Natural and ¹³⁷Cs radioactivity in coastal marine sediment samples was measured using gamma spectrometry. Samples were collected at 16 locations from four beaches along the coastal area of Muscat City, Gulf of Oman. Radioactivity in beach sand was used to estimate the radiological risk parameters to humans, whereas the radioactivity in marine sediments was used to assess the radiological risk parameters to non-human biota, using the ERICA Tool. The average radioactivity concentrations (Bqkg⁻¹) of ²²⁶Ra, ²³²Th, ⁴⁰K, ²¹⁰Pb and ¹³⁷Cs in sediments (sand) were as follows: 16.2 (16.3), 34.5(27.8), 54.7 (45.6), 46.8 (44.9) and 0.08 (0.10), respectively. In sand samples, the estimated average indoor (${\mathrm{D}}_{\mathrm{in}}$) and outdoor (${\mathrm{D}}_{\mathrm{out}}$) air absorbed dose rates due to natural radioactivity were 49.26 and 27.4 and the total effective dose (${\mathrm{AED}}_{\mathrm{Total}}$; µSvy⁻¹) ranged from 150.2 to 498.9 (average: 275.2). The measured radioactivity resulted in an excess lifetime cancer risk (ELCR) in the range of 58–203 (average: 111) in and an average gonadal dose (AGD; µGy.y⁻¹) ranged from 97.3 to 329.5 (average: 181.1). Total dose rate per marine organism ranged from 0.035 µGy h⁻¹ (in zooplankton) to 0.564 µGy h⁻¹ (in phytoplankton). The results showed marine sediments as an important source of radiation exposure to biota in the aquatic environment. Regular monitoring of radioactivity levels is vital for radiation risk confinement. The results provide an important radiological risk profile parameter to which future radioactivity levels in marine environments can be compared.

In an attempt to reutilize marble waste, a new approach is presented in the current study to promote its use in the field of shielding against ionizing radiation. In this study, we aimed to develop a novel and sustainable/eco-friendly lead-free radiation shielding material by improving artificial marble (AM) produced from marble waste combined with polyester by reinforcing it with bismuth oxide (Bi₂O₃) nanoparticles. Six samples of AM samples doped with different concentrations ($0\%$,$5\%$,$10\%$,$15\%$, $20\%$, and $25\%$) of Bi₂O₃ nanoparticles were prepared. The linear attenuation coefficient ($LAC$) values were measured experimentally through the narrow beam method at different energies $(0.0595 \mathrm{M}\mathrm{e}\mathrm{V}$, $0.6617 \mathrm{M}\mathrm{e}\mathrm{V}$, $1.1730 \mathrm{M}\mathrm{e}\mathrm{V}$, and $1.330 \mathrm{M}\mathrm{e}\mathrm{V}$) for all samples with various concentrations of Bi₂O₃. Radiological shielding parameters such as half value layer ($HVL$), tenth-value layer ($TVL$), and radiation shielding efficiency ($RSE$) were estimated and compared for all the different samples. The results prove that increasing the concentration of Bi₂O₃ leads to the enhancement of the radiation shielding properties of the AM as a shielding material. It was observed that as the energy increases, the efficiency of the samples falls. High energy dependence was found when calculating the $HVL$ and $TVL$ values of the samples, which increased with increases in the energy of the incident photons. A comparison between the sample with the most efficient gamma radiation attenuation capability (AM-$25\%$), concrete, and lead was conducted, and a discussion regarding their radiation shielding properties is presented herein. The results show that the AM-$25\%$ sample is superior to the ordinary concrete over all the studied energy ranges, as evidenced by its significantly lower $HVLs$. On the contrary, lead is superior to the AM-$25\%$ sample over all the studied energy ranges owing to its unbeatable density as a shielding material. Overall, this new type of artificial marble has the potential to be used as a radiation shielding material at low- to medium-gamma energy regions, specifically in medical imaging and radiation therapy.

