1. Equipment, Terminology and Positioning
Equine Radiology
Equipment, Terminology and Positioning

2. Equine Radiology Introduction Restraint Equipment
Introduction: Equine radiology is no different than small animal radiology as it relates to the production and physics behind the machine. Positioning is similar but different names may be used. A lateral is still a lateral.
Two major differences are the size of the animal and were the radiographs are taken.
Most radiographs are taken in the field with horses. Some may be taken in the clinic if equipment and room is available while others must be taken in a clinic usually a university or large equine hospital.
Restraint: Patient restraint is of paramount importance in equine radiology. Horses tend to be scared of unfamiliar objects. The radiology equipment definitely falls into this category. Allowing the animal to sniff the equipment prior to use, refraining from quick movements and keeping the area quiet will greatly reduce the animal’s stress.
What makes restraint so important?
The doctor and technician are in easy reach of the horse (legs and body).
The equipment is very expensive.
Some vets will try to take radiographs on a fully awake animal. This can be difficult on more easily stressed horses. Other vets will use sedation to help keep the horse still and quiet. Chemical restraint is recommended on all but the most bombproof horses.
You must remember the vets safety, your safety and equipment safety is extremely important. The machine cost ranges from $9,000 to over $12,000.
Equipment: There are several pieces of equipment needed.
1. The machine
2. Cassette and film
3. Cassette Holder

3. Equine Radiology Machine
Portable Machine
Mobile Machine
Stationary Machine
Most equine units must be mobile as most radiographs are taken in the field. A large unit like the one in our radiology room is not portable enough for field use. However, there are units with the versatility of our small animal unit that are mobile. And there are large stationary units.
Portable Machine: The most common unit in equine medicine is the portable unit. This is used on farms were most radiographs will be taken. These units have limited power (kVp = 90 and mA = 20). The time is adjustable. These machines are susceptible to the line voltage of the farm it is being used on. Collimation and illumination is difficult, especially, outside. The biggest problem with these units is the power settings. Because the power is limited the time must be longer to expose the film. This means motion plays a major role in a good radiograph. The technician is much more likely to be exposed to radiation so PPE is a must (gloves, apron, thyroid shields). Fast speed cassettes and film is recommended for equine radiographs.
Mobile Units: mobile units have more power with varied mA settings ( ) and up to 120 kVp. This allows for shorter exposure time. The drawback is the unit is larger and must be set on a rolling stand. The stand does not work well on uneven surfaces. This type of machine is more useful in a equine clinic setting with level floors than in the barn. They also tend to be more costly.
Stationary Unit: the stationary unit is very large but will allow the body of the horse to be radiographed. The mA will go as high as 1000mA. These units are mounted on the wall, ceiling or floor. They tend to be loud and are very expensive. These are generally only seen in very large equine hospitals or at universities.

4. Cassette Holder Positioning Devices PPE
Cassette holders can be the technician with a metal pole the cassette sets in or a box that will hold the cassette in position.
Positioning devices are used to position the foot so the cassette can be set correctly for the film and in some cases hold the cassette as well.

5. Equine Radiology

6. Equine Radiology

7. Preparation and Positioning
Preparation: All artifacts need to be removed from the leg and hoof.
1. Brush the hair in the area of the radiograph.
2. Remove any poultice or other ointments and medications from the area, especially iodine based products. Iodine is radio-opaque.
3. Remove bandages when possible.
4. Pack the sole and frog with radiolucent clay to fill in air pockets for hoof radiographs.
Positioning: horses should bear full weight on the leg being radiographed when possible. Pay close attention to the markers (cranial, lateral, medial, etc). The cassette must be marked correctly for an accurate diagnosis. The cassette must be labeled with an ID (horse name, client name, date and part being radiographed [include the side]). You should take your time and get the radiograph right the first time. Repeat radiographs after developing are not practical.

8. Anatomy of the Equine Leg

9. Equine Radiology

10. Terminology Dorsal Medial Plantar/Palmar Lateral Medial DP PD LM ML
DPMLO
DPLMO
Skyline

11. Radiograph Positioning
Hot P3
P3 Straight Up DP

12. Equine Radiology
P3 Straight Up DP
Hot P3

13. Equine Radiology
Lateral P3
Lateral P3

14. Navicular Bone
60° PD
Lateral

15. Equine Radiology
60° PD
Lateral

16. Equine Radiology
60° DP

17. Metacarpals DP
Lateral
Obliques seen in Carpals

18. Carpus and Tarsus DP
Lateral
Flexed Lateral

19. Equine Radiology
Flexed Lateral
DPLMO
DPMLO

20. Equine Radiology
Skyline
Skyline

21. Views needed for other parts
Pastern
Fetlock
Straight Up DP
Lateral
DPLMO
DPMLO
Flexed Lateral
DPMLO & DPLMO

22. Equine Radiology
Radius
Elbow
Shoulder DP
Lateral