Tomographic 99mTc radioactivity quantification in three-dimensional printed polymeric phantoms with bioinspired geometries

• Published in: Radiation physics and chemistry (Oxford, England : 1993) England : 1993), 2020-12, Vol.177, p.109130, Article 109130
• Main Authors: Ramírez-Nava, Gerardo J., Santos-Cuevas, Clara L., Chairez-Oria, Isaac, Rioja-Guerrero, Eurídice, Oroz-Duarte, Jael
• Format: Article
• Language: English
• Subjects: 3D printing; Algorithms; Attenuation; Bioinspired phantoms; Biomimetics; Computed tomography; Correlation analysis; Correlation coefficients; Image acquisition; Image degradation; Image quality; Image reconstruction; Iterative methods; Mathematical analysis; Medical imaging; Photon emission; Photons; Photopeak; Quantitative SPECT; Radioactivity; Regression analysis; Scattering; Sensitivity; SPECT/CT; Statistical analysis; Three dimensional printing; Tomography
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2020.109130

To characterize quantitatively a single-photon emission computed tomography/computed tomography (SPECT/CT) system through experiments carried out on three-dimensional (3D) printed phantoms with bioinspired anatomic geometries. The sensitivity factor of the SPECT/CT system was obtained after correcting the image quality degrading effects. Photon attenuation correction was carried out through CT attenuation maps. Scattering was corrected by 2 methods. The first method introduces a compensation factor based on photopeak and scatter window widths, which corrects the 3D image during iterative reconstruction algorithm. The second estimates scatter within a photopeak window, which is applied projection by projection before the 3D reconstruction. Partial volume effect was corrected using a calibration method based on spheres of different sizes. A liver-like and a multisphere phantom were designed and 3D printed. SPECT/CT images of the designed phantoms filled with different activities were acquired and quantified. A correlation coefficient based on linear regression was calculated with the aim of comparing proposed methods. The quantitative SPECT methodology allowed quantification with percentage errors between 1.01-8.96%. The activity measurements validated the 99mTc quantitative performance of the SPECT/CT system. The statistical analysis showed correlation coefficients of 1.00 for the first method and 0.99 for the second one. The implementation of two alternative methodologies for the calculation of sensitivity factors, allowed to correct image quality degrading effects, satisfying all the suggested stages in imaging quantification. The designed phantoms allowed to assess the characterization of a SPECT/CT system. This study demonstrates the effectiveness of 3D printing to develop bioinspired phantoms for the quantitative assessment of 99mTc imaging. •A single-photon emission computed tomography was characterized quantitatively .•Three-dimensional printed phantoms with bioinspired geometries were developed .•SPECT images were corrected for attenuation, scattering and partial volume effect .•99mTc was assessed quantitatively with experiments which used 3D printed phantoms .•The followed methodology quantified SPECT images with errors less than 8.96% .