Radiology 2 PP

• Positioning


  Can make or break a diagnostic quality radiograph
• Tools to help restrain and position patients

  • Tape
  • Gauze
  • Ties
  • Sandbags
  • Foam Wedges
  • Wooden spoons
  • Troughs
• Good radiographic images

  • At least 2 orthogonal views are needed
  • The area of interest should be closest to the plate to reduce distortion
  • When radiographing extremities, consider taking images of the contralateral limb for comparison
  • The area of interest should be centered in the central beam to allow for the least amount of distortion
  • Patient measurements should be taken at the widest part
  • Ideally, the patient should be measured in the same position as the x-ray will be taken
  • Position the patient with the thickest portion towards the cathode
• Patient positioning for small animal radiography


  • Minimize patient manipulation
  • Position and restrain in one position, expose both thoracic and abdominal studies
  • Switch patient to other position, expose both thoracic and abdominal studies
• Standard small animal radiographic projections (2-views)


  • Ventrodorsal (VD)
  • Lateral
• Ventrodorsal (VD) projection

  • Beam enters patient ventrally and exits dorsally
  • Patient in dorsal recumbency
  • L or R marker indicates patient left or right
• Lateral projection

  • Patient in lateral recumbency
  • L or R marker indicates side on table
  • Right lateral recumbency standard for routine radiography
  • Left lateral if area of interest is on left side or do both lateral views to check for metastasis
• Proper patient positioning for lateral and VD views


  • Front and hind legs extended and symmetrical
  • Spine straight
  • Sternum and spine at same height above table (lateral)
  • Front and hind legs extended and symmetrical
  • Spine straight
  • Thorax and head in the trough can help
  • Sternum directly above spine (VD)
• Timing of radiographic exposures

  Ideally, wait for inspiration on thoracic studies and expiration for abdominal studies
• Thoracic radiographic collimation


  • Entire rib cage
  • Cranial margin - thoracic inlet, tip of manubrium, cranial aspect of scapula
  • Caudal margin - last (13th) rib
• Abdominal radiographic collimation

  • Caudal half of rib cage to hip joint
  • Cranial margin – middle of the ribcage
  • Liver lies within the rib cage
  • Caudal margin – greater trochanter or pubis
• Skull radiographic projections

  • VD
  • DV
  • Lateral
  • Oblique
  • Rostrocaudal
• Skull radiographic positioning

  • Accurate symmetry important
  • Sedation or anesthesia usually required
• Intraoral (dental) radiography

  Cassette in mouth to isolate upper or lower jaw
• Spine radiographic positioning

  • Standard VD and right lateral
  • Center on area of interest (cervical, thoracic, lumbar)
  • Collimate narrowly to reduce scatter and improve image quality
• Extremity radiographic positioning

  Limb of interest closest to cassette
• Extremity radiographic collimation

  • Bones - include joints above and below the bone
  • Joints - include bones above and below the joint
• Hip evaluation techniques

  • OFA (Orthopedic Foundation for Animals)
  • PennHip
• OFA hip positioning


  • VD with perfect symmetry
  • Legs extended and parallel
  • Stifles rotated internally
  • Patellas centered on distal femurs
• PennHip hip positioning

  • Anesthesia required
  • Distraction view
  • Compression view
  • Extended view
• Abdominal and thorax radiographic technique

  • Density (brightness) - adjust mAs if too light or too dark
  • Penetration (contrast) - adjust kVp if poor contrast
• Portable radiography guidelines


  • Cassette and collimation square/line up with ground
  • Beam centered on area of interest and on cassette
  • Cassette perpendicular to beam (for most views)
  • Maintain source-image distance (26 inches)
• Equine radiography

  • Requires special high-powered equipment
  • Source-image distance 80 inches to accommodate patient size
  • Positioning - standing lateral
  • Collimation - multiple views, center beam on cassette then walk patient into collimation area
• Upper GI study

  1. NPO 12-24 hours

  2. Barium sulfate oral

  3. Series of radiographs over time (0, 15, 30, 60, 90 min, 2 hrs, 4 hrs)

  4. VD and lateral views
• Lower GI study

  1. NPO 24 hours

  2. Warm water enema

  3. Anesthesia if necessary

  4. Barium sulfate enema

  5. VD and lateral views
• Intravenous Pyelogram (IVP)

  1. NPO 24 hours

  2. IV iodide (diatrizoate)

  3. Series of radiographs over time (0, 5, 15 min+)

  4. VD and lateral views
• Cystogram


  1. Place urinary catheter

  2. Drain bladder

  3. Infuse contrast medium (positive/barium, negative/air, or double contrast/both)
• Myelography


  • Contrast study used to localize and characterize spinal cord lesions
  • Nonionic contrast medium injected into subarachnoid space
  • General anesthesia required
• Collimation of Hips- Wings of ileum to tibial crest