ESTIMATION OF UNCERTAINTY IN MEASUREMENT OF DOSE EQUIVALENT AT LABORATORY LEVEL USING CASO4 :Dy-BASED TLD BADGE SYSTEM IN INDIA

2019 ◽  
Vol 188 (2) ◽  
pp. 135-147 ◽  
Author(s):  
S M Pradhan ◽  
D Datta ◽  
Munir S Pathan ◽  
Kshama Srivastava ◽  
T Palani Selvam
Keyword(s):  
Coefficient Of Variation ◽  
Whole Body ◽  
Dose Equivalent ◽  
Radiation Quality ◽  
Variance Model ◽  
Factors Affecting ◽  
Uncertainty In Measurement ◽  
Photon Dose ◽  
Combined Uncertainty ◽  
Quality Coefficient

Abstract The objective of this paper is to estimate the combined uncertainty in the measurement of dose equivalent at laboratory level using CaSO4:Dy-based thermoluminescent dosemeter badge system by including variations in the components of the system. The variability of performance of the system is analysed using random effects one way analysis of variance model. The model enables estimation of the overall variance of the performance of the sampled population. The population in the study comprises all possible indicated dose equivalents on irradiation of dosemeters to a specific dose equivalent and radiation quality. Coefficient of variation and combined uncertainty at 95% level of confidence in the measurement of Hp(10) due to S-Cs radiation quality are found to be 6.6 and 14.3%, respectively, at the dose level of 5.31 mSv. The above parameters in the measurement of in-use quantity, i.e. whole body dose or photon dose equivalent are found to be 7.4 and 16.4%, respectively. The performance of the monitoring system on relative response has been observed to be satisfactory. Various factors affecting the variability of performance of the system are identified for further improvement in coefficient of variation.

scholarly journals Experimental study on the factors affecting torque of beam-type implant torque wrenches

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hiroki Shiba ◽  
Yuji Sato ◽  
Junichi Furuya ◽  
Tokiko Osawa ◽  
Akio Isobe ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Leading Edge ◽  
Beam Width ◽  
Factors Affecting ◽  
Tightening Force ◽  
Torque Wrench ◽  
Screw Breakage ◽  
Beam Type ◽  
Accuracy And Repeatability ◽  
Excellent Accuracy

Abstract Background Screw breakage and loosening are the most common mechanical complications associated with implant treatment, and they may occur due to excess or inadequate screw tightening torque. When fastening and fixing the implant superstructure, screws are tightened using a torque wrench, which is essential for an accurate tightening force. However, the characteristics of the torque wrench have not been fully verified. Therefore, we aimed to clarify the factors affecting the torque with a focus on beam-type torque wrenches, which are the main types of wrenches. Methods The torque values generated by beam-type torque wrenches from eight manufacturers were measured using a torque gauge. To investigate the influence of the location of the beam relative to the scale, measurements were performed with a scale aligned with the trailing edge, center, and leading edge of the beam respectively. Additionally, measurements were taken at 90°, 60°, and 30° to examine the effect of the angle at which the examiner read the torque value. Under each condition, a single examiner applied the recommended torque to each manufacturer's screws five times in a clockwise direction. The average measured torque, standard deviation, bias, and coefficient of variation were calculated and compared accordingly. Results Wrenches from six manufacturers demonstrated excellent accuracy for measurements at the center of the beam (bias within ± 4%). For measurements at 90°, equipments from five manufacturers displayed excellent accuracy (bias within ± 7%), and seven showed excellent repeatability (coefficient of variation ≤ 2%). Conclusion The scale should be aligned with the center of the beam and read from 90° while using a torque wrench. The accuracy and repeatability torques generated by the wrenches differed according to the manufacturer, scale width, scale line width, beam width, and distance between the scale and beam center. Based on these results, we suggest that a torque wrench must be selected after determining the difference in the structure of the torque wrench.

