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ABSTRACT: The caldose_x 5.0 software has been used to assess the entrance skin doses (ESD) and effective doses (ED) of adult patients undergoing x-ray examinations of the thorax/chest (PA/RLAT), pelvis (AP), cervical spine (AP/LAT), thoracic spine (AP) and lumber spine (AP) in three public hospitals each equipped with constant potential generators (no ripple), an x-ray emission angle of 17° and a total filtration of 2.5 mm Al. In all, 320 patients were surveyed with an average of over 100 patients per a hospital. The patients' data and exposure parameters captured into the software included age, sex, examination type, projection posture, tube potential and current-time product. The mean ESD and ED of seven different examinations were calculated using the software and compared with published works and internationally established diagnostic reference levels. The mean ESD calculated were 0.27 mGy, 0.43 mGy, 1.31 mGy, 1.05 mGy, 0.45 mGy, 2.10 mGy, 3.25 mGy and the mean effective doses were 0.02 mSv, 0.01 mSv, 0.09 mSv, 0.05 mSv, 0.03 mSv, 0.13 mSv, 0.41 mSv for thorax (PA), thorax/chest (RLAT), Pelvis (AP), cervical spine (AP), cervical spine (LAT), thoracic spine (AP) and lumber spine (AP) respectively.
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ABSTRACT: Natural radioactivity levels in some selected medicinal plants commonly used in Ghana from the Centre for Scientific Research into Plant Medicine were investigated to determine the activity concentration and the annual committed effective dose due to naturally occurring radionuclides of (238)U, (232)Th and (40)K. The activity concentration was determined using gamma-ray spectrometry. The results of the analysis indicated an average activity concentration of (238)U, (232)Th and (40)K in the medicinal plants to be 31.8±2.8 Bq kg(-1), 56.2±2.3 Bq kg(-1) and 839.8±11.9 Bq kg(-1) respectively. Khaya ivorensis recorded the highest activity concentration of (238)U and (232)Th while Lippia multiflora recorded the highest activity concentrations of (40)K. The total annual committed effective doses ranged from 0.026±0.001 to 0.042±0.002 mSv a(-1) with an average value of 0.035±0.001 mSv a(-1). The average annual committed effective dose due to ingestion of the natural radionuclides in the medicinal plant samples were far below the world average annual committed effective dose of 0.3 mSv a(-1) for ingestion of natural radionuclides provided in UNSCEAR 2000 report. Therefore, the radiological hazard associated with intake of the natural radionuclides in the medicinal plants is insignificant. The results provide baseline values which may be useful in establishing rules and regulations relating to radiation protection as well as developing standards and guidelines for the use of medicinal or herbal plants to the appropriate authorities.
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ABSTRACT: An effective method for determination of indicator polychlorinated biphenyls (PCBs) has been validated using gas chromatography (GC) equipped with electron capture detector (ECD). The GC-ECD method was validated by determining the linear range (working range) for determination of the compounds, minimum detectable quantities (MDQ), the precision and accuracy of the method for the analysis of the compounds. MDQ obtained for the compounds ranges from 0.0005 to 0.002ng. Indeed the method was found to be more sensitive as the number of chlorine atoms attached to the biphenyl increases. The precision and accuracy of the GC method validated ranges from 2.4% to 14.5% and -7.0% to 14.6% respectively. Coefficient of variation associated with the repeatability of the retention times and corresponding peak areas was found to be 0.0001-0.0007 for the retention times and 0.0014-0.059 for the peak areas. Percentage recoveries for the compounds were in the range of 95.7-101.0%. The validated method was then applied to determine levels of indicator PCBs in sediments sampled from eleven sampling points along the Lake Bosuntwi in Ghana and the highest PCB load of 19.17ngg(-1) was recorded at Pipie No. 2. PCB 52 and PCB 101 were found to be the most ubiquitous indicator PCBs in the study area, both with 90.91% occurrence.
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