scholarly journals Influence of absorbed radiation dose following computed tomography on the antioxidative status in rabbit testicles

2018 ◽  
Vol 70 (4) ◽  
pp. 675-680
Author(s):  
Marko Mitrovic ◽  
Nikola Tatalovic ◽  
Aleksandra Nikolic-Kokic ◽  
Olivera Ciraj-Bjelac ◽  
Nikola Krstic ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Absorbed Dose ◽  
Antioxidant Enzyme Activities ◽  
Radiation Doses ◽  
Applied Current ◽  
Antioxidative Status ◽  
Absorbed Doses ◽  
Absorbed Radiation Dose ◽  
Dose Dependent ◽  
Low Radiation Doses

In recent years, computed tomography (CT) has become very common in veterinary medicine. It is well known that testicles are organs with high radiosensitivity and their function can be impaired even after exposure to low radiation doses. In this work, we calculated the absorbed radiation doses after CT was performed with different voltage/current levels and correlated it with the activity of antioxidant enzymes in rabbit testicles. Two hours after CT, the activities of catalase (CAT) and glutathione peroxidase (GSH-Px) were increased in the testicles of animals that received an absorbed dose of 29.2 mGy. The same changes, along with elevated glutathione reductase (GR) activity, were observed after 7 days in animals that received the highest absorbed dose (46.3 mGy). It would appear that absorbed doses above 27.8 mGy provoked the antioxidant reaction but the time scale of the reaction was dose-dependent. Examination of the obtained results revealed that the main denominator of CT influence was a higher current. Our results suggest that CT influences the antioxidant status in rabbit testicles. The changes in antioxidant enzyme activities were dose- and time-dependent and influenced by the applied current.

scholarly journals Dosimetry in CBCT with Different Protocols: Emphasis on Small FOVs Including Exams for TMJ

2017 ◽  
Vol 28 (4) ◽  
pp. 511-516 ◽  
Author(s):  
Helena Aguiar Ribeiro Nascimento ◽  
Marcos Ely Almeida Andrade ◽  
Marco Antonio Gomes Frazão ◽  
Eduarda Helena Leandro Nascimento ◽  
Flavia Maria Moraes Ramos-Perez ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Great Influence ◽  
Absorbed Dose ◽  
Skin Surface ◽  
Field Of View ◽  
Cone Beam ◽  
Anthropomorphic Phantom ◽  
Thermoluminescent Dosimeters ◽  
Absorbed Doses ◽  
Mode Size

Abstract This study aimed to estimate the absorbed dose in cone beam computed tomography (CBCT) exams according to different exposure parameters and size and position of the field of view (FOV). In addition was compared the absorbed dose of two smaller FOV scans with that of a larger FOV scan for evaluation of temporomandibular joint (TMJ), as it is a bilateral structure. CBCT scans were obtained on OP300 Maxio unit varying scanning mode (standard, high and endo) as well as size (5x5, 6x8 and 8x15 cm) and positioning of FOV. With a small FOV, different areas were scanned (maxilla or mandible, anterior or posterior and TMJ). Absorbed doses were determined using thermoluminescent dosimeters on the skin surface of sensitive organs of an anthropomorphic phantom. Endo mode showed the highest dose, followed by the high and standard modes in all FOV positions. With small FOV, doses were higher in the posterior region, especially in the mandible. Dose reduction occurred when small FOVs were used, but it was not proportional to FOV size reduction. For TMJ, the dose in a single acquisition with large FOV was greater than two acquisitions with small FOV, but lower than two acquisitions with medium FOV (6x8 cm). In conclusion, scanning mode, size and FOV position have great influence on the absorbed dose. Small FOV decreases the dose, but there is no linear relation between FOV size and dose. For bilateral exams of TMJ, double acquisition with small FOVs produces decrease in absorbed dose relative to a large FOV.

scholarly journals Simple model for estimation of absorbed dose by organs and tumors after PRRT from a single SPECT/CT study

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Alexandre Chicheportiche ◽  
Moshe Sason ◽  
Jeremy Godefroy ◽  
Yodphat Krausz ◽  
Mahmoud Zidan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Marrow ◽  
Activity Concentration ◽  
Absorbed Dose ◽  
The Body ◽  
Emission Computed Tomography ◽  
Standard Protocol ◽  
Independent Variables ◽  
Absorbed Doses ◽  
Mlr Model

