Natural radioactivity due to ²²⁶Ra, ²³²Th and ⁴⁰K in the rock samples collected from Dhanbad city of Jharkhand, India was measured using gamma-ray spectrometry. The concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in the studied rock samples range from below the detection limit to 3.08 Bq/kg, 5.35-37.39 Bq/kg and 168.8-416.9 Bq/kg, respectively. The concentrations of these radionuclides are compared with the recommended values. To evaluate the radiological impact of the natural radioactivity, the radium equivalent activity, the annual effective dose rate, the values of both external and internal indices and the gamma index were estimated and compared with the internationally acceptable values.

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The activity concentrations of the naturally occurring nuclides ²²⁶Ra, ²²⁸Ra, and ⁴⁰K were determined in vegetable crops largely consumed by people in Jordan. Samples of potatoes, tomatoes, cucumber, radish, spinach, and cabbage were collected from several markets in the capital Amman. The activity concentrations in Bq/kg of ²²⁶Ra, ²²⁸Ra and ⁴⁰K were measured by the gamma-ray spectroscopy using the high purity germanium detector. The ranges of the activity concentration of ²²⁶Ra, ²²⁸Ra and ⁴⁰K in the chosen vegetables were found to be 7.1–11.7 Bq/kg, nondetectable - 3.3 Bq/kg, and 201–684 Bq/kg, respectively. The daily intake of ⁴⁰K was the highest among the radioisotopes measured, but it was lower than the intake in other countries. The estimated total annual effective dose resulting from the ingestion of the above-mentioned vegetable samples is 51.56 µSv/y according to the measured activity concentration of ²²⁶Ra, ²²⁸Ra, and ⁴⁰K. ²²⁶Ra was the highest contributor to the total annual effective dose (23.98 μSv/y).

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A study was carried out to estimate the ingestion dose for the general population residing around Kalpakkam nuclear site due to ⁴⁰K activity in the fresh and cooked food samples collected from the surrounding areas. For the estimation of specific activity of ⁴⁰K, food samples consisting of 31 numbers of market basket samples (MBS) and 33 numbers of duplicate diet samples (DDS) were collected, conditioned, and analyzed by gamma spectrometry. The annual effective dose (AED) received by the population was estimated based on ⁴⁰K activity in the food samples, food consumption data, and ICRP model. Uncertainty associated with the estimates was quantified based on the guide to the expression of uncertainty in measurement framework approach. The ⁴⁰K specific activity in MBS ranged from 10.44 ± 1.11 to 129.00 ± 13.64 Bq/kg fresh weight. Similarly, the ⁴⁰K specific activity in DDS ranged from 10.85 ± 1.10 to 60.71 ± 6.15 Bq/kg fresh weight. The AED due to the ingestion of ⁴⁰K estimated based on MBS was 93.81 ± 7.30 μSv/year. Similarly, the AED due to the ingestion of ⁴⁰K estimated based on DDS was 33.47 ± 0.79 μSv/year among males and 26.31 ± 0.62 μSv/year among females.

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Natural radioactive substances may be present in the environmental substances that have uses in pharmacy and medicine as health supplements. This paper presents natural radioactivity levels in some of the medicinal plants available in Egypt. Natural radionuclides such as ²²⁶Ra, ²²⁸Ra, and ⁴⁰K were measured in medicinal plants samples collected from the local market in Qena, Upper Egypt. All measurements were performed with a gamma spectrometry with high-purity germanium detector. The radioactivity concentration ranged from 0.4 ± 0.2 to 21.0 ± 1.2 Bq/kg for ²²⁶Ra, from <0.3 to 42.3 ± 5.9 Bq/kg for ²²⁸Ra, and from 140 ± 6 Bq/kg to 1538 ± 54 Bq/kg for ⁴⁰K. The total annual committed effective doses ranged from 0.003 to 0.073 mSvy⁻¹ with an average value of 0.02 mSva⁻¹

