Implications of laser shot dosage on image quality in LA-ICP-QMS imaging

Author(s):  
Martin Šala ◽  
Vid Simon Šelih ◽  
Ciprian C. Stremtan ◽  
Tudor Tămaş ◽  
Johannes T. van Elteren

Higher dosages in LA-ICP-QMS imaging increases image quality; especially noticeable for low elemental concentrations, and generally dominates the slight loss in spatial resolution.

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2275
Author(s):  
Hae Gyun Lim ◽  
Hyung Ham Kim ◽  
Changhan Yoon

High-frequency ultrasound (HFUS) imaging has emerged as an essential tool for pre-clinical studies and clinical applications such as ophthalmic and dermatologic imaging. HFUS imaging systems based on array transducers capable of dynamic receive focusing have considerably improved the image quality in terms of spatial resolution and signal-to-noise ratio (SNR) compared to those by the single-element transducer-based one. However, the array system still suffers from low spatial resolution and SNR in out-of-focus regions, resulting in a blurred image and a limited penetration depth. In this paper, we present synthetic aperture imaging with a virtual source (SA-VS) for an ophthalmic application using a high-frequency convex array transducer. The performances of the SA-VS were evaluated with phantom and ex vivo experiments in comparison with the conventional dynamic receive focusing method. Pre-beamformed radio-frequency (RF) data from phantoms and excised bovine eye were acquired using a custom-built 64-channel imaging system. In the phantom experiments, the SA-VS method showed improved lateral resolution (>10%) and sidelobe level (>4.4 dB) compared to those by the conventional method. The SNR was also improved, resulting in an increased penetration depth: 16 mm and 23 mm for the conventional and SA-VS methods, respectively. Ex vivo images with the SA-VS showed improved image quality at the entire depth and visualized structures that were obscured by noise in conventional imaging.


2021 ◽  
pp. 110012
Author(s):  
Eu Hyun Kim ◽  
Moon Hyung Choi ◽  
Young Joon Lee ◽  
Dongyeob Han ◽  
Mahmoud Mostapha ◽  
...  

2017 ◽  
Vol 8 (2) ◽  
pp. 87-91
Author(s):  
Samsun Samsun ◽  
Legia Prananto ◽  
Novita Wulandari

The picture quality get from CT Scan of Thorax which required optimal parameter selection that’s right, one of them the selection of slice thickness. The method taken from theses that have been publish in the year 2013. The results of the research show the percentage of the value of the average spatial resolution of 2.5 mm slice thickness is (33.3%), noise (17.8%), artefact (1%). On the thickness of the slices 5 mm spatial resolution is (17%), noise (8.9%), artefacts (0%). On the thickness of slices of 7.5 mm spatial resolution is (8.9%), noise (11.1%), artefacts (53.3%). While the thickness of the slices the spatial resolution is 10 mm (8.9%), noise (22.2%), artefacts (68.9%). Based on the research results obtained the conclusion that thickness 2.5 mm slices on Thorax CT-Scan images produce better picture quality than with the thickness of the slices 5 mm, 7.5 mm, 10 mm, because the spatial resolution is more clear so as to reduce noise and artifacts.


Author(s):  
Miri Weiss Cohen ◽  
John A. Kennedy ◽  
Archil Pirmisashvili ◽  
Gleb Orlikov

This paper describes an automatic system for analyzing phantom images from two types of PET/CT scanners. The system was developed for the purpose of obtaining tomographic image quality parameters, which determine a number of different performance parameters, primarily scanner sensitivity, tomographic uniformity, contrast and spatial resolution. The system provides a method for generating and altering image masks used for the analysis of PET images, which are then automatically aligned with the PET data. The system automatically generates Quality Control (QC) reports and is currently being used at clinical PET/CT center.


1986 ◽  
Vol 27 (4) ◽  
pp. 467-479 ◽  
Author(s):  
B. Nielsen ◽  
G. Fagerberg

Some of the parameters determining image quality in mammography are analyzed: the effects of primary photon spectra, focal spot size and screen-film systems on spatial resolution are discussed as are scattered radiation, development temperature and absorbed dose. The parameters limiting spatial resolution and contrast are evaluated for the standard and magnification techniques. Methods of reducing scattered radiation to improve contrast are evaluated. Scatter to primary ratios for different scatter reducing methods are compared, using the physical quantity energy imparted. For the standard technique the spatial resolution has been found to be limited by the fluorescent screen. With magnification technique the focal spot is the weakest link for the spatial resolution. The contrast is mainly set by the amount of scatter using the standard technique considering the use of a low tube potential (∼25 kVp). Using the magnification technique the amount of scatter is so small, that the tube potential is the limiting factor. We have found the optimized standard mammographic technique to be achieved under the following conditions: 25 kVp, 0.3 to 0.6 mm focal spot, film-focus distance 500 mm, anti-scatter grid, developing temperature 36 to 38°C and 4 minutes total processing time with the screen-film system we have used. In magnification technique an air gap of at least 20 mm is desired. With an FFD of about 500 mm this will give a magnification ratio of 1.8 to 2.0 and a 0.1 mm × 0.1 mm focus spot is mandatory. With this technique, it is necessary to use a faster screen-film system than that used in standard mammography.


2016 ◽  
Vol 30 (7) ◽  
pp. 927-932 ◽  
Author(s):  
Vilmos Kertesz ◽  
John F. Cahill ◽  
Gary J. Van Berkel

2016 ◽  
Vol 78 (6-7) ◽  
Author(s):  
Varin Chouvatut ◽  
Ekkarat Boonchieng

Radiographic image quality is important in the medical field since it can increase the visibility of anatomical structures and even improve the medical diagnosis. Because the image quality depends on contrast, noise, and spatial resolution, images with low contrast, a lot of noises, or low resolution will decrease image quality, leading to an incorrect diagnosis. Therefore, radiographic images should be enhanced to facilitate medical expertise in making correct diagnosis. In this paper, radiographic images are enhanced by hybrid algorithms based on the idea of combining three image processing techniques: Contrast Limited Adaptive Histogram Equalization for enhancing image contrast, Median Filter for removing noises, and Unsharp Masking for increasing spatial resolution. Two series of medical images consisting of 20 x-ray images and 20 computed radiography images are enhanced with this method. Peak Signal to Noise Ratio (PSNR) and image contrast are computed in order to measure image quality. The results indicate that the enhanced images have better PSNR.


Author(s):  
Eric P. Visser ◽  
Anita A. Harteveld ◽  
Antoi P.W. Meeuwis ◽  
Jonathan A. Disselhorst ◽  
Freek J. Beekman ◽  
...  

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