Background: Multimodality imaging presents a unique opportunity to image the efficacy of candidate compounds against various models of cancer. The challenge is in integrating the complimentary data that these modalities can provide. The purpose of this study was to evaluate the feasibility of quintuple modality image in order to optimize workflows for maximal efficacy testing of candidate compounds using PET, SPECT, CT, MRI, and Bioluminescence imaging (BLI).
Materials and Methods: Male nude mice were injected into the left ventricle with 3x106 PC-3M-luc-C6 cells. BLI was performed to track disease progression and ensure that animals exhibited established metastatic disease prior to initiation of multimodality imaging. Animals were injected with 500µCi Tc99m-MDP and allowed a 1h uptake period prior to imaging. The animals were then placed into an Animal Handling System (AHS, ASI Instruments) that coupled to multiple integrated Positioning Receiver Assemblies (PRA's, ASI Instruments) designed for the PET, SPECT, CT, and MRI scanners, and a 15min, multi-pinhole SPECT scan was acquired. After completion of the SPECT scan, 200µCi of 18F-FDG was administered under anesthesia. MicroCT and MRI anatomical images were acquired during the FDG uptake period. Body temperature was maintained via the integrated warm water circulation in the AHS to ensure adequate FDG uptake and clearance during the procedures. Whole body CT images were acquired at 512 projections, 75kVp, and 220µA. A series of T2-weighted and T1-weighted gadolinium-enhanced images were acquired using a 7T MRI system. At 1h post-FDG administration, a 10min static PET emission scan was acquired and reconstructed using a 3DOSEM/MAP algorithm.
Results: Animals were maintained under anesthesia for a total of approximately 2 hours in order to acquire data from all the modalities. Data was able to be co-registered in various forms in order to verify the location and extent of disease, as well as the usefulness of 18F-FDG PET and Tc99m-MDP to serve as biomarker probes for tumor cell metabolism, and osteolytic and osteoblastic activity in bone lesions.
Conclusions: Animals tolerated the length of anesthesia well. The feasibility of this imaging was only made possible through the use of the multimodality AHS bed and docking system that permitted reproducible imaging across the different platforms. In order to further optimize workflows, multiple AHS bed systems should be employed so that data can be acquired on the various modalities in parallel, instead of sequentially, thereby greatly increasing animal throughputs.
Citation Format: John L. Chunta, Deanne Lister, Chris Bull, Deepa Balagurunathan, Erin Trachet, Chris Chiodo, Scott Wise, Dick Leopold, Patrick McConville. Evaluating the feasibility and throughput of quintuple modality imaging in a prostate cancer bone metastasis model with PET, SPECT, CT, MRI, and bioluminescence imaging. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4945. doi:10.1158/1538-7445.AM2014-4945