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Background: Nuclear medicine or diagnostic radiology personnel are always exposed to low-level radiation from radionuclides used in medical diagnostics, which lead to potential biological hazards or effects. Objective: External exposure for workers in two nuclear medicine centers was measured by recruiting 120 patients. Methods: Three nuclear medicine examinations were performed using F18-FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan by a digital radiation dosimeter. Results: The average received accumulative radiation dose for workers was found to be 0.838±0.17, 0.527±0.11, and 0.270±0.05 μSv for F18-FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. The annual effective dose for workers was estimated to be 2.09±0.42, 1.34±0.27, and 0.68±0.14 mSv, respectively. Moreover, the average patient-to-staff dose coefficients were found to be 0.024±0.005, 0.003±0.001, and 0.007±0.002 μSv m2/MBq h for F18-FDG PET/CT, 99mTc-MDP bones scan, and 99mTc thyroid scan, respectively. Conclusion: It is clear from the results that the radiation doses received by workers during the nuclear medicine imaging examinations were less than the doses recommended by the International Commis-sion on Radiological Protection (ICRP) for such examinations.

Radon gas has been recognized as one of the health hazards to humans. Building materials used for the construction of houses, which are considered as one of the major sources of this gas in indoor environments. The radon exhalation rate, radon concentration as well as the annual effective dose for 46 samples of building materials (granite, ceramic, marble, mosaic, rocks, gypsum, block and red brick) used in Yemen were measured using two methods. The can technique, containing CR-39 solid-state detector, and active method containing AlphaGuard detector were used. The results obtained from passive and active techniques were found in good agreement. The results showed that the highest values of radon exhalation rate, radon concentration and the annual effective dose indoor and outdoor were 0.93 ± 0.020 Bqm−2 h−1, 186.48 ± 3.73 Bqm−3, 4.7 ± 0.141 and 1.76 ± 0.053 mSvy−1 for granite samples, whereas the lowest values were 0.0076 ± 0.001 Bqm−2 h−1, 1.51 ± 0.03 Bqm−3, 0.04 ± 0.001 and 0.01 ± 0.001 mSvy−1 for the ceramic samples. The results also showed that the radon exhalation rate, as well as the annual effective dose, was found below the world average values of 57.600 Bq m−2 h−1, 1100 μSv y−1 with exception of some samples. The values of radon concentrations for granite samples were in the range of activity levels from 200 to 600 Bq m−3 recommended by (ICRP, 1994).

Nuclear medicine or diagnostic radiology personnel are always exposed to low-level radiation from radionuclides used in medical diagnostics, which lead to potential biological hazards or effects.External exposure for workers in two nuclear medicine centers was measured by recruiting 120 patients.Three nuclear medicine examinations were performed using F18-FDG PET/CT,The average received accumulative radiation dose for workers was found to be 0.838±0.17, 0.527±0.11, and 0.270±0.05 µSv for F18-FDG PET/CT,It is clear from the results that the radiation doses received by workers during the nuclear medicine imaging examinations were less than the doses recommended by the International Commission on Radiological Protection (ICRP) for such examinations.

The natural radioactivity of 16 cement raw materials samples from Yemen was determined. The average activity concentrations of 226Ra, 232Th and 40K were 32, 18 and 239 Bq.kg−1 in limestone samples, 43, 35 and 1081 Bq.kg−1 in clay samples, 40, 36 and 840 Bq.kg−1 in sandstone samples, 29, 11 and 161 Bq.kg−1 in iron ore samples, 29, 17 and 166 Bq.kg−1 in raw gypsum samples and 48, 23 and 690 Bq.kg−1 in pozzolana samples, respectively. The results indicated that the highest radionuclides concentrations for measured samples were in clay samples, whereas the lowest values were in iron ore samples. Radiological parameters such as external hazard index (Hex), radium equivalent (Raeq), internal hazard index (Hin) and gamma index (Iϒ) were assessed. Moreover, the chemical composition of these raw materials was measured and simulated for their gamma-ray shielding properties. Radiation protection coefficients such as mass attenuation coefficient (MAC), atomic cross section (AC), electron cross section (EC), effective atomic number (Zeff) and electron density (Neff) have been estimated in the photon energy range from 0.015 to 15 MeV using Phy-X/PSD software program. The results indicated that the highest values of the gamma-ray shielding parameters were at the energy 0.015 MeV, while the lower values were at the energy 15 MeV. Also, the results indicated that the iron ore sample has the best gamma-ray shielding properties among other investigated raw materials.

The main purpose of this study was to measure the natural radioactivity in some foodstuffs and agricultural soils from the Abyan Delta in Yemen and study the interaction between soil and foodstuffs...

