scholarly journals Evaluation of the performance of radiological monitors in use, cities Salvador (BA) and Florianópolis (SC)

2019 ◽  
Vol 7 (3) ◽  
Author(s):  
Igor Fernando Modesto Garcia ◽  
Paulo Mauricio Almeida Geambastiani ◽  
Mário De Jesus Ferreira ◽  
Eric Matos Macedo ◽  
Marcus Vínicius Teixeira Navarro ◽  
...  
Keyword(s):  
Quality Control ◽  
Image Quality ◽  
Compliance Rate ◽  
Internal Reflection ◽  
Geometric Distortion ◽  
Contrast Resolution ◽  
Low Contrast ◽  
Room Illumination ◽  
High Illumination ◽  
General Aspects

Evaluate the performance of the monitors used for diagnosis based on the parameters defined by AAMP. Materials and Methods: Using calibrated instrumentation traceable to NIST and RBC, were evaluated in 15 monitors, according to the procedures described in AAMP's report 03 and the Spanish protocol in the following parameters: the general aspects of image quality, geometric distortion, screen reflection and room illumination, luminance response, luminance dependence, spatial and low contrast resolution, noise, internal reflection blanking and screen chromaticity. Results: 100% compliance for geometric distortion tests and 0% compliance for the luminance dependence test. Conclusions: There are nonspecific monitors for diagnosis being used for these purposes, without routinely checking tests, in rooms with high illumination and dirt on the screens and the non-implementation or inadequacy of acceptance and quality control tests. The monitors declared by the manufacturers as diagnostic specific on average showed a higher compliance rate

scholarly journals [OA161] Quantification of low contrast resolution and noise of dual energy CT using software for automated quality control

2018 ◽  
Vol 52 ◽  
pp. 61-62
Author(s):  
Bartosz Pawalowski ◽  
Hubert Szweda ◽  
Piotr Romanski ◽  
Krzysztof Matuszewski ◽  
Urszula Sobocka-Kurdyk ◽  
...  
Keyword(s):  
Quality Control ◽  
Dual Energy ◽  
Dual Energy Ct ◽  
Contrast Resolution ◽  
Low Contrast ◽  
Automated Quality Control

scholarly journals A proposal for a quality control protocol in breast CT with synchrotron radiation

2018 ◽  
Vol 52 (3) ◽  
pp. 329-336 ◽  
Author(s):  
Adriano Contillo ◽  
Anna Veronese ◽  
Luca Brombal ◽  
Sandro Donato ◽  
Luigi Rigon ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Quality Control ◽  
Synchrotron Radiation ◽  
Image Quality ◽  
Ct Number ◽  
Breast Ct ◽  
Low Contrast ◽  
Control Protocol ◽  
Custom Made ◽  
Quality Measurements

Abstract Background The SYRMA-3D collaboration is setting up the first clinical trial of phase-contrast breast CT with synchrotron radiation at the Elettra synchrotron facility in Trieste, Italy. In this communication, a quality control protocol for breast CT is proposed, and a first test of image quality measurements is performed by means of a custom-made radiographic phantom. Materials and methods A set of projections is acquired and used to perform a CT reconstruction of two selected portions of the phantom. Such portions contain a uniform layer of water and a set of radiographic inserts, respectively. Together, they allow to perform several image quality measurements, namely CT number linearity, reconstruction accuracy, uniformity, noise, and low contrast resolution. All measurements are repeated at different beam energies in the range of interest, and at two different dose values. Results Measurements show a good linearity in the soft tissue range, paired to a high accuracy of the CT number reconstruction. Uniformity and noise measurements show that reconstruction inhomogeneities are bound to a few percent of the average pixel values. However, low contrast detectability is limited to the higher portion of the explored energy range. Conclusions The results of the measurements are satisfactory in terms of their quality, feasibility and reproducibility. With minimal modifications, the phantom is promising to allow a set of image quality measurements to be used in the upcoming clinical trial.

scholarly journals Comparison of image quality of an abdominal acquisition mode of angiography systems from four major manufacturers

