scholarly journals Analysis of thyroid absorbed dose in cervical CT scan with the use of bismuth shielding

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Fernanda Stephanie Santos ◽  
Alvaro Mauricio Ladino Gomez ◽  
Clarysson Alberto Melo da Silva ◽  
Priscila Do Carmo Santana ◽  
Arnaldo Prata Mourao
Keyword(s):  
Ct Scan ◽  
Absorbed Dose ◽  
Conventional Radiography ◽  
Exposure Dose ◽  
Radiochromic Film ◽  
Noninvasive Test ◽  
Additional Information ◽  
Bismuth Shielding ◽  
Radiosensitive Organs ◽  
The Individual

The Computed Tomography (CT) has become an important tool to diagnose cancer and to obtain additional information for different clinical questions. Today, it is a very fast, painless and noninvasive test that can be performed high quality images. However, CT scan usually requires a higher radiation exposure dose than a conventional radiography examination. The aim of this study is to determine the dose variation deposited in thyroid and in nearby radiosensitive organs, such as: lenses, pharynx, hypophysis, salivary gland and spinal cord with and without the use of bismuth shielded. A cervical CT scan was performed on anthropomorphic male phantom model Alderson Rando, using a GE scanner, Discovery model with 64 channels. Dose measurements have been performed by using radiochromic film strips to register the individual doses in the organs of interest. The results show us that the thyroid received the highest dose, 24.70 mGy, in the phantom, according to the incidence of the primary X-ray beam.

scholarly journals Application of Different methods for Reducing Radiation Dose to Breast during MDCT

2018 ◽  
Author(s):  
M Keshtkar ◽  
V Saba ◽  
M A Mosleh-Shirazi
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Low Income ◽  
Low Income Countries ◽  
Radiological Protection ◽  
Reconstruction Algorithms ◽  
Radiation Induced Cancer ◽  
Bismuth Shielding ◽  
Ct Scanners ◽  
Radiosensitive Organs

The increased use of computed tomography (CT) and its high radiation dose have led to great concerns about its potential for radiation induced cancer risks. Breast is a radiosensitive tissue based on tissue weighting factors assigned by the International Commission on Radiological Protection (ICRP). Moreover, the dose is maximal on the surface of the patient. Therefore, strategies should be taken to reduce radiation dose to the breast. The aim of this review is to introduce methods used for reducing radiation dose to breast in thoracic CT and review related performed studies. The literature indicates that bismuth shielding increases image noise and CT numbers as well as introducing streak artifacts. Tube current modulation (TCM) technique and iterative reconstruction algorithms can provide some levels of dose reduction to radiosensitive organs and superior image quality without the disadvantages of bismuth shielding. However, they are not available on all CT scanners, especially in low-income countries. Such centers may have to continue using bismuth shields to reduce the dose until these superior techniques become available at lower costs in all CT scanners. Furthermore, design and manufacture of new shields with the lower impact on image quality are desirable.

Proposed Dose Constraints in the Duties of Radiation Workers at the Department of Nuclear Medicine

2019 ◽  
Vol 187 (4) ◽  
pp. 535-539
Author(s):  
Woon-Kwan Chung ◽  
Nam-Hee Yang ◽  
Kyung-Rae Dong ◽  
Jiwon Choi
Keyword(s):  
Nuclear Medicine ◽  
Exposure Dose ◽  
Individual Exposure ◽  
Limit Value ◽  
Positron Emission ◽  
Pet Ct ◽  
Dose Constraint ◽  
Dose Limits ◽  
The Individual ◽  
Dose Constraints

Abstract This study aimed to set a dose constraint for certain duties of radiological technologists in the department of nuclear medicine. From 2013 to 2017, the 5 y radiation exposure data of employees performing PET-CT and γ-CAMERA of eight hospitals in Korea were measured individual exposure doses to estimate the frequency and set a representative dose of 75 and 95% from the low dose in the whole category is presented. The dose constraint was 5.5 mSv for PET-CT, 4.5 mSv for γ-CAMERA and 3.5 mSv for Positron Emission Tomography (PET)-Computed Tomography(CT) and Gamma CAMERA (γ-CAMERA). Therefore, it would be appropriate to set a dose-limit value of ~5 mSv corresponding to 75–80% of the individual exposure dose of radiological technologists in the department of nuclear medicine. The finding of this study may be used as reference data for setting future radiation dose limits.

