scholarly journals Restrainer exposure to scatter radiation in practical small animal radiography measured using thermoluminescent dosimeters

2018 ◽  
Vol 63 (No. 2) ◽  
pp. 81-86 ◽  
Author(s):  
H. Oh ◽  
S. Sung ◽  
S. Lim ◽  
Y. Jung ◽  
Y. Cho ◽  
...  
Keyword(s):  
Small Animal ◽  
Exposure Dose ◽  
Study Data ◽  
Cathode Side ◽  
Scatter Radiation ◽  
X Ray ◽  
Thermoluminescent Dosimeters ◽  
Radiation Shields ◽  
A Prospective Study ◽  
Occupational Radiation

This study was aimed at estimating restrainer exposure to scatter radiation in veterinary radiography using thermoluminescent dosimeters (TLDs) in different positions, and at different anatomic regions. A prospective study was conducted to measure exposure dose of two restrainers: A (cathode side) and B (anode side), and an observer C (at a 1-meter distance from the X-ray table) over two months. Protective devices included panorama mask, thyroid shield and arm shield. TLDs were placed on the inside and outside of the protective gear at five different anatomic sites (eye, thyroid, breast, gonad and arm). The study data consisted of 778 exposures, 82 patients (78 dogs, four cats), a mean kVp of 58.7 and a mean mAs of 11.4. The doses (outside the shield/inside the shield, in mSv) measured by restrainers A, B and C were eye (3.04/0.42), (2.29/0.17), (0.55/0.01), thyroid (2.93/0.01), (1.97/0.01), (0.19/0.01), breast (1.01/0.04), (0.73/0.01), (0.32/0.01), gonad (0.07/0.01), (0.01/0.01), (0.16/0.01) and arm (2.81/1.43), (1.17/0.01), (0.08/0.01), respectively. This study describes the extent of occupational radiation exposure in small animal radiography. The exposure dose for eyes outside lead protection showed the highest value in all participants. With lead protection, the reduction in the exposure dose of eyes was significant (A: 86%, B: 93%, C: 98%), and the highest reduction was 99% in the thyroid region. These results suggest the necessity of radiation shields in manual restraint, particularly for eye protection.

scholarly journals Radiation exposure during C-arm-guided (fluoroscopy) small animal orthopaedic surgery

2018 ◽  
Vol 63 (No. 11) ◽  
pp. 527-531
Author(s):  
S. Sung ◽  
S. Lim ◽  
K. Min ◽  
Y. Jung ◽  
Y. Cho ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Orthopaedic Surgery ◽  
Small Animal ◽  
Exposure Dose ◽  
Exposure Level ◽  
Body Parts ◽  
Thermoluminescent Dosimeters ◽  
Protective Devices ◽  
A Prospective Study ◽  
Operating Surgeon

The purpose of the current study was to investigate the radiation exposure level of surgeons performing C-arm guided small animal orthopaedic surgery using thermoluminescent dosimeters located inside and outside personnel shielding devices at major body parts. A prospective study was conducted to measure the radiation exposure dose of individuals in three positions (first assistant, operating surgeon and anaesthesiologist) using thermoluminescent dosimeters placed inside and outside protective devices. The lead equivalent protective devices included panorama mask, thyroid shield, apron and arm shield placed at five anatomic sites (eye, thyroid, breast, gonad and hand). Radiation exposure was measured during 12 surgical procedures with mean kVp of 51 and mean mAs of 1.6. The equivalent doses for thyroid, breast and gonad (outside/inside in mSv) were 1.75/0.58, 2.01/0.13 and 3.03/0.11, respectively, for the first assistant and 1.69/1.46, 4.82/0.35 and 5.25/0.22 for the operating surgeon. The dose of eye, thyroid, breast, gonad and arm for the anaesthesiologist were 0.61/0.51, 0.35/0.3, 0.67/0.34, 0.72/0.29 and 0.62/0.35, respectively. The exposure dose to gonads outside the lead protection showed the highest values in all participants. With lead protection, there was a significant reduction in the exposure dose to the gonads (first assistant, 96%; operating surgeon, 96%; anaesthesiologist, 60%). These results suggest that a radiation shield is essential in veterinary surgery with C-arms, particularly for gonad protection. In addition, these results demonstrate that exposure dose decreases with increasing distance from the C-arm machine.

