scholarly journals Determination of Calibration Factors and Uncertainties Associated with the Irradiation of MTS-N (LiF: Mg, Ti) Chips with Cesium-137 and X-ray Sources Under Low Doses for Personal Dosimetry in Diagnostic Radiology

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Akintayo Daniel Omojola ◽  
Michael Onoriode Akpochafor ◽  
Samuel Olaolu Adeneye ◽  
Moses Adebayo Aweda
Keyword(s):  
Line Graph ◽  
Coefficient Of Determination ◽  
Radiological Protection ◽  
Dose Equivalent ◽  
X Ray ◽  
Calculated Dose ◽  
Cesium 137 ◽  
Personal Dosimetry ◽  
The Mean

Purpose: The purpose of this study was to compare calibration factors for deep dose equivalent Hp (10) and shallow dose equivalent Hp (0.07) between Cesium (Cs)-137 and X-ray sources when they are exposed to same dose and to determine uncertainties with MTS-N (LiF: Mg, Ti) chips when they are exposed to low dose ≤ 2mGy. Material and Methods: Thermoluminescent (TL) chips were annealed at 400oC for one hour and allowed to cool and were subjected to a temperature of 100oC for another two hours using a TLD Furnace Type LAB-01/400. They were then taken to a Secondary Standard Dosimetry Laboratory (SSDL) for irradiation using a Cs-137 source at known doses (0.2-2mGy). A RadPro Cube 400 manual TLD Reader was used to determine corresponding TL signal. The above process was replicated but with a calibrated X-ray unit as the source for calibration. Results: The calibration factors (CF) from the line graph of dose (mGy) against TL signal (count) for Cs-137 source with Hp (10) and Hp (0.07) were 3.72 x 10-6 and 5.97x10-6 mGy/count respectively. Those with X-ray source for Hp (10) and Hp (0.07) were 3.44x10-6 and 4.05x10-6 mGy/count respectively with an overall coefficient of determination (R2) = 0.99. The adjusted maximum percentage deviation between the actual and calculated dose for both sources was -2.74%. The percent (%) deviation of the mean with both sources for Hp (10) and Hp (0.07) was 3.9% and 19% respectively. Conclusion: Adjusted percent deviation from both sources were within the recommended dose limit of ±30% by the Radiological Protection Institute of Ireland (RPII) and within the International Commission on Radiological Protection (ICRP) limit respectively. Better accuracy was seen for Hp (10) with both sources compared to Hp (0.07). Calibration of the MTS-N chips using both sources was successful and can be used for personal dosimetry.

scholarly journals Radiation eye dose to medical staff during respiratory endoscopy under X-ray fluoroscopy

2020 ◽  
Vol 61 (5) ◽  
pp. 691-696
Author(s):  
Yoshihiro Haga ◽  
Koichi Chida ◽  
Yuichiro Kimura ◽  
Shinsuke Yamanda ◽  
Masahiro Sota ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Medical Staff ◽  
International Commission ◽  
Radiological Protection ◽  
Dose Equivalent ◽  
Dose Limit ◽  
Clinical Value ◽  
Correct Evaluation ◽  
X Ray ◽  
The Mean

Abstract Although the clinical value of fluoroscopically guided respiratory endoscopy (bronchoscopy) is clear, there have been very few studies on the radiation dose received by staff during fluoroscopically guided bronchoscopy. The International Commission on Radiological Protection (ICRP) is suggesting reducing the occupational lens dose limit markedly from 150 to 20 mSv/year, averaged over defined periods of five years. The purpose of this study was to clarify the current occupational eye dose of bronchoscopy staff conducting fluoroscopically guided procedures. We measured the occupational eye doses (3-mm-dose equivalent, Hp(3)) of bronchoscopy staff (physicians and nurses) over a 6-month period. The eye doses of eight physicians and three nurses were recorded using a direct eye dosimeter, the DOSIRIS. We also estimated eye doses using personal dosimeters worn at the neck. The mean ± SD radiation eye doses (DOSIRIS) to physicians and nurses were 7.68 ± 5.27 and 2.41 ± 1.94 mSv/6 months, respectively. The new lens dose limit, 20 mSv/year, may be exceeded among bronchoscopy staff, especially physicians. The eye dose of bronchoscopy staff (both physicians and nurses) was underestimated when measured using a neck dosimeter. Hence, the occupational eye dose of bronchoscopy staff should be monitored. To reduce the occupational eye dose, we recommend that staff performing fluoroscopically guided bronchoscopy wear Pb glasses. correct evaluation of the lens dose [Hp(3)] using an eye dosimeter such as the DOSIRIS is necessary for bronchoscopy staff.