ISO/TS 20914:2019 – a critical commentary

2020 ◽  
Vol 58 (8) ◽  
pp. 1182-1190 ◽  
Author(s):  
Ian Farrance ◽  
Robert Frenkel ◽  
Tony Badrick
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Data ◽  
International Normalized Ratio ◽  
Medical Laboratory ◽  
Uncertainty In Measurement ◽  
Medical Laboratories ◽  
Functional Relationships ◽  
Critical Commentary ◽  
Combined Uncertainty ◽  
Expression Of Uncertainty

AbstractThe long-anticipated ISO/TS 20914, Medical laboratories – Practical guidance for the estimation of measurement uncertainty, became publicly available in July 2019. This ISO document is intended as a guide for the practical application of estimating uncertainty in measurement (measurement uncertainty) in a medical laboratory. In some respects, the guide does indeed meet many of its stated objectives with numerous very detailed examples. Even though it is claimed that this ISO guide is based on the Evaluation of measurement data – Guide to the expression of uncertainty in measurement (GUM), JCGM 100:2008, it is with some concern that we believe several important statements and statistical procedures are incorrect, with others potentially misleading. The aim of this report is to highlight the major concerns which we have identified. In particular, we believe the following items require further comment: (1) The use of coefficient of variation and its potential for misuse requires clarification, (2) pooled variance and measurement uncertainty across changes in measuring conditions has been oversimplified and is potentially misleading, (3) uncertainty in the results of estimated glomerular filtration rate (eGFR) do not include all known uncertainties, (4) the international normalized ratio (INR) calculation is incorrect, (5) the treatment of bias uncertainty is considered problematic, (6) the rules for evaluating combined uncertainty in functional relationships are incomplete, and (7) specific concerns with some individual statements.

scholarly journals Reproducibility of 24 h energy expenditure measurements using a human whole body indirect calorimeter

1987 ◽  
Vol 57 (2) ◽  
pp. 201-209 ◽  
Author(s):  
Janna O. De Boer ◽  
Aren J. H. Van Es ◽  
Joop E. Vogt ◽  
Joop M. A. Van Raaij ◽  
Joseph G. A. J. Hautvast
Keyword(s):  
Energy Expenditure ◽  
Coefficient Of Variation ◽  
Weight Maintenance ◽  
Metabolizable Energy ◽  
Whole Body ◽  
Time Interval ◽  
Daily Routine ◽  
Individual Level ◽  
Period 2 ◽  
Significant Difference

1. Ten female subjects completed two similar experimental procedures (periods 1 and 2) to obtain values of reproducibility of energy intake and 24 h energy expenditure (24hEE) measurements in a whole body indirect calorimeter. The periods consisted of consumption of a provided weight-maintenance diet for 6–8 d, faeces and urine collection during the last 4 d and occupation of the calorimeter during the last 3 d. The daily routine inside the calorimeter simulated a sedentary day in normal life with some physical activity: 8 h sleep, 75 min bicycling and the remaining time spent on sedentary activities. The metabolizable energy (ME) content of the diet (14% energy as protein, 46% energy as carbohydrate, 40% energy as fat) was calculated using food tables. The actual ME intake as well as digestibility and metabolizability of the diet were obtained later by analyses of food, faeces and urine for energy. Three consecutive 24hEE measurements were performed during the stay in the calorimeter in each period. The time interval between the two periods varied from 2 to 24 months. Reproducibility was assessed at group and individual level.2. Mean digestibility and metabolizability of the diet showed no significant difference between periods. The within-subject coefficient of variation of metabolizability between periods was 1.7%.3. Mean 24hEE (MJ) over 3 d did not differ between period 1 (8.78 (SD 0.63)) and period 2 (8.73 (SD 0.66)). The within-subject coefficient of variation in mean 24hEE over three successive days between periods was 3.1% but decreased, after deletion of values for subjects who were less adapted to the calorimeter, to 1.9%.4. The results are discussed with regard to length of trial and the number of subjects required to test a difference in energy metabolism using whole body indirect calorimeters.