Nd3+ doped lithium-zinc-phosphate glasses were synthesized by melt-quenching technique. FTIR spectra were recorded in the wavenumber range of 400–4000 cm−1. Elastic parameters such as Debye temperature and fractal bond connectivity were calculated. The results revealed that these parameters were influenced by the glass system's composition and dopant concentration. The mass and linear attenuation coefficients (MAC, LAC) of gamma-ray photons at the energy range from 0.015 to 15 MeV have been investigated using the Phy-X/PSD software program as well as the XCOM database program. Both MAC and LAC increase with the increase in the amount of Nd2O3. Also, the mean free path values and the half-value layer decrease while the density increases with the increase of the Nd2O3 content. Moreover, the fast neutron removal cross section was also presented and the results were compared with the concrete and commercial shielding glasses.

Composition of 5Li2O-(40-x) Na2O-xZnO-55P2O5 doped with 2 wt% (CdO + Te) where (x = 0, 7, 14, 21, 28, 35 and 40) mol% glass system have been prepared and simulated for their gamma-ray shielding properties. The studied glasses were labeled as LNZP0–LNZP6 according to the values of Na2O and ZnO. Mass attenuation coefficient (MAC), Linear attenuation coefficient (LAC), half-value layer (HVL) and mean free path (MFP) have been calculated by the Phy-X/PSD software program in the photon energy range from 0.015 to 15 MeV. The results show that the highest values of MAC were 30.64, 31.98, 33.34, 34.62, 35.89, 36.82 and 38.09 cm2/g at the energy 0.015 MeV for LNZP0-LNZP6 glass samples, respectively. Also, atomic cross section (ACS), electron cross section (ECS), effective atomic number (Zeff) and electron density (Neff) have been estimated. The results showed that the LNZP6 glass sample has the best gamma-ray protection properties among other examined glasses. The ACS and ECS parameters were found to have the maximum value at 0.015 MeV and decreased with increasing energy of photons for all samples. The Maximum values of Zeff were at the energy 0.04 MeV equal to 48.92, 48.72, 48.56, 48.37,48.19, 48.02 and 47.85 for LNZP0-LNZP6, respectively.

Lithium-zinc-borophosphate glasses with the composition of (100-x)[20Li2O-10ZnO-20B2O3-50P2O5]-xNd2O3,x = 0.0 (LZBP:0.0Nd) to 4.0 (LZBP:4.0Nd) wt%, were synthesized. DSC curves were used to determine Tg of the samples. The density of the samples increased from 2.528 to 2.588 g.cm−3. The physical properties such as ion concentration and field strength were estimated using standard formulae. Both of UV–visible and FTIR spectra were recorded in the range of 190–1000 nm and 400–4000 cm−1, respectively. The indirect optical band gap ( E opt . ASF , I ) measured by ASF method were in the range of 3.36–3.66 eV. FTIR spectra revealed the presence of PO4, BO3 and PO4 units within glass matrix. The radiation shielding parameters such as the mass attenuation coefficients (MAC) and the half value layer (HVL) for the glasses were estimated via Phy-X/PSD program within the photon energy (0.015−15 MeV). The glass LZBP:4.0Nd has the lowest HVL and hence the high shielding capacity of gamma rays.

Twenty rock samples (Marble, Biotite gneiss, Migmatite gneiss, Granite gneiss and Mylonites granite) were analyzed to determine the activity concentrations of 226Ra, 232Th and 40K in Bq kg−1 and their radiological parameters using gamma-ray spectrometer consisting of NaI (Tl) detector. 226Ra activity varied in the range from 7.45 ± 1.3 to 148.4 ± 15 Bq kg−1. The activity concentrations of 232Th ranged from 9.8 ± 1.6 to 432 ± 29 Bq kg−1, whereas activity concentration of 40K ranged from 519 ± 24 to 4491 ± 95 Bq kg−1. The highest average values concentration of 226Ra, 232Th and 40K were 112.1, 301 and 3875.9 Bq kg−1, respectively, which was observed in mylonites granite samples. The radiological parameters as radium-equivalent (Raeq) and external and internal hazard index (Hex, Hin) were determined. Raeq varied between 65.7 and 1147.5 Bq kg−1, which exceeded the permitted value (370 Bq kg−1) and the internal hazard index (Hin) (0.2–3.8), which is higher than 1. The total absorbed dose rates in air were calculated from the concentrations of the three radionuclides ranged from 33.2 to 521.1 nGy h−1, and the external annual effective dose rates were determined to be between 40.8 and 639.1 μSv y−1. The radiological maps of study area were obtained. The calculated average value of the radiological parameters in mylonites granite, granite gneisses and migmatite gneisses rocks samples were higher than the safe limit recommended by the Organization for Economic Cooperation and Development (OECD).

This paper presents the concentrations of naturally occurring radionuclides 226Ra, 232Th and 40K measured in Groundwater collected from Abyan delta on Gulf of Aden in Yemen. Concentrations of radionuclides in samples were determined by gamma-ray spectrometer using HPGe detector with specially designed shield. The average activity concentrations were (1.71 ± 0.09 Bq l−1), (1.43 ± 0.05 Bq l−1) and (14.16 ± 0.45 Bq l−1) for 226Ra, 232Th and 40K, respectively. The annual effective doses mSv y−1 due to ingestion of 226Ra and 232Th for different age groups were also calculated. The results compared with the recommended value reported by World Health Organization.