scholarly journals Estimation of dose and cancer risk to newborn from chest X-ray in South-South Nigeria: a call for protocol optimization

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Akintayo Daniel Omojola ◽  
Michael Onoriode Akpochafor ◽  
Samuel Olaolu Adeneye ◽  
Isiaka Olusola Akala ◽  
Azuka Anthonio Agboje
Keyword(s):  
Cancer Risk ◽  
Age Groups ◽  
Field Size ◽  
Radiological Protection ◽  
International Studies ◽  
X Ray ◽  
Thermoluminescent Dosimeters ◽  
Chest X Ray ◽  
Neonatal Patient ◽  
The Mean

Abstract Background The use of X-ray as a diagnostic tool for complication and anomaly in the neonatal patient has been helpful, but the effect of radiation on newborn stands to increase their cancer risk. This study aims to determine the mean, 50th percentile (quartile 2 (Q2)), and 75th percentile (quartile 3 (Q3)) entrance surface dose (ESD) from anteroposterior (AP) chest X-ray and to compare our findings with other relevant studies. The study used calibrated thermoluminescent dosimeters (TLDs), which was positioned on the central axis of the patient. The encapsulated TLD chips were held to the patients’ body using paper tape. The mean kilovoltage peak (kVp) and milliampere seconds (mAs) used was 56.63(52–60) and 5.7 (5–6.3). The mean background TLD counts were subtracted from the exposed TLD counts and a calibration factor was applied to determine ESD. Results The mean ESDs of the newborn between 1 and 7, 8 and 14, 15 and 21, and 22 and 28 days were 1.09 ± 0.43, 1.15 ± 0.50, 1.19 ± 0.45, and 1.32 ± 0.47 mGy respectively. A one-way ANOVA test shows that there were no differences in the mean doses for the 4 age groups (P = 0.597). The 50th percentile for the 4 age groups was 1.07, 1.26, 1.09, and 1.29 mGy respectively, and 75th percentile were 1.41, 1.55, 1.55, and 1.69 mGy respectively. The mean effective dose (ED) in this study was 0.74 mSv, and the estimated cancer risk was 20.7 × 10−6. Conclusion ESD was primarily affected by the film-focus distance (FFD) and the patient field size. The ESD at 75th percentile and ED in this study was higher compared to other national and international studies. The estimated cancer risk to a newborn was below the International Commission on Radiological Protection (ICRP) limit for fatal childhood cancer (2.8 × 10−2Sv−1).

The Use of the Pseudo-Voigt Function in the Variance Method of X-ray Line-Broadening Analysis

1997 ◽  
Vol 30 (4) ◽  
pp. 427-430 ◽  
Author(s):  
F. Sánchez-Bajo ◽  
F. L. Cumbrera
Keyword(s):  
Crystallite Size ◽  
Original Form ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Variance Method ◽  
The Mean ◽  
Voigt Function

A modified application of the variance method, using the pseudo-Voigt function as a good approximation to the X-ray diffraction profiles, is proposed in order to obtain microstructural quantities such as the mean crystallite size and root-mean-square (r.m.s.) strain. Whereas the variance method in its original form is applicable only to well separated reflections, this technique can be employed in the cases where there is line-profile overlap. Determination of the mean crystallite size and r.m.s. strain for several crystallographic directions in a nanocrystalline cubic sample of 9-YSZ (yttria-stabilized zirconia) has been performed by means of this procedure.

