scholarly journals Establishing a Reference Dose–Response Calibration Curve for Dicentric Chromosome Aberrations to Assess Accidental Radiation Exposure in Saudi Arabia

2020 ◽  
Vol 8 ◽  
Author(s):  
Ghazi A. Alsbeih ◽  
Khaled S. Al-Hadyan ◽  
Najla M. Al-Harbi ◽  
Sara S. Bin Judia ◽  
Belal A. Moftah
Keyword(s):  
Radiation Exposure ◽  
Dose Response ◽  
Calibration Curve ◽  
Goodness Of Fit ◽  
Dicentric Chromosome ◽  
Homogeneity Test ◽  
X Rays ◽  
Blood Samples ◽  
Reference Dose ◽  
Effect Of Age

In cases of nuclear and radiological accidents, public health and emergency response need to assess the magnitude of radiation exposure regardless of whether they arise from disaster, negligence, or deliberate act. Here we report the establishment of a national reference dose–response calibration curve (DRCC) for dicentric chromosome (DC), prerequisite to assess radiation doses received in accidental exposures. Peripheral blood samples were collected from 10 volunteers (aged 20–40 years, median = 29 years) of both sexes (three females and seven males). Blood samples, cytogenetic preparation, and analysis followed the International Atomic Energy Agency EPR-Biodosimetry 2011 report. Irradiations were performed using 320 kVp X-rays. Metafer system was used for automated and assisted (elimination of false-positives and inclusion of true-positives) metaphases findings and DC scoring. DC yields were fit to a linear–quadratic model. Results of the assisted DRCC showed some variations among individuals that were not statistically significant (homogeneity test, P = 0.66). There was no effect of age or sex (P > 0.05). To obtain representative national DRCC, data of all volunteers were pooled together and analyzed. The fitted parameters of the radiation-induced DC curve were as follows: Y = 0.0020 (±0.0002) + 0.0369 (±0.0019) *D + 0.0689 (±0.0009) *D2. The high significance of the fitted coefficients (z-test, P < 0.0001), along with the close to 1.0 p-value of the Poisson-based goodness of fit (χ2 = 3.51, degrees of freedom = 7, P = 0.83), indicated excellent fitting with no trend toward lack of fit. The curve was in the middle range of DRCCs published in other populations. The automated DRCC over and under estimated DCs at low (<1 Gy) and high (>2 Gy) doses, respectively, with a significant lack of goodness of fit (P < 0.0001). In conclusion, we have established the reference DRCC for DCs induced by 320 kVp X-rays. There was no effect of age or sex in this cohort of 10 young adults. Although the calibration curve obtained by the automated (unsupervised) scoring misrepresented dicentric yields at low and high doses, it can potentially be useful for triage mode to segregate between false-positive and near 2-Gy exposures from seriously irradiated individuals who require hospitalization.

scholarly journals Development of dose-response calibration curve for dicentric chromosome induced by X-rays

2019 ◽  
Vol 10 (1) ◽  
pp. 2 ◽  
Author(s):  
Yanti Lusiyanti ◽  
Mukh Syaifudin ◽  
Tuti Budiantari ◽  
Sofiati Purnami ◽  
Dwi Ramadhani
Keyword(s):  
Dose Response ◽  
Calibration Curve ◽  
Dicentric Chromosome ◽  
X Rays

CONSTRUCTION AND VALIDATION OF IN VITRO DOSE–RESPONSE CALIBRATION CURVE USING DICENTRIC CHROMOSOME ABERRATION

2020 ◽  
Vol 189 (2) ◽  
pp. 198-204
Author(s):  
Ehsan Mirrezaei ◽  
Saeed Setayeshi ◽  
Farideh Zakeri ◽  
Samaneh Baradaran
Keyword(s):  
Dose Response ◽  
Calibration Curve ◽  
Radiation Effects ◽  
Standard Dose ◽  
Absorbed Dose ◽  
Dicentric Chromosome ◽  
Blood Samples ◽  
Radiation Induced ◽  
Occupational Radiation

Abstract Cytogenetic biodosimetry is a well-known method for quantifying the absorbed dose based on measuring biological radiation effects. To correlate the induced chromosomal abberrations with the absorbed dose of the individuals, a reliable dose–response calibration curve should be established. This study aimed to use frequencies and distributions of radiation-induced dicentric chromosome aberrations to develop a standard dose–response calibration curve. Peripheral blood samples taken from six male donors irradiated by an X-ray generator up to 4 Gy were studied. Three different blood samples were irradiated by known doses, then scored blindly for verification of the proposed calibration curve. Dose estimation was also carried out for three real overexposed cases. The results showed good accordance with the other published curves. The constructed dose–response curve provides a reliable tool for biological dosimetry in accidental or occupational radiation exposures.