2018 ◽  
Vol 5 (2) ◽  
pp. 6
Author(s):  
Lucie Sukupova ◽  
Jan Rydlo ◽  
Ondrej Hlavacek ◽  
Daniel Vedlich ◽  
Jan H. Peregrin
Keyword(s):  
Image Quality ◽  
Line Pair ◽  
Obese Patients ◽  
Clinical Images ◽  
Contrast Resolution ◽  
Low Contrast ◽  
System A ◽  
Acquisition Mode ◽  
Air Kerma Rate

Objective: The aim of this study was to compare image quality of different abdominal acquisition modes under conditions simulating obese patients whose images suffer more from noise and scatter radiation. Images were acquired in clinically used acquisition modes on the static and dynamic phantom for four angiography systems.Methods: A LEGO cart with 34 cm of PMMA and Pro-RTG Fluo18 phantom were used to simulate obese patients. The low-contrast resolution was assessed subjectively by two readers and objectively using signal-difference-to-noise ratio (SDNR) and using SDNR to air kerma rate. The line-pair resolution was assessed using the transmitted contrast value for line-pair groups.Results: Systems use different exposure parameters and dose but they differ in postprocessing too. Qualitative and quantitative assessments of noise produced similar results, images produced by systems A and C were noisier than by systems B and D. Highest SDNR was provided by System B, whilst System A produced the lowest values, which were almost the same for objects with different contrast. The image quality was affected mainly by frame lengths and postprocessing, but also by the dose. The images of the static phantom were better compared to the images of the dynamic phantom, which was an expected result.Conclusions: It was possible to identify image quality differences and to characterize features of postprocessing from measurements on standardized objects. A potential for optimization on some systems was identified, although further work, including assessment of clinical images, would be needed as part of the optimization process.

Improvements to image quality using hybrid and model-based iterative reconstructions: a phantom study

2016 ◽  
Vol 58 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Marie-Louise Aurumskjöld ◽  
Kristina Ydström ◽  
Anders Tingberg ◽  
Marcus Söderberg
Keyword(s):  
Image Quality ◽  
Radiation Dose ◽  
Iterative Reconstruction ◽  
Power Spectra ◽  
Reconstruction Method ◽  
Noise Power ◽  
Contrast Resolution ◽  
Low Contrast ◽  
Model Based ◽  
Reconstruction Methods

Background The number of computed tomography (CT) examinations is increasing and leading to an increase in total patient exposure. It is therefore important to optimize CT scan imaging conditions in order to reduce the radiation dose. The introduction of iterative reconstruction methods has enabled an improvement in image quality and a reduction in radiation dose. Purpose To investigate how image quality depends on reconstruction method and to discuss patient dose reduction resulting from the use of hybrid and model-based iterative reconstruction. Material and Methods An image quality phantom (Catphan® 600) and an anthropomorphic torso phantom were examined on a Philips Brilliance iCT. The image quality was evaluated in terms of CT numbers, noise, noise power spectra (NPS), contrast-to-noise ratio (CNR), low-contrast resolution, and spatial resolution for different scan parameters and dose levels. The images were reconstructed using filtered back projection (FBP) and different settings of hybrid (iDose4) and model-based (IMR) iterative reconstruction methods. Results iDose4 decreased the noise by 15–45% compared with FBP depending on the level of iDose4. The IMR reduced the noise even further, by 60–75% compared to FBP. The results are independent of dose. The NPS showed changes in the noise distribution for different reconstruction methods. The low-contrast resolution and CNR were improved with iDose4, and the improvement was even greater with IMR. Conclusion There is great potential to reduce noise and thereby improve image quality by using hybrid or, in particular, model-based iterative reconstruction methods, or to lower radiation dose and maintain image quality.

scholarly journals Evaluation of Self-Produced Phantom Usafulness for image Quality Control of Radiation Generator for Diagnosis

2021 ◽  
Vol 12 (6) ◽  
pp. 828-834
Author(s):  
Ye-Won Park Et.al
Keyword(s):  
Quality Control ◽  
Medical Care ◽  
Qualitative Evaluation ◽  
High Contrast ◽  
Contrast Resolution ◽  
Low Contrast ◽  
X Ray ◽  
Image Quality Control ◽  
Exposure Dosage ◽  
The Difference

