Atom Indonesia (E-Journal)
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Dose Response of Hp(0.07) on TLD-700 and TLD-900 Based Ring Dosimeters to the Sr-90 Exposure
No full textThe preparation of radiopharmaceuticals may necessitate close contact with the radioactive source. In this case, high-energy beta-emitting nuclides can cause a high exposure. There are two methods of measuring the dose in the extremities, including using a bracelet and a ring dosimeter. In this study, the response of Hp(0.07) dose in TLD-700 and TLD-900-based ring dosimeters to Sr-90 beta radiation will be compared for parameters of distance, time, and angle of irradiation. The dosimeters were irradiated using Sr-90 at a distance of 5, 7, and 10 cm from the source surface and all of them were subsequently read with TLD Reader. The same type of dosimeters were exposed to Sr-90 for 1 day, 2 days, and 3 days at a distance of 7 cm and read. At a distance of 7 cm, the other dosimeters were irradiated at angles of 30°, 60°, -30°, and -60°, and then read. The study shows that the relationship between the distance of irradiation to Hp(0.07) dose is polynomial with a correlation factor of 1, both for TLD-700 and TLD-900-based ring dosimeters. The dose response at the variation of irradiation time showed linear behavior with correlation coefficients of 0.9942 and 0.9999 for TLD-700 and TLD-900, respectively. The decrease in Hp(0.07) response in TLD-700 reached 14-31 % for the irradiation angle of ±30o and 23-27 % in TLD-900 for the same angle. Meanwhile, the decrease in Hp(0.07) response at the angle of irradiation ±60o reached 48 % for TLD-700 and 66-67 % for TLD-900
Effects of Patient Dose Reduction Efforts on Image Quality for Thoracic CT in A Moroccan Hospital
No full textThoracic CT imaging is a strongly recommended means of medical imaging. It is accompanied by a high exposure to radiation due to the number of examinations carried out, which requires efforts to reduce the CT dose index (CTDI) while trying to preserve image quality. To this end, this study proposed the possibility of introducing two new imaging protocols for chest tomography. A 16-slice HITACHI SUPIA CT scanner and two phantoms were used to investigate CTDIvol and image quality; the first phantom was made of PMMA and the other of AAPM model 610. Three tube voltages were studied by varying the intensity of the tube current (mA): 120 kVp (120-160-210-230) mA, 100 kVp (160-200-240-290) mA, and 80 kVp (230-260-300-350) mA. The values for noise uniformity and accuracy, contrast-to-noise ratio (CNR), and spatial resolution (SR) were determined using IndoQCT c22a. 92 software. The first thoracic protocol proposed with 100 kVp compared to 120 kVp resulted in a 27.51 % reduction in CTDIvol, a 20 % increase in mA, and a 19.50 % increase in noise. The CNR showed a slight regression of 23.08 %. For the second scan procedure at 80 kVp, the CTDIvol was reduced by 53.32 %, while noise was increased by 53.95 %. There was no statistically significant difference in CNR and SR (p > 0.05) when kVp and mA were reduced compared to the routine protocol. It is suggested that it is possible to adopt two new acquisition protocols at 100 kVp and 80 kVp while reducing the patient exposure dose (CTDIvol) by 28 % and 54 % and taking into account the effect of varying these parameters on image quality. Their choices must be made by integrating and considering clinical issues and a good understanding of the pathophysiology and imaging results of the suspected condition. Consequently, radiologists and technicians should always take a part in improving imaging practices in such a way as to make more effective use of radiation
Neutronic Design Modification of Passive Compact-Molten Salt Reactor
No full textPassive compact molten salt reactor (PCMSR) is a design concept of a molten salt reactor (MSR) currently under development in Universitas Gadjah Mada, Indonesia. It is designed as a thermal breeder reactor using thorium fuel cycle. However, our previous study shows that the original PCMSR design was incorrectly modelled, primarily overestimating its thorium breeding capability. To improve PCMSR neutronic design, we modified the core configuration by the addition of radial fuel channel layers previously nonexistent in original PCMSR core design in various configurations. Neutronic parameters of modified PCMSR geometries in the beginning of life (BOL) were simulated using MCNP6.2 radiation transport code with ENDF/B-VII.0 library. All variations of fuel layer addition show improvement in both temperature coefficient of reactivity (TCR) and breeding ratio (BR), with TCR values became more negative and BR values are larger than unity, ensuring proper breeding capability. Configuration Inner Core-Outer Blanket (IC-OB) achieves the largest BR and lowest doubling time (DT), whilst its TCR is an improvement from the original design. Therefore, IC-OB fuel layer configuration can be applied to redesign the original PCMSR and used in various design optimization scenarios