Interlaboratory Study of Blood Selenium Determinations

1987 ◽  
Vol 70 (4) ◽  
pp. 664-667
Author(s):  
Tee-Siaw Koh
Keyword(s):  
Hydride Generation ◽  
Atomic Absorption Spectrophotometry ◽  
Bovine Blood ◽  
Blood Samples ◽  
X Ray ◽  
Absorption Spectrophotometry ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Se Deficiency

Abstract Fifty-one laboratories from 14 countries participated in a survey on the determination of selenium (Se) in 8 bovine blood samples with Se concentrations ranging from 0.2 μmol/L (0.016 μg/mL) to 14 μmol/L (1.1 μg/mL). The methods used (and the percentage of participants using each method) were fiuorometry (61), hydride-generation atomic absorption spectrophotometry (AAS) (23), graphitefurnace AAS (6), gas chromatography (4), neutron activation analysis (4), and X-ray fiuorometry (2). There was little difference in the mean Se results obtained by fiuorometry or hydride-generation AAS (P > 0.05). Mean intralaboratory coefficients of variation (CVs) from known replicates ranged from 4 to 14% for all samples. Interlaboratory CVs were related to blood Se concentration and increased to 55% at Se levels below 0.4 μmol/L (0.032 μg/mL). Laboratories that used quality control (QC) schemes had lower interlaboratory CVs than those that did not, but the advantage began to diminish at blood Se concentration below 0.4 μmol/L (0.032 μg/mL). The high interlaboratory CVs, coupled with the false assurance from the low intralaboratory CVs and the ineffectiveness of the QC schemes at blood Se concentrations below 0.4 μmol/L (0.032 μg/mL), are of concern in diagnosis of marginal Se deficiency in livestock where the concentrations of interest are in the range 0.15-0.5 μmol/L (0.012-0.039 μg/mL).

Determination of Heavy Metals in Damascus Drinking Water Using Total Reflection X-Ray Fluorescence

1999 ◽  
Vol 34 (2) ◽  
pp. 305-316 ◽  
Author(s):  
E.H. Bakraji ◽  
J. Karajo
Keyword(s):  
Trace Elements ◽  
Drinking Water ◽  
Total Reflection ◽  
World Health ◽  
X Ray ◽  
Quality Guidelines ◽  
The World ◽  
The Mean ◽  
Health Organization

Abstract Total reflection X-ray fluorescence spectrometry and chemical preconcentration have been applied for multi-elemental analysis of Damascus drinking water. Water was taken directly from taps of several city sectors and analyzed for the following trace elements: Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Se and Pb. The detection limits were found to be in the range of 0.1 to 0.4 µg/L. The mean levels of trace elements in the Damascus drinking water were below the World Health Organization drinking water quality guidelines.

Determination of conversion factors from air kerma to operational dose equivalent quantities for low-energy X-ray spectra

2006 ◽  
Vol 125 (1-4) ◽  
pp. 198-204 ◽  
Author(s):  
A. Hakanen ◽  
A. Kosunen ◽  
P. Poyry ◽  
M. Tapiovaara
Keyword(s):  
Low Energy ◽  
Dose Equivalent ◽  
Conversion Factors ◽  
X Ray ◽  
Air Kerma

scholarly journals Measurement of Environmental Radioactivity within Dangote Cement Escavation Site Gboko, Benue State.

2015 ◽  
Vol 6 ◽  
pp. 168-172
Author(s):  
A A Tyovenda ◽  
A A Akombor ◽  
S T Tamaugee
Keyword(s):  
Environmental Radioactivity ◽  
Radiological Protection ◽  
Limit Set ◽  
Exposure Rate ◽  
Dose Equivalent ◽  
Background Count ◽  
Equivalent Rate ◽  
The Mean ◽  
Excavation Site ◽  
Safety Limit

The radioactivity of rocks from Dangote Cement excavation site in Gboko, Benue State were monitored and measured using the radiation meter inspector 06250 and dose meter 6150AD 2/4/6. The meters measure the dose rate, exposure rate and the activity. The meters were held 1 meter above the surface of the soil at the excavation site. Each reading was taken 10 times at varying distances between zero and 100 meters from the excavation site after which the mean readings for each of the distance were then found. Finally, the background count was taken 200 meters away from the excavation point. The highest value of dose equivalent rate of 0.428±0.006 mSv/yr, exposure rate of 0.206±0.003 mR/hr and activity of 6.8±0.4kBq were measured at zero distance from the excavation point while the least value of dose equivalent rate of 0.212±0.002 mSv/yr, exposure rate of 0.081±0.001 mR/hr and activity of 3.2±0.8kBq were obtained at 100 meters away from the excavation point. The result shows that the excavation site is within the safety limit set by the international commission on Radiological protection (ICRP) (1990).