A simulation approach to predict the calibration curve of low LET radiations for biological dosimetry using the Geant4-DNA toolkit

2022 ◽  
Vol 17 (01) ◽  
pp. P01014
Author(s):  
E. Mirrezaei ◽  
S. Setayeshi ◽  
F. Zakeri ◽  
S. Baradaran
Keyword(s):  
Dose Response ◽  
Calibration Curve ◽  
Cellular Response ◽  
Mechanistic Model ◽  
Scaling Factor ◽  
X Rays ◽  
Simulation Approach ◽  
Response Curves ◽  
Biological Dosimetry ◽  
Dicentric Chromosomes

Abstract Ionizing radiation is extensively utilized in various applications; however, it can lead to significant harm to living systems. In this regard, the radiation absorbed dose is usually evaluated by performing biological dosimetry and physical reconstruction of exposure scenarios. But, this is costly, time-consuming, and maybe impractical for a biodosimetry lab to perform biological dosimetry. This study aimed to assess the applicability and reliability of the Geant4-DNA toolkit as a simulation approach to construct a reliable dose-response curve for biodosimetry purposes as an appropriate substitution for experimental measurements. In this matter, the total number of double-strand breaks (DSBs), due to different doses of low LET radiation qualities on DNA molecules, was calculated and converted to the values of dicentric chromosomes using a mechanistic model of cellular response. Then, the number of dicentric chromosomes induced by 200 kVp X-rays were modified by using a semi-empirical scaling factor for compensating the restriction of simulation code to consider what can happen in a real cell. Next, the trend of dicentrics for 137Cs and 60Co were calculated and modified by the above scaling factor. Finally, the dose-response curves for these gamma sources compared to several published experiments. The suggested calibration curves for 137Cs and 60Co followed a linear quadratic equation: Ydic = 0.0054 (± 0.0133) - 0.0089 (± 0.0212) × D + 0.0568 (± 0.0051) × D2 and Ydic = 0.0052 (± 0.0128) - 0.00568 (± 0.0203) × D + 0.0525 (± 0.0049) × D2 respectively. They revealed a satisfactory agreement with the experimental data reported by others. The Geant4 program developed in this work could provide an appropriate tool for predicting the dose-response (calibration) curve for biodosimetry purposes.

scholarly journals Predicting chromosome damage in astronauts participating in international space station missions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alan Feiveson ◽  
Kerry George ◽  
Mark Shavers ◽  
Maria Moreno-Villanueva ◽  
Ye Zhang ◽  
...  
Keyword(s):  
International Space Station ◽  
Dose Response ◽  
Ex Vivo ◽  
Space Station ◽  
Space Radiation ◽  
Blood Samples ◽  
International Space ◽  
Significant Difference ◽  
Subject Specific

AbstractSpace radiation consists of energetic protons and other heavier ions. During the International Space Station program, chromosome aberrations in lymphocytes of astronauts have been analyzed to estimate received biological doses of space radiation. More specifically, pre-flight blood samples were exposed ex vivo to varying doses of gamma rays, while post-flight blood samples were collected shortly and several months after landing. Here, in a study of 43 crew-missions, we investigated whether individual radiosensitivity, as determined by the ex vivo dose–response of the pre-flight chromosome aberration rate (CAR), contributes to the prediction of the post-flight CAR incurred from the radiation exposure during missions. Random-effects Poisson regression was used to estimate subject-specific radiosensitivities from the preflight dose–response data, which were in turn used to predict post-flight CAR and subject-specific relative biological effectiveness (RBEs) between space radiation and gamma radiation. Covariates age, gender were also considered. Results indicate that there is predictive value in background CAR as well as radiosensitivity determined preflight for explaining individual differences in post-flight CAR over and above that which could be explained by BFO dose alone. The in vivo RBE for space radiation was estimated to be approximately 3 relative to the ex vivo dose response to gamma irradiation. In addition, pre-flight radiosensitivity tended to be higher for individuals having a higher background CAR, suggesting that individuals with greater radiosensitivity can be more sensitive to other environmental stressors encountered in daily life. We also noted that both background CAR and radiosensitivity tend to increase with age, although both are highly variable. Finally, we observed no significant difference between the observed CAR shortly after mission and at > 6 months post-mission.

scholarly journals In Vivo Usability Test of Vascular Intervention Robotic System Controlled by Two Types of Master Devices

