Comparison of Calculated Percentage Depth Doses at Extended Source-to-Surface Distance for 6 MV And 15 MV Photon Beam of a Linear Accelerator

Background: Research findings from percentage depth dose (PDD) are crucial in evaluating patient doses received in radiation therapy. Objective: To compare calculated percentage depth doses at an extended source-to-surface distance (SSD) for 6 MV and 15 MV photon beams of a linear accelerator. Methodology: Measured PDD values of the 100 cm source to surface distance (SSD) and calculated values at extended SSDs for 6 MV and 15 MV photon beams of an Elekta NHA SLi 1998 linear accelerator were analyzed. The PDD data was collected by placing ionization chamber inside water phantom for depths ranging from z = 0 - 30 cm in a water phantom and using a square field sizes of 10 x 10 cm2. Photon energies of 6 MV and 15 MV were used for the measurement, with both gantry and collimator angles fixed at zero degree. PDD was calculated at extended SSD of 110 cm, 120 cm, 130 cm, and 140 cm from the measured PDD values of 100 cm SSD for both 6 MV and 15 MV photon energies using Mayneord factor. Results:  The depth dose maximum (Dmax) for field size 10 x 10 cm2  for 6 MV and 15 MV photon energies were 1.62 cm and 2.65 cm, respectively and the PDD at 10 cm  (D10) were 67.9% and 75.9%, respectively. The mean deviation of the calculated PDD at extended SSDs was found to be between 0.2% and 1%. Conclusion: The calculated PDD values at extended SSDs are considered suitable for clinical use at all clinically relevant depths and field sizes. &nbsp

Assessment of Background Radiation Levels at the Radiology Department of a Tertiary Hospital in North-central Nigeria

Background: Background radiation has over the years become a public health concern. It is therefore, imperative to ascertain its levels within strategic areas in our radiology facility for monitoring and compliance with international standards.Objectives: To determine the background radiation levels in the Radiology Department of Federal Medical Centre (FMC), Keffi, Nigeria.Methodology: The design was prospective and cross-sectional and involved the measurement of background radiation levels at various locations in the radiology department. Calibrated thermo Scientific RadEye TM B20 / B20-ER survey meter, an associated scalar counter, and a stopwatch, were used for measurements at each point, based on standard guidelines recommended by the International Atomic Energy Agency (IAEA).Results: The least mean radiation (0.11µSv/hr) was detected in the computed tomography (CT) suite while the maximum value (0.13µSv/hr) emanated from the radiographers' common room. The coefficient of variation for the Chief Radiographers office, Head of Department's office and the Radiologist’s office were similar 8.3%. The radiographers’ common room was slightly higher (10.9%). The main diagnostic room and seminar room had 16.7%, while it was 9.09% for the CT suite. The standard error ranged between 0.002 and 0.004. There was statistically significant difference in all test values at a level of significance of 5% (p < 0.05). Conclusion: Background radiation values obtained were within recommended standards. However, there is need for regular radiation monitoring as part of radiation safety culture in our radiology facility

Estimation of public radiological dose from mining activities in some selected cities in Nigeria

Mining activities is one of the most significant sources of radiation exposure from long-lived naturally occurring radioactive materials (NORMs), and have resulted in unjustifiable public exposure doses which contravene radiation protection standards. As a result, estimating the extent of such exposure is essential for keeping the recommended public dose limit. This study therefore aims at estimating the public radiation dose around mining areas and its environs in some selected cities across Nigeria. Data on measured activity concentration of NORMs radionuclides comprising of U-238, Ra-226, Th-232 and K-40 from soil round mining areas in some selected cities in Nigeria were extracted from previous literatures and are used for public dose estimation using RESRAD computer code. From the calculated mean activity concentration, the results from each mining locations shows the maximum dose are lower than International Commission on Radiological Protection (ICRP), commended public dosage boundary of 1 mSv/yr with highest dose of 0.91 mSv/yr from Ra-226, Th-232 and K-40 over the period of 47.9 years reported from Gura Top mining site in Jos, Plateau State, while the lowest dose of 0.09 mSv/yr each over the period of 14.06 and 20.27 years occurred at Itagunmodi and Arufu sites for U-238, Th-232 and K-40. The highest dose recorded in Gura Top was due to numerous mining activities in the region. According to the ICRP, there is no safe level of radiation exposure. Therefore, there is need for competent authorities to conduct periodic assessment of radiation exposure from mining sites to ensure that all exposure emanating as a result of such activities are kept below the prescribed dose limit in accordance to the principle of As Low As Reasonably Achievable (ALARA), thereby ensuring public protection from unjustified radiation exposure

Toxicity of Radon-222 in Groundwater across Keana in Nasarawa, Nigeria

The most common supply of freshwater for drinking, irrigation, and other domestic uses is groundwater; however, because of increased radon concentrations brought on by mining activities, its quality is still a severe concern. Using a liquid scintillation detector, this study investigated the radon content, its related toxicity, and its risk to human health in the groundwater of the Keana in Nasarawa, Nigeria. Ten (10) borehole samples and five (5) well samples totaling fifteen (15) groundwater samples were taken. The results showed that the average radon concentration in water samples from Keana was 2.25 Bq/L. The mean annual effective dosage (ingestion) for adults and children in Keana was 0.016 mSv/y and 0.027 mSv/y, respectively. In Keana, the additional lifetime cancer risk per adult was 5.65 × 10–5, and per child, it was 8.79 × 10–5. The study’s radon concentration was lower than the benchmark of 11.1 Bq/L established in 1991 by the Nigerian Standard Organization and the US Environmental Protection Agency. The results of this study indicate that the level of radon is safe; as a result, people can continue farming and other activities. To reduce the risk of cancer, however, more research could be done in the area. Further research should be done by looking at additional sources in the study area in order to cover the entire zone. Further investigation should be carried out both during the dry and wet seasons because radon concentrations in groundwater alter over time due to dilution by recharge from rainfall