Comparative Study of Imaging Characteristics of I-125 Imaging Using the Siemens Inveon Scanner and Siemens Symbia TruePoint

Young Jun Kim¹, Ilhan Lim^1,2*, A Ram Yu¹, Byung Il Kim^1,2, Chang Woon Choi^1,2, Sang Moo Lim^1,2, Jin Su Kim^1,3,4*

¹Molecular Imaging Research Center, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul, Korea.
²Department of Nuclear Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (KIRAMS), Seoul, Korea.
³Korea Drug Development Platform Using Radio-Isotope (KDePRI), Seoul, Korea.
⁴Radiologcial and Medico-Oncological Sciences, University of Science and Technology (UST), Seoul, Korea.

DOI: 10.4236/jbise.2015.810064                

Abstract

Objective: Although Iodine-125 (¹²⁵I) has been widely used for in vitro studies because of its relatively long half-life (60.1 days), ¹²⁵I imaging is limited because of its low energy (27 - 35 keV), even in an animal-dedicated system. In this study, imaging characteristics of ¹²⁵I were assessed using a small animal-dedicated imaging system and clinical scanner. Methods: Using the Siemens Inveon and Siemens Symbia TruePoint systems, imaging characteristics such as resolution, sensitivity, and image quality were compared. Mouse high resolution (MHR-0.5), mouse general purpose (MGP-1.0), and mouse high sensitivity (MHS-2.0) collimators were used for the Inveon scanner, and low energy high-resolution (LEHR) and low energy all-purpose (LEAP) collimators were used for the Symbia TruePoint. For animal imaging, 16.8 MBq of ¹²⁵I was administered to BALB/c mice intravenously, and the planar image and single-photon emission computed tomography (SPECT) were obtained using both scanners. Results: The resolution of 125I for the Inveon scanner was 3.98 mm full width at half maximum (FWHM) at a 30-mm distance with the MHR-0.5 collimator, and the value of Symbia scanner was 8.72 mm FWHM at a 30-mm distance with the LEHR collimator. The sensitivity of ¹²⁵I for the Inveon scanner was 21.87 cps/MBq, and the value for the clinical scanner was 30.55 cps/MBq. The planar images of mice were successfully obtained at the level of evaluating specific binding in both scanners. Conclusion: ¹²⁵I small animal imaging can be achieved with a clinical scanner. This result may enhance the utilization of ¹²⁵I small animal imaging using a clinical scanner.

Keywords

I-125, Animal Imaging, Performance Measurement

Conflicts of Interest

The authors declare no conflicts of interest.

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