scholarly journals Evaluation of radiation exposure from fluoroscopic examination in small animal veterinary staff using thermoluminescent dosimeters

2019 ◽  
Vol 64 (No. 6) ◽  
pp. 266-270
Author(s):  
J An ◽  
S Lim ◽  
S Lee ◽  
H Kim ◽  
K Min ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Radiation Exposure ◽  
Small Animal ◽  
Radiation Doses ◽  
Thermoluminescent Dosimeters ◽  
Fluoroscopic Examination ◽  
Protection Devices ◽  
Exposure Levels ◽  
A Prospective Study ◽  
Occupational Radiation

The purpose of this study was to evaluate the occupational radiation exposure levels of veterinary staff during fluoroscopic examination using thermoluminescent dosimeters (TLDs). A prospective study was conducted to measure radiation doses in three positioned persons (two restrainers and one observer) using TLDs. The TLDs were placed on the inside and outside of the lead-equivalent protective devices of the panorama mask, thyroid shield, apron and arm shield. The TLDs were placed at five anatomic sites (eye, thyroid, breast, gonad and hand). Radiation exposure was measured in 65 fluoroscopic examinations at 80 kVp and 100 mAs. The doses (mSv) (outside/inside the shield) measured in restrainers A and B and observer C were 3.09/0.59, 3.80/0.65 and 0.63/0.44 in the eye; 2.20/0.73, 1.88/1.10 and 0.79/0.45 in the thyroid; 3.42/0.44, 3.94/2.35 and 0.61/0.34 in the breast; 1.84/0.45, 1.69/0.23 and 0.46/0.36 in the gonad; and 5.56/3.16, 8.29/2.99 and 0.79/0.34 in the hand, respectively. Out of all the lead protection devices, the radiation dose of the hand was the highest in all three participants, with the thyroid radiation dose value being the same as the hand in the observer C. Radiation doses received by the eyes of all three participants were also not negligible. Veterinary workers exposed to radiation through not only radiography but also fluoroscopy should wear protective gear, especially for the eyes.

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).

scholarly journals Radiation dose estimation for pencil beam X-ray luminescence computed tomography imaging

2021 ◽  
pp. 1-12
Author(s):  
Ignacio O. Romero ◽  
Changqing Li
Keyword(s):  
Computed Tomography ◽  
Radiation Dose ◽  
Small Animal ◽  
Pencil Beam ◽  
Computed Tomography Imaging ◽  
Step Size ◽  
Imaging Protocol ◽  
X Ray ◽  
Beam Geometry ◽  
Muscle Tissues

BACKGROUND: Pencil beam X-ray luminescence computed tomography (XLCT) imaging provides superior spatial resolution than other imaging geometries like sheet beam and cone beam geometries. However, the pencil beam geometry suffers from long scan times, resulting in concerns overdose which discourages the use of pencil beam XLCT. OBJECTIVE: The dose deposited in pencil beam XLCT imaging was investigated to estimate the dose from one angular projection scan with three different X-ray sources. The dose deposited in a typical small animal XLCT imaging was investigated. METHODS: A Monte Carlo simulation platform, GATE (Geant4 Application for Tomographic Emission) was used to estimate the dose from one angular projection scan of a mouse leg model with three different X-ray sources. Dose estimations from a six angular projection scan by three different X-ray source energies were performed in GATE on a mouse trunk model composed of muscle, spine bone, and a tumor. RESULTS: With the Sigray source, the bone marrow of mouse leg was estimated to have a radiation dose of 44 mGy for a typical XLCT imaging with six angular projections, a scan step size of 100 micrometers, and 106 X-ray photons per linear scan. With the Sigray X-ray source and the typical XLCT scanning parameters, we estimated the dose of spine bone, muscle tissues, and tumor structures of the mouse trunk were 38.49 mGy, 15.07 mGy, and 16.87 mGy, respectively. CONCLUSION: Our results indicate that an X-ray benchtop source (like the X-ray source from Sigray Inc.) with high brilliance and quasi-monochromatic properties can reduce dose concerns with the pencil beam geometry. Findings of this work can be applicable to other imaging modalities like X-ray fluorescence computed tomography if the imaging protocol consists of the pencil beam geometry.

