Small Angle Gamma Ray Scatter: What Is The Impact On Image Quality

10.5580/2331 ◽  
2008 ◽  
Vol 4 (2) ◽  
Keyword(s):  
Image Quality ◽  
Small Angle ◽  
Gamma Ray ◽  
The Impact

scholarly journals P‐13.5: The impact of Gate Loading on Image Quality for large & middle size AM‐OLED display devices

2021 ◽  
Vol 52 (S1) ◽  
pp. 643-646
Author(s):  
Yang Guobo ◽  
Qiu Haijun ◽  
Huang Weiyun ◽  
Yang Yuqing ◽  
Long Yue ◽  
...  
Keyword(s):  
Image Quality ◽  
Display Devices ◽  
The Impact ◽  
Oled Display

scholarly journals Modeling and image quality enhancement for dynamic compressive imaging system

2021 ◽  
Vol 15 ◽  
pp. 174830262110080
Author(s):  
Changjun Zha* ◽  
Qian Zhang* ◽  
Huimin Duan
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Quality Enhancement ◽  
Target Image ◽  
Compressive Imaging ◽  
Image Quality Enhancement ◽  
System A ◽  
Single Column ◽  
The Impact

Traditional single-pixel imaging systems are aimed mainly at relatively static or slowly changing targets. When there is relative motion between the imaging system and the target, sizable deviations between the measurement values and the real values can occur and result in poor image quality of the reconstructed target. To solve this problem, a novel dynamic compressive imaging system is proposed. In this system, a single-column digital micro-mirror device is used to modulate the target image, and the compressive measurement values are obtained for each column of the image. Based on analysis of the measurement values, a new recovery model of dynamic compressive imaging is given. Differing from traditional reconstruction results, the measurement values of any column of vectors in the target image can be used to reconstruct the vectors of two adjacent columns at the same time. Contingent upon characteristics of the results, a method of image quality enhancement based on an overlapping average algorithm is proposed. Simulation experiments and analysis show that the proposed dynamic compressive imaging can effectively reconstruct the target image; and that when the moving speed of the system changes within a certain range, the system reconstructs a better original image. The system overcomes the impact of dynamically changing speeds, and affords significantly better performance than traditional compressive imaging.

scholarly journals Evaluation of Organ Dose and Image Quality Metrics of Pediatric CT Chest-Abdomen-Pelvis (CAP) Examination: An Anthropomorphic Phantom Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2047
Author(s):  
Nor Azura Muhammad ◽  
Zunaide Kayun ◽  
Hasyma Abu Hassan ◽  
Jeannie Hsiu Ding Wong ◽  
Kwan Hoong Ng ◽  
...  
Keyword(s):  
Image Quality ◽  
Multidetector Ct ◽  
Organ Dose ◽  
Quality Metrics ◽  
Ct Scanner ◽  
Image Quality Metrics ◽  
Tube Current ◽  
Significant Difference ◽  
Noise Ratio ◽  
The Impact

The aim of this study is to investigate the impact of CT acquisition parameter setting on organ dose and its influence on image quality metrics in pediatric phantom during CT examination. The study was performed on 64-slice multidetector CT scanner (MDCT) Siemens Definition AS (Siemens Sector Healthcare, Forchheim, Germany) using various CT CAP protocols (P1–P9). Tube potential for P1, P2, and P3 protocols were fixed at 100 kVp while P4, P5, and P6 were fixed at 80 kVp with used of various reference noise values. P7, P8, and P9 were the modification of P1 with changes on slice collimation, pitch factor, and tube current modulation (TCM), respectively. TLD-100 chips were inserted into the phantom slab number 7, 9, 10, 12, 13, and 14 to represent thyroid, lung, liver, stomach, gonads, and skin, respectively. The image quality metrics, signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were obtained from the CT console. As a result, this study indicates a potential reduction in the absorbed dose up to 20% to 50% along with reducing tube voltage, tube current, and increasing the slice collimation. There is no significant difference (p > 0.05) observed between the protocols and image metrics.

scholarly journals Effect of Gamma-Ray Energy on Image Quality in Passive Gamma Emission Tomography of Spent Nuclear Fuel

2019 ◽  
Vol 66 (1) ◽  
pp. 487-496
Author(s):  
Camille Belanger-Champagne ◽  
Pauli Peura ◽  
Paula Eerola ◽  
Tapani Honkamaa ◽  
Timothy White ◽  
...  
Keyword(s):  
Image Quality ◽  
Nuclear Fuel ◽  
Spent Nuclear Fuel ◽  
Gamma Ray ◽  
Emission Tomography ◽  
Gamma Emission

scholarly journals Two simple criteria to estimate an objective’s performance when imaging in non design tissue clearing solutions

2019 ◽  
Author(s):  
Sabrina Asteriti ◽  
Valeria Ricci ◽  
Lorenzo Cangiano
Keyword(s):  
Image Quality ◽  
High Refractive Index ◽  
Optimal Conditions ◽  
Point Spread Functions ◽  
Tissue Clearing ◽  
Fluorescent Microscope ◽  
Immersion Medium ◽  
Quality Degradation ◽  
Point Spread ◽  
The Impact

