An Automatic System for Analyzing Phantom Images to Determine the Reliability of PET/SPECT Cameras

2015 ◽  
Author(s):  
Miri Weiss Cohen ◽  
John A. Kennedy ◽  
Archil Pirmisashvili ◽  
Gleb Orlikov
Keyword(s):  
Quality Control ◽  
Image Quality ◽  
Spatial Resolution ◽  
Automatic System ◽  
Quality Parameters ◽  
Tomographic Image ◽  
Performance Parameters ◽  
Pet Ct ◽  
Ct Scanners

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.

scholarly journals Comparison of Image Quality and Spatial Resolution Between 18F, 68Ga and 64Cu Phantom Measurements Using a Digital Biograph Vision PET/CT

2022 ◽  
Author(s):  
Anja Braune ◽  
Liane Oehme ◽  
Robert Freudenberg ◽  
Frank Hofheinz ◽  
Jörg van den Hoff ◽  
...  
Keyword(s):  
Image Quality ◽  
Spatial Resolution ◽  
Ct Scans ◽  
Reconstruction Method ◽  
Recovery Coefficient ◽  
Positron Energy ◽  
Pet Ct ◽  
The Individual ◽  
The Impact

Abstract Background: The PET nuclide and reconstruction method can have a considerable influence on spatial resolution and image quality of PET/CT scans, which can, for example, influence the diagnosis in oncology. The individual impact of the positron energy of 18F, 68Ga and 64Cu on spatial resolution and image quality of PET/CT scans acquired using a clinical, digital scanner was compared. Furthermore, the impact of different reconstruction parameters on image quality and spatial resolution was evaluated for 18F-FDG PET/CT scans acquired with a scanner of the newest generation. Methods: PET/CT scans of a Jaszczak phantom and a NEMA PET body phantom, filled with 18F-FDG, 68Ga-HCl and 64Cu-HCl, respectively, were performed on a Siemens Biograph Vision. Images were assessed using spatial resolution and image quality (Recovery Coefficients (RC), coefficient of variation within the background, Contrast Recovery Coefficient (CRC), Contrast-Noise-Ratio (CNR), and relative count error in lung insert). In a subsequent analysis, the scan of the NEMA PET body phantom filled with 18F-FDG was reconstructed applying different parameters (with/without the application of Point Spread Function (PSF), Time of Flight (ToF) or post-filtering; matrix size). Spatial resolution and quantitative image quality were compared between reconstructions. Results: We found that image quality was comparable between 18F-FDG and 64Cu-HCl PET/CT measurements featuring similar maximal endpoint energy. In comparison, RC, CRC and CNR were worse in 68Ga-HCl data, despite similar count rates. Spatial resolution was up to 18 % worse in 68Ga-HCl compared to 18F-FDG images. Post-filtering of 18F-FDG acquisitions changed image quality the most and reduced spatial resolution by 52 % if a Gaussian filter with 5 mm FWHM was applied. ToF measurements especially improved the recovery of the smallest lesion (RCmean = 1.07 compared to 0.65 without ToF) and improved spatial resolution by 29 %.Conclusions: The positron energy of PET nuclides influences spatial resolution and image quality of digital PET/CT scans. Image quality of 68Ga-HCl PET/CT images was worse compared to 18F-FDG and 64Cu-HCl, respectively, despite similar count rates. Reconstruction parameters have a high impact on image quality and spatial resolution and should be considered when comparing images of different scanners or centers.

scholarly journals PENGUKURAN KUALITAS CITRA DIGITAL COMPUTED RADIOGRAPHY MENGGUNAKAN PROGRAM PENGOLAH CITRA

2016 ◽  
Vol 12 (2) ◽  
pp. 161-168 ◽  
Author(s):  
D. R. Ningtias ◽  
S. Suryono ◽  
S. Susilo
Keyword(s):  
Quality Control ◽  
Image Quality ◽  
Transfer Function ◽  
Spatial Resolution ◽  
Digital Image ◽  
Modulation Transfer Function ◽  
Computed Radiography ◽  
Modulation Transfer ◽  
Cr System

