Low Dose Assessment Uncertainty Analysis for Landauer® nanoDot™ OSLDs

2021 ◽  
Author(s):  
Egemen Aras ◽  
Robert Hayes
Keyword(s):  
Low Dose ◽  
Background Radiation ◽  
Measurement Data ◽  
Initial Step ◽  
Dose Assessment ◽  
Statistical Fluctuation ◽  
Nuclear Facility ◽  
Data Set ◽  
Significant Difference ◽  
Dose Levels

Abstract This study aims to low-level background range measurements of commercial OSLDs. This work is the initial step to put a framework to detect any illicit nuclear activities in any nuclear facility at any time. The idea in this framework is to utilize already placed OSLDs in the facility which are normally read-out periodically. The results of these measurements could be distinguishable from the background radiation since this paper shows how the background dose with its statistical fluctuation provide detection limits in these applications. To do this, we measured dosimeters in two ways; without removal or replacement and full removal for each measurement. As a result of measurements, the initial dose, bleaching constant, and background dose was evaluated for different measurements. ANOVA was applied to all measurements and all measurements considered a measurement data set to analyze results. Consequently, we observed no statistically significant difference in these different kinds of measurement approaches relative to the total propagated uncertainty in any given dose estimate. This shows a passive detection can be verified with iterative measurements to improve statistics without compromising data quality when coupled with dose levels of potential interest serves to advance this potential nonproliferation application.

scholarly journals Iterative reconstruction improves image quality and reduces radiation dose in trauma protocols; A human cadaver study

2021 ◽  
Vol 10 (10) ◽  
pp. 205846012110553
Author(s):  
Johannes Clemens Godt ◽  
Cathrine K Johansen ◽  
Anne Catrine T Martinsen ◽  
Anselm Schulz ◽  
Helga M Brøgger ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Dose Reduction ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Human Cadaver ◽  
Full Dose ◽  
Significant Difference ◽  
Noise Ratio ◽  
Dose Levels

Background Radiation-related cancer risk is an object of concern in CT of trauma patients, as these represent a young population. Different radiation reducing methods, including iterative reconstruction (IR), and spilt bolus techniques have been introduced in the recent years in different large scale trauma centers. Purpose To compare image quality in human cadaver exposed to thoracoabdominal computed tomography using IR and standard filtered back-projection (FBP) at different dose levels. Material and methods Ten cadavers were scanned at full dose and a dose reduction in CTDIvol of 5 mGy (low dose 1) and 7.5 mGy (low dose 2) on a Siemens Definition Flash 128-slice computed tomography scanner. Low dose images were reconstructed with FBP and Sinogram affirmed iterative reconstruction (SAFIRE) level 2 and 4. Quantitative image quality was analyzed by comparison of contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). Qualitative image quality was evaluated by use of visual grading regression (VGR) by four radiologists. Results Readers preferred SAFIRE reconstructed images over FBP at a dose reduction of 40% (low dose 1) and 56% (low dose 2), with significant difference in overall impression of image quality. CNR and SNR showed significant improvement for images reconstructed with SAFIRE 2 and 4 compared to FBP at both low dose levels. Conclusions Iterative image reconstruction, SAFIRE 2 and 4, resulted in equal or improved image quality at a dose reduction of up to 56% compared to full dose FBP and may be used a strong radiation reduction tool in the young trauma population.

scholarly journals Medical imaging tests: Assessment of staffs and students' knowledge about radiation protection and risks and dose levels

2020 ◽  
Author(s):  
Omid Azadbakht ◽  
Seyedeh Leila Dehghani ◽  
mohsen shafiee ◽  
Parsa faghani scandarkolaei ◽  
Amirmasoud asadi ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Medical Imaging ◽  
Radiation Protection ◽  
Background Radiation ◽  
Radiation Risk ◽  
Dose Assessment ◽  
Sufficient Information ◽  
Average Dose ◽  
Sensitive Organ ◽  
Dose Levels

