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Installation Instructions
Instructions to Installers:
Proper installation of this
Cephalometric System
requires exposure of film to
x-rays without patient
participation. Legal
requirements for radiation
exposure vary and should be
reviewed before
installation. Good practice
assumes the installer is
qualified o expose film to
radiation and that
appropriate user safeguards
are used.
FILM CASSETTE: A Standard
8XIO film cassette with two
intensifying screens is
required. Best choice is
Kodak XOMATIC cassette, with
LANEX REGULAR screen and
Kodak T-MAT-L film. That
combination works well with
a 70 KVP output at about 1
second. If to shorten the
focal length up to 6 inches.
Mounting Instructions:
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The head holder and beam
limiter are designed to
bolt to the wall
approximately 60 inches
apart.
-
It may be mounted on
either a single wall or
adjacent walls.
-
An adjustable operating
stool is used to
position the patient.
-
The desired mounting
height from the floor is
a function of the
operating stool height.
A. First place an adult on the stool adjusted to
a full DOWN position and
measure the
height of the patient's
ears from the floor.
B. Then place a child on the same stool adjusted
in a full UP position
and re-measure
the child's ear height.
-
Using those parameters,
determine the ear rod
height from the floor.
A. That measurement will apply to the center of
the beam limiter tube,
(which is 4" outside
measurement).
Mounting the Headholder:
-
Using the determined
height from the floor,
mount the head holder to
the wall using the
enclosed anchors and
screws.
Pre-plan the layout to
allow a distance of
54-60 inches between the
film and the aluminum
disc in the X-Ray head.
Depending on your x-rays
KVP and ma. (See
exposure guide)
This is a good time to
talk about walls and
corners. None are truly
straight and the x-ray
beam we are aiming is
absolutely straight. Any
variation in the wall's
true or plumb become a
problem.
Assume your walls are
off and accept them. By
using the orange plastic
caps installed on the
beam limiter, you can
overcome irregularities
in walls and corners.
The trick is to mount
the head holder, using a
level to get the
ear-rods true, and then
use the enclosed string
to position the beam
limiter.
Plan to use tongue blade
wedges or washers to
shim the mounting bases
to compensate for
errors.
-
Use a carpenter's level
to level the ear rods.
A good system is to
drill one mounting hole
for the upper right
corner, use that screw
to hold the head holder,
(a little help is
handy), and level the
ear rods. Then mark and
drill the other three
mounting holes. Before
you snug the mounting
screws, rotate the gear
box 90 degrees and use
the level to check the
ear rods in that
position. Use shims to
correct as necessary.
Shims work find if you
don't need too many of
them. Occasionally it is
better to bend the bead
holder itself. This can
be done with a moderate
sized adjustable wrench
applied to the 1/2 X 1'
aluminum main supporting
bar. Be careful to make
your bends sparingly,
and recheck with the
level between the ear
rods.
Perfection is a goal,
not a necessity. Patient
heads are not
symmetrical; ears vary
in height from right to
left, ear rods are
rarely inserted
perfectly. In short
cephalometries analysis
is flawed at best. The
most accurate part of
the system is the
cephalostat, so don't
lose prospective.
Mounting The Beam Limiter:
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With a helper, use the
string provided to make
a loop large enough to
go around the ear rods.
-
Then stretch the string
to a pre-marked spot on
the wall which will give
you the 60" from film to
aluminum disc.
The string should start
in the back of the beam
limiter and pass through
the larger "float" hole
in the front of the
cylinder. This "float"
hole allows you to move
the beam limiter in any
plane to position the
string in the center of
the hole. Since the
string mimics the
central x-ray beam, it
compensates for
irregularities in the
wall.
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Move the beam limiter as
necessary to align the
string in the center of
the hole and have your
helper mark the mounting
base corners. Remember:
you may need to use
shims to align the
string.
This string and "float"
hole system will net an
alignment to about 1/16"
accuracy. The ret can be
done with the alignment
screws in a beam
limiter.
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Without a patient, take
an x-ray to check
alignment.
Use regular dental x-ray
film taped to the back
of the ear rod farthest
from the x-ray. Note
that one ear rod has a
brass wire around it to
let you see which is
which on the x-ray.
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Adjust the six screws in
the beam limiter to
compensate, and continue
check and adjusting
until you are satisfied
with the alignment.
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Then lock the adjusting
screw nuts to prevent
slippage.
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Loosen the black knobs
on top of the limiter
and remove the tube
head. Re-insert it and
check again to be sure
the position can be
duplicated.
Adjusting Field Size:
The variable aperture has
been preset to provide a 7
1/2" x 9 1/2" pattern at
60'. It may be necessary to
change the setting to fit
your application. This is
easily done by loosening the
four small screws in the
front of the beam limiter
slightly and sliding the
required slide to the
desired position. Do not
over tighten the four
screws.
The goal is to limit the
x-ray beam to a film target
slightly smaller than the
film itself to assure there
is no stray scatter
radiation. Adjust the slides
to provide about a 1/4n
border around the film.
Technically the border is
not necessary, since federal
regulations only require
that 98% of the x-rays
strike the film receptor:
however, when a border, is
left, there is no doubt that
the system meets and exceeds
federal regulations.
Testing:
When an acceptable film has
been exposed with the
desired border, snug all
adjustment screws to remove
any slack in the system.
Tighten all lock nuts to
prevent movement. Remove the
tube head from the beam
limiter and re-insert for a
final test.
See
Information to
User/Operating Instructions
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