Animal positioning for radiography

Question 1

For xrays of horses’ feet you need to first…?

Answer 1

clean the hooves due to artifacts from dirty hooves.

Question 2

The need to sedate or anesthetize an xray patient is determined by: (3)

Answer 2

 Clinical condition
 Projection required
 Temperament

Question 3

Radiological projection refers to

Answer 3

the region where the X-ray beam enters and exits the patient.

Question 4

Radiographical examination of the thorax.
Parameters to favor?

Answer 4

High kV (tube voltage, contrast) and low mAs (milliampere-seconds, xrays density) should be used.

➢ High kV - the scale of contrast can be
increased to maximum for thorax.

➢ Low mAs, reduces exposure time
(breathing in and out, loss in detail).

Radiographs of the thorax should be made in inspiration (very difficult to get the timing right).

Question 5

Thorax Lat - Centre primary beam on

Answer 5

cardiac silhouette (fifth intercostal space).

Question 6

Correct or incorrect positioning?
Explain!

Answer 6

no side mark otherwise fine

Question 7

Correct or incorrect positioning? Explain!

Answer 7

collimation too wide, no side mark

Question 8

Correct or incorrect positioning? Explain!

Answer 8

side mark is too far to edge in upper left, collar not removed.
patient is not straight/ spinal column is rotated.
limbs should be extended cranially.
collimation is too large.

Question 9

Correct or incorrect positioning? Explain!

Answer 9

they’re correct/fine

Question 10

Correct or incorrect positioning?
Explain!

Answer 10

collimation is too small

Question 11

Neck Lat (trachea) radiography (4)

Answer 11

 Head extended. Place a wedge
beneath the nose.

 Be sure there is no rotation and if
needed use foam blocks to keep the
spine parallel to the table.

 Forelimbs extended caudally towards
the abdomen.

 Collimate to include the area from
temporomandibular joint to the
thoracic inlet.

Question 12

Trachea image
Correct or incorrect positioning?
Explain!

Answer 12

blurry
no side mark
legs are forward, they should be extended caudally instead

Question 13

radiographical exam of the abdomen.
parameters you should favor?

Answer 13

High mAs and low kV should be used.

mAs (milliampere-seconds, xrays density)
kV (tube voltage, contrast)

➢ Abdomen contains many organs (soft
tissue density), high mAs provides
better definition of these organs.

Lower kV settings increase the contrast between different tissues. Higher kV would result in more penetrating X-rays, reducing the contrast between these tissues and making it harder to distinguish between them.

➢ They recommend expiration when
doing abdomen projections (difficult
when the patient is not sedated).

Question 14

positioning for abdo lat xrays

Answer 14

 Forelimbs extended cranially and the
hind limbs slightly extended caudally.

 Centre the X-ray beam on the last rib
of the abdomen (middle of the
abdomen) - touch the iliac crest (hip bone), the radiation field should include this area
also.

Question 15

Correct or incorrect positioning?
Explain!

Answer 15

off center collimation
no side mark

Question 16

Correct or incorrect positioning?
Explain!

Answer 16

collimation way too big
hindlegs are not extended back
no side mark

Question 17

Correct or incorrect positioning?
Explain!

Answer 17

the entire abdomen is not in the image, collimation too small from diaphragm side as well as ventral side

no side mark

Question 18

Correct or incorrect positioning?
Explain!

Answer 18

correct/ good image

Question 19

Correct or incorrect positioning?
Explain!

Answer 19

collimation too big, thorax is included
not straight, there is rotation in the spine

Question 20

Whole body study xray study

Answer 20

Sometimes done when client funds are restricted.

Parameters:
➢ Depends which part of the body is
more important, thorax or
abdomen (parameters can be
adjusted).

Whole body study can favor thorax parameters.

Question 21

xray Examination of the head

Answer 21

Depends on the location of the
structure to be examined.

2 general projections:
 Skull Lat
 Skull DV

There are many special skull
projections.

The scattering filter (anti scatter
grid) is not usually used (only in
large breeds). Depends on thickness of the structure.

Question 22

Skull lat xrays

Answer 22

Forelimbs extended caudally, out of the field of view.

