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Computer tomography image quality control assessment take part of Cuban national legislation, which could be difficult to accomplish for many reasons. This work is part of the set-up verifications of "in house tool" (EvaCT) designed to calculate parameters of quality control of CT images (CCCT) in various manufacturer's phantoms, "at distance". For this, the behavior of the established parameters was studied in 17 studies of the stablished CCCT routine with the Mediso PET/SPECT/CT Anyscan Trio equipment, comparing the results using manufacture´s reference values, and/ or the international recommended parameter´s tolerances. The results of the system were compared numerically with those obtained by the manufacturer, for each available related parameter, in the corresponding protocol, and did not show significant differences (p≥0.05). In general, the system showed a satisfactory behavior, taking as reference the values and tolerances of the manufacturer, CECMED and IAEA. The correlation between quality descriptors established with different methodologies was analyzed. The tool showed correspondence with the manufacturer's results, making available a greater number of parameters and more operational conditions to be evaluated. The mean values ±SD characterize these parameters in the equipment and its phantom, and can be used for periodic, independent and remote CCCT verification. [ABSTRACT FROM AUTHOR]

Evaluation of image quality in digital radiography is important to ensure accurate diagnosis. However, to perform image quality tests accurately and effectively, complex techniques and numerous phantoms are required. The aim of the study was to develop a novel phantom to allow a comprehensive evaluation of image quality in digital radiography. High-Density Polyethylene (HDPE) was used as the main material for the phantom. Physical image quality parameters such as effective Modulation Transfer Function (eMTF), effective Normalized Noise Power Spectra (eNNPS), effective Detective Quantum Efficiency (eDQE), as well as contrast and signal-to-noise ratio (SNR) evaluations can be conducted using the phantom. Preliminary preparation work was carried out through Monte Carlo simulations. The validation of the phantom was performed by comparing with standard phantom results. Physical image quality measurements were performed using an indirect digital radiography system. It was observed that there was a good agreement between the image quality measurement results performed with the standard phantom and the developed phantom. A strong correlation was determined between integrated effective DQE (IeDQE) results (R ≥ 0.97) obtained with HDPE and PMMA phantom. Simulation results regarding the transmission factor showed that HDPE could be an alternative to Polymethyl Methacrylate (PMMA) as a phantom material. • A phantom was prepared for image quality measurements in digital radiology. • Image quality results were compatible with that obtained from the standard phantom. • MC simulations show that HDPE could be an alternative to PMMA as a phantom material. [ABSTRACT FROM AUTHOR]

Radionuclide uptake and contrast for positron emission tomography-computed tomography (PET-CT) images have been assessed in this study using NEMA image quality phantom filled with background activity concentration of 5.3 kBq/mL fluorodeoxyglucose (F-18 FDG). Spheres in the phantom were filled in turns with water to mimic cold lesions and FDG of higher activity concentrations to mimic tumor sites. Transaxial image slices were acquired on the PET-CT system and used for the evaluation of mean standard uptake value (SUVmean) and contrasts for varying sphere sizes at different activity concentrations of 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL. For spheres of same sizes, SUVmean increased with increase in activity concentration. SUVmean was increased by 80.6%, 83.5%, 63.2%, 87.4%, and 63.2% when activity concentrations of spheres with a diameter of 1.3 cm, 1.7 cm, 2.2 cm, 2.8 cm, and 3.7 cm, respectively, were increased from 10.6 kBq/mL to 42.4 kBq/mL. Average percentage contrast between cold spheres (cold lesions) and background activity concentration was estimated to be 89.96% for the spheres. Average contrast for the spheres containing 10.6 kBq/mL, 21.2 kBq/mL, and 42.4 kBq/mL were found to be 110.92%, 134.48%, and 150.52%, respectively. The average background contrast variability was estimated to be 2.97% at 95% confidence interval (P < 0.05). [ABSTRACT FROM AUTHOR]

The purpose of this work is to assess the image quality of dental digital systems with computed radiography (phosphor plate) and direct radiography (charge-coupled-device sensor), by developing a specific dental phantom named RADEN and software to analyze the phantom image automatically. The phantom developed to evaluate the image quality of dental radiographic equipment has specific test objects of contrast-detail combinations appropriated for the resolution of the dental digital systems. The image quality is evaluated by using contrast-detail curves and an image quality index. The phantom was made of a square aluminum block 7.5 x 7.5 cm that has a lodge of size 3.2 X 3.2 cm for fixing the sensor of the digital dental system, and it contains specific test objects of contrast-detail combinations that are cylindrical holes. The diameters of the holes ranged from 0.3 to 1.6 mm, and the depths ranged from 0.14 to 1.28 mm; these ranges for the diameters and depths are suitable for resolution of the dental digital systems and the contrast attenuation curves of the X-radiation, and the results are sensitive to the operating conditions of the dental radiographic system. We have also developed specific software to analyze the RADEN phantom image automatically obtained by the digital radiographic equipment. The algorithms are based on digital image processing techniques, and they have been implemented in a user-friendly tool with a graphical interface. [ABSTRACT FROM AUTHOR]

The development of specific phantoms to study the image obtained by computerized and direct digital radiographic equipment is the objective of this work to characterize the physical properties of the image chain. We have developed a specific phantom, named RACON, that is applied to an acceptance and constancy test to assess the image quality of digital radiographic equipment. This phantom has been designed with different test objects recommended by international and national associations (IEC-61223-2-9, RD 1976-1999) as low-contrast objects varying in diameter and size for threshold contrast resolution, a high-resolution test for the limiting spatial resolution, a dynamic step wedge for the dynamic range of the system, and a homogeneity zone and alignment marks for the position and size of the radiation field. Furthermore, we have developed specific software to analyze automatically and objectively the phantom images. The algorithms are based on digital image processing techniques, and they have been specifically designed for each test object in the phantom. The developed phantom is sensitive enough to the operating conditions of the radiographic digital system, and the automatic image evaluation allows the objective study of the global state of the image system. [ABSTRACT FROM AUTHOR]