Atom Indonesia (E-Journal)
Not a member yet
530 research outputs found
Sort by
Dose Planning Evaluation of Intensity-Modulated Proton Therapy (IMPT) Technique Based on In-House Dynamic Thorax Phantom
Full text linkOne of the drawbacks of the Intensity Modulated Radiation Therapy (IMRT) technique is that the absorbed dose in healthy tissue is relatively high. Proton beam has characteristics that can compensate for these drawbacks. The Bragg peak characteristic of a proton beam allows the administration of high radiation doses to the target organ only. Non-Small Cell Lung Cancer (NSCLC) cases are located in the vicinity of many vital organs, so radiation doses that exceed a certain limit will have a significant impact on these organs. Proton is a heavy particle that exhibits interaction patterns with tissue heterogeneity that differ from that of photon. This study aims to determine the distribution of proton beam planning doses in the NSCLC cases with the Intensity Modulated Proton Therapy (IMPT) technique and compare its effectiveness with the IMRT technique. Treatment planning was done by using TPS Eclipse on the water phantom and on the in-house thorax dynamic phantom. The water phantom planning parameters used are one field at 0° and three fields at 45°, 135°, and 225°. In this study, a single, sum, and multiple field techniques on the in-house thorax dynamic phantom were used. The evaluation was performed by calculating Conformity Index (CI), Homogeneity Index (HI), and Gradient Index (GI) parameters for each treatment planning. As a result, a bit of difference in the CI the HI values are shown between IMPT and IMRT planning. The GI values of IMPT planning are in the range between 4.15-4.53, while the GI value of IMRT is 7.89. The histogram results of the planar dose distribution show that the IMPT treatment planning provides fewer off-target organ doses than the IMRT planning. Evaluation was also carried out on the IMPT treatment planning of target organs in five areas of interest and four OAR positions. The evaluation results were then compared with the IMRT measurement data. As a result, the value of the point doses at the target organ did not differ significantly. However, the absorbed dose with the IMPT technique at four OAR positions is nearly zero, which had a large difference compared to the IMRT technique
Neural Network Predictions of Atomic Form Factors and Incoherent Scattering Functions
Full text linkIn order to predict atomic form factors and incoherent scattering functions which are used to calculate the coherent and incoherent total scattering cross sections, a technique based on artificial neural networks of the multilayer type was implemented. In this context, two neural models have been developed and compared with those in the literature. This study revealed both the accuracy of the results obtained and the effectiveness of the designed model. The mean relative error for the least estimated property does not exceed 16.5 %. The software realized in this way give a prediction of the above parameters for the input variables Z: Atomic number, x: sin(ϑ/2)/λ and E: Photon energy, and it provides users with flexibility for prediction. The advantages of this technique lie in its very fast handling, due to its ease of use, and in the two integrated networks, which it guarantees for a variety of input parameters such as atomic number, photon energy, and momentum transfer variable
Simulation of Leksell Gamma Knife-4C System with Different Phantoms Using PHITS and Geant4
Full text linkThis study used PHITS and Geant4 code packages to simulate a Leksell Gamma Knife system in order to determine radiation dose distribution in two types of phantoms. The results observed in the water phantom with configurations of single source and 201 sources are in good accord with the prior research, including both simulation and experiment. Several characteristics of Leksell Gamma Knife 4C, such as dose profiles, output factor, FWHM, and penumbra size, are calculated based on Monte Carlo simulations, which show the best consistency with other results. The output factors for collimators of 14 mm, 8 mm, and 4 mm are 0.984, 0.949, and 0.872, respectively. The simulation results with an adult mesh-type reference phantom reveal considerable similarities with the established radiosurgery plans. It indicates that the absorbed dose in brain tumors was highest when utilizing the 18 mm collimator and subsequently reduced with collimator size to 0.65, 0.25, and 0.5 with the 14 mm, 8 mm, and 4 mm collimators, respectively. The absorbed dose has a very low value for other essential organs and decreases with distance from the brain tumor. These findings may explain why the dose to organs decreases linearly as target distance, volume, and collimator size increase
Dose Evaluation of Head and Neck Cancer IMRT Treatment Planning Based on Gamma Index Analysis of Varian Halcyon 2.0 Linac