Penelitian yang telah dilakukan adalah pembuatan dan penghitungan kualitas citra digital menggunakan program Modulation Transfer Function (MTF) pada sistem Computed Radiography (CR) untuk kegiatan Quality Control (QC). MTF dapat digunakan untuk menganalisis resolusi spasial citra digital secara akurat. Pada penelitian ini menggunakan phantom yang terbuat dari tembaga berukuran 15x15 cm dengan ketebalan 1 mm. Phantom dieksposi dengan variasi tegangan 50 kV, 60 kV, 70 kV dan 81 kV dan masing-masing dilakukan variasi arus. Data yang diperoleh berupa file citra digital radiografi format DICOM yang kemudian dilakukan analisis kualitas citranya menggunakan PC diluar sistem CR dengan metode MTF. Metode ini sangat efisien dalam melakukan QC resolusi spasial secara kuantitatif sehingga dapat digunakan untuk menilai kualitas pesawat CR. Hasil pengukuran menunjukkan bahwa semakin tinggi tegangan yang digunakan, maka kualitas citra semakin baik dengan arus optimal pada rentang 4-8 mAs dengan rata-rata nilai resolusi spasial 7,26 lp/mm.The research was analyzing of digital image quality by using Modulation Transfer Function (MTF) on Computed Radiography (CR) system for Quality Control (QC). MTF can be used for analyzing digital image spatial resolution accurately. The research used phantom that made of 15x15 cm2 copper and 1 mm thickness. The phantom was expounded with voltage variations by 50 kV, 60 kV, 70 kV dan 81 kV and each of them have been taken by variations of the current. The the image quality of data obtained in the form of radiography digital image files with DICOM format were then analyzed using PC out of CR system with methode of MTF. This methode is really efficient for QC spatial resolution quantitatively and so it can be used for assesing the quality of CR. The measurement results showed that the higher the voltage, the better image quality with optimal current was on the range between 4-8 mAs with the average value of MTF 7,26 lp/mm.

scholarly journals EP-2088: Quantification of image quality parameters of dual energy CT using software for quality control

2018 ◽  
Vol 127 ◽  
pp. S1146-S1147
Author(s):  
B. Pawalowski ◽  
H. Szweda ◽  
D. Radomiak ◽  
K. Matuszewski ◽  
U. Sobocka-Kurdyk ◽  
...  
Keyword(s):  
Quality Control ◽  
Image Quality ◽  
Quality Parameters ◽  
Dual Energy ◽  
Dual Energy Ct

scholarly journals PET/CT NEMA Body Phantom Image Reconstruction Study Using 2 mm Voxel Size for Improved Image Quality

2021 ◽  
Author(s):  
Sebastijan Rep ◽  
Petra Tomše ◽  
Luka Jensterle ◽  
Katja Zaletel ◽  
Luka Ležaič
Keyword(s):  
Image Quality ◽  
Spatial Resolution ◽  
Standardized Uptake Value ◽  
Volume Effect ◽  
Ct Imaging ◽  
Recovery Coefficient ◽  
Voxel Size ◽  
Phantom Image ◽  
Pet Ct ◽  
Anatomic Information

Abstract Background PET/CT imaging is widely used in oncology and provides both metabolic and anatomic information. Because of the relatively poor spatial resolution of PET/CT imaging technique the detection of small lesions is limited. The low spatial resolution introduces the partial-volume effect (PVE) which negatively affects images both visually and quantitatively. The aim of our research was to investigate the effect of 4 mm and 2 mm voxel size on image quality and on detection of small spheres. MethodsWe used the NEMA body phantom with six fillable spheres. The spheres and background were filled with a solution of 18F-FDG, in ratio spheres vs background 2:1, 3:1, 4:1 and 8:1 In all images reconstructed with 2 mm and 4 mm voxel size the contrast recovery coefficient (CRC), contrast to noise ratio (CNR) in standardized uptake value (SUV) were evaluated.ResultsFor phantom spheres ≤ 13 mm, we found significant higher CRC, SUV and CNR using small-voxel reconstructions. CRC and SUV did not differ for large spheres (≥ 17 mm) using 2 mm and 4 mm voxel size. On the other hand, CNR for large spheres (≥ 17 mm) was significantly decreased in 2 mm voxel size images compared to the 4 mm.ConclusionAccording to our results, the reconstruction with 2 mm voxel size can improve precise lesion localization, image contrast, and image quality.