Use of the Leksell Gamma Knife for Localized Small Field Lens Irradiation in Rodents

2003 ◽  
Vol 2 (5) ◽  
pp. 449-454 ◽  
Author(s):  
Colleen DesRosiers ◽  
Marc S. Mendonca ◽  
Craig Tyree ◽  
Vadim Moskvin ◽  
Morris Bank ◽  
...  
Keyword(s):  
Gamma Knife ◽  
High Precision ◽  
Small Animal ◽  
Small Animals ◽  
Small Field ◽  
Thermoluminescent Dosimeters ◽  
Ion Chamber ◽  
Order Of Magnitude ◽  
Contralateral Eye

For most basic radiobiological research applications involving irradiation of small animals, it is difficult to achieve the same high precision dose distribution realized with human radiotherapy. The precision for irradiations performed with standard radiotherapy equipment is ±2 mm in each dimension, and is adequate for most human treatment applications. For small animals such as rodents, whose organs and tissue structures may be an order of magnitude smaller than those of humans, the corresponding precision required is closer to ±0.2 mm, if comparisons or extrapolations are to be made to human data. The Leksell Gamma Knife is a high precision radiosurgery irradiator, with precision in each dimension not exceeding 0.5 mm, and overall precision of 0.7 mm. It has recently been utilized to treat ocular melanoma and induce targeted lesions in the brains of small animals. This paper describes the dosimetry and a technique for performing irradiation of a single rat eye and lens with the Gamma Knife while allowing the contralateral eye and lens of the same rat to serve as the “control”. The dosimetry was performed with a phantom in vitro utilizing a pinpoint ion chamber and thermoluminescent dosimeters, and verified by Monte Carlo simulations. We found that the contralateral eye received less than 5% of the administered dose for a 15 Gy exposure to the targeted eye. In addition, after 15 Gy irradiation 15 out of 16 animals developed cataracts in the irradiated target eyes, while 0 out of 16 contralateral eyes developed cataracts over a 6-month period of observation. Experiments at 5 and 10 Gy also confirmed the lack of cataractogenesis in the contralateral eye. Our results validate the use of the Gamma Knife for cataract studies in rodents, and confirmed the precision and utility of the instrument as a small animal irradiator for translational radiobiology experiments.

Scattering Ray and Exposure Dose Reduction by Using Metal Sheet in X-ray Imaging System

2021 ◽  
Vol 58 (6) ◽  
pp. 89-96
Author(s):  
Ho-Il Lee ◽  
Seok-Hwan Bae ◽  
Yeun-Chul Ryu ◽  
Young-Joon Park ◽  
Yong-Gwon Kim
Keyword(s):  
Dose Reduction ◽  
Imaging System ◽  
Exposure Dose ◽  
Metal Sheet ◽  
X Ray ◽  
X Ray Imaging

Impact of considering non-occupational radiation exposure on the association between occupational dose and solid cancer among French nuclear workers

2017 ◽  
Vol 75 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Lucie Fournier ◽  
Enora Cléro ◽  
Eric Samson ◽  
Sylvaine Caër-Lorho ◽  
Dominique Laurier ◽  
...  
Keyword(s):  
Occupational Exposure ◽  
Cancer Risk ◽  
Radiation Exposure ◽  
Cancer Mortality ◽  
Environmental Radiation ◽  
Occupational Radiation Exposure ◽  
X Ray ◽  
Work Related ◽  
The Mean ◽  
Occupational Radiation

