The present study aimed to determine the levels of contamination with Natural Occurring Radioactive Materials NORM in one of the south oil company fields. The external gamma absorbed dose rate Dγ ...measured in units of µSv/h was caused by gamma rays of Radium 222, Radium 228 (Thorium 232), and Potassium 40, respectively. The largest value is 9.220 µSv/h. It was found that the highest specific activity (concentration) for Radium 226 is 1136 Bq/kg and the lowest is 0.06 and the highest specific activity for Radium 228 is 721 Bq/kg and the lowest is 0.02 Bq/kg. As for Radium 224, its highest specific activity is 631 Bq/kg and the lowest is 0.02 Bq/kg. Radium-228 is higher than that of Radium-224 or Radium-226, as the Radium-224 is from the Uranium-232 series, and the Radium-228 and Radium-224 are from the Thorium-232 series, meaning that the percentage of the daughters of the Thorium chain is lower than the percentage of the daughters of the Thorium chain Uranium, because the half-life of Radium-226 is 1600 years, which is greater than the half-life of Radium-228, which is 5.75 years. A comparison was made between the local results with the results of soil in Amman. Methods of treating pollution with natural radioactive materials in the oil industry were also discussed.
•An electron beam was used to decompose volatile fatty acids (VFAs).•Decomposition characteristics by various influential factors were investigated.•The removal efficiency was increased with an ...increase of the molecular weight of these compounds.•The RE of all target VFAs were highest when used with O2 as a background gas.•Valeric acid was decomposed to more low molecular weight acids by electron beam irradiation.
Volatile fatty acids (VFAs) are representative odorous compounds. This study was carried out to decompose VFAs using electron beam irradiation. Acetic acid, propionic acid, butyric acid, isovaleric acid, and valeric acid were used as target VFAs. In order to confirm the decomposition efficiency and characteristics by various influential factors, experiments on the absorbed dose, background gas, and initial concentration were performed. The results confirmed that the removal efficiency increased with an increase of the absorbed dose. In addition, the removal efficiency was increased with an increase of the molecular weight of these compounds (in the following order: acetic acid < propionic acid < butyric acid < isovaleric acid < valeric acid). The removal efficiencies of all target VFAs were highest when used with O2 as a background gas. We found the lowest removal efficiency at the He atmosphere. The results of by-product analysis confirmed that valeric acid was decomposed into butyric acid and propionic acid, and then decomposed into acetic acid. That is, high molecular weight acids would be decomposed into low molecular weight acids by electron beam irradiation.
In 2005, the term
(theranostics) was introduced for describing the use of imaging for therapy planning in radiation oncology. In nuclear medicine, this expression describes the use of tracers for ...predicting the absorbed doses in molecular radiotherapy and, thus, the safety and efficacy of a treatment. At present, the most successful groups of isotopes for this purpose are
I/
I/
I,
Ga/
Lu, and
In/
Y/
Y. The purpose of this review is to summarize available data on the dosimetry and dose-response relationships of several theranostic compounds, with a special focus on radioiodine therapy for differentiated thyroid cancer and peptide receptor radionuclide therapy. These are treatment modalities for which dose-response relationships for healthy tissues and tumors have been demonstrated. In addition, available data demonstrate that posttherapeutic dosimetry after a first treatment cycle predicts the absorbed doses in further cycles. Both examples show the applicability of the concept of theranostics in molecular radiotherapies. Nevertheless, unanswered questions need to be addressed in clinical trials incorporating dosimetry-related concepts for determining the amount of therapeutic activity to be administered.
The first (inner) layer of a VVER-1200 reactor shielding is made of serpentinite concrete, which is heat-treated (dried) for 10–12 days after concrete placement (installation). Currently, the ...possibility of eliminating the heat treatment is discussed. In this regard, an estimate is made of the water radiolysis rate in serpentinite concrete during the reactor operation. Calculations are made of the field of the absorbed dose rate for neutrons and gamma radiation in the water of serpentinite concrete after the first reactor power start, when the neutron leakage from the core loaded with fresh fuel assemblies is the highest. The estimate of the hydrogen yield due to the radiolysis of free and bound water in serpentinite concrete is carried out for the cases where the concrete is dried or not dried after the placement.
The radiolytic degradation of vector molecules is a major factor affecting the shelf life of therapeutic radiopharmaceuticals. The development of time-stable dosage forms of radiopharmaceuticals is ...the key to their successful implementation in clinical practice. Using sup.177LuLu-PSMA-617 molecule as an example, the time dependence of the change in radiochemical purity (RCP, %) under radiolysis conditions was studied. The dependence of sup.177LuLu-PSMA-617 radiolysis on parameters such as time, radionuclide activity, buffer agent concentration, precursor amount, and preparation volume was evaluated. It was shown that the absorbed dose was the dominant factor influencing the RCP. The RCP value is inversely proportional to the absorbed dose in the sup.177LuLu-PSMA-617 preparation and has an exponential dependence. The lutetium-177 dose factor ψ (Gy·mL·MBqsup.−1) and PSMA-617 concentration-dependent dose constant κ (Gysup.−1) were evaluated for absorbed dose estimation via computer modeling, chemical dosimetry, and radiochemical purity monitoring under various conditions. The further refinement and application of the dependencies found can be useful for predicting the RCP value at the stage of optimizing the composition of the finished dosage form of therapeutic radiopharmaceuticals. The influence of the buffer agent (sodium acetate) concentration on sup.177LuLu-PSMA-617 radiolytic degradation was shown and should be considered both when developing a dosage form, and when comparing the results of independent studies. The effectiveness of the addition of various stabilizing agents, such as DMSA, cysteine, gentisic acid, vanillin, methionine, adenine, dobesilic acid, thymine, uracil, nicotinamide, meglumine, and mannitol, in suppressing the effects of radiolysis was evaluated.