Abstract Background Identifying the level of radiology students and radiologist's awareness about their knowledge of radiation risks and radiation protection and their understanding of radiation dose levels in medical imaging tests will help global and national lawmakers adjust laws according to the recognized need in studies. The significance of this study is further enhanced when it is considered a lack of radiation awareness may increase the risk of radiation damage to themselves and patients. Method: This Crossectional study is done on 180 people, including 62 people were students (radiology residents and technologists), and 118 people were radiology staff (radiologists and radiographers). For measuring the awareness of participants, a prepared questionnaire which had a total of 22 questions. The poll was divided into three sections of which: Demographics data, Radiation protection awareness, and knowledge of radiologists about dose assessment. The questionnaire reliability was assessed in terms of internal consistency utilizing the Cronbach’s alpha (0.85_). A P-value of less than 0.05 was set a threshold for statistical sig-nuisance. Statistical analysis was carried out using software SPSS version 22. Result Most students believed that 1-year-old girls had the most sensitivity to radiation, while most staff found that radiation risk was unrelated to age and sex. Both staff and students found that crews working in nuclear medicine departments were more exposed to radiation (the majority). Most students and faculty also chose breast tissue as the most sensitive organ against radiation. It should be noted that among the staff responses, a significant number of bones were also selected. In general, students and staff did not have sufficient information about radiation-related illnesses. Approximately 82 percent of students chose a dose of Lumbar X-ray exams between 1 and 50 times the PA chest, and only 9 percent answered the question correctly (100 − 50 times). However, 27% of employees chose the correct answer. Students on the average dose of mammography had more choice (1–10 times) of a PA chest test, while staff preferred 100–500. (Both groups did not perform well in this question). The crew performed better on the dose resulting from a PET-CT test as well as the dose estimate from a nuclear medicine heart scan, and selected 36% correct response (more than 500 times the PA chest), while students had a lower rating (1–10 times) than others. Conclusion Most students and staff believed that they had a suitable or sufficient level of awareness of ionizing radiation. Overall, 45% of students and staff rarely had any training or retraining (37%). Radiology students had a better level of knowledge about radiation protection than team, while team had better estimates in discussing dose assessment. In general, students and staff did not have sufficient information about radiation-related illnesses. Students and staff had accurate estimates of the dose received in a PA chest and the average dose of background radiation. Both groups had little information on mammography, but had good knowledge of ultrasound, MRI, and CT scans. In general, staff and students had a good understanding of nuclear medicine dose assessment. (Staff performed better)

scholarly journals Awareness assessment of radiation protection, dose levels and complications of radiation exposure in imaging procedures among radiology residents, undergraduate radiology students, radiologists and technicians.

2020 ◽  
Author(s):  
omid azadbakht ◽  
Seyedeh Leila Dehghani ◽  
mohsen shafiee ◽  
Parsa faghani scandarkolaei ◽  
Amirmasoud asadi ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Radiation Protection ◽  
Background Radiation ◽  
Dose Assessment ◽  
Sufficient Information ◽  
Average Dose ◽  
Imaging Procedures ◽  
Sensitive Organ ◽  
Radiology Residents ◽  
Dose Levels

