for study purpose

1. DEPARTMENT OF
VETERINARY SURGERY & RADIOLOGY
SUBMITTED BY
SUMEET PAL
M.V.SC.(1ST YEAR)
SUBMITTED TO
Dr. Rukmani Dewangan mam
Topic
Radiographic accessories used in veterinary sciences
(VSR 606)

2. Radiographic Accessories
The radiographic accessories are divided into 4 groups:
1. Intensification of X-ray image
2. Limitation of scattered radiation
3. Positioning equipment’s
4. Miscellaneous equipment’s

3. Intensification of X-ray image:
1. Intensifying screen:
• used to reduce the amount of X-Rays necessary for
exposure and thus reduces the time for exposure of the
X- ray film
• consists of a uniform homogenous coating of minute
crystals of calcium tungstate mounted on a plastic base
Construction of screen:
• consisting of four distinct layers of total thickness of
about 0.4 mm
• layers are of four types -
Cont….

4. a) Base:
• provides mechanical support to active phosphor Layer
• made up of either high grade of card board or Polyester
b) Reflecting layer:
• present in between base and phosphor layer
• made up of titanium dioxide or magnesium oxide.
• The light emitted by interaction of X-ray and phosphor layer is directed
in all directions including to wards base. The reflecting layer reflects
back the light directed towards the base of film.
c) Phosphor layer:
• main function is to convert X-rays energy into visible light.
• The materials most commonly used in phosphor layer of fluorescent
screen are calcium tungstsate, barium lead phosphate or zinc cadmium
sulfide.

5. d) Protective layer:
• transparent layer placed
above the phosphor layer
close to the film.
• consists of cellulose
compound and serves
following purposes:
1. Physical protection of
phosphor layer
2. Prevents static electricity
3. Provides a surface that can
be cleaned

7. Screen is of five types:
1) High definition or slow speed screen:
• very fine crystal of calcium tungstate to give sharpest possible image
• require 50% more exposure time than the time required by standard screens.
2) Standard screens or medium speed screen:
• crystal size is larger than the high speed, gives maximum fluorescence thus time required is
very less
• contains crystals of calcium tungstate and are very commonly used in veterinary
radiography
Cont….

8. 3) Fast or high speed screen:
• nearly twice the speed of standard screen and permits reduction in exposure factors
• major drawback of these screens is poor definition or poor quality radiograph.
Therefore its use is limited in radiography
4) Fluorazure screen:
• very fast screen and have the coating of zinc cadmium sulfide but now a days these are
not available
5) Rare Earth intensifying screen:
• Over the last 10 years anew range of intensifying screen based on rare earth phosphor
have been developed and marketed
• Considered faster than calcium tungstate screen and requires 15 to 50% less exposure

9. Care of intensifying screen:
1. Screens are expensive and easily damaged splashes of developer or scratches can damage
screen permanently and artifacts will be seen on all films taken with this type of damaged
screen.
2. Dust and animal hair can also cause damage, to avoid this the intensifying screens should be
cleaned with soft hair brush before use.
3. The super coating can be cleaned by careful swabbing with cotton wool soaked with quality
soap and than rinsed with water soaked in cotton.
4. Cassette should be kept close when not in use to prevent damage to screen.
5. Never touch the screen with the finger.
6. Maintain good screen film contact.

10. The different devices used to avoid scattered
radiation are:
• Main scatter radiation control devices are beam
collimators and grid
• Beam collimators refers to the regulation of X-ray
beam by beam restricting devices
• Metal disc with small opening in center to control
the shape and size of x-ray

11. • Collimators are of different types –
1. Cones or lead diaphragm: This
equipment is essential for safety.
• used to limit the primary beam to the
size of the X-ray film cassette being
used.
2. Aluminum filters: 1-2 mm thickness
are used on the window of the X-ray tube
head
• markedly reduces scattered radiation.

