Since its inception in 1972, computerized tomography has revolutionized the ability to diagnose, treat, and monitor injuries and pathology in humans. Computerized tomography (CT) involves serial, radiological, cross-sectional scans, resulting in detailed, three-dimensional images of internal anatomy (Wellington & Vinegar, 1987). This tool was adopted for use in domestic veterinary medicine in 1989 and later utilized in post-mortem assessments of wild, stranded cetaceans (Schwarz & Saunders, 2011). In 2004, the U.S. Navy Marine Mammal Program conducted the first live dolphin CT scans to provide insight into cranial anatomy (Houser et al., 2004).
Since 2013, Dolphins Plus Marine Mammal Responder has utilized CT scans to diagnose and monitor the progression and treatment of chronic diseases in our extended resident dolphin population. But how do you take a dolphin to get a CT Scan?
Read on to find out…
All of the dolphins at DPMMR are trained to participate in what we call a “voluntary beach” behavior, where they slide out of the water onto a stretcher, atop a soft pad on our mechanical lift/platform. When we train this behavior, we also train the animals to allow passive restraint by a team of up to 8 people and being lifted in a stretcher. By using positive reinforcement techniques, we teach the animals to voluntarily participate in their restraints which, in turn, makes coming out of the water for veterinary procedures or environmental emergencies less stressful (and more fun) for the dolphins.
On the morning of a CT Scan, we put this training to the test and ask the dolphin to voluntarily beach or slide out of the water, allow passive restraint, and then remain calm while they are lifted in a stretcher into a dolphin-sized ambulance.
Once inside of the transport vehicle, the veterinary team places an IV Catheter in a large vein in the dolphin’s peduncle area. Should an emergency arise, the IV Catheter allows the attending veterinarian the ability to immediately administer necessary medication and serves as an additional safety measure during the CT procedure.
Following catheter placement, the transport van begins the 20-minute drive to Mariner’s Hospital, where the radiology team awaits our arrival with a gurney. The dolphin is then transferred onto a backboard, onto the gurney, and then wheeled to the CT room.
Once on the CT Table, a trainer asks the dolphin to take multiple deep breaths, which encourages the dolphins hold their breath while going through the CT machine. If a dolphin takes a breath or moves at all while a scan is underway, it can distort the images and make it difficult, if not impossible, for the radiologist to evaluate the CT scan. Thus, if the dolphin breathes or moves during the scan, we repeat the scan. Thankfully we have training on our side to help ensure the dolphin remains calm, immobile, and does not take a breath while passing through the machine.
After the vet team is convinced we have quality images of the dolphin, the dolphin is transferred back onto a gurney and then into the transport van to make the quick trip back home.
The last step in the CT process is reintroducing the animals back to their lagoon environment at DPMMR. For this step, the trainers lower the dolphin and stretcher down to the water and allow the dolphin to slide back in the water. The trainer will then wait for the dolphin to come back to the lift and asks the dolphin to voluntarily beach again right away. Once the animal is successful with this step, the entire transport team claps and cheers for the dolphin while they are treated to a buffet of fresh fish and a variety of reinforcement.
This final stage is arguably one of the most important parts of the CT process. During this step we train the animals to understand that, despite traveling to the hospital and leaving their lagoon for an extended period, sliding out of the water can still be fun. In doing so, we are encouraging the animals to continue to participate in this behavior and are able to utilize the voluntary beach behavior again in the future for subsequent veterinary procedures. This is not only beneficial in the event of an emergency, but also for routine medical procedures, or even to monitor the dolphins’ weight via a scale.
You might be wondering why we would go through so much trouble just to get a CT scan of a dolphin…
The short answer is computerized tomography imaging provides our vet team with an invaluable diagnostic tool, far superior to X-ray or ultrasound, which allows us to diagnose lung disease, that may otherwise go undetected. CTs not only allow for the diagnosis of serious and potentially fatal respiratory diseases (such as fungal pneumonia), but also for these diseases to be monitored over the course of several years. Ultimately, this tool allows us to provide the best veterinary care to our animals.
The long answer involves the many other benefits of CT scanning, including but not limited to; research of dolphin anatomy, establishing baseline conditions for healthy animals, monitoring the progression or remission of previously diagnosed conditions, more complete imaging when compared to X-rays, and advancing the gold standard of care for marine mammals in human care.
To date, the team at DPMMR has participated in over 25 CT scans with our extended population. Not only are we are proud of the training and veterinary accomplishments our team achieves with each voluntary beach behavior, but we are proud to be providing the absolute best care and welfare for our dolphin population. We believe the CT could definitely save a life of one of our precious marine mammals. Who knows, it may already have!
Houser, D. S. (2004). Structural and functional imaging of bottlenose dolphin (Tursiops truncatus) cranial anatomy. Journal of Experimental Biology, 207(21), 3657-3665.
Schwarz, T., & Saunders, J. (2011). Veterinary computed tomography. Chichester, West Sussex, UK: Wiley-Blackwell.
Wellington, S., & Vinegar, H. (1987). X-Ray Computerized Tomography. Journal of Petroleum Technology, 39(08), 885-898