Abstract Background Following each cycle of peptide receptor radionuclide therapy (PRRT), absorbed doses by tumors and normal organs are typically calculated from three quantitative single-photon emission computed tomography (SPECT)/computed tomography (CT) studies acquired at t1 = 24 h, t2 = 96 h, t3 = 168 h after the first cycle of treatment and from a single study at t1 after the subsequent cycles. In the present study, we have assessed the feasibility of a single SPECT/CT study after each PRRT cycle using a trained multiple linear regression (MLR) model for absorbed dose calculation and have evaluated its impact on patient management. Quantitative [177Lu]-DOTA-TATE SPECT/CT data after PRRT of seventy-two consecutive metastatic neuroendocrine tumors patients were retrospectively evaluated. A set of 40 consecutive studies was used to train the MLR model. The two independent variables of the model included the time of imaging after administration of the treatment and the radiopharmaceutical activity concentration in a given  organ/tumor. The dependent variable was the dose absorbed by the organ/tumor obtained with the standard protocol. For bone marrow dosimetry, the independent variables included the time of imaging, and the blood and remainder of the body activity concentration. The model was evaluated in 32 consecutive patients. Absorbed doses were assessed for kidneys, bone marrow, liver, spleen and tumor sites. Results There was no difference in management decisions, whether PRRT can be safely continued or not because unsafe absorbed dose to risk organs between the standard and the MLR model-based protocol using a single SPECT/CT study performed at t3 = 168 h after the first cycle and at t1 = 24 h after the subsequent cycles. Cumulative absorbed doses were obtained with mean relative differences of − 0.5% ± 5.4%, 1.6% ± 15.1%, − 6.2% ± 7.3%, − 5.5% ± 5.8% and 2.9% ± 12.7% for kidneys, bone marrow, liver, spleen and tumors, respectively (Pearson’s r correlation coefficient 0.99, 0.91, 0.99, 0.99 and 0.97, respectively). Conclusion Dosimetry calculations using a MLR model with a single SPECT/CT study are in good agreement with the standard protocol, while avoiding the use of dosimetry software and enabling improved patient comfort and reduced scanner and staff time.

scholarly journals Assessment of the absorbed doses in the fetus from the computed tomography of the chest for the pregnant women

2021 ◽  
Vol 14 (3) ◽  
pp. 126-135
Author(s):  
A. V. Vodovatov ◽  
L. A. Chipiga ◽  
P. A. Piven ◽  
G. E. Trufanov ◽  
G. V. Berkovich ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pregnant Women ◽  
Russian Federation ◽  
Imaging Modality ◽  
Absorbed Dose ◽  
Developed Countries ◽  
High Dose ◽  
Maximal Increase ◽  
Absorbed Doses ◽  
The Russian Federation

The number and contribution of high dose imaging modalities, computed tomography in particular, is rapidly increasing both in the 'Russian Federation and other developed countries. Maximal increase in the number of computed tomography examinations in Russia was observed in 2020 due to the full-scale application of this imaging modality for the diagnostics of the novel coronavirus infection COVID-19. The use of computed tomography for the examination of the chest for the pregnant women is associated with several issues. An internationally accepted approach for the provision of the radiation safety of the pregnant patients is the assessment of the absorbed dose in the fetus after each X-ray examination. However, there are no existingn approved methods for the assessment of the absorbed dose in the fetus in the Russian Federation. The aim of the current study was to assess the doses in the fetus for the pregnant women undergoing computed tomography of the chest due to the COVID-19 and to estimate the probability of the development of the deterministic effects for the fetus. The study was based on the collection of the parameter of Russian and international computed tomography protocols. Parameters of the international computed tomography protocols were collected viameta-analysis of the existing publications; Russian protocols — via data collection in computed tomography departments in St-Petersburg hospitals. Absorbed dose in the uterus of the female patient and effective dose for the fetus were calculated using NCICT 3.0 software for 8, 10, 15, 20, 25, 30, 35 and 38 weeks of pregnancy. The results of the calculations indicate the lack of significant differences between absorbed doses in the uterus and effective doses for the fetus for all stages of pregnancy. Maximal doses for the selected computed tomog­ raphy protocols were in the range of 0.5 mGy (mSv) for 8-25 weeks, 0.6 mGy (mSv) for 30 week, 1.4 mGy (mSv) for 35 week and 2.7 mGy (mSv) for 38 week. The threshold for the development of the deterministic effects equal to 100 mGy cannot be exceeded even for repeated (10-15) computed tomography chest scans. Hence, the use of computed tomography as the primary method of COVID-19 diagnostics and staging will not be associated with the development of deterministic effects in the fetus.

