Atom Indonesia (E-Journal)
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Estimation of Population Size and Dispersal Pattern of Sterile Male Aedes aegypti Using Mark-Release-Recapture (MRR) Technique
Get PDFAedes aegypti is currently emerging as a main vector of Dengue, Zika, and Chikungunya transmission. Chemical control was reported to be less effective due to the resistance of this mosquito to some types of insecticides. Therefore, another vector control is needed which is most appropriate to be used, i.e. the sterile insect technique (SIT). Information about optimum range dispersal sterile male Aedes aegypti for optimalization SIT program are needed. This study was designed to determine the dispersal pattern and population estimation of Aedes aegypti sterilized with gamma rays using mark-release-recapture (MRR) method. After the male Aedes aegypti (pupal stage) was irradiated with 70 Gy of gamma rays, the mosquitoes were then marked with Rhodamine-B and released into the study site. MRR experiments were carried out in Batan Indah residential area, and the Aedes aegypti were released in center of the site. Mosquitoes were recaptured at 28 points spread over the Batan Indah Residence for 2, 4, 6, and 8 days after release by using BG-Sentinel Traps. The result showed that the population of Aedes aegypti in the site was estimated to be 5.402 (1.347–14.636; CI 95 %) with the furthest spread distance was 119 meters from the release point. This study also showed that the MRR experiment can be used to estimate the population size and dispersal pattern of Aedes aegypti movement in a given locality. The result of present study provide better understanding for optimalization mosquito-borne disease prevention based on SIT programs
Implementation of Beam Matching Concept for the New Installed Elekta Precise Treatment System Medical LINACs in Indonesia
Get PDFA concept of radiation beam matching of some medical linear accelerators (LINACs) that have identical characteristics of the models, radiation quality, and multileaf collimator features may be implemented as long as the manufacturer provides complete specifications so that a Treatment Planning System (TPS) can be used for many beam-matched LINACs. This paper describes a preliminary study on the implementation of the beam matching concept for five units Elekta Precise Treatment System LINACs that have recently been installed in Indonesia. The beam matching criteria were based on the percentage depth dose (PDD) and beam profile for photon and electron beams. Dosimetry measurements were carried out by using an SNC 125 ionization chamber of 0.125 cm3 in volume, PTW Pinpoint 3D of 0.016 cm3 in volume, and PTW Farmer Chamber of 0.6 cm3 in volume. The results indicated that the PDD10 of 6 and 10 MV photon beams among installed five units LINACs have excellent compatibility each others with a maximum deviation of less than 0.4 %, while the maximum deviation for dose depth of 80 % (R80) for the electron beams with nominal energies of 4, 6, 8, 10, 15 and 18 MeV is 1 mm. The measurement results for the flatness profile were less than 6 %, and symmetry profiles were less than 3 %. It also outlines the determination of the absorbed dose to water under reference conditions. The results of the calibration of output doses show that the absorbed dose in the water was 1 cGy ≈ 1 MU. The data obtained from measurements for each LINAC conform with the requirements of the beam matching process set by the manufacturer
Proposed Managements of 137Cs Contaminated Soil: Case Study in South Tangerang City
Get PDFRecently, BAPETEN found contamination of 137Cs while testing environmental radiation monitoring equipment in an area in South Tangerang City. The area, therefore, needs to be cleaned up by performing decontamination followed by the activity of treating the contaminated soil. The decontamination works were carried out by excavating the contaminated soil on the surface to a depth of more than 1.5 m, and then the soils were put into the 100L drum. Decontamination work resulted in a significant reduction dose exposure in the area to 0.3-0.75 mSv/h. The drums containing contaminated soil were then sent to the interim storage facility in BATAN Serpong facility for further treatment. To resolve the 137Cs contaminant, some alternatives in the decontamination and management of the contaminated soils were studied. Some techniques and strategies for decontamination and managing 137Cs are presented in this paper. Management that involves wet and dry methods will be proposed in this paper. By comparing and evaluating various alternative management methods, an appropriate method for treating the contaminated soil in South Tangerang City can be obtained. The objective of the study was to find a suitable management method for the contaminated soil based on the proposed alternative management methods.In the present case, the compaction method seems promising for use soon