scholarly journals Beyond two-point statistics: using the minimum spanning tree as a tool for cosmology

2019 ◽  
Vol 491 (2) ◽  
pp. 1709-1726 ◽  
Author(s):  
Krishna Naidoo ◽  
Lorne Whiteway ◽  
Elena Massara ◽  
Davide Gualdi ◽  
Ofer Lahav ◽  
...  
Keyword(s):  
Spanning Tree ◽  
Large Scale ◽  
Minimum Spanning Tree ◽  
Cosmological Parameters ◽  
Skeletal Structure ◽  
Additional Information ◽  
The Rich ◽  
Unique Graph ◽  
The Individual ◽  
First Time

ABSTRACT Cosmological studies of large-scale structure have relied on two-point statistics, not fully exploiting the rich structure of the cosmic web. In this paper we show how to capture some of this cosmic web information by using the minimum spanning tree (MST), for the first time using it to estimate cosmological parameters in simulations. Discrete tracers of dark matter such as galaxies, N-body particles or haloes are used as nodes to construct a unique graph, the MST, that traces skeletal structure. We study the dependence of the MST on cosmological parameters using haloes from a suite of COmoving Lagrangian Acceleration (COLA) simulations with a box size of $250\ h^{-1}\, {\rm Mpc}$, varying the amplitude of scalar fluctuations (As), matter density (Ωm), and neutrino mass (∑mν). The power spectrum P and bispectrum B are measured for wavenumbers between 0.125 and 0.5 $h\, {\rm Mpc}^{-1}$, while a corresponding lower cut of ∼12.6 $h^{-1}\, {\rm Mpc}$ is applied to the MST. The constraints from the individual methods are fairly similar but when combined we see improved 1σ constraints of $\sim 17{{\ \rm per\ cent}}$ ($\sim 12{{\ \rm per\ cent}}$) on Ωm and $\sim 12{{\ \rm per\ cent}}$ ($\sim 10{{\ \rm per\ cent}}$) on As with respect to P (P + B) thus showing the MST is providing additional information. The MST can be applied to current and future spectroscopic surveys (BOSS, DESI, Euclid, PSF, WFIRST, and 4MOST) in 3D and photometric surveys (DES and LSST) in tomographic shells to constrain parameters and/or test systematics.

scholarly journals Quantifying changes and trends in glacier area and volume in the Austrian Ötztal Alps (1969-1997-2006)

2009 ◽  
Vol 3 (2) ◽  
pp. 205-215 ◽  
Author(s):  
J. Abermann ◽  
A. Lambrecht ◽  
A. Fischer ◽  
M. Kuhn
Keyword(s):  
Length Change ◽  
High Temporal Resolution ◽  
Glacier Area ◽  
Thickness Change ◽  
Additional Information ◽  
Digital Elevation ◽  
Glacier Changes ◽  
The Individual ◽  
Individual Size ◽  
Area And Volume

Abstract. In this study we apply a simple and reliable method to derive recent changes in glacier area and volume by taking advantage of high resolution LIDAR (light detection and ranging) DEMs (digital elevation models) from the year 2006. Together with two existing glacier inventories (1969 and 1997) the new dataset enables us to quantify area and volume changes over the past 37 years at three dates. This has been done for 81 glaciers (116 km2) in the Ötztal Alps which accounts for almost one third of Austria's glacier extent. Glacier area and volume have reduced drastically with significant differences within the individual size classes. Between 1997 and 2006 an overall area loss of 10.5 km2 or 8.2% occurred. Volume has reduced by 1.0 km3 which accounts for a mean thickness change of −8.2 m. The availability of three comparable inventories allows a comprehensive size and altitude dependent analysis of glacier changes but lacks a high temporal resolution. For the comparison of rates of changes between the two different periods (1969 to 1997 with 1997 to 2006) we propose two approaches in this study: a) to estimate mean overall rates of changes (including a period of advance) and b) to extract periods of net-retreat by using additional information (length change and mass balance measurements). Analysis of the resulting acceleration factors reveals that the retreat of volume and mean thickness changes has accelerated significantly more than that of area changes.