Abstract Background: Identifying the level of radiology students and staffs's awareness of their knowledge of radiation risks and radiation protection and their understanding of radiation dose levels in medical imaging procedures will help global and national lawmakers adjust laws according to the recognized need in studies. The significance of this study is further enhanced when it is considered a lack of radiation awareness may increase the risk of radiation damage to themselves and patients.Method: This Crossectional study is done on 180 participants, including 62 participants were students (radiology residents and technologists), and 118 participants were radiology staff (radiologists and radiographers). For measuring the awareness of participants, a prepared questionnaire which had a total of 22 questions. The poll was divided into three sections of which: Demographics data, Radiation protection awareness, and knowledge of radiologists about dose assessment. The questionnaire reliability was assessed in terms of internal consistency utilizing the Cronbach’s alpha (0.85_). A P-value of less than 0.05 was set a threshold for statistical sig-nuisance. Statistical analysis was carried out using software SPSS version 22. Result: Most students believed that 1-year-old girls had the most sensitivity to radiation, while most staff found that radiation risk was unrelated to age and sex. Both staff and students found that crews working in nuclear medicine departments were more exposed to radiation (the majority). Most students and faculty also chose breast tissue as the most sensitive organ against radiation. It should be noted that among the staff responses, a significant number of bones were also selected. In general, students and staff did not have sufficient information about radiation-related illnesses. Approximately 82 percent of students chose a dose of Lumbar X-ray exams between 1 and 50 times the PA chest, and only 9 percent answered the question correctly (100-50 times). However, 27% of employees chose the correct answer. Students on the average dose of mammography had more choice (1-10 times) of a PA chest test, while staff preferred 100-500. (Both groups did not perform well in this question). The crew performed better on the dose resulting from a PET-CT test as well as the dose estimate from a nuclear medicine heart scan, and selected 36% correct response (more than 500 times the PA chest), while students had a lower rating (1-10 times) than others.Conclusion: In self-reported; most students and staffs believed that they had a suitable or sufficient level of awareness of ionizing radiation. Overall, 45% of students and staff rarely had any training or retraining (37%). Radiology students had a better level of knowledge about radiation protection than team, while team had better estimates in discussing dose assessment. In general, students and staff did not have sufficient information about radiation-related illnesses. Students and staff had accurate estimates of the dose received in a PA chest and the average dose of background radiation. Both groups had little information on mammography, but had good knowledge of ultrasound, MRI, and CT scans. In general, staff and students had a good understanding of nuclear medicine dose assessment.

scholarly journals The assessment of a manikin-based low-dose, high-frequency cardiac resuscitation quality improvement program in early UK adopter hospitals

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Katherine Kuyt ◽  
Montana Mullen ◽  
Catherine Fullwood ◽  
Todd P. Chang ◽  
James Fenwick ◽  
...  
Keyword(s):  
Quality Improvement ◽  
High Frequency ◽  
Low Dose ◽  
Training Session ◽  
Control Site ◽  
Improvement Program ◽  
Data Set ◽  
Significant Difference ◽  
The Uk ◽  
Cpr Training

Abstract Background Adult and paediatric basic life support (BLS) training are often conducted via group training with an accredited instructor every 24 months. Multiple studies have demonstrated a decline in the quality of cardio-pulmonary resuscitation (CPR) performed as soon as 3-month post-training. The ‘Resuscitation Quality Improvement’ (RQI) programme is a quarterly low-dose, high-frequency training, based around the use of manikins connected to a cart providing real-time and summative feedback. We aimed to evaluate the effects of the RQI Programme on CPR psychomotor skills in UK hospitals that had adopted this as a method of BLS training, and establish whether this program leads to increased compliance in CPR training. Methods The study took place across three adopter sites and one control site. Participants completed a baseline assessment without live feedback. Following this, participants at the adopter sites followed the RQI curriculum for adult CPR, or adult and infant CPR. The curriculum was split into quarterly training blocks, and live feedback was given on technique during the training session via the RQI cart. After following the curriculum for 12/24 months, participants completed a second assessment without live feedback. Results At the adopter sites, there was a significant improvement in the overall score between baseline and assessment for infant ventilations (N = 167, p < 0.001), adult ventilations (n = 129, p < 0.001), infant compressions (n = 163, p < 0.001) adult compressions (n = 205, p < 0.001), and adult CPR (n = 249, p < 0.001). There was no significant improvement in the overall score for infant CPR (n = 206, p = 0.08). Data from the control site demonstrated a statistically significant improvement in mean score for adult CPR (n = 22, p = 0.02), but not for adult compressions (N = 18, p = 0.39) or ventilations (n = 17, p = 0.08). No statistically significant difference in improvement of mean scores was found between the grouped adopter sites and the control site. The effect of the duration of the RQI curriculum on CPR performance appeared to be minimal in this data set. Compliance with the RQI curriculum varied by site, one site maintained hospital compliance at 90% over a 1 year period, however compliance reduced over time at all sites. Conclusions This data demonstrated an increased adherence with guidelines for high-quality CPR post-training with the RQI cart, for all adult and most infant measures, but not infant CPR. However, the relationship between a formalised quarterly RQI curriculum and improvements in resuscitation skills is not clear. It is also unclear whether the RQI approach is superior to the current classroom-based BLS training for CPR skill acquisition in the UK. Further research is required to establish how to optimally implement the RQI system in the UK and how to optimally improve hospital wide compliance with CPR training to improve the outcomes of in-hospital cardiac arrests.

