when compared to the theoretical optimal results of the organ-dose approach. Conclusion: Our results demonstrated the intra-organ heterogeneity of pharmacokinetics may complicate pre-therapy dosimetry prediction. DL has the potential to bridge this gap for pre-therapy prediction of voxel-wise heterogeneous dose map. [ABSTRACT FROM AUTHOR]

Purpose: Ruling out that healthy organs receive doses higher than those allowed in treatments with Iodo-131 (131I) for ablation of thyroid remnant is crucial for the radiological protection of the patient who also received the recombinant human thyroid-stimulating hormone (rhTSH). So, the investigation aimed to determine the changes in energy imparted by 131I in multiple organs due to the rhTSH in thyroid remnants and metastases of patients treated with high 131I activities (≥ 5,550 MBq). Materials and methods: Nine patients were divided into three groups (three per group); Group I included thyroid hormone withdrawal (THW) patients, while patients in groups II and III were stimulated with rhTSH. The activity and absorbed dose in regions of interest (ROIs) was quantified using the conjugated views method using gamma camera images. Results and discussion: Dosimetric variations of 131I produced by using rhTSH in the remnant thyroid (groups II and III) were observed, absorbed doses were minor for groups treated with rhTSH. Conclusion: The application of the high activities > 5,500 MBq administered together with the application of rhTSH is safe in dosimetric terms, also for 9250 MBq do not exceed established limits of absorbed dose in the bone marrow. Furthermore, these high activities provide more than three times the radiation dose to remaining thyroid tissue and approximately 1.5 times to metastases. [ABSTRACT FROM AUTHOR]

This study compares various methodologies for lung dosimetry in radioembolization using Monte Carlo (MC) simulations. A voxelized anthropomorphic phantom, created from a real patient's CT scan, preserved the actual density distribution of the lungs. Lung dosimetry was evaluated for five lung-shunt (LS) cases using traditional methods: the mono-compartmental organ-level approach (MIRD), local energy deposition (LED), and convolution with voxel S-values, either with local density corrections (SVOX_L) or without (SVOX_ST). Additionally, a novel voxel S-value (VSV) kernel for lung tissue with an ICRU density of 0.296   g / c m 3 was developed. Calculations were performed using either the ICRU lung density (Lung_296), the average lung density of the phantom (Lung_221), or the local density (Lung_L). The comparison revealed significant underestimations in the mean absorbed dose (AD) for the classical approaches: approximately − 40 % for MIRD, − 27 % for LED, − 28 % for SVOX_L, and − 88 % for SVOX_ST. Similarly, calculations with the lung VSV kernel showed underestimations of about − 62 % for Lung_296, − 50 % for Lung_221, and − 35 % for Lung_L. Given the high heterogeneity of lung tissue, traditional dosimetric methods fail to provide accurate estimates of the mean AD for the lungs. Therefore, MC dosimetry based on patient images is recommended as the preferred method for precise assessment of lung AD during radioembolization. [ABSTRACT FROM AUTHOR]

This study aimed to clarify the dosimetric impact of calibration beam quality for calibration coefficients of the absorbed dose to water for an ionization chamber in an on-site dosimetry audit. Institution-measured doses of 200 photon and 184 electron beams were compared with the measured dose using one year data before and after the calibration of the ionization chamber used. For photon and electron reference dosimetry, the agreements of the institution-measured dose against two measured doses in this audit were evaluated using the calibration coefficients determined using 60Co (⁠|${N}_{D,\mathrm{w},{}^{60}\mathrm{Co}}$|⁠) and linear accelerator (linac) (⁠|${N}_{D,\mathrm{w},Q}$|⁠) beams. For electron reference dosimetry, the agreement of two institution-measured doses against the measured dose was evaluated using |${N}_{D,\mathrm{w},Q}$|⁠. Institution-measured doses were evaluated using direct- and cross-calibration coefficients. For photon reference dosimetry, the mean differences and standard deviation (SD) of institution-measured dose against the measured dose using |${N}_{D,\mathrm{w},{}^{60}\mathrm{Co}}$| and |${N}_{D,\mathrm{w},Q}$| were −0.1% ± 0.4% and −0.3% ± 0.4%, respectively. For electron reference dosimetry, the mean differences and SD of institution-measured dose using the direct-calibration coefficient against the measured dose using |${N}_{D,\mathrm{w},{}^{60}\mathrm{Co}}$| and |${N}_{D,\mathrm{w},Q}$| were 1.3% ± 0.8% and 0.8% ± 0.8%, respectively. Further, the mean differences and SD of institution-measured dose using the cross-calibration coefficient against the measured dose using |${N}_{D,\mathrm{w},Q}$| were −0.1% ± 0.6%. For photon beams, the dosimetric impact of introducing calibration coefficients determined using linac beams was small. For electron beams, it was larger, and the measured dose using |${N}_{D,\mathrm{w},Q}$| was most consistent with the institution-measured dose, which was evaluated using a cross-calibration coefficient. [ABSTRACT FROM AUTHOR]