ObjectivesThe French nuclear worker cohort allows for the assessment of cancer risk associated with occupational radiation exposure, but workers are also exposed to medical and environmental radiation which can be of the same order of magnitude. This study aims to examine the impact of non-occupational radiation exposures on the dose-risk analysis between occupational radiation exposure and cancer mortality.MethodsThe cohort included workers employed before 1995 for at least one year by CEA, AREVA NC or EDF and badge-monitored for external radiation exposure. Monitoring results were used to calculate occupational individual doses. Scenarios of work-related X-ray and environmental exposures were simulated. Poisson regression was used to quantify associations between occupational exposure and cancer mortality adjusting for non-occupational radiation exposure.ResultsThe mean cumulative dose of external occupational radiation was 18.4 mSv among 59 004 workers. Depending on the hypotheses made, the mean cumulative work-related X-ray dose varied between 3.1 and 9.2 mSv and the mean cumulative environmental dose was around 130 mSv. The unadjusted excess relative rate of cancer per Sievert (ERR/Sv) was 0.34 (90% CI −0.44 to 1.24). Adjusting for environmental radiation exposure did not substantially modify this risk coefficient, but it was attenuated by medical exposure (ERR/Sv point estimate between 0.15 and 0.23).ConclusionsOccupational radiation risk estimates were lower when adjusted for work-related X-ray exposures. Environmental exposures had a very slight impact on the occupational exposure risk estimates. In any scenario of non-occupational exposure considered, a positive but insignificant excess cancer risk associated with occupational exposure was observed.

Dosimetric challenges of small animal irradiation with a commercial X-ray unit

2014 ◽  
Vol 24 (4) ◽  
pp. 363-372 ◽  
Author(s):  
Peter Kuess ◽  
Eva Bozsaky ◽  
Johannes Hopfgartner ◽  
Gerhard Seifritz ◽  
Wolfgang Dörr ◽  
...  
Keyword(s):  
Small Animal ◽  
X Ray

scholarly journals Interest of Ultrasound in the Exploration of Rotator Cuff Lesions - Confrontation of Clinical Examination and Ultrasound Finding

2018 ◽  
Vol 5 ◽  
Author(s):  
Nessrine Akasbi ◽  
Asmae El Aissaoui ◽  
Ikrame Yazghich ◽  
Samira El Fakir ◽  
Taoufik Harzy
Keyword(s):  
Rotator Cuff ◽  
Physical Examination ◽  
Clinical Examination ◽  
High Sensitivity ◽  
Diagnostic Value ◽  
Ultrasound Finding ◽  
X Ray ◽  
Rotator Cuff Lesion ◽  
Rotator Cuff Lesions ◽  
A Prospective Study

Introduction: The aim of our study was to evaluate the interest of ultrasound in the exploration of painful shoulders evoking rotator cuff lesions and to determine the diagnostic value of the different tendon tests through a confrontation physical examination versus shoulder ultrasound. Materials and methods: A prospective study was conducted including patients consulting for shoulder pain that suggests a rotator cuff lesion. All patients underwent a clinical examination, an x ray and shoulder ultrasound.Results: The confrontation physical examination versus shoulder ultrasound showed that Jobe's test is very sensitive (100%) but less specific (27%), the Patte test, has a high sensitivity (100%) but an average specificity (51%), the Palm-Up test was fairly sensitive (91%) but not very specific (43%) and the Gerber test was more specific (95.7%) and less sensitive (38%). The comparison between x ray and ultrasound showed that ultrasound of shoulder is more efficient in the detection of calcifications and erosions of humeral head.Conclusion: Ultrasound of shoulder is more performant than physical examination and x ray in exploring the rotator cuff lesions.

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