Different rock types (syenogranite, alkali feldspar granite and quartz syenite intruded by microgranite dikes and quartz veins) were investigated in the Nikeiba region in Egypt. The main components of the studied intrusive rocks, comprised of granites and quartz syenite, are plagioclase, amphibole, biotite, quartz and K-feldspar in different proportions. Ground gamma ray measurements show that syenogranite, quartz syenite and microgranite dikes have the highest radioactivity (K, eU, eTh and their ratios) in comparison with alkali feldspar granite. Geochemically, syenogranite, alkali feldspar granite and quartz syenite are enriched with large-ion lithophile elements (LILE; Ba, Rb, Sr) and high field-strength elements (HFSE; Y, Zr and Nb), but have decreased Ce, reflecting their alkaline affinity. These rocks reveal calc–alkaline affinity, metaluminous characteristics, A-type granites and post-collision geochemical signatures, which indicates emplacement in within-plate environments under an extensional regime. U and Th are increased in syenogranite and quartz syenite, whereas alkali feldspar granite shows a marked decrease in U and Th. The highest average values of A_U (131 ± 49 Bq·kg⁻¹), A_Th (164 ± 35) and A_K (1402 ± 239) in the syenogranite samples are higher than the recommended worldwide average. The radioactivity levels found in the samples are the result of the alteration of radioactive carrying minerals found inside granite faults. The public’s radioactive risk from the radionuclides found in the investigated granitoid samples is estimated by calculating radiological risks. The excess lifetime cancer (ELCR) values exceed the permissible limit. Therefore, the granitoids are unsuitable for use as infrastructure materials.

The present work is concerned with assessing the cancer risk contributed by the studied granite types including valuable metals, such as Cu, Au, and Ba mineralization, as well as radioactive-bearing mineralization, such as monazite and zircon, in south Monqul at Wadi Makhrag El Ebel, north Eastern Desert, Egypt. The mineralization analyses illustrated that copper mineralization containing chrysocolla and tenorite minerals were restricted to the alteration zone, especially (argillic, phyllic, and propylitic) in monzogranite. However, barite veinlets had an ENE–WSW trend, while gold mineralization was confined to quartz veins having NE–SW trends. Monazite and zircon are radioactive-bearing minerals recorded in monzogranite causing high radioactive zones in south Monqul. The radionuclide activity concentrations were detected in the studied monzogranites. The mean values of A_U (103 ± 91 Bq kg⁻¹), A_Th (78 ± 19 Bq kg⁻¹), and A_K (1484 ± 334 Bq kg⁻¹) in the monzogranite samples were higher than the recommended worldwide average. The change in radioactive-transporting minerals found inside granite faults caused the high amounts of radioactivity seen in the samples. Due to the monzogranites being applied in building materials, the radiological hazards were assessed by calculating risk indices such as annual effective dose (AED) and excess lifetime cancer risk (ELCR). The acceptable limit for the ELCR readings was surpassed. As a result, the investigated monzogranite samples are not suitable for use in infrastructure materials.

The aim of this study was to evaluate radiation protection techniques in computed tomography (CT) scanning, address concerns on the increased population exposure during CT procedures, and provide a review on dose management and optimization procedures. Radiation protection in CT requires regular dose surveys and optimization of CT exposure parameters, establishing and/or implementing diagnostic references (DRLs), implementation of a comprehensive quality assurance program, reference dose levels, and CT dose saving protocols. Patient dose reduction of 40-60%, 50% , 20-30%, 20-40%, 30-50% can be achieved using tube current modulation, beam filters, thyroid and breast shields, low tube voltage for abdominal CT, automatic pitch adaptation; respectively. CT users are strongly encouraged to take advantage of these dose reduction techniques while maintaining diagnostic image quality. Current review provides updated radiation protection measures for minimizing patient radiation dose in CT without adversely affecting the quality of diagnostic information.