STUDIES ON SULFATION FACTOR (SF) ACTIVITY OF HUMAN SERUM

1960 ◽  
Vol XXXV (III) ◽  
pp. 381-396 ◽  
Author(s):  
Sven Almqvist
Keyword(s):  
Human Serum ◽  
Normal Serum ◽  
Treatment Level ◽  
Response Curves ◽  
Normal Children ◽  
Significant Difference ◽  
Human Sera ◽  
Normal Humans ◽  
Pre Treatment ◽  
Dose Levels

ABSTRACT The sulfation factor (SF) activity of human sera has been estimated using a modification of the method of Daughaday et al. (1959). Each assay was statistically evaluated. The method had a mean precision of 0.14 and, used as an assay of GH of human serum, a sensitivity in three pituitary dwarfs of 0.1 to 0.6 μg of HGH/ml of serum. SF activity was found at all ages between 1 month and 75 years. There was a significantly lower mean SF activity below the age of half a year. Three cases of pituitary dwarfism had significantly low SF activities of sera. There was no significant difference between the SF activities of sera from untreated pituitary dwarfs and the sera from normal children below half a year of age. Dose-response curves with large volumes of sera from pituitary dwarfs and small volumes of sera from normal humans had the same slopes. Four mg of HGH prepared according to the method of Li & Papkoff (1956) resulted in a normal serum SF activity in each of the three dwarfs. A significant (P < 0.01) linear relationship was found between the concentration of SF activity of sera from these subjects and the logarithm of the dose of HGH given with dose levels of 1, 2 and 4 mg daily for three days. The decline of serum SF activity to the pre-treatment level following HGH in one dwarf suggested a half life not different from that indicated by others for growth hormone.

Neutron dose evaluation of Elekta Linac at two energies (10 & 18 MV) by MCNP code and comparison with experimental measurements

2014 ◽  
Vol 6 (1) ◽  
pp. 1006-1015
Author(s):  
Negin Shagholi ◽  
Hassan Ali ◽  
Mahdi Sadeghi ◽  
Arjang Shahvar ◽  
Hoda Darestani ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Measurement Data ◽  
Calculated Data ◽  
High Energy ◽  
Neutron Dose ◽  
Dose Assessment ◽  
Photon Flux ◽  
Dose Equivalent ◽  
Monte Carlo Techniques ◽  
Neutron Dose Equivalent

Medical linear accelerators, besides the clinically high energy electron and photon beams, produce other secondary particles such as neutrons which escalate the delivered dose. In this study the neutron dose at 10 and 18MV Elekta linac was obtained by using TLD600 and TLD700 as well as Monte Carlo simulation. For neutron dose assessment in 2020 cm2 field, TLDs were calibrated at first. Gamma calibration was performed with 10 and 18 MV linac and neutron calibration was done with 241Am-Be neutron source. For simulation, MCNPX code was used then calculated neutron dose equivalent was compared with measurement data. Neutron dose equivalent at 18 MV was measured by using TLDs on the phantom surface and depths of 1, 2, 3.3, 4, 5 and 6 cm. Neutron dose at depths of less than 3.3cm was zero and maximized at the depth of 4 cm (44.39 mSvGy-1), whereas calculation resulted  in the maximum of 2.32 mSvGy-1 at the same depth. Neutron dose at 10 MV was measured by using TLDs on the phantom surface and depths of 1, 2, 2.5, 3.3, 4 and 5 cm. No photoneutron dose was observed at depths of less than 3.3cm and the maximum was at 4cm equal to 5.44mSvGy-1, however, the calculated data showed the maximum of 0.077mSvGy-1 at the same depth. The comparison between measured photo neutron dose and calculated data along the beam axis in different depths, shows that the measurement data were much more than the calculated data, so it seems that TLD600 and TLD700 pairs are not suitable dosimeters for neutron dosimetry in linac central axis due to high photon flux, whereas MCNPX Monte Carlo techniques still remain a valuable tool for photonuclear dose studies.