2021 ◽  
Vol 11 (12) ◽  
pp. 5453
Author(s):  
Hwa-Seob Song ◽  
Jae-Hong Woo ◽  
Jong-Yun Won ◽  
Byung-Ju Yi
Keyword(s):  
Radiation Exposure ◽  
Animal Experiments ◽  
X Rays ◽  
Physical Damage ◽  
Vascular Intervention ◽  
Task Load ◽  
Usability Test ◽  
Usability Tests ◽  
System Usability Scale

Conventional vascular intervention (VI) procedures are typically performed manually under exposure to X-rays, whereby several problems are presented that need to be addressed owing to the patients and doctors being exposed to large amounts of radiation. In such cases, employing radiation protection units is not a long-term solution to avoid physical damage. Therefore, to overcome these issues, we propose a robotic VI system in this study. Moreover, we compare the extent of radiation exposure in the case of the conventional manual VI procedure with that in the case of the robotic procedure. The radiation exposure is then analyzed from the perspective of the doctor. Subsequently, the results of usability tests for two proposed master devices are presented in terms of the NASA task load index (NASA-TLX) and the system usability scale (SUS) score. To verify the effectiveness of the robotic VI system, animal experiments are conducted using a pig model. Among the two types of master devices tested with the proposed robotic VI system, the ergonomically designed 2-degree-of-freedom master device is found to be more effective than the joystick-type device in terms of the usability test scores. Hence, the proposed robotic VI procedure is shown to be advantageous in terms of reducing radiation exposure and improving usability.

scholarly journals Determination of Dose–Response Relationship to Derive Odor Impact Criteria for a Wastewater Treatment Plant

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 371
Author(s):  
Yan Zhang ◽  
Weihua Yang ◽  
Günther Schauberger ◽  
Jianzhuang Wang ◽  
Jing Geng ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Dose Response ◽  
Goodness Of Fit ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Odor Annoyance ◽  
Time Periods ◽  
Odor Exposure

Municipal wastewater treatment plants (WWTPs) inside cities have been the major complained sources of odor pollution in China, whereas there is little knowledge about the dose–response relationship to describe the resident complaints caused by odor exposure. This study explored a dose–response relationship between the modelled exposure and the annoyance surveyed by questionnaires. Firstly, the time series of odor concentrations were preliminarily simulated by a dispersion model. Secondly, the perception-related odor exposures were further calculated by combining with the peak to mean factors (constant value 4 (Germany) and 2.3 (Italy)), different time periods of “a whole year”, “summer”, and “nighttime of summer”, and two approaches of odor impact criterion (OIC) (“odor-hour” and “odor concentration”). Thirdly, binomial logistic regression models were used to compare kinds of perception-related odor exposures and odor annoyance by odds ratio, goodness of fit and predictive ability. All perception-related odor exposures were positively associated with odor annoyance. The best goodness of fit was found when using “nighttime of summer” in predicting odor-annoyance responses, which highlights the importance of the time of the day and the time of the year weighting. The best predictive performance for odor perception was determined when the OIC was 4 ou/m3 at the 99th percentile for the odor exposure over time periods of nighttime of summer. The study of dose–response relationship could be useful for the odor management and control of WWTP to maximize the satisfaction of air quality for the residents inside city.

Reactive oxygen species in cell responses to toxic agents

2002 ◽  
Vol 21 (2) ◽  
pp. 85-90 ◽  
Author(s):  
L E Feinendegen
Keyword(s):  
Radiation Exposure ◽  
Mammalian Cells ◽  
Low Dose ◽  
X Rays ◽  
Low Dose Radiation ◽  
Cell Responses ◽  
Toxic Agents ◽  
Particle Tracks ◽  
Dose Radiation

This review first summarizes experimental data on biological effects of different concentrations of ROS in mammalian cells and on their potential role in modifying cell responses to toxic agents. It then attempts to link the role of steadily produced metabolic ROS at various concentrations in mammalian cells to that of environmentally derived ROS bursts from exposure to ionizing radiation. The ROS from both sources are known to both cause biological damage and change cellular signaling, depending on their concentration at a given time. At low concentrations signaling effects of ROS appear to protect cellular survival and dominate over damage, and the reverse occurs at high ROS concentrations. Background radiation generates suprabasal ROS bursts along charged particle tracks several times a year in each nanogram of tissue, i.e., average mass of a mammalian cell. For instance, a burst of about 200 ROS occurs within less than a microsecond from low-LET irradiation such as X-rays along the track of a Compton electron (about 6 keV, ranging about 1 μm). One such track per nanogram tissue gives about 1 mGy to this mass. The number of instantaneous ROS per burst along the track of a 4-meV ¬-particle in 1 ng tissue reaches some 70000. The sizes, types and sites of these bursts, and the time intervals between them directly in and around cells appear essential for understanding low-dose and low dose-rate effects on top of effects from endogenous ROS. At background and low-dose radiation exposure, a major role of ROS bursts along particle tracks focuses on ROS-induced apoptosis of damage-carrying cells, and also on prevention and removal of DNA damage from endogenous sources by way of temporarily protective, i.e., adaptive, cellular responses. A conclusion is to consider low-dose radiation exposure as a provider of physiological mechanisms for tissue homoeostasis.

