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Image Quality Assessment Using NEMA Standards for Lu-177 Radionuclide

International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2022年第3期11卷 125-134页

作者： Olivia Adu-Poku bright kwakye-awuah Eric Kotei Addison Stephen Inkoom Department of Physics Kwame Nkrumah University of Science and Technology Kumasi Ghana Komfo Anokye Teaching Hospital Oncology Directorate Department of Medical Physics Kumasi Ghana Department of Medical Physics Graduate School of Nuclear and Allied Sciences University of Ghana Accra Ghana Radiation Protection Institute Ghana Atomic Energy Commission Accra Ghana

A lutetium 177 (177Lu) radiopharmaceutical has been used as a theragnostic agent in molecular radiotherapies. This study aimed to produce images simulating those obtained in a total body imaging study with hot lesions to assess and investigate the image quality of the Hawkeye SPECT/CT images from Lu-177. The NEMA image quality phantom (PTW) with spheres (inner diameters of 10, 13, 17, 22, 28 and 37 mm) and lung insert was used. The measured volume in the background of the current phantom setting was 9482 mL. The five smaller spheres were filled with an activity concentration of 0.461 MBq/mL and the biggest sphere was filled with water. The phantom was placed on the couch and scanned at four hot sphere-to-background concentrations, which are no background, 16:1, 8:1 and 4:1. The images obtained from the scans were imported onto the OXIRIS image analysis tool. Regions of interest (ROIs) were drawn on each sphere of the reconstructed SPECT image. Image contrast and background variability ratios for hot spheres were used as measures of image quality. In addition, the accuracy of corrections were determined from the uniform background and cold lung insert regions. The 37 mm cold sphere had the highest percent contrast, whiles the 10 mm hot sphere had the least for the various hot sphere to background ratios. The background variability for each hot sphere was also determined. The average lung residual error was calculated to be 23.13% for the 16:1 and 22.57% for both the 8:1 and 4:1 hot sphere to background ratio. The results show that the scanner has very good overall performance.

关键词： Lutetium-177 Activity Concentration Dose Calibrator SPECT/CT

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Quality Assurance in SPECT/CT for Radionuclide Therapy with Lutetium-177

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2022年第1期11卷 60-76页

作者： Olivia Adu-Poku Eric Kotei Addison bright kwakye-awuah Stephen Inkoom Francis Hasford Cletus Ahadzie Joseph Adom Isaac Kojo Wilson Department of Physics Kwame Nkrumah University of Science and Technology Kumasi Ghana Komfo Anokye Teaching Hospital Oncology Directorate Department of Medical Physics Kumasi Ghana Department of Medical Physics Graduate School of Nuclear and Allied Sciences University of Ghana Accra Ghana Radiation Protection Institute Ghana Atomic Energy Commission Accra Ghana Nuclear Regulatory Authority Ghana Atomic Energy Commission Accra Ghana

This study was done to quality assure the Hawkeye SPECT/CT at the St. Olav’s hospital and create a clinical method for doing individual dosimetry with 177Lu-octreotate in targeted radionuclide therapy for neuroendocrine tumors. Various quality control parameters were performed on Infinia Hawkeye SPECT/CT. A calibration dose of 160% ± 2% MBq was ordered and first calibrated for all the dose calibrators. The uniformity test was obtained using a 40 MBq Tc-99m point source positioned 2.5 m away from the two detectors. A 200 MBq Tc-99m was diluted in 70 ml of water, dispersed in six syringes for the registration test. A Lu-177 point source was placed in front of the detectors, one at a time, to check the energy peaks. The Jaczczak phantom with a hollow sphere set (volumes: 0.5, 1, 2, 4, 8, and 16) ml with an additional 60 ml sphere was used for the 3D sensitivity and recovery with Lu-177. Total activity of 945.3 MBq was added to 160 ml of water yielding an activity concentration of 5.908 MBq/ml in the spheres. The phantom was then scanned at various time intervals. A cylindrical phantom with a volume of 6283 ml was also used to obtain the cross-calibration measurement (cps/MBq). Total activity of 995.6 MBq was added and the phantom was scanned at days 0, 6, 13 and 23. The dose calibration factor was changed from 762 to 760 to achieve correct doses. The 2D mean sensitivity factor was 5.56 cps/MBq. Uniformities for both detectors were approved after iteration calibration of the PM tubes. The X-ray to SPECT registration was found to be accurate and within specifications. The energy peak test revealed off-centered 208 keV energy peaks for the two detectors. Quality assurance of imaging devices using radiation is essential for radiation protection and ensures a high-quality image.