INITIAL STEP OF SPECIALIZED CORPORA BUILDING: CLEANING PROCEDURES

2020 ◽  
Author(s):  
Vera Yakubson ◽  
Victor Zakharov
Keyword(s):  
Text Processing ◽  
Research Question ◽  
Initial Step ◽  
Main Research ◽  
Academic Texts ◽  
Linguistic Annotation ◽  
Significant Difference ◽  
Cleaning Procedures ◽  
Unique Source ◽  
Future Work

This paper deals with the specialized corpora building, specifically academic language corpus in the biotechnology field. Being a part of larger research devoted to creation and usage of specialized parallel corpus, this piece aims to analyze the initial step of corpus building. Our main research question was what procedures we need to implement to the texts before using them to develop the corpus. Analysis of previous research showed the significant quantity of papers devoted to corpora creation, including academic specialized corpora. Different sides of the process were analyzed in these researches, including the types of texts used, the principles of crawling, the recommended length of texts etc. As to the text processing for the needs of corpora creation, only the linguistic annotation issues were examined earlier. At the same time, the preliminary cleaning of texts before their usage in corpora may have significant influence on the corpus quality and its utility for the linguistic research. In this paper, we considered three small corpora derived from the same set of academic texts in the biotechnology field: “raw” corpus without any preliminary cleaning and two corpora with different level of cleaning. Using different Sketch Engine tools, we analyzed these corpora from the position of their future users, predominantly as sources for academic wordlists and specialized multi-word units. The conducted research showed very little difference between two cleaned corpora, meaning that only basic cleaning procedures such as removal of reference lists are can be useful in corpora design. At the same time, we found a significant difference between raw and cleaned corpora and argue that this difference can affect the quality of wordlists and multi-word terms extraction, therefore these cleaning procedures are meaningful. The main limitation of the study is that all texts were taken from the unique source, so the conclusions could be affected by this specific journal’s peculiarities. Therefore, the future work should be the verification of results on different text collections

Restaging of patients with lymphoma

2008 ◽  
Vol 47 (01) ◽  
pp. 37-42 ◽  
Author(s):  
T. Pfluger ◽  
V. Schneider ◽  
M. Hacker ◽  
N. Bröckel ◽  
D. Morhard ◽  
...  
Keyword(s):  
Low Dose ◽  
Non Hodgkin Lymphoma ◽  
Contrast Enhanced ◽  
Pet Ct ◽  
Significant Difference ◽  
18F Fdg ◽  
Sensitivity Specificity ◽  
Fdg Pet Ct

SummaryAim: Assessment of the clinical benefit of i.v. contrast enhanced diagnostic CT (CE-CT) compared to low dose CT with 20 mAs (LD-CT) without contrast medium in combined [18F]-FDG PET/CT examinations in restaging of patients with lymphoma. Patients, methods: 45 patients with non-Hodgkin lymphoma (n = 35) and Hodgkin's disease (n = 10) were included into this study. PET, LD-CT and CECT were analyzed separately as well as side-by-side. Lymphoma involvement was evaluated separately for seven regions. Indeterminate diagnoses were accepted whenever there was a discrepancy between PET and CT findings. Results for combined reading were calculated by rating indeterminate diagnoses according the suggestions of either CT or PET. Each patient had a clinical follow-up evaluation for >6 months. Results: Region-based evaluation suggested a sensitivity/specificity of 66/93% for LD-CT, 87%/91% for CE-CT, 95%/96% for PET, 94%/99% for PET/LD-CT and 96%/99% for PET/CE-CT. The data for PET/CT were obtained by rating indeterminate results according to the suggestions of PET, which turned out to be superior to CT. Lymphoma staging was changed in two patients using PET/ CE-CT as compared to PET/LD-CT. Conclusion: Overall, there was no significant difference between PET/LD-CT and PET/CE-CT. However, PET/CE-CT yielded a more precise lesion delineation than PET/LD-CT. This was due to the improved image quality of CE-CT and might lead to a more accurate investigation of lymphoma.