How much is a calorie worth? A study of willingness to pay for calorie labels in restaurant menus

2019 ◽  
pp. 1-24
Author(s):  
SANA RAFIQ
Keyword(s):  
Willingness To Pay ◽  
Well Being ◽  
Economic Benefits ◽  
Individual Level ◽  
Additional Information ◽  
Health Related ◽  
The Individual ◽  
Types Of Information ◽  
Caloric Consumption ◽  
The Impact

AbstractWe asked individuals about their willingness to pay (WTP) either: (1) for a mandate requiring restaurants to post calorie information on their menus; or (2) to avoid such a mandate. On average, more people were in in favor of the mandate and were willing to pay four times more than those who were against it, thereby leading to a Kaldor–Hicks improvement from this policy. To ensure robustness, we tested the impact of providing three types of information during individuals’ WTP determinations: (1) visual examples of the proposed calorie labels; (2) data on their effectiveness at the individual level; and (3) data on their wider social and economic benefits. For those in favor, providing a simple visual of the label had no impact on WTP. Data on the individual effectiveness of the labels increased the WTP, while evidence on broader obesity reduction and economic benefits reduced it. For opponents, WTP did not change with provision of additional information except when provided with information on social and economic benefits. Under this condition, the opponents increased their WTP 12-fold to avoid a mandate of this policy. Finally, we measured individual well-being under this policy and found directionally similar results, confirming a net improvement in aggregate welfare. Our results suggest that messaging that focuses on private benefits (providing calorie information so that individuals can effectively choose to reduce excessive caloric consumption) rather than wider public benefits (reduction in overall health-related costs and obesity) is more likely to be effective.

The Effects of Information and Augmentative Communication Technique on Attitudes Toward Nonspeaking Individuals

1991 ◽  
Vol 34 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Carole Wood Gorenflo ◽  
Daniel W. Gorenflo
Keyword(s):  
Physical Disabilities ◽  
Dependent Measure ◽  
Augmentative Communication ◽  
Factual Information ◽  
Additional Information ◽  
Communication Techniques ◽  
Communication Aid ◽  
Communication Technique ◽  
Computer Based ◽  
The Individual

This study investigated the effects of printed factual information and three augmentative communication techniques on attitudes of nondisabled individuals toward nonspeaking persons with physical disabilities. Employing a 3 (augmentative communication techniques) x 2 (presence/absence of information) factorial design, subjects viewed a videotape depicting a nonspeaking adult having a conversation with a normal-speaking individual. Subjects in Condition 1 viewed a tape depicting the nonspeaking individual using unaided communication techniques; Condition 2 subjects viewed the individual using an alphabet board; subjects in Condition 3 viewed the individual using a computer-based voice output communication aid (VOCA). A scale assessing attitudes toward nonspeaking persons, the Attitudes Toward Nonspeaking Persons Scale (ATNP), was developed and validated for purposes of this study and was employed as the dependent measure. Results revealed that subjects expressed more favorable attitudes when provided with the additional information concerning the nonspeaking individual. Attitude favorability also increased with the sophistication of the augmentative communication technique.

scholarly journals Design and implementation of a prototype Human Protein Index.

1982 ◽  
Vol 28 (4) ◽  
pp. 861-866 ◽  
Author(s):  
J Taylor ◽  
N L Anderson ◽  
A E Scandora ◽  
K E Willard ◽  
N G Anderson
Keyword(s):  
Cellular Localization ◽  
Graphical Form ◽  
Two Dimensional ◽  
Reference Pattern ◽  
Two Dimensional Electrophoresis ◽  
Additional Information ◽  
Design And Implementation ◽  
Analysis System ◽  
The Individual ◽  
Dimensional Electrophoresis

Abstract This paper describes information-handling aspects of the TYCHO I analysis system (Clin, Chem. 27: 1807--1820, 1981), which analyzes two-dimensional electrophoresis gels, matches the individual protein spots with those in a reference pattern, and stores various information--including spot measurements, identifications, treatment profiles, set memberships, and comments--in a computerized database. This and additional information such as amino acid composition and cellular localization is then accessible from an interactive program that includes a pictorial user interface and presents much of the data in graphical form. Use of the TYCHO I system is illustrated by examples drawn from analyses of gel patterns from human leukocytes.

