• Practically all X-ray equipment used in veterinary radiography was designed and constructed for human use and suffers from various disadvantages when used for veterinary purposes.

• While there is a very wide variety of machines of different size, power and manufacture, they may be divided into three main groups.

Portable-X-ray Apparatus.

• Commonly used in veterinary practice because of convenient transportation. The maximum output usually varies from 70-110 kv and 15-35 mA.

• In such machines the transformers are of small size and low weight and are located within the tube head immediately adjacent to the X-ray tube.

• The tube head itself is supported on a tube stand which may comprise either a small table top model or a considerably more substantial floor stand mounted on wheels.

• The apparatus also has a small control panel which is attached to the tube stand or the tube head or supported on a separate stand.

 Advantages

• Relatively cheap and require little maintenance.

• They cost less than other types of machine.

• They are strongly constructed and need little maintenance.

• They can be operated from any 12 – or 15-A electrical point.

• They can be easily transported for use on farms or other premises.

• They are light and easily maneuvered and therefore suitable for radiographing the legs of restless horses.

Disadvantages

• Because of low electrical output, these machines are of limited value in radiographic examination.

Range of use

• Large animals. Such machines are particularly suitable for radiography of the feet of horses but of limited use for any examinations above the corpus or tarsus. Small animals.

• Portable apparatus should be satisfactory for the radiographic examination of the entire skeletal system of the dog and cat (with the possible exception of the vertebral column of particularly large dogs).

• There are, however, limitations on the usefulness of these smaller machines for radiography of the abdomen and chest in these species.

Dental X-ray Apparatus

• Apparatus manufactured for dental use is sometimes advocated for veterinary use because of its low price.

• Such machines are of low output (in the region of 10 m A and 70 k V) and are designed to only cover a small area of the patient.

• The precise use which could be made of such machines would depend in part on the skill of the operator, but they are likely to be restricted to the examination of cats and the smallest dogs.

Mobile X-ray Apparatus

• These machines have higher output than portable machines by virtue of their larger transformers and are mounted on wheels with output of 90-125kv and 40 to 300mA. Most machines are movable on smooth surface within the radiology section.

• In machines of this type the transformers are larger to permit higher output and because of their increased weight are no longer located in the tube head but are mounted on wheels and form the best of the apparatus.

• These sets cannot be taken apart and the tube stand and control panel are built into the apparatus .

• These machines can be moved over level surfaces and, in most instances, operated from 13-15 A sockets.

Range of use

• Large animals. The difficulty of maneuvering these heavier machines quickly and the fact that in many instances the tube cannot be positioned at near ground level (unless the support arm is modified) will limit its usefulness for equine work. Provided that the patient can be cast or otherwise effectively immobilized, the greater output of the most of these sets will enable examination of the upper limbs, head and neck to be undertaken.

• Small animals. These machines are very suitable for dog and cat work and increased output of the medium and higher powered units would enable practically all radiographic examinations to be attempted.

• These units are usually installed in a room specially constructed for the purpose. Output of this machine vary from 120-200kv and 300-1000 mA. but are expensive.

• The machines which fall into this group are characterized by the fact that they require transformers of such size and output that they have to be built into the room and provided with special electrical connections to the mains.

• The X-ray tube is connected to the transformer by high-tension cables and is mounted on some form of gantry which allows only limited movement.

• Such machines are likely to be capable of an output of at least 300 m A and 120 k V and in some instances much higher ( 1000 m A and 200 lV). The expense of such apparatus normally restricts its use to the teaching schools and research institutes .

• Large animals: The higher kilovoltage and milliamperge  provided by these machines should facilitate radiography of the trunk and spine of cattle and horses.

• Small animals: Apparatus of this type is very suitable for all small animal radiographic examinations and may incorporate facilities for additional techniques such as rapid film changing, image intensification , or tomography.

• Advantages

• Suitable for all types of radiographic examinations in case of small and large animals.

• Because of high kv and mA output exposure time is less.

•  Disadvantages

• More scatter radiation occur because of higher kv output.

• Expensive to purchase and three phase electricity supply is required for installation of the machine.

Fixed X-ray Apparatus

• The machines which fall into this group are characterized by the fact that they require transformers of such size and output that they have to be built into the room and provided with special electrical connections to the mains.

• The X-ray tube is connected to the transformer by high-tension cables and is mounted on some form of gantry which allows only limited movement. Such machines are likely to be capable of an output of at least 300 m A and 120 k V and in some instances much higher ( 1000 m A and 200 l V ). The expense of such apparatus normally restricts its use to the teaching schools and research institutes .

• Large animals: The higher kilovoltage and milliamperge  provided by these machines should facilitate radiography of the trunk and spine of cattle and horses.

• Small animals: Apparatus of this type is very suitable for all small animal radiographic examinations and may incorporate facilities foe additional techniques such as rapid film changing, image intensification , or tomography.