A new PET resolution measurement method through Monte-Carlo simulations

Καρπέτας, Γεώργιος; Michail, C.; Fountos, G.; Kandarakis, I.; Panayiotakis, George

doi:10.1097/mnm.0000000000000151

Cited by 13 publications

(2 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Image quality in PET scanners is affected by a variety of parameters, including the crystal's properties, size and arrangement, the mode of operation (2D or 3D), photon noncollinearity and positron range, oblique detector penetration, photon scatter, the measured standardized uptake values (SUVs), patient motion, the position of the source within the FOV, sensitivity, and noise, all of which contribute to PET system's performance [8,40,46,[74][75][76][77]. Among the other factors affecting resolution, the most dominant is positron range, which can degrade resolution up to a few millimeters, depending the system settings, from the ideal resolution, which is defined as twice the pixel size, due to the Nyquist theorem [76,78]. Furthermore, image quality is dependent on the number of iterations and subsets in ordered subset-type algorithms, filters in FBP, and post-filtering [75].…”

Section: Discussionmentioning

confidence: 99%

Information Capacity of Positron Emission Tomography Scanners

et al. 2018

View full text Add to dashboard Cite

Background: The aim of the present study was to assess the upper information content bound of positron emission tomography (PET) images, by means of the information capacity (IC). Methods: The Geant4 Application for the Tomographic Emission (GATE) Monte Carlo (MC) package was used, and reconstructed images were obtained by using the software for tomographic image reconstruction (STIR). The case study for the assessment of the information content was the General Electric (GE) Discovery-ST PET scanner. A thin-film plane source aluminum (Al) foil, coated with a thin layer of silica and with a 18F-fludeoxyglucose (FDG) bath distribution of 1 MBq was used. The influence of the (a) maximum likelihood estimation-ordered subsets-maximum a posteriori probability-one step late (MLE-OS-MAP-OSL) algorithm, using various subsets (1 to 21) and iterations (1 to 20) and (b) different scintillating crystals on PET scanner’s performance, was examined. The study was focused on the noise equivalent quanta (NEQ) and on the single index IC. Images of configurations by using different crystals were obtained after the commonly used 2-dimensional filtered back projection (FBP2D), 3-dimensional filtered back projection re-projection (FPB3DRP) and the (MLE)-OS-MAP-OSL algorithms. Results: Results shown that the images obtained with one subset and various iterations provided maximum NEQ values, however with a steep drop-off after 0.045 cycles/mm. The single index IC data were maximized for the range of 8–20 iterations and three subsets. The PET scanner configuration incorporating lutetium orthoaluminate perovskite (LuAP) crystals provided the highest NEQ values in 2D FBP for spatial frequencies higher than 0.028 cycles/mm. Bismuth germanium oxide (BGO) shows clear dominance against all other examined crystals across the spatial frequency range, in both 3D FBP and OS-MAP-OSL. The particular PET scanner provided optimum IC values using FBP3DRP and BGO crystals (2.4829 bits/mm2). Conclusions: The upper bound of the image information content of PET scanners can be fully characterized and further improved by investigating the imaging chain components through MC methods.

show abstract

Section: Discussionmentioning

confidence: 99%

Information Capacity of Positron Emission Tomography Scanners

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The modulation transfer function (MTF) was measured by irradiating a PTW Freiburg tungsten edge test device, following the procedures described in the IEC standard [11,32,33]. The updated IEC 62220-1-1:2015 [11,33,40] standard describes certain modifications, such as the method for the determination of the modulation transfer function (MTF) in which the final MTF can be now obtained only through averaging of the oversampled edge spread function (ESF) [33,[41][42][43]. The average of all oversampled ESFs was then fitted with a modified Fermi-Dirac distribution function as follows [11,21]:…”

Section: Modulation Transfer Function (Mtf)mentioning

confidence: 99%

Imaging performance of a CaWO4/CMOS sensor

Martini

Koukou

Fountos

et al. 2019

Frattura Ed Integrità Strutturale

View full text Add to dashboard Cite

The aim of this study was to investigate the modulation transfer function (MTF) and the effective gain transfer function (eGTF) of a nondestructive testing (NDT)/industrial inspection complementary metal oxide semiconductor (CMOS) sensor in conjunction with a thin calcium tungstate (CaWO 4) screen. Thin screen samples, with dimensions of 2.7x3.6 cm 2 and thickness of 118.9 μm, estimated from scanning electron microscopy-SEM images, were extracted from an Agfa Curix universal screen and coupled to the active area of an active pixel (APS) CMOS sensor. MTF was assessed using the slanted-edge method, following the IEC 62220-1-1:2015 method. MTF values were found high across the examined spatial frequency range. eGTF was found maximum when CaWO 4 was combined with charge-coupled devices (CCD) of broadband anti-reflection (AR) coating (17.52 at 0 cycles/mm). The combination of the thin CaWO4 screen with the CMOS sensor provided very promising image resolution and adequate efficiency properties, thus could be also considered for use in CMOS based X-ray imaging devices, for various applications.

show abstract