NOVEL ‘PHOTONEUTRON VOLUME DOSE EQUIVALENT’ HYPOTHESIS AND METHODOLOGY FOR SECOND PRIMARY CANCER RISK ESTIMATION IN HIGH-ENERGY X-RAY MEDICAL ACCELERATORS

2020 ◽  
Vol 188 (4) ◽  
pp. 432-443 ◽  
Author(s):  
Mehdi Sohrabi ◽  
Amir Hakimi
Keyword(s):  
Risk Estimation ◽  
High Energy ◽  
Second Primary ◽  
Radiological Protection ◽  
Primary Cancer ◽  
Second Primary Cancer ◽  
Dose Equivalent ◽  
X Ray ◽  
Risk Estimates ◽  
First Time

Abstract A novel ‘photoneutron (PN) volume dose equivalent’ methodology was hypothesized and applied for the first time for estimating PN second primary cancer (PN-SPC) risks in high-energy X-ray medical accelerators. Novel position-sensitive mega-size polycarbonate dosimeters with 10B converter (with or without cadmium covers) were applied for determining fast, epithermal and thermal PN dose equivalents at positions on phantom surface and depths. The methodology was applied to sites of tumors such as brain, stomach and prostate in 47 patients. The PN-SPC risks were estimated for specific organs/tissues using linear International Commission on Radiological Protection cancer risks and were compared with some available data. The corresponding PN-SPC risk estimates ranged from 1.450 × 10−3 to 1.901 cases per 10 000 persons per Gray. The method was applied to 47 patients for estimating PN-SPC risks in patients undergoing radiotherapy. The PN-SPC risk estimates well match those calculated by simulation but are comparatively different from those estimated by ‘PN point dose equivalent’ methods, as expected.

An X-Ray Structure Determination of the Twinned Crystals of Dinitrato-2,2′-dipyridylsilver(II)

1972 ◽  
Vol 50 (3) ◽  
pp. 315-323 ◽  
Author(s):  
G. W. Bushnell ◽  
M. A. Khan
Keyword(s):  
Silver Atom ◽  
Unit Cell ◽  
Planar Geometry ◽  
X Ray ◽  
Square Planar ◽  
Distorted Octahedral ◽  
Cell Dimensions ◽  
The Mean ◽  
Unit Cell Dimensions

The crystal structure of dinitrato-2,2′-dipyridylsilver(II) has been solved and refined to an R-value of 0.070. Four circle diffractometer measurements were obtained from the twinned triclinic crystals. The unit cell dimensions at 22 °C are: a = 697.5 ± 0.2 pm, b = 999.4 ± 0.2 pm, c = 1032.2 ± 0.2 pm, α = 113.46 ± 0.02°, β = 100.71 ± 0.02°, γ = 95.28 ± 0.02°. The space group is [Formula: see text] (No. 2) with two molecules per unit cell. The density is 2.06 ± 0.04 g cm−3 (measured), 2.02 g cm−3 (calculated). The four shortest bond lengths to silver are: Ag—O(1), 214.8 ± 1.5 pm; Ag—O(4), 213.6 ± 1.5 pm; Ag—N(1), 212.4 ± 1.6 pm; Ag—N(2), 220.7 ± 1.6 pm. These four bonds are distorted from square planar geometry with the silver atom lying 19.90 ± 0.17 pm out of the mean plane of the other four atoms. There are also long bonds to the nitrato groups of neighboring molecules: Ag—O(1′), 275.3 ± 1.3 pm; Ag—O(2″), 276.3 ± 1.6 pm. Inclusion of these bonds gives a distorted octahedral silver coordination. Though predominantly unidentate, there is a slight tendency toward bidentate bonding in both nitrato ligands: Ag—O(2), 305.8 ± 1.4 pm; Ag—O(5), 295.0 ± 1.7 pm. O(2) and O(5) approach the convex side of the distorted square planar coordination. The deviation from planarity of the closely bonded square, and angular distortions in the above mentioned octahedral coordination can be rationalized by considering the silver as eight coordinate. The bonds to silver may be grouped 4:2:2 by length or 4:3:1 by angular disposition.

Sign in / Sign up

Export Citation Format

Share Document