Radiography of Limbs and Radiation Safety

Radiography of Limbs

• In a bovine radiograph, the distal end of the forelimb or hindlimb has one complete digit, the 3rd, with two reduced splints metacarpals (2nd and 4th), each exhibiting a ventral ridge.
• The main digits in a bovine radiograph are the 3rd and 4th, while the 2nd and 5th are represented by small dew claws.

Radiation and Safety

• Alpha radiation can be stopped by 2 cm of air or a thin shield, but it is not suitable for human protection.
• Beta radiation can pass several meters through the air, but can be stopped by a 0.6 cm plastic shield.
• X-ray radiation can be stopped by a lead shield, while gamma radiation is less penetrating than X-ray and requires a concrete shield for protection.
• The current annual occupational limit for adults is 0.5 Sv per year for individual organs or tissues, except for the lens of the eye, which is 0.15 Sv per year.

Contrast Agents in Radiology

• Contrast agents are used to visualize internal structures in radiography.
• Iodine compounds are the most common contrast agents used, but barium sulfate is used in cases of suspected gastrointestinal perforation.

Radiography of the Esophagus and Stomach

• The most common views for the esophagus are the lateromedial and oblique views, as the ventrodorsal view is superimposed by the vertebrae.
• The normal existence of gas within the gastric cardia helps identify the first part of the stomach on the right lateral view.
• On the left lateral view, care must be taken to distinguish the pylorus from an abnormality.

Radiography of the Abdomen and Urogenital System

• For emergency examination, the digestive system should be empty, and a laxative should be given to the animal for better visualization of the abdominal contents.
• The kidneys and esophagus are seen in about 50% of total images, clarified by fat surrounding the esophagus or a trace of air in the kidney.

Radiography of the Lung and Pleural Cavity

• Accumulation of fluids in the pleural cavity decreases the opacity of the cavity and reduces the size of the lung radiographically.
• Hydrothorax leads to a reduction in lung size and an increase in lung opacity compared to the pleural cavity.

Radiography of Bones and Muscles

• Bones are easily seen radiographically due to the presence of calcium and phosphorus, which absorb radiation.
• The muscular system is not easily seen radiographically due to the low absorption of radiation.

Radiology of the Kidneys

• In dogs, the right kidney is usually cranial to the left, located at approximately T13-L2, while the left kidney is located at approximately L1-L3.
• The length of the kidney is about 2.5-3.5 times the length of the body of the L2.
• In cats, the kidney is about 2.4-3.0 times the length of the L2 and has an oval shape with more mobility in its location.

Radiological Reports

• A radiological report should include the diagnosis and any abnormalities seen in the radiograph.
• Examples of radiological reports include:
  • Gastric dilatation and volvulus
  • Transverse fracture lines within the 3, 4, and 5 metacarpal bones
  • Oblique unstable metatarsal bones fractures
  • Normal appearance of the humerus, elbow joint, and radius and ulna with soft tissue recommendations
  • Cystolithiasis and Urethral lithiasis

Canine Hip Dysplasia

• Radiological findings of hip dysplasia or dislocation include:
  • Norberg angle (105o) is considered normal
  • Loss of spherical shape of the head
  • Shallow "C" or cup-shaped acetabulum