Full text linkVarian Halcyon 2.0 linear accelerator was launched and became available for clinical use in 2018. Therefore, it is necessary to evaluate the accuracy of exit fluence of the Halcyon 2.0 for quality assurance (QA) of head and neck cancer treatment planning, pretreatment, and treatment. The accuracy of the exit fluence for twenty treatment plannings has been evaluated by conducting gamma analysis for QA pretreatment and treatment in each field and composite field by using criteria for gamma index 3 %/3 mm and 2 %/2 mm. The QA pretreatment results are in the average value for each criterion for each field and composite fields on actual gantry angle and null gantry angle with gamma passing rate (GPR) of over 99 % (range 99.78 %-99.95 %) The total treatments consisted of 2717 fractions. The analysis results of GPR for fields were 99.32 % and 97.74 % for gamma indexes of 3 %/3 mm and 2 %/2 mm, respectively. In addition, the analysis results of GPR for composites were 95.46 % and 81.38 % for gamma indexes of 3 %/3 mm and 2 %/2 mm, respectively. Based on this result, the average GPRs of QA pretreatment are ≈ 99 % of the total pixels. This means the prediction dose of Varian Halcyon 2.0 is accurate. The average GPRs of treatment is nearly 90 %, showing that Varian Halcyon 2.0 is effective for creating treatment plans for complex cases
Homogeneity Test on Collimators for Boron-Neutron Capture Therapy based on SNI 8506:2018
Full text linkA serial homogeneity test based on Indonesian Standard SNI 8506:2018 were undertaken to investigate 12 manufactured collimators by using double wall single image radiography (DWSI) technique with an x-ray machine ranging from 120 to 150 kV. The standard stated that the film density should be measured on seven different points, and the result obtained must not exceed ± 0.05 from the average density. This paper outlines a testing work for the collimators, calculating the density on six different points in the film. Six different points were selected due to technical constrains of the collimator manufacturing and radiography capabilities of the selected laboratory. The results of film the density for the 12 collimators are: (1) 2.59; (2) 2.57; (3) 2.14; (4) 1.88; (5) 2.10; (6) 1.96; (7) 2.33; (8) 2.28; (9) 2.06; (10) 2.18; (11) 2.24; and (12) 2.33. The result shows that collimator-2 has the most homogenous density. This study concludes that established parameters and process are needed to manufacture the collimator for BNCT in achieving proper performance testing based on the standard
Elemental Mapping and Quantities in Different Soybean Seed Colors Using Micro X-Ray Fluorescence and Their Correlations with Germination
Full text linkMicro X-ray fluorescence (μ-XRF) possesses a powerful analytical technique able to detect macro- and micro-elements. Each plant variety has a unique elemental composition and important role in the germination process. The aims of this study were to (1) map the elements and quantities in the soybean seed coat and endosperm, (2) investigate how the various elements might mediate the inter-relationship or correlation between elements within soybean seed genotypes with different seed coat colors, and (3) investigate that the targeted morphological characteristics especially in germination would be affected by seed elements. A μ-XRF technique was used for the elemental analysis and quantification. Three genotypes of Indonesian soybean were used in this study: greenish, black, and yellowish. In this study, we found that the silicon (Si) and magnesium (Mg) elements have a significant correlation. The high quantity of Si element in the embryo axis has a positive correlation with root length. The high quantity of Mg element which is evenly distributed on the endosperm has a positive correlation with normal germination. Si and Mg elements in the seeds have a negative correlation with imbibition water absorption. Based on the comparison between the three genotypes, the black genotype was superior in terms of germination and higher Si and Mg elements. Thus, the Si and Mg elements can be used as a reference in determining superiority of genotypes at the germination stage
Geologic Influence on Radon Concentrations Levels in Cave: A Case Study of Mimpi Cave in the Maros Karst of South Sulawesi, Indonesia
Full text linkRadon gas in the natural environment mainly comes from the release of local bedrock geology and easily accumulate in closed spaces such as basements and caves. This study was performed to investigate the radon concentrations in Mimpi Cave, Bantimurung-Bulusaraung National Park, in the Maros karst area, South Sulawesi, and discussed a possible relationship between the radon concentrations and the local geology. Measurements were carried out using a passive detection technique with CR-39 nuclear tracks detectors by exposing it for a period of three months. The 222Rn levels measured inside the cave ranges from 64.03 Bq m‑3 to 3396.02 Bq m‑3, with an average value of 1075.05 Bq m‑3.The results are comparable with radon concentration in different caves environments reported from other surveys in several countries. Geological background of the Maros Karst areas could sustain the measured radon values, due to the presence of limestone rock with a mineral composition which can lead to higher radon concentrations in Mimpi Cave