Dosimetric evaluation of methyl red radiochromic film for radiation processing

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Awad AL Zahrany ◽  
Khalid Rabaeh ◽  
Molham Eyadeh ◽  
Ahmed Basfar
Keyword(s):  
Gamma Ray ◽  
Dose Range ◽  
Absorbed Dose ◽  
Radiochromic Film ◽  
High Dose ◽  
Methyl Red ◽  
Radiation Processing ◽  
Content Type ◽  
The Stability ◽  
The Impact

Purpose The purpose of this paper is to present a radiochromic film dosimeter containing polyvinyl alcohol (PVA) matrix and various concentrations of methyl red (MR) dye for high dose measurements. Design/methodology/approach The MR-PVA films were exposed to irradiation up to 60 kGy using 60Co source of gamma ray. The ultraviolet and visible regions (UV/VIS) spectrophotometry were used to examine the optical density of pre-and post-irradiated dosimeters at 424 nm. Findings The dose sensitivity of MR-PVA films increases significantly with increasing MR dye concentrations in the dose range of 5 to 60 kGy. The impact of relative humidity, irradiation temperature, dose rate and the stability of the films has been analyzed. The overall uncertainty of the MR-PVA film dosimeter is 6.12% (Double Standard-deviation, 95% confidence level). Practical implications It was found that the MR-PVA films may be used as high dose dosimeter with an acceptable overall uncertainty in routine industrial radiation processing. Originality/value The color bleaching of irradiated MR-PVA films in terms of specific absorbance curves increases significantly with increasing absorbed dose up to 60 kGy.

Recommendation of dose banding of cytotoxics according to pharmacokinetic criteria.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2549-2549
Author(s):  
Etienne Chatelut ◽  
Melanie White-Koning ◽  
Ron H.J. Mathijssen ◽  
Sharyn D. Baker ◽  
Alex Sparreboom
Keyword(s):  
Capacity Planning ◽  
Simple Procedure ◽  
Drug Stability ◽  
Exposure Dose ◽  
Analytical Control ◽  
Individual Dose ◽  
Significant Difference ◽  
Patient Waiting Time ◽  
The Individual

2549 Background: Dose-banding has been recently suggested in order to optimize chemotherapy preparation. Ranges (or bands) of body surface area (BSA) are predefined. The individual dose of a particular patient is calculated according to a single BSA value per band, usually the mid-point of the BSA band in which the actual BSA of the patient lies. Thanks to this simple procedure, chemotherapy provision can be rationalized and chemotherapies can be prepared in advance for drugs with sufficient long-term drug stability. The primary purpose of dose-banding is to reduce patient waiting time and improve capacity planning of the pharmacy production, but additional benefits can also be found, such as reduced potential for medication errors, reduced drug wastage, and prospective quality control of preparations. The objective of this analysis was to compare dose-banding to individual BSA-dosing (current practice) according to pharmacokinetic (PK) criteria. Methods: Dose-banding was defined according to three bands of BSA: BSA<1.7m², 1.7m²≤BSA<1.9m², and BSA≥1.9m² for which the values of 1.55m², 1.80m², and 2.05m² were allocated, respectively. By using individual actual values of clearance of six drugs (cisplatin, docetaxel, paclitaxel, doxorubicin, topotecan, and irinotecan) from a total of 1,206 adult cancer patients, the AUCs corresponding to the two dosing methods were compared to a target value of AUC for each drug. Results: Over all 6 drugs, by using dose-banding the percent change of individual dose in comparison with BSA dosing ranged between -14% and +22%. In terms of capacity to attain the target AUC, there was no significant difference in precision when using dose-banding as compared to BSA-dosing for all drugs except paclitaxel (precision of 23.2% versus 21.8%, respectively). For all drugs including paclitaxel, distributions of AUC values were very similar with both dosing methods. Conclusions: For these 6 drugs and maybe others, dose-banding may be implemented without any risk of increasing interindividual plasma exposure. Dose-banding would make it possible to anticipate chemotherapy preparation and analytical control without any delay for the patients.

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