关键词： Lutetium-177 Activity Concentration Dose Calibrator SPECT/CT

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Image Quality Assessment Using NEMA Standards for Lu-177 Radionuclide

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2022年第3期

作者： olivia adu-poku bright kwakye-awuah eric kotei addison stephen inkoom

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A conceptual framework for characterizing mineralized waste rocks as future resource

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International Journal of Mining Science and Technology 2019年第3期29卷 429-435页

作者： bright Oppong Afum Dylan Caverson Eugene Ben-awuah Mining Optimization Laboratory Bharti School of Engineering Laurentian University

Conventional mining practices do not extract all mineralized rocks due to prevailing *** in mineral prices and processing recovery(technology)could potentially make mineralized waste rocks profitable.A well-integrated mining strategy that focuses on both economic and physical resource depletion is vital to the management of non-renewable mineral *** this paper,a conceptual framework that maximizes the benefits of mining and processing mineralized waste rocks as future resource is *** policy and technical reforms that ensure mining companies incorporate the proposed mineralized waste rocks management framework in their long-term strategic mine plans have been recommended.

关键词： Resource depletion Mineralized waste Conventional mining practices Policy reform Technical reform Future resource

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Jump Diffusion Modeling of Stock Prices on Ghana Stock Exchange

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Journal of Applied Mathematics and Physics 2020年第9期8卷 1736-1754页

作者： Osei Antwi Kyere bright Kwasi awuah Wereko Mathematics & Statistics Department Accra Technical University Accra Ghana Accountancy Department Accra Technical University Accra Ghana Business School Ghana Institute of Public Administration (GIMPA) Accra Ghana

The behaviour of stocks on the Ghana stock exchange is examined to show that stock prices on the exchange are subject to sudden price changes. It is shown that such unexpected events and uncertainties affecting trading on the exchange cannot be modeled solely by the conventional geometric Brownian motion outlined in the Black-Scholes model. A new concise and simpler approach is developed to derive the Jump diffusion model and consequently, its suitability to model stocks on the exchange is emphasized and given rigorous treatment. The model is subsequently used to predict the behaviour of stocks using historical stock prices as input parameters. The simulated stock returns are compared to actual returns to determine the model’s suitability to predict the market. The results show that the jump diffusion model is appropriate in predicting the behaviour of approximately 25% percent of stocks listed on the exchange.

关键词： Diffusion Jump Diffusion Skewness Kurtosis Jump Sizes

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A review of the effects of forest fire on soil properties

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Journal of Forestry Research 2022年第5期33卷 1419-1441页

作者： Alex Amerh Agbeshie Simon Abugre Thomas Atta-Darkwa Richard awuah Department of Environmental Management University of Energy and Natural Resources(UENR)SunyaniGhana Department of Forest Science University of Energy and Natural Resources(UENR)SunyaniGhana Department of Mechanical and Manufacturing Engineering University of Energy and Natural Resources(UENR)SunyaniGhana

Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest *** extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil *** impact on soil properties is intricate,yielding different results based on these *** paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such ***-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and *** intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest *** intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil *** soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological *** this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil ***,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire *** review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy *** addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.

关键词： Forest fires Low-severity fire Mineralization Soil available nutrients Soil organic matter Volatilization

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Strategic mining options optimization:Open pit mining, underground mining or both

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International Journal of Mining Science and Technology 2016年第6期26卷 1065-1071页

作者： Ben-awuah Eugene Richter Otto Elkington Tarrant Pourrahimian Yashar Bharti School of Engineering Laurentian University Mining Department Snowden Mining Industry Consultants School of Mining and Petroleum Engineering University of Alberta

Near-surface deposits that extend to considerable depths are often amenable to both open pit mining and/or underground mining. This paper investigates the strategy of mining options for an orebody using a Mixed Integer Linear Programming(MILP) optimization framework. The MILP formulation maximizes the Net Present Value(NPV) of the reserve when extracted with(i) open pit mining,(ii) underground mining, and(iii) concurrent open pit and underground mining. Comparatively, implementing open pit mining generates a higher NPV than underground mining. However considering the investment required for these mining options, underground mining generates a better return on investment than open pit mining. Also, in the concurrent open pit and underground mining scenario, the optimizer prefers extracting blocks using open pit mining. Although the underground mine could access ore sooner, the mining cost differential for open pit mining is more than compensated for by the discounting benefits associated with earlier underground mining.