Tunable Diode Laser Absorption Spectroscopy Sensor for Calibration Free Humidity Measurements in Pure Methane and Low CO2 Natural Gas

2016 ◽  
Vol 71 (5) ◽  
pp. 888-900 ◽  
Author(s):  
Javis Anyangwe Nwaboh ◽  
Sonja Pratzler ◽  
Olav Werhahn ◽  
Volker Ebert
Keyword(s):  
Natural Gas ◽  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Amount Of Substance ◽  
Uncertainty In Measurement ◽  
Laser Absorption ◽  
Combined Uncertainty ◽  
Diode Laser Absorption

We report a new direct tunable diode laser absorption spectroscopy (dTDLAS) sensor for absolute measurements of H2O in methane, ethane, propane, and low CO2 natural gas. The sensor is operated with a 2.7 µm DFB laser, equipped with a high pressure single pass gas cell, and used to measure H2O amount of substance fractions in the range of 0.31–25 000 µmol/mol. Operating total gas pressures are up to 5000 hPa. The sensor has been characterized, addressing the traceability of the spectrometric results to the SI and the evaluation of the combined uncertainty, following the guide to the expression of uncertainty in measurement (GUM). The relative reproducibility of H2O amount of substance fraction measurements at 87 µmol/mol is 0.26% (0.23 µmol/mol). The maximum precision of the sensor was determined using a H2O in methane mixture, and found to be 40 nmol/mol for a time resolution of 100 s. This corresponds to a normalized detection limit of 330 nmol mol−1·m Hz−1/2. The relative combined uncertainty of H2O amount fraction measurements delivered by the sensor is 1.2%.

CORRELATION OF EYE LENS DOSES AND PERSONAL DOSE EQUIVALENT MEASURED ON THE ARM OF INTERVENTIONAL CARDIOLOGISTS FOR A RETROSPECTIVE ASSESSMENT OF DOSES TO OPERATORS’ EYE LENS

2020 ◽  
Vol 189 (3) ◽  
pp. 271-278
Author(s):  
Joanna Domienik-Andrzejewska ◽  
Marcin Brodecki ◽  
Marek Zmyślony
Keyword(s):  
Threshold Dose ◽  
Whole Body ◽  
Eye Lens ◽  
Dose Equivalent ◽  
Retrospective Assessment ◽  
Time Period ◽  
Conversion Coefficients ◽  
Left And Right ◽  
Lens Opacities

Abstract Coefficients converting the readings of the whole body dosemeter worn on the left arm to eye lens doses were determined by analysing the correlations between Hp(10) and Hp(3) values. Doses were measured on a phantom for specific C-arm projections typically used during CA/PCI procedures. In order to estimate the cumulative eye lens doses, conversion coefficients were then applied to the dose records of interventional cardiologists collected in the database of dosimetry service between the years 1995 and 2009. The Hp(10) to Hp(3) conversion coefficients are 0.29 (CV = 34%) and 0.17 (CV = 42%) for left and right eye lens, respectively. However, they can vary from one laboratory to another depending on working technique. From among 61 interventional cardiologists, none exceeded the threshold dose of 0.5 Gy for eye lens opacities. However, 44% of interventional cardiologists were likely to exceed the annual limit of 20 mSv for the most exposed eye at least once in the analysed time period.

UNCERTAINTY EVALUATION IN MEASUREMENT OF THE PERSONAL DOSE EQUIVALENT AT NINE INDIVIDUAL MONITORING SERVICES IN ASIA AND THE PACIFIC REGION

2020 ◽  
Vol 190 (2) ◽  
pp. 217-225
Author(s):  
Chadia Rizk ◽  
Panagiotis Askounis ◽  
H Burçin Okyar ◽  
John Konsoh Sangau ◽  
Samaneh Baradaran ◽  
...  
Keyword(s):  
Uncertainty Evaluation ◽  
Radiological Protection ◽  
International Electrotechnical Commission ◽  
Pacific Region ◽  
Dose Equivalent ◽  
Annual Dose ◽  
Uncertainty In Measurement ◽  
The Pacific ◽  
Dose Limits ◽  
Relevant Dose