Common building materials collected from Aden, Yemen were analyzed for the natural radioactivity of 226Ra, 232Th and 40K using gamma-ray spectroscopy. The average activity concentrations of 226Ra, 232Th and 40K in the studied building materials range from 20.78 to 68.6, from 15.48 to 95.08 and from 116.7 to 2636.68 Bq kg− 1, respectively. The measured activity concentrations for these radionuclides were compared with chemical data obtained by XRF analysis and with the reported data of other countries and compared also with the worldwide average activities. The radium equivalent activities of the studied samples that range from 69 to 369.3 Bq kg− 1 are below the internationally accepted values (370 Bq kg− 1), except those of Hapach hard rock (407.6 Bq kg− 1). The external and internal hazard indices that range from 0.2 to 1.1 and from 0.3 to 1.3, respectively, of all analyzed building materials are less than unity, except those of Hapach hard rock (Hex = 1.1 and Hin = 1.3) and hard rock of Crater (Hin = 1.2). The mean values of indoor absorbed dose rate for all building materials range from 30.7 to 199.8 nGy h− 1 except those for cement, macadam, hard rock of Habaylin and hard rock of Abyan which are higher than the world population-weighted average of 59 nGy h− 1 and the total annual effective dose values of building materials that range from 0.15 to 0.98 mSv y− 1 are lower than 1 mSv y− 1 except for the samples of Hapach hard rock (0.98 mSv y− 1) which have the closed value (the limit of accepted value (1 mSv y− 1) reported in the UNSCEAR (2000)). The study shows that the measured radioactivity for building materials does not pose as significant source of radiation hazard and is safe for use in the construction of dwellings, while when using Hapach hard rock and hard rock of Crater for construction, their natural radioactivity level should be monitored.

The knowledge of environmental hazards resulted from natural radioactivity and human activities is very important for monitoring of environmental contamination. In this study, the environmental hazards due to the natural radioactivity and human activities in Tuban delta in Yemen were discussed and evaluated using gamma ray spectroscopy. Thirty soil samples were collected from the study area. The results showed that the mean activity concentrations of 238U series (226Ra), 232Th, and 40K were 16.83 ± 2.3, 24.76 ± 2.3, 646.48 ± 13 Bq kg-1 and 15.22 ± 1.5, 21.99 ± 2.1, 472.58 ± 10 Bq kg-1 for farm soil samples treated with organic and urea fertilizer and farm soil samples treated with urea fertilizer, respectively. The corresponding values were 19.53 ± 1.5, 24.46 ± 3, and 500.76 ± 17 Bq kg-1 for uncultivated soil samples. The activity concentrations of 137Cs showed a significant value in some uncultivated soil samples. Also, physical and chemical properties of some soil samples were discussed and evaluated. A Radiological parameter, an absorbed dose rate in air, and an annual effective dose were calculated and evaluated. The results were compared with those of literature.

The cement industry is considered as one of the basic industries that plays a significant role in the national economy of developing countries. Activity concentration of 226 Ra, 232 Th, and 40 K in 38 samples of local cement types from different Yemeni factories has been measured by using the gamma ray spectrometry and their mean values were in the ranges (25.18-40.39 Bq/kg), (14.6-24.75 Bq/kg) and (160.01-596.38 Bq/kg), respectively. The average values obtained for 226 Ra, 232 Th, and 40 K activity concentration in different types of cement are lower than the corresponding global values reported in United Nation Scientific Committee on the Effect of Atomic Radiation publications. The obtained results show that the averages of radiation hazard parameters for all types of local cement in the current study are lower than the acceptable level of 370 Bq/kg for radium equivalent, 1 for level index (Iγ), the external hazard index ≤ 1 and (59 nGy/h) for absorbed dose rate. The measured activity concentrations for these natural radionuclides were compared to the reported data for other countries. Therefore, the natural radioactivity of cement samples under study was lower than the recommended values in the established standard and hence safe for use in building constructions.

The level of natural radioactivity in rocks and soil of 32 samples collected from locations at North Sana'a in Yemen was measured. Concentrations of radionuclides in rocks and soils samples were determined by gamma-ray spectrometer using HPGe detector with specially designed shield. The average radioactivity concentrations of 226 Ra, 232 Th and 40 K were determined and expressed in Bq kg −1 . The results showed that these radionuclides were present in concentrations of 21.79 ± 3.1, 19.5 ± 2.6 and 399.3 ± 16 Bq kg −1 , respectively, for rocks. For soil, the corresponding values were 48.2 ± 4.4, 41.7 ± 4.5 and 939.1 ± 36 Bq kg −1 . Also, the radiological hazard of the natural radionuclides content, radium equivalent activity, total dose rates, external hazard index and gamma activity concentration index of the (rocks/soils) samples in the area under consideration were calculated. The data were discussed and compared with those given in the literature.