12. 3. Compression bands:
• The use of compression band is simple
and effective way of reducing the depth
of abdominal tissue of fat animals and
also helps in immobilizing them.
• The compression of tissue thickness
reduces the amount of scattered
radiation
• It consists of a band of cloth 8-12 inch
wide, which is placed across the patient
and hooked on other side of the table
• The band can be tightened across the
animal by turning the roller

13. 4. Grids:
• flat plate of about 2-4 mm in thickness
• made up of fine strips of lead which
alternate with stripes of radio lucent
material either plastic or aluminum
• placed immediately on the top of
cassette
• acts as a filter and only allows
radiation traveling in the line of
primary beam to pass through and
reach the film below
• Lead plates absorb secondary radiation
hitting the grid from other direction

14. Types of grids :
A. Stationary grids:

15. B. Movable grids (Potter Bucky diaphragm):
• This device is used
extensively in human
radiography.
• They are incorporated just
below the top of the X-ray
table, where cassette is
placed.
• It filters out the scattered
radiation while eliminating
the grid lines from the film.

16. 1. Positioning Equipment’s:
1. Table:
• most important requirement of table
used for veterinary radiography is its
rigidity
• It should be 54 inch long, 20 inch in
width and 36 inch in height
• The under surface of table should have
either Potter Bucky Diaphragm or
have lead sheet to absorb any portion
of primary beam which goes below the
cassette

17. 2. Cassette stand:
• In so many cases use of horizontal beam is
desirable and for this vertical position of
cassette is require
• . Gloves can prevent against scattered radiation
but not from the primary beam
• A movable cassette holder having facility to fit
any size of cassette and to move up or down is
the best to use for the purpose

18. 3. Troughs:
• Troughs are useful when animal had to
be placed on its back
• Radiolucent plastic foam covered
• Any size small animal can be placed
on its back
4. Hickman navicular Block:
• devised by Lt. Col. John Hickman for
critical radiography of equine navicular
bone.
• consist of block of hard board with a
longitudinal wedge and grove cut on it.

19. 6. Sand bags and soft bags:
• Sandbags can be used for raising the
part to be radiographed or holding the
cassette.
• Now a days in place of sandbags,
radiolucent bags made up of either
cotton or foam are used.
5. Plane wooden blocks:
• Wooden block of above of 6” x6” x1” are
useful for holding the cassette of
raising the part to radiographed.

20. 4. Miscellaneous equipment’s
1. Film cassette:
• light proof metal container which is designed to
hold stationary grids.
• The front face, which is of aluminum faces the
tube. It is hinged to the back section, which is
more strongly made
• Cassettes and screens are available in different
sizes as per the size of X-ray film available.
Care of cassette:
• Do not drop on the hard floor.
• Cassettes should be kept clean
• If more than one type of screen is in use then
mark outside of cassette

21. 2. Lead plates for masking :
• When more than one radiograph is to be
taken on one film than these lead plates are
used.
• The part of X-ray cassette to be radiographed
is left open, whereas other part of cassette
are covered with these lead plates
• According to the sizes of cassette, they are
available in different sizes
Cassettes Lead masking plate
15” x 12” 15”x8”
12”x10” 12”x6”
10”x8” 10”x5”
8.5”x6.5” 9”x5”
6.5”x4.57” 7”x4”

22. 1. Identification:
• Opaque lead letters and numbers of
different types are available.
• available for numbering the film, placing
date, month and year, name, right, left,
lateral or medial.
1. Measurement and centering aids:
• center of the X-ray beam is important in
radiographic positioning
• For measuring thickness of object and focal
spot film distance, measuring tape is used.

23. 2. Lead Aprons:
• designed to protect body against scattered
radiation
• should be of minimum 0.25 mm lead
equipment for voltage up to 100 KV.
• material used is lead rubber covered with
cloth or plastic impregnated with metallic
lead.
3. Lead rubber gloves:
• wide rage of types, sizes, and lead
equivalent lead gloves are available but in
veterinary radiography most commonly
0.5mm or 0.3 mm lead equivalent gloves
are used for voltage up to 100 KV.