Nuclear medicine in veterinary practice : preliminary experiences at Az. Polo Veterinario di Lodi

Background-Aim: Nuclear Medicine have been widely used on animal models. However, in routinary veterinary medicine only few diagnostic techniques, employing radiopharmaceuticals, have been described. Bone scintigraphy has become a well-accepted tool in the investigation of equine lameness but it has not been recognized as a useful clinical tool in small animal practice. Moreover to- mographic studies (SPECT) have not received much enthusiasm in veterinary medicine, mainly because of a lack of dedicated equipments. In current literature there are only few studies high- lighting the clinical relevance of nuclear medicine also in veterinary oncology, internal medicine and orthopedics. The aim of this report was to describe the preliminary clinical and ex- perimental experience in nuclear medicine at the Az. Polo Veterinario di Lodi, University of Milan. Methods: We study primarily horses but also small animals (dogs and cats) as clinical subjects, as well as pigs and rabbits for experimental protocols. Horses usually underwent sedation while small animals were examined under general anaesthesia. In our Nuclear Medicine facility we have a single head gammacamera, performing SPECT and planar scintigraphy, and a ceiling suspended stand alone gam- macamera head, to investigate large animals like horses. Equine scintigraphic scans were performed using 99mTc-labelled methylene diphosphonate (99mTc-MDP 1 Gbq/100 kg). Bone scan were also acquired in dogs in order to investigate lameness localized to the elbow (planar acquisition) and shoulder regions (planar acquisition and SPECT). Thyroid scans (both planar and SPECT) were performed in dogs injecting 99mTc-Pertecnetate. Feline injection-site sarcoma (FISS) has been investigated using 99mTc-sestaMIBI. For ex- perimental purposes gated myocardial perfusion SPECT with 99mTc- sestaMIBI was performed in piglets affected by induced myocardial infarction. Results: A total of 26 horses underwent bone scintigraphy. In 24 lame horses bone scan allowed to recognize the site of injuries while in two cases, referred for poor performance, no lesions were detected. In two lame dogs a focal and intense uptake of the ra- diotracer was observed in planar or SPECT images at level of elbow or shoulder. Thyroid scintigraphy allowed identification of a mass in two dogs. In one case, the mass showed a focal and severe IRU while in the other case, a mild IRU and poorly defined gland margins have been observed. In the cat with a diagnosis of FISS a very intense and well-defined uptake was observed in the mass localized on the back. No uptake was visible in other sites sus- pected of metastases as lung or satellite lymph nodes. Gated myocardial perfusion SPECT allowed the exact localization of myocardial lesions in two piglets. Conclusion: Nuclear medicine has high potentiality in veterinary medicine. In our preliminary experience we can assert that nuclear medicine could be a very useful diagnostic tool, especially in asso- ciation with other diagnostic techniques as CT or MRI. Furthermore, experimental studies could be helpful in veterinary like human medicine not only for research purposes but also as pre-clinical ex- periences for future development of new clinical approaches.