Pharmacokinetics of Ceftolozane-Tazobactam during Prolonged Intermittent Renal Replacement Therapy

Chemotherapy ◽  
2018 ◽  
Vol 63 (4) ◽  
pp. 203-206 ◽  
Author(s):  
Matthew Rawlins ◽  
Vesa Cheng ◽  
Edward Raby ◽  
John Dyer ◽  
Adrian Regli ◽  
...  
Keyword(s):  
Renal Replacement Therapy ◽  
Replacement Therapy ◽  
Goodness Of Fit ◽  
Final Model ◽  
Blood Samples ◽  
Compartment Models ◽  
Log Likelihood ◽  
New Antibiotics ◽  
Plasma Pharmacokinetics ◽  
Intermittent Renal Replacement Therapy

Background: Prolonged intermittent renal replacement therapy (PIRRT) eliminates many drugs, and without dosing data, for new antibiotics like ceftolozane/tazobactam, suboptimal concentrations and treatment failure are likely. Objectives: Herein, we describe the effect of PIRRT on the plasma pharmacokinetics of ceftolozane/tazobactam ad­ministered in a critically ill 55-year-old patient with a polymicrobial sternal wound osteomyelitis, including a multiresistant Pseudomonas aeruginosa. Method: Blood samples were taken over 4 days where the patient received a 7.5-h PIRRT treatment. One- and 2-compartment models were tested for ceftolozane and tazobactam separately, and the log-likelihood ratio and goodness-of-fit plots were used to select the final model. Results: Two-compartment models were developed for ceftolozane and tazobactam separately and described significant differences in clearance of ceftolozane and tazobactam with and without PIRRT (8.273 vs. 0.393 and 8.020 vs. 0.767 L/h, respectively). Conclusions: A ceftolozane/tazobactam dose of 500 mg/250 mg appears to be sufficient to attain pharmacokinetic/pharmacodynamic targets during PIRRT while the manufacturer’s recommended dosing of 100 mg/50 mg every 8 h was sufficient during non-PIRRT periods.

scholarly journals Radiation dose from common radiological investigations and cumulative exposure in children with cystic fibrosis: an observational study from a single UK centre

BMJ Open ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. e017548 ◽  
Author(s):  
Rebecca Ward ◽  
William D Carroll ◽  
Paula Cunningham ◽  
Sheng-Ang Ho ◽  
Mary Jones ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Radiation Dose ◽  
Radiation Exposure ◽  
Cumulative Exposure ◽  
X Rays ◽  
Modern Equipment ◽  
Increased Risk ◽  
Risk Of Malignancy ◽  
The Mean ◽  
Cumulative Radiation Exposure

ObjectivesCumulative radiation exposure is associated with increased risk of malignancy. This is important in cystic fibrosis (CF) as frequent imaging is required to monitor disease progression and diagnose complications. Previous estimates of cumulative radiation are outdated as the imaging was performed on older equipment likely to deliver higher radiation. Our objectives were to determine the radiation dose delivered to children during common radiological investigations using modern equipment and to identify the number of such investigations performed in a cohort of children with CF to calculate their cumulative radiation exposure.Design, setting and participantsData including age at investigation and radiation exposure measured as estimated effective dose (EED) were collected on 2827 radiological studies performed on children at one UK paediatric centre. These were combined with the details of all radiological investigations performed on 65 children with CF attending the same centre to enable calculation of each child’s cumulative radiation exposure.ResultsThe mean EED for the common radiological investigations varied according to age. The range was 0.01–0.02 mSv for chest X-rays, 0.03–0.11 mSv for abdominal X-rays, 0.57–1.69 mSv for CT chest, 2.9–3.9 mSv for abdominal and pelvic CT, 0.20–0.21 mSv for sinus CT and 0.15–0.52 mSv for fluoroscopy-guided procedures. The mean EED was three to five times higher for helical compared with axial chest CT scans. The mean annual cumulative EED for our cohort of children with CF was 0.15 mSv/year with an estimated cumulative paediatric lifetime EED (0–18 years) of 3.5 mSv.ConclusionsThis study provides up-to-date estimations of the radiation exposure when using common radiological investigations. These doses and the estimates of cumulative radiation exposure in children with CF are lower than previously reported. This reflects the reduced EED associated with modern equipment and the use of age-specific scanning protocols.

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