Background/Objectives: Quality control can improve the quality of medical care along with the stability of diagnostic X-ray generator. Regular quality control provides reliable quality control of the machine and maintains consistency of general imaging using radiation for efficient diagnosis. Methods/Statistical analysis: A phantom for quality control of diagnostic X-ray generator was produced using a 3D printer. Quantitative and qualitative evaluation of the phantom utility was conducted by modifying images acquired using S and D companies’ tools with Source to Image-Receptor Distance (SID) levels ranging between 130 cm and 180 cm. The evaluation indices were determined based on the analysis of field compliance, uniformity, low and high-contrast resolution, and linearity. Findings: The evaluation was conducted by acquiring and changing the radiographic image to SIDs between 130 cm and 180 cm using the indigenous phantom. The field compliance of S and D companies in terms of quantitative evaluation indices was both appropriate within ± 1% according to the SID change. To ensure a uniform SID 130 cm, the internal and external means of S company were 893 and 943, respectively, while those of the D company were 228.1 and 261.4, respectively. At an SID of 180 cm, the internal and external means of the S company were 928.1 and 958.4, respectively, while those of the D company were 257.2 and 299, respectively. A characteristic of the DR system was identified to ensure linearity, altered exposure dosage according to the step wedge height, and the difference in SI values according to the characteristics of the equipment and linearity. The qualitative evaluation indices were determined by identifying the size of the hole under high-contrast resolution up to 0.8㎜ and the bar size up to 1.6 lp/㎜. The low contrast resolution was evaluated with a C-D pattern, and at SID 130 cm, the S company scored 124.6 points and the D company 116 points, and at 180 cm, the S company scored 111.4 and the D company 104.6 points. Improvements/Applications: The utility of the homegrown phantom in quality control was confirmed for each index. The medical institutions are required to introduce quality control regulations for general image examination using radiation. It is helpful to efficiently manage old equipment and improve public health and medical care by linking with the health insurance fee.

scholarly journals Collimation and Exposure Parameter Influence Image Quality and Potential Radiation Dose to the Eye Lens of Personnel in Computed Radiography of the Canine Pelvis

2021 ◽  
Vol 8 ◽  
Author(s):  
Malene Bisgaard ◽  
Fintan J. McEvoy ◽  
Dorte Hald Nielsen ◽  
Clara Allberg ◽  
Anna V. Müller ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Image Quality ◽  
Radiation Dose ◽  
Scattered Radiation ◽  
Computed Radiography ◽  
Eye Lens ◽  
Image Sharpness ◽  
Contrast Resolution ◽  
Low Contrast ◽  
Pelvic Radiographs

Introduction: The purpose of this study was to evaluate the effect of collimation on image quality and radiation dose to the eye lenses of the personnel involved in computed radiography of the canine pelvis.Materials and Methods: A retrospective study of canine pelvic radiographs (N = 54) was undertaken to evaluate the relationship between image quality and the degree of field the collimation used. This was followed by a prospective cadaver study (N = 18) that assessed the effects on image quality and on scattered radiation dose of different collimation field areas and exposure parameters. All radiographs were analyzed for image quality using a Visual Grading Analysis (VGA) with three observers. Finally, the potential scattered radiation dose to the eye lens of personnel restraining a dog for pelvic radiographs was measured.Results: The retrospective study showed a slightly better (statistically non-significant) VGA score for the radiographs with optimal collimation. Spatial and contrast resolution and image sharpness showed the greatest improvement in response to minimizing the collimation field. The prospective study showed slightly better VGA scores (improved image quality) with the optimal collimation. Increasing the exposure factors especially the tube current and exposure time (mAs) resulted in improved low contrast resolution and less noise in the radiographs. The potential eye lens radiation dose increased by 14, 28, and 40% [default exposures, increased the tube peak potential (kVp), increased mAs, respectively] as a result of reduced collimation (increased beam size).Conclusion: The degree of collimation has no statistically significant on image quality in canine pelvic radiology for the range of collimation used but does have an impact on potential radiation dose to personnel in the x-ray room. With regard to radiation safety, increases in kVp are associated with less potential scatter radiation exposure compared to comparable increases in mAs.

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