Comparison of image quality of different radionuclides technetium-99m, samarium-153, and iodine-123

• Published in: Indian journal of nuclear medicine 2019-07, Vol.34 (3), p.201-204
• Main Authors: Bouzekraoui, Youssef, Bentayeb, Farida, Asmi, Hicham, Bonutti, Faustino
• Format: Article
• Language: English
• Subjects: CAT scans; Collimation; Computed tomography; Computer simulation; Detection equipment; Diagnostic imaging; EDTA; Energy; Gamma rays; Image contrast; Image quality; Image resolution; Iodine; Iodine isotopes; Isotopes; Medical imaging; Nuclear medicine; Original; Photon emission; Photons; Point spread functions; Quality; Radioisotopes; Rare earth metal compounds; Samarium; Sensitivity; Sensors; Single photon emission computed tomography; Spatial resolution; Technetium; Technetium isotopes; Tomography
• ISSN: 0972-3919; 0974-0244
• DOI: 10.4103/ijnm.IJNM_42_19

Introduction: The choice of the radionuclide has a key role in nuclear medicine which appearing the lowest scatter fraction. In addition, the presence of penetrated and scattered photons from collimator in single-photon emission computed tomography images degrades resolution and contrast. Thus, image quality depends on sensitivity and resolution of the collimator-detector system. The goal of this study was to compare the image quality that can be achieved by three radionuclides: technetium-99 m (Tc-99 m), iodine-123 (I-123), and samarium-153 (Sm-153). Materials and Methods: Tc-99 m and Sm-153 were imaged with low-energy high resolution (LEHR) collimator, while I-123 was imaged with medium-energy (ME) collimator. We modeled the Siemens Symbia Medical system using Monte Carlo simulation code SIMIND. The imaging characteristics of each radionuclide were investigated by simulated data: point spread function, sensitivity (Cps/MBq) and geometric, penetration and scattering distribution. Results: Tc-99 m and Sm-153 give best and results with LEHR collimator for spatial resolution (full width at half maximum [FWHM] = 3.19 mm; full width at tenth maximum [FWTM] = 6.73 mm) and (FWHM = 3.22 mm; FWTM = 7.39 mm), respectively. Whereas, I-123 provided with ME collimator a lower resolution (FWHM = 4.89 mm; FWTM = 9.89 mm). The sensitivity recorded by Tc-99 m, Sm-153, and I-153 were (31.21 Cps/MBq), (10.16 Cps/MBq), and (51.22 Cps/MBq), respectively. Conclusion: Tc-99 m and Sm-153 give the best and generally similar imaging properties with LEHR. For I-123, the ME collimator helps lowering the influence of high-energy gamma rays.