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Monitoring of radiation workers of fuel reprocessing plant and fuel fabrication facility for internal contamination is carried out by analyzing their urine and fecal samples. Assessment of intake is made from these results using standard biokinetic and dosimetric models. In the analysis of fecal samples, there is a need for improvement in the pretreatment technique for complete dissolution of the sample. Conventional alkali fusion method has yielded recovery of plutonium in the range of 12–60% with a mean of 36%. Newly adopted acid leaching followed by hydrogen fluoride treatment method achieved recovery in the range of 43 to 90% with a mean of 70%. Conventionally, the separation of "Pu" and "Am" was carried out at Bioassay Lab., Tarapur by alkali fusion followed by the anion exchange separation for Pu and cation exchange separation for Am. This paper deals with an alternative method in which initially the entire ash of the sample spiked with ²³⁶Pu tracer (3–11 mBq) and ²⁴³Am tracer (2.8–14.5 mBq) was acid leached and Pu was separated by anion exchange method and Am by using TRU resin.

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To study the effect of respiration (end expiration [EE] and end inspiration [EI]) on tumor and normal structure doses and volumes in carcinoma lung. Five patients with squamous cell carcinoma of the lung were selected for this retrospective study. Computerized tomography (CT) data set was subsequently obtained for all patients in EE and EI phases of the respiratory cycle. Gross tumor volume, clinical target volume, planning target volume (PTV) and organs at risk were delineated in both EE and EI on CT data sets. Prescribed dose was 60 Gy in 30 fractions for all patients. The PTV coverage and organs at risks (OARs) were evaluated using radiation therapy oncology group conformity indices (CI) and homogeneity indices (HI) and volume doses respectively. The CI and HI were comparable for both phases. Volumes of all OARs were comparable except the lung. OAR doses were almost same in both phases. Significantly higher normal lung volume was found in the EI phase. Based on our dosimetric data and statistical analysis we conclude that both EE and EI are dosimetrically comparable.

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Studies have been carried out to assess exposure of the public due to natural radioactivity associated with soil, tailing and water at the Bibiani gold mine in Ghana. Concentrations of radionuclides in samples were determined by γ-ray spectrometry using high purity germanium detector. Gross-α and gross-β activity concentrations were also determined for the water samples using a low background gas-less automatic α/β counter. The mean activity concentrations of 238U, 232Th and 40K in soil/tailing samples were 16.1 ± 3.6, 16.6 ± 6.0 and 380 ± 15 bq/kg, respectively. The mean activity concentrations in water samples were 0.20 ± 0.04, 0.38 ± 0.03 and 3.05 ± 0.11 Bq/L for ²²⁶Ra, ²³²Th and ⁴⁰K respectively. The total annual effective dose to the public was estimated to be 0.125 mSv. The radium equivalent activity, internal hazard index, and external hazard index for all soil/tailing samples are lower than the accepted safety limit value of 370 Bq/kg and 1.0 respectively. The gross-α and gross-β activity concentrations for the water samples were below the World Health Organisation recommended guideline values for drinking water quality. The results indicate an insignificant radiation exposure to the public.

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Ten samples each of the eight commonly consumed powdered milk by adults were collected from local markets in Oke-Ogun area, Nigeria and analyzed using gamma ray spectrometer with NaI(Tl) detector for radioactive analysis and Atomic Absorption Spectrophotometer for heavy metal analysis (Pb, Fe, Cd and Cu). The mean activity concentration detected is that of ⁴⁰K with average of 39.6 Bqkg^-1 while the activities of ²²⁶Ra and ²³²Th were below detection limit (BDL). The total annual effective dose due to the ingestion of radionuclide in the milk sample was estimated to be 3.2 µSvy^-1. The geometric mean of Pb, Cd, Fe and Cu in the samples were found to be 0.024, 0.033, 2.168 and 0.242 mgkg^-1, respectively and the annual daily dose estimated were 0.1490, 0.010, 0.0002 and 0.0003 mgday^-1, respectively. The results of the hazard index revealed that the intake of heavy metal through ingestion of the milk samples did not exceeds the limit of unity as recommended by USEPA, 2002. Therefore, the consumption of these milk samples is safe.

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