The first experience of multi-modal in vivo PET/SPECT/CT and MRI imaging of laboratory mice with melanoma B16F10 (short message)

Background. For in vivo determination of size and metabolic characteristics of model tumors in laboratory animals, it is recommended to use imaging methods: positron emission tomography (PET), single-photon emission computed tomography (SPECT), computed tomography (CT) and magnetic resonance imaging (MRI). Due to the limited availability of hybrid scanners, it is necessary to investigate the feasibility of obtaining tomograms on separate devices with subsequent geometric comparison of images.

Aim. To investigate the feasibility of multimodal imaging of mice with subcutaneous melanoma B16F10.

Materials and methods. PET, SPECT and CT were performed using a preclinical VECTor 6 tomograph (MILabs, the Netherlands), MRI was performed using a preclinical nanoScan^® 3T tomograph (Mediso, Hungary). The following modality combinations were studied: MRI and PET / CT with ¹⁸F-fluorodeoxyglucose; MRI and PET / CT with ¹⁸F-boronphenylalanine; MRI and PET / SPECT / CT with ¹⁸F-fluoroethyltyrosine (¹⁸F-FET) and ¹⁷⁷lutetium – prostate-specific membrane antigen (¹⁷⁷Lu-PSMA). Mice were immobilized in a custom-made device during scanning and during movement between tomographs. PET and MRI, SPECT and MRI images were fused in the program InterView FUSION 3.09.008.0000 through an intermediate stage of fusion with CT.

Results. Multimodal PET / CT / MRI and PET / SPECT / CT / MRI images of tumor-bearing mice were obtained for the first time in Russia. PET / MRI data confirmed development of the tumor from 6 × 4 × 4 mm in size. PET / SPECT / CT / MRI enabled to image visceral organs with high accumulation of radionuclide tracers: pancreas with ¹⁸F-FET (standardized uptake value 2.6) and kidneys with ¹⁷⁷Lu-PSMA (standardized uptake value 4.4), while the obtained images of organs did not merge and did not overlap.

Conclusion. Multimodal imaging enables the selection of experimental animals with tumors of specific size and metabolic activity for the study of new radiopharmaceuticals, including those with vector delivery.

1. Dillenseger J.P., Guillaud B., Goetz C. et al. Coregistration of datasets from a micro-SPECT/CT and a preclinical 1.5 T MRI. Nucl Instrum Methods Phys Res Sect A 2013;702:144–7. DOI: 10.1016/j.nima.2012.08.023

2. Constantinesco A., Choquet P., Goetz C., Monassier L. PET, SPECT, CT, and MRI in mouse cardiac phenotyping: an overview. Curr Protoc Mouse Biol 2012;2(2):129–44. DOI: 10.1002/9780470942390.mo110225

3. Aguiar P., Silva-Rodríguez J., Herranz M., Ruibal A. Preliminary experience with small animal SPECT imaging on clinical gamma cameras. Biomed Res Int 2014;2014:369509. DOI: 10.1155/2014/369509