Abstract This paper presents the results of the evaluation of the uncertainty in measurement of the personal dose equivalent, Hp(10), at nine individual monitoring services (IMSs) in Asia and the Pacific region. Different types of passive dosemeters were type-tested according to the International Electrotechnical Commission 62387 requirements. The uncertainty in measurement was calculated using the Guide to the Expression of Uncertainty in Measurement approach. Expanded uncertainties ranged between 24 and 86% (average = 38%) for Hp(10) values around 1 mSv and between 14 and 40% (average = 27%) for doses around the annual dose limit, Hp(10) = 20 mSv. The expanded uncertainties were lower than the 1.5 factor in either direction proposed by the International Commission on Radiological Protection for doses near the relevant dose limits. This indicates an acceptable level of uncertainty for all participating IMSs. Uncertainty evaluation will help the IMSs to acknowledge the accuracy of their measurements.

Development of an Image-Based Biomechanical Model for Assessment of Hip Fracture Risk

2015 ◽  
Author(s):  
Masoud Nasiri Sarvi ◽  
Yunhua Luo
Keyword(s):  
Hip Fracture ◽  
Fracture Risk ◽  
Biomechanical Model ◽  
The Elderly ◽  
Whole Body ◽  
Fe Model ◽  
Factors Affecting ◽  
Hip Fracture Risk ◽  
Proposed Model ◽  
Subject Specific

Low-trauma hip fracture, usually caused by fall from standing height, has become a main source of morbidity and mortality for the elderly. Factors affecting hip fracture include sex, race, age, body weight, height, body mass distribution, etc., and thus, hip fracture risk in fall differs widely from subject to subject. It is therefore necessary to develop a subject-specific biomechanical model to predict hip fracture risk. The objective of this study is to develop a two-level, image-based, subject-specific biomechanical model consisting of a whole-body dynamics model and a proximal-femur finite element (FE) model for more accurately assessing the risk of hip fracture in lateral falls. Required information for constructing the model is extracted from a whole-body and a hip DXA (Dual Energy Xray Absorptiometry) image of the subject. The proposed model considers all parameters subject-specifically, which will provide a fast, accurate, and non-expensive method for predicting hip fracture risk.

Factors Affecting Survival and Cation Concentration in the Blackflies Prosimulium fuscum/mixtum and the Mayfly Leptophlebia cupida during Spring Snowmelt

1988 ◽  
Vol 45 (12) ◽  
pp. 2123-2132 ◽  
Author(s):  
Ronald J. Hall ◽  
R. C. Bailey ◽  
Joseph Findeis
Keyword(s):  
Whole Body ◽  
Toxicity Tests ◽  
Transplant Experiment ◽  
Gut Content ◽  
Short Term ◽  
Factors Affecting ◽  
Ph Values ◽  
Zn Concentration ◽  
Spring Snowmelt

We used a transplant experiment to examine the effects of short-term pH depressions in spring on whole-body concentrations of nine metal cations (Ca, Mg, Na, Zn, Pb, Al, Mn, Cd, and Fe) and survival of two species of aquatic insects collected from two habitats with year-round differences in pH. Survival of Leptophlebia cupida and Prosimulium fuscum/mixtum was close to 100% in 4- and 10-d in situ toxicity tests prior to and during snowmelt at pH levels ranging from 6.5 to 4.2. Differences in metal concentrations (Zn, Cd, and Na) existed between mayflies collected from different streams with pH values of 6.2−5.6. Both species transplanted from pH 6.2 to 4.2 streamwater had significant decreases in whole-body concentrations of Ca, Al, and Mn. Additionally, mayflies had significant losses of Mg, Fe, and Pb, while blackflies decreased in whole-body Na and Zn concentration. Percentages of the whole-body Al concentration in the adsorbed, absorbed, and gut content fractions were 3.3, 31.7, and 65%, respectively, for L. cupida and 1.6, 56.4, and 42%, respectively, for P. fuscum/mixtum. The percent adsorbed doubled in transplanted (versus control) mayflies, but the overall whole-body Al concentration decreased.

Sign in / Sign up

Export Citation Format

Share Document