A PET/CT Phantom for Evaluating The PET Image Quality of Micro-Lesion and CT Performance Parameters

2020 ◽  
Author(s):  
Shujie Lu ◽  
Peng Zhang ◽  
Chengwei Li ◽  
Jie Sun ◽  
Wenli Liu ◽  
...  
Keyword(s):  
Image Quality ◽  
Pure Water ◽  
Performance Testing ◽  
Reconstruction Algorithm ◽  
Performance Parameters ◽  
Imaging Quality ◽  
Imaging Results ◽  
Pet Ct ◽  
Testing Module

Abstract Background: Recent years, PET/CT equipment has played an increasingly important role in the medical field, and its quality control and evaluation requirements have become more stringent. Correspondingly, the performance testing phantom used for PET/CT quality control needs to be upgraded and optimized to meet the requirement of equipment imaging quality testing. The commonly used NEMA IEC Body performance testing phantom has the defects that it cannot detect micro-lesion and cannot measure CT performance parameters. This article proposes a NIM PET/CT phantom capable of simultaneously testing the performance of PET and CT equipment, and evaluates its imaging quality.Methods: Compared with the NEMA IEC Body phantom, the PET performance testing module in the phantom has new balls with inner diameters of 4mm and 7mm. Combined with the CT performance testing module, it can be used for both PET and CT performance testing. The 28mm and 37mm balls are filled with pure water as a cold stove, and the remaining balls are filled with F-FDG solution as a hot stove. The activity concentration ratio of the hot ball to the background is 4:1. This study compares the imaging results of the NIM PET/CT phantom and the NEMA IEC Body phantom to verify its effectiveness; compares the imaging results of 3 different brands of PET/CT on the NIM phantom to verify that it is on different equipment The generalization ability of the system; apply PSF and TOF technology to the reconstruction algorithm and compare the improvement of the image quality; finally, the accuracy of the CT low-contrast module and the uniformity of the background are verified.Results: The imaging quality of the NIM PET/CT phantom and the NEMA IEC Body phantom is relatively consistent. The NIM phantom under different types of PET/CT scans can detect 7mm balls without affecting the imaging quality of other areas, which is better The device can detect 4mm small balls, which can clearly classify the ability of different devices to present images of small lesions; the integration of PSF technology into the reconstruction algorithm significantly improves the image resolution and hot bulb contrast, but the edges of the lesions are still blurred , TOF technology improves the detection limit of the equipment and improves the overall quality of the image. PSF&TOF technology combines the advantages of the two, significantly reducing image noise and strengthening image details, so that the image quality has been comprehensively improved; the measurement in the CT module The result is consistent with the true value, and the relative error is within ±5%. The CT value transition between the background and pure water area is smooth, and the background uniformity is good.Conclusion: NIM PET/CT Phantom and NEMA IEC Body phantom are comparability, and the former includes all the functions of the latter. In addition, the phantom can meet the testing requirement of different grades of PET/CT.

scholarly journals The impact of reconstruction algorithms and time of flight information on PET/CT image quality

2015 ◽  
Vol 49 (3) ◽  
pp. 227-233 ◽  
Author(s):  
Alen Suljic ◽  
Petra Tomse ◽  
Luka Jensterle ◽  
Damijan Skrk
Keyword(s):  
Image Quality ◽  
Spatial Resolution ◽  
Time Of Flight ◽  
Triple Line ◽  
Internal Diameter ◽  
Ct Image ◽  
Reconstruction Algorithms ◽  
Pet Ct ◽  
Ct Image Quality ◽  
The Impact