LONG-TERM OPERATION OF DOSIMETRY FACILITY «PILLE» ONBOARD THE ISS

2021 ◽  
Vol 55 (4) ◽  
pp. 86-90
Author(s):  
V.G. Mitrikas ◽  
◽  
E.G. Khorosheva ◽  
Keyword(s):  
Dose Rate ◽  
Absorbed Dose ◽  
Radiation Monitoring ◽  
The Other ◽  
Radiation Doses ◽  
Absorbed Dose Rate ◽  
Term Operation ◽  
Low Radiation Doses

Malfunctioning of the reader is likely to be the reason for low radiation doses measured by the Pille dosimeters over the more than 20 years of ISS. Rectified measurements of the average daily absorbed dose rate agreed satisfactorily with readings of the other onboard tools of radiation monitoring.

scholarly journals Dose mapping of products with different density irradiated in 60co irradiation facility of the Vinca institute, Serbia

2020 ◽  
Vol 35 (1) ◽  
pp. 56-63
Author(s):  
Bojan Rankovic ◽  
Nikolina Nikolic ◽  
Slobodan Masic ◽  
Ivica Vujcic
Keyword(s):  
Radiation Dose ◽  
Radiation Source ◽  
Complex Function ◽  
Absorbed Dose ◽  
Radiation Doses ◽  
Product Density ◽  
Dosimetry System ◽  
Absorbed Radiation Dose ◽  
Dose Mapping

The distribution of the absorbed dose within the irradiated product is a complex function of the product density and homogeneity, the position and shape of the radiation source, as well as the design of the irradiator. In this paper, detailed mapping of absorbed radiation doses in products of different density: gauze, plastic, and soil, is performed. Positions of minimum and maximum absorbed radiation dose were determined, and the homogeneity of irradiation of products was calculated using the ethanol-monochlorobenzene oscillotitrator dosimetry system.

Effect of low radiation doses on microbe population in space stations

2002 ◽  
Vol 8 (5-6) ◽  
pp. 58-61
Author(s):  
V.V. Tsetlin ◽  
◽  
E.A. Deshevaya ◽  
N.D. Novikova ◽  
N.A. Polikarpov ◽  
...  
Keyword(s):  
Radiation Doses ◽  
Low Radiation Doses ◽  
Microbe Population

Evaluation of Velopharyngeal Closure Function With 4-Dimensional Computed Tomography and Assessment of Radiation Exposure in Pediatric Patients: A Cross-Sectional Study

2021 ◽  
pp. 105566562110017
Author(s):  
Yoshikazu Kobayashi ◽  
Masanao Kobayashi ◽  
Daisuke Kanamori ◽  
Naoko Fujii ◽  
Yumi Kataoka ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Radiation Exposure ◽  
Exposure Dose ◽  
Velopharyngeal Insufficiency ◽  
Radiation Doses ◽  
Secondary Surgery ◽  
Cross Sectional ◽  
Computed Tomography Images ◽  
Velopharyngeal Closure ◽  
Closure Function

Objective: Some patients with cleft palate (CP) need secondary surgery to improve functionality. Although 4-dimensional assessment of velopharyngeal closure function (VPF) in patients with CP using computed tomography (CT) has been existed, the knowledge about quantitative evaluation and radiation exposure dose is limited. We performed a qualitative and quantitative assessment of VPF using CT and estimated the exposure doses. Design: Cross-sectional. Setting: Computed tomography images from 5 preoperative patients with submucous CP (SMCP) and 10 postoperative patients with a history of CP (8 boys and 7 girls, aged 4-7 years) were evaluated. Patients: Five patients had undergone primary surgery for SMCP; 10 received secondary surgery for hypernasality. Main Outcome Measures: The presence of velopharyngeal insufficiency (VPI), patterns of velopharyngeal closure (VPC), and cross-sectional area (CSA) of VPI was evaluated via CT findings. Organ-absorbed radiation doses were estimated in 5 of 15 patients. The differences between cleft type and VPI, VPC patterns, and CSA of VPI were evaluated. Results: All patients had VPI. The VPC patterns (SMCP/CP) were evaluated as coronal (1/4), sagittal (0/1), circular (1/2), and circular with Passavant’s ridge (2/2); 2 patients (1/1) were unevaluable because of poor VPF. The CSA of VPI was statistically larger in the SMCP group ( P = .0027). The organ-absorbed radiation doses were relatively lower than those previously reported. Conclusions: Four-dimensional CT can provide the detailed findings of VPF that are not possible with conventional CT, and the exposure dose was considered medically acceptable.

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