Dosimetric Assessment of Routine X-Ray Examination at Selected Health Clinics in Perak Using Commercialized Optically-Stimulated Luminescence Dosimeter (OSLD)
Get PDFThis study aims to compare entrance surface dose (ESD) values measured with nanoDot Al2O3:C optically-stimulated luminescence dosimeter (OSLD) and guidance level set under the second national dose survey which utilized old-version LiF:Mg,Ti thermoluminescence dosimeter (TLD). In this study, we conducted a dosimetric assessment for posteroanterior chest X-ray (PA-CXR) examinations performed at various community clinics in Perak, Malaysia. These clinics were selected as they were excluded from the first and second national dose survey conducted in Malaysia in 1993-1995 and 2005-2009, respectively. The ESD is obtained by mounting the OSLD on the surface of polymethyl methacrylate (PMMA) slabs. The PMMA slabs were then exposed to X-ray based on the current practice of respective clinics. The results show that the 3rd quartile of ESDs ranged from 0.180 mGy to 0.229 mGy which is less than the recommended guidance level of the second national dose survey by 77 %. ESD measured using OSLD was found to be lower than the guidance values recommended from the second national dose survey. The finding showed a good competency of the radiographer to optimize radiological practice specifically in routine X-ray examination
Analysis of 137Cs Radionuclide Content in Sediment in Musi Watershed Using Gamma Spectrometer and its Affecting Factors
Get PDFThe concentration of the radionuclide 137Cs on sediment in watershed in Palembang has been analyzed. This study aims to determine the influence of sampling location and the water quality indicators of water pH, sediment pH, conductivity, turbidity, and sediment type on the concentration of 137Cs and to determine the distribution pattern of 137Cs in sediments. Sampling was conducted at seven stations spaced approximately 5 km apart, placed from the western end to the eastern end of the Musi river segment located within Palembang City.Sediment samples were prepared and their 137Cs contents were measured with gamma spectrometry. The results showed that their 137Cs concentrations ranged from below MDC (minimum detectable concentration) to 1.51 Bq/kg. This was within the 1×103 Bq/kg limit set by the quality standard. The varied and very low concentrations of 137Cs are thought to have originated from global fallout. The location point of sampling affects the concentration of radionuclide 137Cs while the characteristics of water quality are do not. The 137Cs concentration spread pattern in Musi sediment is influenced by tidal currents and river morphology
Synthesis and Characterization of Ordered and Disordered Mesoporous Alumina as High-Performance Molybdenum-99 Adsorbents
Get PDFMolybdenum-99 (99Mo) is the parent radioisotope of technetium-99m (99mTc),an essential medical radioisotope for diagnostic agents in nuclear medicine.In 99Mo/99mTc generator, a chromatography column system with 99Mo adsorbent as afiller is usually used to produce 99mTc in hospitals. However, it is still challenging to find high-performance adsorbentsfor Mo adsorption.We have synthesized both ordered and disordered mesoporous alumina and compared their performance as 99Mo adsorbents. These materials were prepared via a soft-templated method using a triblock copolymer as the template, followed by air calcination at 400°C.The amount of nitric acid (HNO3) and the drying time were adjusted systematically to synthesize the ordered mesoporous alumina. The obtained ordered and disordered mesoporous alumina were characterized by low-and wide-angle X-ray diffractions (XRD), nitrogen adsorption-desorption, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The 99Mo adsorption capacities of these materials were evaluated by using the batch method. The experimental results show that the ordered mesoporous alumina hasa higher 99Mo adsorption capacity of 72.06 mg(Mo)g-1 than the disordered mesoporous alumina (50.12 mg(Mo)g-1). The results indicate the excellent potential of ordered mesoporous alumina as an adsorbent for the 99Mo/99mTc generator column
Coupled Analysis of Thorium-based Fuels in the High-Performance Light Water Reactor Fuel Assembly