Abstract Background. The aim of the study was to explore the influence of various time-of-flight (TOF) and non-TOF reconstruction algorithms on positron emission tomography/computer tomography (PET/CT) image quality. Materials and methods. Measurements were performed with a triple line source phantom, consisting of capillaries with internal diameter of ~ 1 mm and standard Jaszczak phantom. Each of the data sets was reconstructed using analytical filtered back projection (FBP) algorithm, iterative ordered subsets expectation maximization (OSEM) algorithm (4 iterations, 24 subsets) and iterative True-X algorithm incorporating a specific point spread function (PSF) correction (4 iterations, 21 subsets). Baseline OSEM (2 iterations, 8 subsets) was included for comparison. Procedures were undertaken following the National Electrical Manufacturers Association (NEMA) NU-2-2001 protocol. Results. Measurement of spatial resolution in full width at half maximum (FWHM) was 5.2 mm, 4.5 mm and 2.9 mm for FBP, OSEM and True-X; and 5.1 mm, 4.5 mm and 2.9 mm for FBP+TOF, OSEM+TOF and True-X+TOF respectively. Assessment of reconstructed Jaszczak images at different concentration ratios showed that incorporation of TOF information improves cold contrast, while hot contrast only slightly, however the most prominent improvement could be seen in background variability - noise reduction. Conclusions. On the basis of the results of investigation we concluded, that incorporation of TOF information in reconstruction algorithm mostly affects reduction of the background variability (levels of noise in the image), while the improvement of spatial resolution due to incorporation of TOF information is negligible. Comparison of traditional and modern reconstruction algorithms showed that analytical FBP yields comparable results in some parameter measurements, such as cold contrast and relative count error. Iterative methods show highest levels of hot contrast, when TOF and PSF corrections were applied simultaneously.

scholarly journals Evaluation of image quality with four positron emitters and three preclinical PET/CT systems

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jarmo Teuho ◽  
Leon Riehakainen ◽  
Aake Honkaniemi ◽  
Olli Moisio ◽  
Chunlei Han ◽  
...  
Keyword(s):  
Image Quality ◽  
Small Animal ◽  
Quality Parameters ◽  
Acquisition Time ◽  
Image Quantification ◽  
Recovery Coefficient ◽  
Positron Range ◽  
Positron Emission ◽  
Pet Ct ◽  
Positron Emitters

Abstract Background We investigated the image quality of 11C, 68Ga, 18F and 89Zr, which have different positron fractions, physical half-lifes and positron ranges. Three small animal positron emission tomography/computed tomography (PET/CT) systems were used in the evaluation, including the Siemens Inveon, RAYCAN X5 and Molecubes β-cube. The evaluation was performed on a single scanner level using the national electrical manufacturers association (NEMA) image quality phantom and analysis protocol. Acquisitions were performed with the standard NEMA protocol for 18F and using a radionuclide-specific acquisition time for 11C, 68Ga and 89Zr. Images were assessed using percent recovery coefficient (%RC), percentage standard deviation (%STD), image uniformity (%SD), spill-over ratio (SOR) and evaluation of image quantification. Results 68Ga had the lowest %RC (< 62%) across all systems. 18F had the highest maximum %RC (> 85%) and lowest %STD for the 5 mm rod across all systems. For 11C and 89Zr, the maximum %RC was close (> 76%) to the %RC with 18F. A larger SOR were measured in water with 11C and 68Ga compared to 18F on all systems. SOR in air reflected image reconstruction and data correction performance. Large variation in image quantification was observed, with maximal errors of 22.73% (89Zr, Inveon), 17.54% (89Zr, RAYCAN) and − 14.87% (68Ga, Molecubes). Conclusions The systems performed most optimal in terms of NEMA image quality parameters when using 18F, where 11C and 89Zr performed slightly worse than 18F. The performance was least optimal when using 68Ga, due to large positron range. The large quantification differences prompt optimization not only by terms of image quality but also quantification. Further investigation should be performed to find an appropriate calibration and harmonization protocol and the evaluation should be conducted on a multi-scanner and multi-center level.

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