NEMA BODY PHANTOM ANALYSIS IN HYBRID IMAGING SPECT/CT AND PET/CT

ANALIZA NEMA BODY FANTOMA PRI HIBRIDNEM SLIKANJU SPECT/CT IN PET/CT

Abstract

Introduction: The distribution of radiopharmaceuticals in the body after administration can be demonstrated with two tomography methods. The first is a single-photon emission computed tomography and the second positron emission tomography, which (in combination with computer tomography) enables the viewing of physiological and morphological information from the body.

Purpose: The research performed aims to qualitatively and quantitatively evaluate the contrast-to-noise ratio (CNR) and the signal-to-noise ratio (SNR) in PET/CT and SPECT/CT images obtained with a NEMA body phantom.

Methods: The NEMA body phantom was filled with 99mTc and 18F FDG in ratios of 1 : 2, 1 : 4, and 1 : 8. Phantom imaging was done with SPECT/CT and PET/CT. The obtained scintigrams were evaluated qualitatively and quantitatively by using the OASIS processing software. The SNR was quantitatively evaluated for the background of phantoms and CNRs for assessing the spheres according to the background. SPSS 21 software was used for analysis.

Results: Quantitative analysis of spheres in the NEMA body phantom shows spheres with diameters of 17, 22, 28 and 37 mm in ratios of 1 : 2, 1 : 4, and 1 : 8 on SPECT/CT. In a ratio 1 : 8, SPECT/CT also shows spheres with diameters of 13 mm. All spheres in the NEMA body phantom are visible on the PET/CT at ratios of 1 : 4 and 1 : 8, and at a ratio of 1 : 2 only spheres with diameters of 17, 22, 28, and 37 mm are visible. The quantitative value of the SNR for the background was higher in PET/CT according to SPECT/CT. A comparison of CNR for PET/CT and SPECT/CT showed a significant difference between the two methods (p = 0.002). For both methods, the SNR value is higher in relation to the height of the ratio and shows a good correlation between (r = 0.85 and p <0.001).

Conclusion: The results of the analysis between SPECT/CT and PET/CT imaging methods showed a better SNR and CNR ratio in the PET/CT image method compared to SPECT/CT.