This paper focuses on the natural radioactivity concentrations of 238U, 232Th, and 40K in the eruptive products of the Gölcük Volcano (SW Turkey) and its environmental radiation risks. Concentrations ...of these radionuclides (238U, 232Th, and 40K) have been measured on different igneous rocks, using a portable gamma-ray spectrometer at 450 points. Based on the obtained data, distribution maps of these radionuclides and the maps showing the absorbed dose rate in the air and radiogenic heat production (RHP) have been generated. We conclude that tephriphonolite and trachytes in potassic-ultrapotassic character display high radioactivity levels. On the other hand, it is revealed that the absorbed dose rate in the air ranging from 21 nGy/h to 482 nGy/h has been calculated as 8 times more than the world average (55 nGy/h). The results indicate that this region has crucial importance on human health and the environment. Therefore, the area requires special attention in terms of radiological hazards and further research should be done in the area regarding this issue.
•Radionuclide concentrations definition using the gamma-ray spectrometer in Gölcük volcano.•The comparison of radionuclide concentrations with geology.•The absorbed dose rate in the air has been calculated as 8 times more than the world average.•Radiological hazards on human health and the environment have been determined.
The oxygen content in graphene oxide (GO) can be reduced by the ion beam irradiation in high vacuum conditions. The reduction changes the C/O atomic ratio that increases with the absorbed ion dose. ...Moreover, as the level of reduction increases, the surface flattens and the material becomes denser. At high absorbed doses, greater than about 100 MGy, the material is affected by the high energy deposited with damage radiation effects which make the C/O ratio not proportional to the dose. At low doses, less than about 100 MGy, the C/O atomic ratio shows an optimal linearity with the ion dose and is independent of the ion stopping power, thus assuming the characteristics of a good biocompatible water-tissue equivalent dosimeter.
The aim of the work was that to explore the possibility to use GO as ionizing radiation dosimeter for energetic ion beams by the measure of the compositional C/O atomic ratio.
•Self-supported GO foils, 10 μm thick, with about 1 cm2 surface can be employed as ion dosimeters.•GO foils are reduced by the impact of ion beams at low and high stopping power.•The GO level of reduction is measurable from the C/O atomic ratio.•The C/O atomic ratio depends linearly with the absorbed dose in the range 1–100 MGy independently on the ion beam.•The C/O atomic ratio growth exponentially for doses higher than 100 MGy and for ions at high stopping power.
•The output dose by the CT scanner varies depending on the table height.•Some CT scanners have a mechanism called AHC that corrects the output dose.•Although AHC maintained the output dose ...comparable, the local absorbed dose varied.
We aimed to prove that the locally absorbed doses in tissues and organs are affected by inaccurate table height in computed tomography.
We compared the volume CT dose index (CTDIvol) and the absorbed doses using an anthropomorphic phantom combined with a breast phantom. The phantom was set at the gantry center, from which the table height was changed every 20 mm between–40 mm and 40 mm. Data acquisition was performed using auto table height correction (AHC) for each table height. The CTDIvol was obtained from the CT console and the tube current value for each image slice (DICOM tag: 0018, 1151). The absorbed dose was measured by a glass dosimeter that was implanted at various positions in the phantom.
The tube current values in the lung were lower at a table height of + 40 mm than those at other heights. The CTDIvol was slightly lower at + 40 mm than at the center (12.78 mGy vs. 13.42 mGy, p < 0.05). The CTDIvol values were almost the same at the other table heights (13.30–13.40 mGy). The absorbed doses at the lens and mammary gland were significantly different from those at the gantry center (−27.27%–17.77% and –24.31%–12.83%, respectively). Compared with the center, both the lens and mammary gland had higher absorbed doses at a table height of –40 mm.
The absorbed dose was affected by the table height, but the CTDIvol was maintained by AHC. The operator should appropriately position patients even when using AHC.
Fluorine 18-deoxyglucose (18FDG) is often used in Positron Emission Tomography (PET). PET imaging is one of the valuable tools used for cancer detection and management. PET growth is limited due to ...problems that depend on the production of Fluorine-18. Imaging results are strongly dependent on the information of nuclear reaction cross-section data. This study calculates the stopping power, RCSDA, and the simulated and distributed absorbed dose of F-18, in water. We use the Geant4/Gate simulation and the Bethe-Bloch theory model to access these goals. The results of this simulation and this theory model agree with each other. The main point of this paper is the presentation of a theoretical approach to the production of Fluorine-18 by using protons production through the main nuclear fusion reaction D(d,p)T and the side fusion reaction 3 He(d,p)4 He uses helium-3 as a catalyzed.
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