Head in natural extension (if needed use
wedge to ensure that muzzle is parallel).

Ensure that ears do not interfere (move them out of the way).

Centre beam on the eyes.

Question 23

Skull DV xray

Answer 23

 Head must be perfectly symmetrical
position, avoiding any rotation.

 Collimate the field of view to include the
whole head.

 Ensure that ears do not interfere (move
them out of the way).

 Centre the primary beam on the cranium.

Question 24

x-ray examination of the spinal column.
Parameters to favor?

Answer 24

High mAs and low kV should be used.
➢ This provides adequate contrast between the bone and soft tissue.

mAs (milliampere-seconds, xrays density)
kV (tube voltage, contrast)

 For correct positioning and a good
examination of the spinal column, it is
necessary at least, sedate the patient:
➢ Examination can be painful.
➢ Positioning is crucial to establish
correct radiological diagnosis.

 Various aids should be used (sand bags, foam blocks and so on).

Question 25

Cervical Lat xray

Answer 25

Head extended, place a wedge beneath the nose, and if the mid-cervical area appears to be sagging, place a flat piece of positioning foam to keep the spine parallel to the tabletop.  Forelimbs extended caudally towards the abdomen.  Center point: mid-cervical

Question 26

Cervical VD xray

Answer 26

Head must be straight Forelimbs are extended caudally The field of view should include the base of the skull and the second thoracic vertebra.

Question 27

Examination of the thoracolumbal Lat

Answer 27

Forelimbs and hind limbs moderately extended cranially and caudally, respectively.  If needed use the wedge and foam blocks.  For thoracolumbar spine, collimate the field of view to include C7 to S1.

Question 28

Examination of the thoracolumbal VD

Answer 28

Forelimbs extended cranially and the hind limbs extended slightly caudally and positioned.  For immobilization use sandbags.  For thoracolumbar spine, collimate the field of view to include C7 to S1.

Question 29

xray Examination of the forelimb. Parameters to favor?

Answer 29

Relatively high mAs, and not too high kV should be used. mAs (milliampere-seconds, xrays density) kV (tube voltage, contrast) Various aids should be used (sand bags, foam blocks and so on). Sedation helps to get good quality (fractures and dislocations can be very painful).

Question 30

xray Examination of the hind limb. Parameters to favor?

Answer 30

mAs are high and kV depend on the thickness of the region. mAs (milliampere-seconds, xrays density) kV (tube voltage, contrast)  Sedation helps to get good quality (fractures and dislocations can be very painful).  Stifle Lat- Lateral recumbent position. The femoral condyles are superimposed.

Question 31

Answer 31

gloves in image no side mark collimation large other leg intruding on the image condyles are not superimposed

Question 32

Answer 32

glove in image poor collimation patient is not straight

Question 33

Answer 33

collimation is poor leg positioning is not symmetrical artefact from foam block aid under right hock

Question 34

Hip dysplasia xray examination.

Answer 34

 Hip dysplasia is a congenital disorder characterized by an abnormal or false hip development. conventional radiography main method for the diagnosis of hip dysplasia for adult dogs ( 12–24 month old).  The dog is either anesthetized or sedated to guarantee adequate muscle relaxation.  The hind legs are extended caudally and the femur has to be parallel to the spine).  Patellas have to be at the center of the femor.

Question 35

Describe this image in the context of hip dysplasia diagnostics. 1-6

Answer 35

1. Spine is straight, no rotation. 2. The pelvis is straight and symmetrical, iliac crests are parallel. 3. The hip joints are parallel. 4. Obturator foramen`s are parallel, have the same shape and size. 5. Patella's are ideally at the center of the femur (generally they don't fit so perfectly) 6. Side mark must be in the radiograph, currently the side mark is added later in the program, which is not actually correct.

Question 36

Elbow dysplasia examination.

Answer 36

Canine elbow dysplasia (ED) is a disease of the elbows of dogs caused by growth disturbances in the elbow joint. The dog is either anesthetized or sedated to guarantee adequate muscle relaxation. Elbow Lat (mediolateral)- elbow extension angle 30-45°. Elbow AP- humerus turned in 10-20°.