ABSTRACTTissue clearing techniques are undergoing a renaissance motivated by the need to image fluorescence deep in biological samples without physical sectioning. Optical transparency is achieved by equilibrating tissues with high refractive index (RI) solutions, which require expensive optimized objectives to avoid aberrations. One may thus need to assess whether an available objective is suitable for a specific clearing solution, or the impact on imaging of small mismatches between cleared sample and objective design RIs. We derived closed form approximations for image quality degradation versus RI mismatch and other parameters available to the microscopist. We validated them with computed (and experimentally confirmed) aberrated point spread functions, and by imaging fluorescent neurons in high RI solutions. Crucially, we propose two simple numerical criteria to establish: (i) the degradation in image quality (brightness and resolution) from optimal conditions of any clearing solution/objective combination; (ii) which objective, among several, achieves the highest resolution in a given immersion medium. These criteria apply directly to the widefield fluorescent microscope but are also closely relevant to more advanced microscopes.

scholarly journals Annihilating dark matter search with 12 yr of Fermi LAT data in nearby galaxy clusters

2021 ◽  
Vol 502 (3) ◽  
pp. 4039-4047
Author(s):  
Charles Thorpe-Morgan ◽  
Denys Malyshev ◽  
Christoph-Alexander Stegen ◽  
Andrea Santangelo ◽  
Josef Jochum
Keyword(s):  
Dark Matter ◽  
Galaxy Clusters ◽  
Gamma Ray ◽  
Nearby Galaxy ◽  
Galactic Latitude ◽  
Dark Matter Search ◽  
Dwarf Spheroidal Galaxies ◽  
Characteristic Signal ◽  
Small Factor ◽  
The Impact

ABSTRACT Galaxy clusters are the largest virialized objects in the Universe and, as such, have high dark matter (DM) concentrations. This abundance of dark matter makes them promising targets for indirect DM searches. Here we report the details of a search, utilizing almost 12 yr of Fermi/LAT data, for gamma-ray signatures from the pair annihilation of WIMP dark matter in the GeV energy band. From this, we present the constraints on the annihilation cross-section for the $b\overline{b}$, W+W−, and γγ channels, derived from the non-detection of a characteristic signal from five nearby, high Galactic latitude, galaxy clusters (Centaurus, Coma, Virgo, Perseus, and Fornax). We discuss the potential of a boost to the signal due to the presence of substructures in the DM haloes of selected objects, as well as the impact of uncertainties in DM profiles on the presented results. We assert that the obtained limits are, within a small factor, comparable to the best available limits of those based on Fermi/LAT observations of dwarf spheroidal galaxies.

Quantitative measurement of small-angle gamma ray scattering from water, nylon, and Lucite

1989 ◽  
Vol 16 (6) ◽  
pp. 851-857 ◽  
Author(s):  
D. A. Bradley ◽  
D. R. Dance ◽  
S. H. Evans ◽  
C. H. Jones
Keyword(s):  
Small Angle ◽  
Quantitative Measurement ◽  
Gamma Ray ◽  
Ray Scattering

Impact of total variation regularized expectation maximization reconstruction on the image quality of 68Ga-PSMA PET: a phantom and patient study

2021 ◽  
pp. 20201356
Author(s):  
Feng-Jiao Yang ◽  
Shu-Yue Ai ◽  
Runze Wu ◽  
Yang Lv ◽  
Hui-Fang Xie ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Image Quality ◽  
Total Variation ◽  
Expectation Maximization ◽  
Image Noise ◽  
Psma Pet ◽  
Pet Ct ◽  
Digital Pet ◽  
The Impact

Objectives: To investigate the impact of total variation regularized expectation maximization (TVREM) reconstruction on the image quality of 68Ga-PSMA-11 PET/CT using phantom and patient data. Methods: Images of a phantom with small hot sphere inserts and 20 prostate cancer patients were acquired with a digital PET/CT using list-mode and reconstructed with ordered subset expectation maximization (OSEM) and TVREM with seven penalisation factors between 0.01 and 0.42 for 2 and 3 minutes-per-bed (m/b) acquisition. The contrast recovery (CR) and background variability (BV) of the phantom, image noise of the liver, and SUVmax of the lesions were measured. Qualitative image quality was scored by two radiologists using a 5-point scale (1-poor, 5-excellent). Results: The performance of CR, BV, and image noise, and the gain of SUVmax was higher for TVREM 2 m/b groups with the penalization of 0.07 to 0.28 compared to OSEM 3 m/b group (all p < 0.05). The image noise of OSEM 3 m/b group was equivalent to TVREM 2 and 3 m/b groups with a penalization of 0.14 and 0.07, while lesions’ SUVmax increased 15 and 20%. The highest qualitative score was attained at the penalization of 0.21 (3.30 ± 0.66) for TVREM 2 m/b groups and the penalization 0.14 (3.80 ± 0.41) for 3 m/b group that equal to or greater than OSEM 3 m/b group (2.90 ± 0.45, p = 0.2 and p < 0.001). Conclusions: TVREM improves lesion contrast and reduces image noise, which allows shorter acquisition with preserved image quality for PSMA PET/CT. Advances in knowledge: TVREM reconstruction with optimized penalization factors can generate higher quality PSMA-PET images for prostate cancer diagnosis.

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