Comparison of the Effects of Fenugreek Vaginal Cream and Ultra Low- Dose Estrogen on Atrophic Vaginitis

2020 ◽  
Vol 17 (9) ◽  
pp. 815-822
Author(s):  
Maryam Safary ◽  
Sevil Hakimi ◽  
Noushin Mobaraki-Asl ◽  
Paria Amiri ◽  
Habib Tvassoli ◽  
...  
Keyword(s):  
Postmenopausal Women ◽  
Low Dose ◽  
Intervention Group ◽  
Clinical Signs ◽  
Control Group ◽  
Conjugated Estrogens ◽  
Atrophic Vaginitis ◽  
Vaginal Cream ◽  
Intergroup Comparison ◽  
Significant Difference

Introduction: Atrophic vaginitis is a common problem in postmenopausal women and results from decreased levels of blood estrogen. It is associated with symptoms of itching, burning, dyspareunia, and postmenopausal bleeding. The present study evaluated the effects of fenugreek extract on atrophic vaginitis. Materials and Methods: This randomized controlled clinical trial was performed on 60 postmenopausal women in Ardabil, Iran, in 2018. The participants were selected using block randomization with the allocation ratio 1:1. Those in the intervention group received 0.5g (the applicator filled to the half-full mark) fenugreek vaginal cream 5% twice a week for 12 weeks. The control group received conjugated estrogens vaginal cream at the dose of 0.625 mg (the applicator filled to the half-full mark) containing 0.3 mg of conjugated estrogens. Atrophic vaginitis was evaluated before and after the treatment through clinical examination, clinical signs, and measurement of Vaginal Maturation Index (VMI). Findings: After the 12-week intervention and modification of the baseline score, the mean (standard error) score for atrophic vaginitis signs was 3.100 (1.43-4.75). This difference was statistically significant in intragroup comparison and in favor of the control group in intergroup comparison (p=0.001). VMI was less than 49% in 86.7% and 46.7% of the participants in the intervention and control groups, respectively. This was a significant difference in favor of the control group (p=0.001). Conclusion: The results of this study showed that total fenugreek extract could be effective in treating signs of atrophic vaginitis, but it was not as effective as ultra-low-dose estrogen.

scholarly journals Ownership Variation in Violated Regulations and National Care Standards: Evidence From Social Care Providers

2021 ◽  
pp. 089976402110014
Author(s):  
Anders M. Bach-Mortensen ◽  
Ani Movsisyan
Keyword(s):  
Social Care ◽  
Negative Binomial ◽  
Third Sector ◽  
Care Providers ◽  
Data Set ◽  
Logistic Regression Models ◽  
For Profit ◽  
Care Services ◽  
Significant Difference ◽  
Research Gap

Social care services are increasingly provisioned in quasi-markets in which for-profit, public, and third sector providers compete for contracts. Existing research has investigated the implications of this development by analyzing ownership variation in latent outcomes such as quality, but little is known about whether ownership predicts variation in more concrete outcomes, such as violation types. To address this research gap, we coded publicly available inspection reports of social care providers regulated by the Care Inspectorate in Scotland and created a novel data set enabling analysis of ownership variation in violations of (a) regulations, and (b) national care standards over an entire inspection year ( n = 4,178). Using negative binomial and logistic regression models, we find that for-profit providers are more likely to violate non-enforceable outcomes (national care standards) relative to other ownership types. We did not identify a statistically significant difference between for-profit and third sector providers with regard to enforceable outcomes (regulations).

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