关键词： Mining options optimization Open pitUnderground Concurrent Open stope Mixed Integer Linear Programming (MILP)

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The intention of banks to adopt green banking in an emerging market:the employees’perspective

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Economic and Political Studies 2021年第4期9卷 497-504页

作者： Eugene Okyere-kwakye Khalil Md Nor aFaculty of Business and Management Studies Koforidua Technical UniversityKoforiduaGhana bFaculty of Management University of Technology Malaysia(UTM)Johor BahruMalaysia

Green banking is a comparatively new development in the financial *** is a form of banking that considers the social and environmental impacts of banking *** studies on green banking focussed on customers,management,and other stakeholders without considering the perspective of employees,whose daily work is normally *** fill in the gap,the primary aim of this study is to assess factors affecting the intention of banks to adopt green banking from the perspective of employees.A questionnaire was used to collect data from 94 employees at selected banks in Koforidua,the eastern region of *** regression was used to analyse the *** study finds a significantly positive relationship between management support and intention of banks to adopt green ***,pressures from competitors and customers are found not to have a significant impact on banks’intention to adopt green *** these results are unexpected and disappointing,they provide important insights in the context that changing initiatives from the perspective of common employees are internally driven instead of externally *** suggests the importance of management’s role in facilitating green banking initiatives.

关键词： Green banking competitor pressure customer pressure management support

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生物扰动对砂岩储集层物性的影响--以马来西亚沙捞越巴拉姆三角洲为例

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石油勘探与开发 2015年第2期42卷 200-208页

作者： Ben-awuah Joel Padmanabhan Eswaran 马来西亚国油科技大学地球科学与石油工程学院地球科学系

以马来西亚沙捞越巴拉姆三角洲为研究对象,进行取样岩心和薄片分析,结合EDX(能量色散X射线)、FESEM(场发射扫描电镜)、压汞测孔隙度和点状渗透率测量等方法评估生物扰动对储集层孔隙度和渗透率的影响。岩心取自巴拉姆三角洲W-1井和W-6井... 详细信息

以马来西亚沙捞越巴拉姆三角洲为研究对象,进行取样岩心和薄片分析,结合EDX(能量色散X射线)、FESEM(场发射扫描电镜)、压汞测孔隙度和点状渗透率测量等方法评估生物扰动对储集层孔隙度和渗透率的影响。岩心取自巴拉姆三角洲W-1井和W-6井,分析结果显示,W-1井样品主要发育双杯迹潜穴(Diplocraterion),为强烈—剧烈生物扰动,可见沉积物充填,沉积物充填活动将宿主沉积物中的细粒物质(黏土和有机物)混入潜穴充填物和潜穴衬里,降低沉积物的均质性和分选性,导致潜穴中局部区域孔隙度和渗透率降低;W-6井样品主要发育蛇形迹潜穴(Ophiomorpha),为强烈—剧烈生物扰动,黏土和泥质被清除出潜穴充填物和宿主沉积物,聚集于潜穴衬里,潜穴生物的沉积物清除活动导致潜穴内部沉积充填物的分选性变好、孔隙度和渗透率升高。生物扰动对储集层孔隙度和渗透率的影响由潜穴及其充填物和潜穴活动的类型决定。

关键词：巴拉姆三角洲沙捞越盆地生物扰动遗迹构造潜穴岩石非均质性孔隙度渗透率蛇形迹双杯迹

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Response of nephelometric turbidity to hydrodynamic particle size of fine suspended sediment

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International Journal of Sediment Research 2020年第5期35卷 444-454页

作者： Christina bright Sarah Mager Sophie Horton School of Geography University of Otago

Turbidity is used as a surrogate for suspended sediment concentration(SSC),and as a regulatory tool for indicating land use disturbance and environmental *** relates linearly to suspended material,however,can show non-linear responses to particulate organic matter(POM),concomitant with changes in particle size distribution(PSD).In the paper the influence of ultra-fine particulate matter(UFPM) on specific turbidity and its association with POM in suspended sediment are shown for alpine rivers in the Southern Alps of New *** approach was two-fold:a field-based investigation of the relations between SSC,POM,and turbidity sampled during event flow;and experimental work on hydrodynamic particle size effects on SSC POM,PSD,and *** turbidity changes over event flow and are sensitive to increasing proportional amounts of sand,UFPM,and POM in ***,the UFPM is the size fraction(<6 μm) where POM *** implications of the current study are that the slopes of turbidity-SSC relations are undesirable in locations that may be dominated by cyclic release of POM or distinct pulses of fine-grained *** locations where the turbidity-SSC slopes approximate 2,the POM proportion is usually <10% of the total suspended ***,when turbidity-SSC slopes are <1 this is likely caused by high amounts of side-scatter from UFPM concomitant with higher proportions of ***,the use of turbidity as a proxy for determining SSC may have serious consequences for the measurement of representative suspended sediment data,particularly in locations where POM may be a significant contributor to overall suspended load.

关键词： Turbidity Nephelometry Suspended sediment concentration Particle size distribution Particulate organic matter

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