Tips and tricks for scintigraphy image acquisition

Acquiring images from scintigraphy can be time consuming, but can also be one of the most rewarding modalities for an equine nurse. From behavioural problems to multi-limb lameness it is like trying to find that one piece of the puzzle that just keeps hiding itself away. Having the understanding of how Tc99mmethylendiphosphonate works on the body, or the training in how to use the camera is such a tiny part of the acquisition. Most gamma cameras allow for the acquisition of images to set by length of time i.e. 90 s, or a series or 1–2 s frames, or for a set number of counts. You are aiming for a minimum of 150,000 counts per image. Whichever protocol is used, it may still need modifying to suit the individual patient.
Preparing the patient, ensuring the body temperature is warm with bandages and rugs the night before and exercising (unless contraindicated) prior to injection can assist with the uptake within the bone. Understanding the patient as an individual and assessing them before they enter the room can give you an idea of how they may react to the camera being moved around them. Sedating them under the direction of a veterinary surgeon should be based on the individual and not as a protocol, you want them relaxed but not so sleepy that they begin to wobble. The use of blinkers and a head stand can support the patient in standing more relaxed.
Obtaining bilateral distal limbs or plantar hocks can be a great image of reference for a veterinary surgeon but ensuring the patient’s position is correct is key. You ideally want them stood square with feet even and facing forward, yet the reality is that they will stand toe out more on one foot. Take the time to position the limbs equally so the image obtained will be more useful and accurate.
Count stealing and superimposition are problems best dealt with before the image is taken. Using lead to block out contralateral limbs or planning the order in which the images will be taken if the bladder is large can decrease time and improve the overall image quality.
Overall it is best to have knowledge in anatomy and nuclear scintigraphy, and be pernickety at the images you save and have patience.