CT Images of Zebrafish for Preclinical Studies in a Micro PET/SPECT/CT Equipment

Abstract

Rationale and Objectives: the use of zebrafish (Danio rerio) as an animal model in scientific studies has increased due to its many advantages for research. The multimodal micro PET/SPECT/CT equipment was developed for preclinical studies that use hybrid images of small rodents. It is not clear in the literature whether this type of equipment can be used for studies of smaller animals. We evaluated the feasibility of using the CT modality of a multimodal PET/SPECT/CT equipment for preclinical studies with zebrafish. Materials and Methods: since the CT modality of the equipment is optimized for imaging of small rodents, structural changes were tested to adapt it to the use of zebrafish: alteration of the additional aluminum filter of the X-ray tube and use of an adapted stretcher of high density extended polystyrene (EPS). The appearance of artifacts, changes in spatial resolution, contrast and image uniformity were evaluated using phantoms. Results: the images were visually analyzed to verify which anatomical structures can be identified after the system adjustments. The best results were obtained with a 0.2 mm thick aluminum filter and the adapted EPS stretcher, for both the phantom and animal images. It was possible to identify diverse structures such as swimming bladders, digestive tract and bone structures. Conclusion: using the proposed adaptations, the CT modality of a multimodal PET/SPECT/CT equipment can be utilized to carry out preclinical studies with zebrafish as the animal model.