Get PDFOne of the six selected concepts to be part of Generation IV nuclear reactors is the Supercritical Light Water Cooled Reactor. The High-Performance Light Water Reactor (HPLWR) is the European version and it is a very promising design. In recent years, interest in the study of thorium-based fuel cycles has been renewed and its possibilities for current LWRs have been evaluated. The use of thorium-based fuels will be fundamental in the future sustainability of nuclear energy, since in addition to its abundance in nature, thorium has an important group of advantages. In this paper, performance of thorium-based fuels in the typical fuel assembly of the HPLWR reactor is evaluated, using a computational model based on CFD and Monte Carlo codes for the neutronic/thermal-hydraulic coupled analysis. The volumetric power density profiles, coolant temperature profiles, fuel temperature profiles and others are compared with those obtained for standard UO2 fuel. When the thorium-based fuels are used, the obtained infinite multiplication coefficients are smaller than the value obtained when UO2 is used, since the 232Th isotope has a lower contribution to the multiplicative properties of the medium than 238U. As a result, a difference of approximately 12 000 pcm was observed. The results verified that the HPLWR is a thermal reactor with a hard spectrum. There are no notable changes in the neutron spectrum if the mass fraction of thorium is slightly varied. With coupled analysis, the potential benefits of the utilization of thorium-based fuels were verified. Moreover, a significant temperature decrease by 136 K on the center line of the fuel elements was observed. When the mass fraction of thorium increases in the oxides mixture, the weighted average temperature on the fuel elements decreases
Investigation on the Background Radiation of Abakaliki Rice Mill in Ebonyi State, Nigeria
Get PDFThis study investigated the background ionizing radiation of Abakaliki rice mills. The requirement to monitor this site is because the prevalent activities in the site suggest that it is a source of ionizing radiation. The activities include fuel stations and excavation sites. Other sources are various chemicals and agrochemicals (like Phosphate, Uranium, Thorium, and Radium) used during the planting of the different rice species. There is, therefore, an urgent need to investigate the radiation level of Abakaliki rice mills in Ebonyi state, Nigeria to ascertain if it has passed the safety standards. The investigation was carried out using the Radalert 100 radiation monitor and a geographical positioning system (Garmin GPSMAP 765). The studied site was split into different points with each representing a mill that houses different grinding plants. This study included all the sections of the mill. The mean background radiation exposure rate ranges from 0.014mRhr-1to 0.0204mRhr-1. The obtained values are higher than the world standard limit of 0.013mRhr-1 recommended by ICRP except point 7 which corresponds to the top of the rice husk dumpsite. The calculated absorbed dose rates for the various sections of the mill ranged from 99.18 nGh-1 to 177.48 nGyh-1. These values of absorbed dose rates were observed to be far higher than the world permissible value of 89 nGyh-1. The annual effective dose equivalent (AEDE) for the exposure values ranged from 0.122 mSvy-1 to 0.218 mSvy-1 which are far lower than the ICRP permissible limits of 1.00 mSvlyr for the public and therefore implies absence of any immediate radiological risk. The excess lifetime cancer risk for the mill users were all above the 0.29 × 10-3 world recommended value. This suggests a possibility of the rice mill workers developing radiation-related illnesses over time
Comparisons of Water-Equivalent Diameter Measured on Images of Abdominal Routine Computed Tomography with and without A Contrast Agent
Get PDFThe size-specific dose estimate (SSDE) is a metric for an estimation of patient dose in computed tomography (CT). The SSDE strongly depends on the water-equivalent diameter (DW). In abdominal CT examinations, a contrast agent is sometimes used to more clearly visualize tissue lesions. The Hounsfield unit (HU) of CT images with and without the use of a contrast agent at specific areas is slightly different and it may affect the DW value. This study aimed to compare the DW values calculated from axial CT images in patients who had undergone routine abdominal scans both with and without the use of a contrast agent. Axial images of 144 patients with a weight range of 3.5 kg to 90 kg who had undergone routine abdominal scans both with and without the use of a contrast agent using a Siemens Sensation 64 CT scanner were retrospectively collected. The DW values were automatically calculated using the Matlab-based IndoseCT (version 15a) software. The results show the percentage difference between DW,contrast and DW,non-contrast is below 2 %.As a result, the mean SSDEcontrast is 1.5 % smaller than SSDEnon-contrast. Due to the effect of a contrast agent on the DW and SSDE values is below 2 %, the axial images of CT abdomen without the use of a contrast agent can be used as the accurate estimation of DW and SSDE for images with the use of a contrast agent