A protocol for setting dose reference level for medical radiography in Nigeria: a review

Patients’ dose audit reports in some Nigerian hospitals had shown large inter- and intra-hospital variations for the same radiological examinations. They have thus presented the need, to have a national standard for radiological diagnostic procedures and set dose limits for individual x-ray examination centers in Nigeria. These will go a long way in reducing inter- and intra-hospital dose range factors, thus reducing doses to as low as reasonably achievable and consistent with clinical objectives of the examinations. In establishing a national dose limit for medical radiological examinations, there is a need to have a national dose survey. This paper suggests a reasonable and easy procedure for achieving a national radiological dose survey. Due to its simplicity of measurement, the use of entrance surface dose as the dose parameter to be used for setting the dose limit as recommended by the European Union and the International Atomic Energy Agency (IAEA) is also suggested. ESD can be measured directly through the use of solid state detectors, or indirectly by measuring free air exposure which can later be converted to ESD using standard formula. The methods of measuring the entrance surface dose and how to derive the dose limit from them are also highlighted

Comparative analysis and simulation of the d-q reference frame model of the three phase induction motor and its modification

Induction motors play an important role in residential, commercial, and industrial centers around the globe. They are rugged, reliable in operation and require low maintenance. The dynamic models of these motors are typically employed to understand their behavior in transient, steady state and under dynamic conditions. Several models of the three-phase induction motor exist in literature, but this paper proposes an alternative to the standard d-q reference frame model of the symmetrical three phase induction motor. The proposed model is obtained by modifying the standard model in a way in which the d-axis of the reference frame is aligned with the rotor flux vector. The alignment decouples the q-axis component from the d-axis component of the stator current using the vector control technique. The model is analyzed in the synchronous reference frame and then a dynamic simulation is performed. A comparison between the standard d-q reference frame model and the proposed model was performed. The simulation showed identical results of motor speed, torque and flux behavior for the two models. The difference between the two models manifests in their alternate characteristics for the d-q axes voltages and currents. It was observed that the magnitudes of the d-axis and q-axis voltages for the standard model are equal to the peak value of the applied phase voltages and zero respectively. However, the results of the proposed model revealed otherwise. Furthermore, it was observed that the d-q axis voltages and currents of the proposed model exhibit oscillations during motor acceleration time because of the dynamics of alignment but attain constant values during the time that motor speed is constant. The proposed model is easier to solve because the rotor dynamics are described by one equation instead of two equations as in the case of the standard d-q reference frame model

Photon and Fast Neutron Transmission Parameters of Metakaolin Doped Concrete

Radiation-shielding properties of metakaolin doped concrete samples wereinvestigated in this report. The gamma photon mass attenuation coefficientsand exposure buildup factor of the samples were determined theoreticallyusing WinXcom and EXABCal software respectively for the energyrange of 15 keV - 15 MeV and fast neutron removal cross section for theconcrete sample was evaluated. Results indicated that, oxides of silicon,aluminum, calcium and iron determined through the energy dispersiveX-ray fluorescence spectrometric analysis constitute more than 85% ofthe chemical composition of the concrete samples. The oxides contribute85.46, 86.47, 87.55, 88.75, and 86.15 % of the total chemical oxides inMK00, MK05, MK10, MK15, and MK20 respectively. Densities of theprepared MK doped concrete were in the range of 2.575-2.667 g/cm3 .Compressive stress of prepared MK doped concretes increased consistentlywith the curing period for each concrete sample. CS grew from 8.71 -10.63, 8.84 - 10.83, 9.44 - 11.22, 10.89 - 11.53, and 10.76 - 11.43 MPafor MK00, MK05, MK10, MK15, and MK20 respectively as the periodextends from 7 to 28 days. Mass attenuation coefficient decrease steadilywith an increase in energy up to about 0.1 MeV and the decrease becomesmaller beyond this energy with increasing energy for all the mixtures. Fastneutron removal cross section results indicate that MK10 (0.07693 cm-1)has the highest value of ΣR followed by MK15 (0.07628 cm-1) and MK20(0.07537 cm-1) while MK00 (0.07380 cm-1) and MK05 (0.07404 cm-1)have approximately the same value. It was found that MK10 concrete hasthe best gamma radiation and fast neutron shielding ability among the MKdoped concrete under study

Antihypertensive Therapy Among Hypertensive Patients as Seen in the Middle Belt of Nigeria

