Animal positioning for radiography Flashcards
For xrays of horses’ feet you need to first…?
clean the hooves due to artifacts from dirty hooves.
The need to sedate or anesthetize an xray patient is determined by: (3)
Clinical condition
Projection required
Temperament
Radiological projection refers to
the region where the X-ray beam enters and exits the patient.
Radiographical examination of the thorax.
Parameters to favor?
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).
Thorax Lat - Centre primary beam on
cardiac silhouette (fifth intercostal space).
Correct or incorrect positioning?
Explain!
no side mark otherwise fine
Correct or incorrect positioning? Explain!
collimation too wide, no side mark
Correct or incorrect positioning? Explain!
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.
Correct or incorrect positioning? Explain!
they’re correct/fine
Correct or incorrect positioning?
Explain!
collimation is too small
Neck Lat (trachea) radiography (4)
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.
Trachea image
Correct or incorrect positioning?
Explain!
blurry
no side mark
legs are forward, they should be extended caudally instead
radiographical exam of the abdomen.
parameters you should favor?
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).
positioning for abdo lat xrays
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.
Correct or incorrect positioning?
Explain!
off center collimation
no side mark
Correct or incorrect positioning?
Explain!
collimation way too big
hindlegs are not extended back
no side mark
Correct or incorrect positioning?
Explain!
the entire abdomen is not in the image, collimation too small from diaphragm side as well as ventral side
no side mark
Correct or incorrect positioning?
Explain!
correct/ good image
Correct or incorrect positioning?
Explain!
collimation too big, thorax is included
not straight, there is rotation in the spine
Whole body study xray study
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.
xray Examination of the head
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.
Skull lat xrays
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.
Skull DV xray
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.
x-ray examination of the spinal column.
Parameters to favor?
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).
Cervical Lat xray
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
Cervical VD xray
Head must be straight
Forelimbs are extended caudally
The field of view should
include the base of the skull and the
second thoracic vertebra.
Examination of the thoracolumbal Lat
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.
Examination of the thoracolumbal VD
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.
xray Examination of the forelimb.
Parameters to favor?
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).
xray Examination of the hind limb.
Parameters to favor?
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.
gloves in image
no side mark
collimation large
other leg intruding on the image
condyles are not superimposed
glove in image
poor collimation
patient is not straight
collimation is poor
leg positioning is not symmetrical
artefact from foam block aid under right hock
Hip dysplasia xray examination.
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.
Describe this image in the context of hip dysplasia diagnostics. 1-6
- Spine is straight, no rotation.
- The pelvis is straight and
symmetrical, iliac crests are parallel. - The hip joints are parallel.
- Obturator foramen`s are parallel,
have the same shape and size. - Patella’s are ideally at the center
of the femur (generally they don’t fit so perfectly) - Side mark must be in the
radiograph, currently the side mark
is added later in the program, which
is not actually correct.
Elbow dysplasia examination.
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°.