Differential Cross Section With Volkov-Thermal Wave Function in Coulomb Potential
No full textLaser-assisted thermal electron-hydrogen atom elastic scattering was studied in the first-born approximation. The initial and final states of the projectile electron are described by the modified Volkov wavefunctions known as Volkov-Thermal wavefunctions. The laser-assisted thermal electron with energy ranges from 0.511 MeV to 4 MeV was considered to study the differential cross section (DCS) at azimuthal angles 30° and 14.7°, and laser-assisted field photon energy 1 eV to 3 eV are very weak at room temperature is around the room temperature 280 K to 300 K. The destructive interference was observed when a thermal electron absorbed a single photon from the laser field but no interference was found when a thermal electron emitted an electron to the laser field at a scattering angle . The DCS with eT scattering was found to be greater than a nonthermal electron in presence of laser field with scattering angle and incidence energy of the electron
Carbone or Oxygen Therapy: A Comparative Dosimetric Study Using PHITS Code
No full textCompared to conventional radiotherapy (X-rays or γ-rays), charged particle therapy shows more potential in treating deep-seated and radio-resistant tumors. Currently, all centers that offer hadron therapy use proton or 12C ion. Ongoing research is exploring the possibility of using others heavier ions, such as oxygen ion 16O or helium ion 4He. In this study, Monte Carlo method was used employing the Particle and Heavy Ion Transport code System (PHITS), to examine the amount of dose deposited by incident particles of 12C ion with energies of 200 and 300 MeV/u, as well as 16O ions with energies of 237.5 and 358.5 MeV/u. In this study, we investigated the depth dose distribution of carbon and oxygen ion beams by comparing their energy deposition in a water phantom and the impact of secondary particles. When considering lower energies, oxygen ions are more advantageous than carbon ions as they have slightly higher peak input ratios. This property enables higher doses to be delivered to tumor targets or lower doses to healthy surrounding tissues
Modeling of 137Cs Dispersion in the Atlantic Ocean at Ahanta West Coast: A Hypothetical Candidate Site for Ghana’s First Nuclear Power Plant
No full textThe government of Ghana has the intention of adding nuclear to its energy mix. Due to water availability for cooling, the coastal areas will be the right place for siting a nuclear power plant. This study was carried out to assess the distribution of 137Cs should liquid radioactive waste be released into coastal waters because of a non-routine event. The distribution was studied for the first month after the release. In the first week following the release, 137Cs was distributed within 16 km of the Ahanta West coastal waters with a concentration of about 9.1 Bq. L-1. On the seventh day, the distribution reached the entire coast of the Nzema East with a lower concentration with the bulk of the concentration still in the Ahanta waters. The 137Cs continued to spread into the eastern coast until the thirty-first day with a concentration of less than 1 Bq. L-1. This study provides useful data for future monitoring along the coast
The Effect of I-131 Treatment on Complete Blood Count
No full textRadioactive iodine-131 (RAI) treatment may cause suppression in the bone marrow. In this study, hemoglobin levels, leukocyte, thrombocyte, and lymphocyte counts will be compared before total thyroidectomy and 6 months after RAI treatment. 97 patients (76 females, 21 males) with a diagnosis of well-differentiated thyroid cancer who had undergone total thyroidectomy and received 50-200 mCi RAI treatment were included in the study. Hemoglobin levels, leukocyte, thrombocyte, and lymphocyte counts of the patients in the last month before the treatment and in the sixth month after the treatment were compared retrospectively. When the whole patients were analyzed, hemoglobin levels, leukocyte, thrombocyte, and lymphocyte counts in pretreatment were statistically lower than after-treatment values. While hemoglobin levels of female patients were similar before and after treatment, lymphocyte, thrombocyte, and leukocyte counts were statistically lower before treatment. Hemoglobin levels, leukocyte,and thrombocyte counts were similar before and after treatment, while lymphocytes decreased significantly after RAI treatment. Thyroid cancer patients who received 50-200 mCi RAI treatment after total thyroidectomy, have bone marrow suppression but are still in normal mean value ranges. This mild bone marrow suppression is more prominent in female patients than in male patients