Performance assessment of the ALBIRA II pre-clinical SPECT S102 system for 99mTc imaging

111Ag phantom images with Cerenkov Luminescence Imaging and digital autoradiography within the ISOLPHARM project

Targeted Radionuclide Therapy (TRT) is a medical technique exploiting radionuclides to combat cancer growth and spread. TRT requires a supply of radionuclides that are currently produced by either cyclotrons or nuclear research reactors. In this context, the ISOLPHARM project investigates the production of innovative radionuclides for medical applications. This production will be based on the forthcoming SPES facility at the Legnaro National Laboratories (LNL) of the National Institute for Nuclear Physics (INFN), an ISOL facility where high-purity radioactive beams will be used to produce carrier-free radiopharmaceuticals. Previous studies demonstrated that a significant amount of 111Ag, an innovative β/γ emitter suitable for TRT with theranostic applications, can be obtained at the SPES facility. The present work describes the first imaging study on phantoms with 111Ag performed by the ISOLPHARM collaboration. This is a fundamental step to pave the way for the upcoming in vivo studies on the 111Ag-based radiopharmaceutical currently being developed. The imaging potential of this radionuclide was investigated by acquiring phantom images with Cerenkov Luminescence Imaging (CLI) and digital autoradiography (ARG).

3D printed anthropomorphic left ventricular myocardial phantom for nuclear medicine imaging applications

Background

Anthropomorphic torso phantoms, including a cardiac insert, are frequently used to investigate the imaging performance of SPECT and PET systems. These phantom solutions are generally featuring a simple anatomical representation of the heart. 3D printing technology paves the way to create cardiac phantoms with more complex volume definition. This study aimed to describe how a fillable left ventricular myocardium (LVm) phantom can be manufactured using geometry extracted from a patient image.

Methods

The LVm of a healthy subject was segmented from ¹⁸F-FDG attenuation corrected PET image set. Two types of phantoms were created and 3D printed using polyethylene terephthalate glycol (PETG) material: one representing the original healthy LVm, and the other mimicking myocardium with a perfusion defect. The accuracy of the LVm phantom production was investigated by high-resolution CT scanning of 3 identical replicas. ^99mTc SPECT acquisitions using local cardiac protocol were performed, without additional scattering media (“in air” measurements) for both phantom types. Furthermore, the healthy LVm phantom was inserted in the commercially available DataSpectrum Anthropomorphic Torso Phantom (“in torso” measurement) and measured with hot background and hot liver insert.

Results

Phantoms were easy to fill without any air-bubbles or leakage, were found to be reproducible and fully compatible with the torso phantom. Seventeen segments polar map analysis of the "in air” measurements revealed that a significant deficit in the distribution appeared where it was expected. 59% of polar map segments had less than 5% deviation for the "in torso” and "in air” measurement comparison. Excluding the deficit area, neither comparison had more than a 12.4% deviation. All the three polar maps showed similar apex and apical region values for all configurations.

Conclusions

Fillable anthropomorphic 3D printed phantom of LVm can be produced with high precision and reproducibility. The 3D printed LVm phantoms were found to be suitable for SPECT image quality tests during different imaging scenarios. The flexibility of the 3D printing process presented in this study provides scalable and anthropomorphic image quality phantoms in nuclear cardiology imaging.