Large animal radiography

Question 1

Restraint LA

Answer 1

Calm voice
Slow movement
Avoid loud noises
Lifting opposite limb
Stocks
Twitch (hand or chain)
Sedation

Question 2

Safety LA

Answer 2

Use cassette holder to increase distance between tech and primary beam
Responsibility of x-ray operator to ensure nobody in primary beam
Everyone involved should be wearing PPE
Restrainer, handler/owner, cassette holder, x-ray operator, etc.
Perform x-rays in area large enough for people to safely move around patient or flee if necessary
Keep this area clean of debris/obstacles

Question 3

SID large animal

Answer 3

Variable in large animal
2 meters for thorax
1 meter for carpus/tarsus and proximal
Navicular bone – may only be inches
Most other views are 65-75 cm
Many portable machines have a sensor that indicates you are the right distance based on area being radiographed
Be consistent!
Technique chart is set up for certain SID
Constantly adjusting SID will impact quality of x-rays

Question 4

Required views LA

Answer 4

From Carpus/Tarsus distally 4 views*
Dorsopalmar/plantar
Lateral
Dorsolateral-Palmaromedial or Dorsolateral-Plantaromedial Oblique
Dorsomedial-Palmarolateral or Dorsomedial-Plantaromedial Oblique
In equine all obliques are 45-55 degrees from dorsal
In bovine all obliques are also 45-55 degrees from dorsal except foot and fetlock
Foot and Fetlock Obliques are 5 - 15 degrees from dorsal in order to separate toes
Above carpus/tarsus only require 2 views

Question 5

Distal phalanx for equine and bovine

Answer 5

Equine
Shoe must be removed
Frog and sole must be picked and cleaned
Frog is packed with radiolucent
Center on coronary band
Bovine
Foot must be picked and cleaned
Center on interphalangeal joint
Foot must be placed on a block
Have foot as close to edge of the block nearest cassette to prevent magnification
4 views:
DP*
Lateral
DLPMO
DMPLO
Use patient’s foot as your guideline for positioning all views
Check to see if foot is toed-in or toed-out and adjust accordingly

Question 6

Foot dorsal plamer/planter of LA

Answer 6

Angle tube head and cassette to angle of P2-3

Question 7

Foot lateral LA

Answer 7

Foot – Lateral
Cassette placed on medial side of limb
Center on coronary band (equine) or proximal interphalangeal joint (bovine)
Use left/right and front/hind markers

Question 8

Foot oblique LA

Answer 8

Equine: cassette placed in tunnel cover and then patient stands on it
Bovine: use wooden block – enough to see separation of claws
Angle tube head and cassette to angle of P2-3
Equine: 45 degrees from dorsal
Bovine: 15 degrees from dorsal

Question 9

How to take X-ray of High coranary

Answer 9

High P3 – Equine Only
Use cassette tunnel
Hollow box which holds the cassette and has plexiglass on top that is roughened to prevent slipping
Put paper towel on foot and then place on top of cassette tunnel to prevent greasy build up and slipping
Angle tube head to 65 degrees from vertical
Distance is approximately 28 inches
Both x-rays are positioned the same way
High Coronary has increased technique to penetrate through short pastern to visualize navicular bone
High P3 uses less technique to visualize coffin bone

Question 10

Navicular bone

Answer 10

Place cassette in cassette tunnel
Have patient stand on cassette tunnel with limb of interest positioned caudally but still bearing weigth
Angle x-ray tube approximately 45 degree angle towards caudal region of hoof
Bring x-ray tube under belly of horse
Ensure tube does not touch underbelly of hind limb region
Center primary beam between bulbs of heel

Question 11

Fetlock

Answer 11

Collimate to just the fetlock
5 views
DP(a/l)
LAT
Flexed LAT (we cannot perform here)
DMP(a/l)LO
DLP(a/l)MO
Equine obliques: 45 degrees from dorsal
Bovine obliques: 15 degrees from dorsal
Use patient’s foot as guideline for positioning all views
Check if foot is toed in or out and adjust accordingly

Question 12

Metacarpus/tarsus LA

Answer 12

Requires 4 views
DP
LAT
DMPLO
DLPMO
Include entire fetlock and as much of the carpus/tarsus as can while maintaining 3 mm border on edges of film
Oblique views are 45 degrees for both species
Require L/R and F/H markers

Question 13

Carpus of LA

Answer 13

Requires 5 views
DP
LAT
Flexed LAT (cannot perform in lab)
DLPMO
DMPLO
Obliques for both species are 45 degrees

Question 14

Skyline views LA

Answer 14

Three skyline views
65, 45, 30 degrees
Each isolates a different row of bones
Use to detect slab fractures

Question 15

Tarsus LA

Answer 15

Horsemanship safety comes first!
Stand as close to patient body as possible so if animal kicks you are only pushed, reducing injury
This means we cannot keep out x-ray safety distance
Obliques for both species are 45 degrees from dorsal
For DP view need to rotate limb slightly lateral to prevent front portion of equine from blocking x-ray tube

Question 16

Elbow LA

Answer 16

May be unable to use cassette holder in standing position
Generally done with anesthesia and in lateral recumbance
Often portable units do not have enough penetration power
Requires two people to position horse – extend and lift the leg
Keep hands out of the primary beam!

Question 17

Shoulder on LA

Answer 17

Only able to perform a lateral view
Not routine
Safest to x-ray medial to lateral

Question 18

Stifle LA

Answer 18

X-ray from caudal aspect
Large amount of scatter radiation due to thickness of area
Patient must be weight bearing in order to penetrate*
SID usually 1 M
May be difficult to use cassette holder

Question 19

Skull LA

Answer 19

Must remove halter
May mean mild sedation required
SID is 28 inches

Question 20

Guttural pouches

Answer 20

Halter removed
Requires 3 views
DorsoVentral
2 Laterals
Head in natural position
Nose pointing to the ground
Looking for fluid line on examination of radiograph

Question 21

Cervical spine LA

Answer 21

Need to use metal numbers to identify where on the spine x-ray is
Only 2-3 vertebrae fit onto a film