Purpose: To assess the number of radiotherapy kilovoltage (kV) units in service, their clinical utilization, and methodology and equipment used for absorbed dose determination across Australia and New Zealand. Methods: A survey was sent to 61 Australian and New Zealand radiotherapy providers in the second half of 2023. Results: Fifty‐seven responses were received, with 43 departments having kV units and providing beam quality data for 185 therapeutic kV beams 20–300 kVp. Percentage depth dose curves were compared between five clinical beams with 100 kVp and 2.13–6.28 mm Aluminum half value layers (HVLs), demonstrating large differences that can occur between beams with the same kVp. Eighteen departments provided clinical utilization data for their kV units, with a total of 4458 treatment courses and their corresponding kVp reported. All departments complied with national and international recommendations with respect to the equipment used for reference dosimetry of kV beams; 77% of ionization chambers used for absorbed dose determination were of Farmer‐type, with the remaining 23% being plane parallel soft x‐ray chambers. Methods of derivation of air‐kerma calibration factors varied, with 73% of respondents using a draft document disseminated by the Australian Primary Standards laboratory, 23% using HVL alone, and 6% using other methods. Conclusions: The results of this survey provide a snapshot of kilovoltage radiation therapy use and the number of kV units across Australia and New Zealand. This data can be used as a point of reference for future investigations into clinical utilization and reference dosimetry methods across Australia and New Zealand or for comparisons with other countries, facilitating standardization of reference dosimetry practice for kilovoltage units. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to systematically measure and analyze the radiation dose distribution in the abdomen and specific areas of interest on the body surface during abdominal CT scans using a dose simulation phantom, providing relevant data to assess patient radiation risks and to develop personalized radiation protection strategies. Methods: The study simulated routine clinical abdominal CT using a dose simulation phantom. Forty-two tissue detection points and eight surface points on the phantom were selected to represent major organs in the trunk and key areas of concern on the body surface. RGD-3B thermoluminescence was used to measure the dose level of the main organs and key parts of the body surface. Results: Experimental data from the dose simulation phantom were analyzed and indicated that the stomach received the highest radiation dose at 15.9 mGy, followed by the kidneys and pancreas, at 15.7 mGy and 14.4 mGy, respectively. The doses for the adrenal glands, gallbladder, and left lobe of the liver were 14.3, 13.2, and 12.9 mGy, respectively. All other areas received doses < 6.9 mGy. Surface area dose measurements showed that the left and right eye lens received a dose of 0.017 and 0.029 mGy, respectively. The dose for the thyroid was 0.062 mGy and 0.057 mGy on the left and right sides, respectively. The doses to the left and right breasts were 1.71 mGy and 1.58 mGy, respectively. The gonads received doses of 0.145 mGy and 0.090 mGy on the left and right sides, respectively. The skin entry dose at the lower edge of the breast, which is near the skin during CT scans, was between 1 and 2 mGy. Conclusion: During abdominal CT, the stomach, kidneys, and pancreas received the highest radiation doses. Although the radiation dose of sensitive areas on the body surface is lower, that in the thyroid, gonads, and lens remain higher than that in other surface tissues. These findings suggest that workers may need further protection in specific high-dose areas to reduce potential radiation hazards.

Multiple building constructions necessitating a regular influx of different soils for building purposes within Federal College of Education (Technical) Akoka, in Lagos State, Nigeria spurred a radiological risk assessment of selected soil samples. Five (5) construction points were identified and ten (10) soil samples were collected. A gamma spectrometer was used to evaluate the natural radionuclides (226Ra, 232Th, and 40K) present in the soils. IAEA-certified standard materials of RGU-1, RGTh-1, and RGK-1 were used to determine the full peak efficiencies of gamma energies 609, 1120, and 1764 keV for 238U, 2614 keV for 232Th and 1460 keV for 40K. Activity concentration, absorbed dose, annual effective dose equivalent, hazard indices, and excess lifetime cancer risk (ELCR) were estimated to assess possible radiological risks in the building soil samples. Results from the analysis revealed the highest radioactivity among soil samples was 674.3 Bq/kg from 40K and the lowest was 18.5 Bq/kg from 226Ra. The absorbed dose (D) varies from 65.8 nGy/h to 215.3 nGy/h with an average value of 136.6 nGy/h, and the annual effective dose equivalent ranged from 0.081 mSv/y to 0.264 mSv/y with an average value 0.168 mSv/y. The internal and external hazard index ranged from 0.49 −1.46 and 0.39 − 1.32 respectively which is not completely below the hazard index threshold value ≤1 as recommended by UNSCEAR. The ELCR values ranging from 0.222 × 10-3 − 0.726 × 10- 3 with an average value of 0.461 × 10-3 predicted an insignificant carcinogenic risk with the probability of four persons in every 10,000 persons.