Background: In spite of increased awareness on hypertension among Nigerians, control of blood pressure among hypertensive patients is still unacceptably poor. This study was therefore designed to assess the compliance rate to antihypertensive therapy among Nigerians and factors influencing it. Method: Two hundred and twenty four consecutive hypertensive patients were prospectively studied using a pre-tested questionnaire. Results: A total of 100 males (44.6%) and 124 females participated in the study. The age ranged between 35-82 years. Calcium channel blockers were the most frequently prescribed medication (39.3%) followed by diuretics (14.3%). Combination therapy was seen in 35.7% of the patients. B-blockers were the rarest drug as a single agent (1.8%). Using multivariate analysis, access to the hospital was the only independent predictor of Systolic Blood Pressure level. 39.3% of the respondents volunteered history of having stopped their drugs at one time or the other over a one year period for different reasons with high cost and scarcity of drugs being the most prevalent. 85.7% of the patients spent between two hundred and two thousand Naira monthly on drug procurement. Conclusion: Calcium channel blockers are rapidly gaining ground as first line antihypertensive agents in tertiary hospitals in Nigeria. This study has underscored the need to bring health care centres closer to the people in a bid to improve the control of blood pressure

High Energy X-Ray Dosimetry Using (ZnO)0.2(TeO2)0.8 Thin Filmbased Real-time X-Ray Sensor

This study reports the dosimetric response of a (ZnO)0.2(TeO2)0.8 thin film sensor irradiated with high-energy X-ray radiation at various doses. The spray pyrolysis method was used for the film deposition on soda-lime glass substrate using zinc acetate dehydrate and tellurium dioxide powder as the starting precursors. The structural and morphological properties of the film were determined. The I-V characteristics measurements were performed during irradiation with a 6 MV X-ray beam from a Linac. The results revealed that the XRD pattern of the AS-deposited thin film is non-crystalline (amorphous) in nature. The FESEM image shows the non-uniform shape of nanoparticles agglomerated separately, and the EDX spectrum shows the presence of Te, Zn, and O in the film. The I-V characteristics measurements indicate that the current density increases linearly with X-ray doses (0-250 cGy) for all applied voltages (1-6 V). The sensitivity of the thin film sensor has been found to be in the range of 0.37-0.94 mA/cm2 /Gy. The current-voltage measurement test for fading normalised in percentage to day 0 was found in the order of day 0 > day 15 > day 30 > day 1 > day 2. These results are expected to be beneficial for fabricating cheap and practical X-ray sensors

A comprehensive study on optical features, gamma photon buildup factors and neutron shielding capability of B2O3-SB2O3-LI2O-BI2O3 glasses

ABSTRACT. Linear, nonlinear optical properties, photon buildup factors, and neutron shielding capability of glasses with chemical composition (65-x)B2O3-10Sb2O3-25Li2O-xBi2O3, where x = 0 (BSLB0) – 20 (BSLB20) mol% with steps of 4 mol% were examined. Molar refractivity (Rmolar) and molar polarizability (αmolar) were increased as Bi2O3 content mol% increase in the examined BSLB-glasses. The values of metallization criterion (Mcriterion) confirmed that the BSLB-glasses were non-metallic materials. The static (εstatic) and optical (εoptical) dielectric constants having the same trend of the refractive index (noptical). Values of optical electronegativity (χ*) were reduced from 0.825 for BSLB0 (Bi2O3 = 0 mol%) glasses to 0.758 for BSLB20 (Bi2O3 = 20 mol%) glasses. The linear electric/dielectric susceptibility (χ(1)) increased from 0.370 to 0.397. The nonlinear optical susceptibility (χ3) and nonlinear refractive index n2optical were enhanced by increasing Bi2O3 content in the BSLB-glasses. The BSLB20 glasses presented the least exposure and energy absorption build-up factors (EBF and EABF) at all considered thickness. BSLB20 sample achieved the best fast neutron removal cross section ( ) shield among all glasses. The total stopping powers (TSP) follows the trend (TSP)BSLB0 < (TSP)BSLB4 < (TSP)BSLB8 < (TSP)BSLB12 < (TSP)BSLB16 < (TSP)BSLB20. The electron absorbing and hence shielding capacity of the BSLB-glasses improves as their Bi2O3 content increase.     KEY WORDS: Antimony lithium-borate glasses, Optical properties, Buildup factors, Neutron shielding   Bull. Chem. Soc. Ethiop. 2022, 36(4), 949-962.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i4.19                                                     &nbsp

Measurement of Background Gamma Radiation Levels at Two Tertiary Institutions in Minna, Nigeria

An in-situ measurement of the background radiation level was carried out at the vicinity of three campuses of two major tertiary institutions in Minna. A portable Geiger-Mueller tube-based environmental radiation dosimeter was used for the measurement. A total of 34 point was surveyed across the three institutions for background environmental radiation. The dose rate range obtained are: at the Niger State College of Education Minna (NCM), the dose rate varies from 0.125 \ub5Sv/hr to 0.171\ub5Sv/hr; at the Federal University of Technology Bosso Campus (FUTB) it wass between 0.152 \ub5Sv/hr and 0.184 \ub5Sv/hr; and at the Federal University of Technology Gidan-Kwano campus FUTG it was between 0.137 \ub5Sv/hr and 0.184 \ub5Sv/hr. In all the 34 points surveyed the mean dose rate was 0.154 \ub5Sv/hr with a standard deviation of 0.017 \ub5Sv/hr. Generally, the dose rate level in each of the institutions surveyed are comparable to one another and could simply be attributed to natural sources. The average annual effective dose obtained from this study is 0.189 mSv/annum which is still less than the recommended limit of 1mSv/annum by International Commission on Radiation Protection [ICRP] for non occupational population exposure. @ JASE

Investigation of Er3+ Ions Reinforced Zinc-Phosphate Glasses for Ionizing Radiation Shielding Applications

Melt quenching technique is used for preparing glasses with chemical formula (70P2 O5)– (16 − x)CdO–(14ZnO)–(xEr2 O3), (x = 1–6 mol%). These glasses were named Er1, Er2, Er3, Er4, Er5, and Er6, respectively. Photon buildup factors, fast neutron absorption, and electron stopping of the prepared glasses were examined. Glasses’ density was varied from 3.390 ± 0.003 for the Er1 glass sample to 3.412 ± 0.003 for the Er6 glass sample. The Buildup factor (BUF) spectra have relatively higher values in the Compton Scattering (CS) dominated areas compared to both Photoelectric effect (PE), and Pair Production (PP) dominated energy regions. The highest BUF appeared at the Er atom K-absorption edge, whose intensity increases as the molar concentration of Er2 O3 in the glasses increases. The photon absorption efficiency (PAE) of the glasses increases according to the trend (PAE)Er1 < (PAE)Er2 < (PAE)Er3 < (PAE)Er4 < (PAE)Er5 < (PAE)Er6. Fast neutron removal cross-section, FNRC (ΣR) values of the glasses obtained via calculation varied from 0.1045–0.1039 cm−1 for Er1–Er6. Furthermore, the continuous slowing down approximation mode (CSDA) range enhances the kinetic energy of electrons for all glasses. Generally, results revealed that the investigated glasses could be applied for radiation shielding and dosimetric media. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Taif University Researchers Supporting Project number (TURSP-2020/23), Taif University, Taif Saudi Arabia. "The APC was covered by "Dunarea de Jos" University of Galati, Romania, through grant no. RF3621/2021

Abdominal ultrasonography in HIV/AIDS patients in southwestern Nigeria

<p>Abstract</p> <p>Background</p> <p>Though the major target of the HIV-virus is the immune system, the frequency of abdominal disorders in HIV/AIDS patients has been reported to be second only to pulmonary disease. These abdominal manifestations may be on the increase as the use of antiretroviral therapy has increased life expectancy and improved quality of life. Ultrasonography is an easy to perform, non invasive, inexpensive and safe imaging technique that is invaluable in Africa where AIDS is most prevalent and where sophisticated diagnostic tools are not readily available. Purpose: To describe the findings and evaluate the clinical utility of abdominal ultrasonography in HIV/AIDS patients in Ibadan, Nigeria</p> <p>Methods</p> <p>A Prospective evaluation of the abdominal ultrasonography of 391 HIV-positive patients as well as 391 age and sex-matched HIV-negative patients were carried out at the University College Hospital, Ibadan.</p> <p>Results</p> <p>Of the 391 cases studied, 260 (66.5%) were females; the mean age was 38.02 years, (range 15–66 years). The disease was most prevalent in the 4th decade with an incidence of 40.4%. Compared with the HIV-negative individuals, the HIV+ group of patients had a significantly higher proportion of splenomegaly (13.5% vs. 7.7%; p < 0.01), lymphadenopathy (2.0% vs. 1.3%; p < 0.70), and renal abnormalities (8.4% vs. 3.8%; p < 0.02). There were no differences in hepatic and pancreatic abnormalities between the HIV+ and HIV- groups. There were significantly fewer gallstones in the HIV+ group (1.4% vs. 5.1%; p < 0.01).</p> <p>Conclusion</p> <p>AIDS is a multi-systemic disease and its demographic and clinical pattern remains the same globally. Ultrasonography is optimally suited for its clinical management especially in Africa. Its accuracy and sensitivity may be much improved with clinico-pathologic correlation which may not be readily available in developing countries; further studies may provide this much needed diagnostic algorithms.</p