MTR221/A - MTR221/A DHHS
MANUALE ISTRUZIONI / INSTRUCTION MANUAL
Modello/Model R221/A - R221/A DHHS
CALIBRATION
19
R221/A - R221/A DHHS - Calibration
Ralco srl
CALIBRATION
CENTERING X-RAY BEAM WITH COLLIMATOR LIGHT
• Place a 35 x 43 cm. (14 x 17") cassette on the table top or other flat, horizontal surface.
• Position the X-ray tube/collimator assembly with the focal spot at 1 meter (40") over the
cassette with the X-ray beam perpendicular to the cassette surface. Do not use
measurement indicators on the system as reference values, but measure the distance from
the focal spot to the cassette surface with a tape measure of similar device.
• Use the collimator light to center the cassette in the field.
• Mark the location of the cassette with masking tape
or other means so that it may be removed and
replaced in the same position.
• Place white paper on top of the cassette to provide
maximum contrast for the light field.
• Set the collimator to provide a field size of 30 x 30
cm. (12” x 12") at 1 meter (40").
• Activate the light field and use it to position 18 coins
as shown in the diagram.
• Position each pair of coins touching one another so
that the inner coin is lighted as much as possible and
the outer coin is lighted as little as possible.
• The points where the coins contact will define the
edges of the light field.
• The extra two coins are to be set:
• One in a corner to ascertain film position.
• The other at the intersection of the diagonals to define film center.
THE FOLLOWING PROCEDURES REQUIRE THAT X-RADIATION BE PRODUCED. TAKE ADEQUATE
PRECAUTIONS TO MAKE CERTAIN THAT NO PART OF THE HUMAN BODY IS EXPOSED
TO X-RADIATION, DIRECT OR INDIRECT.
IF THE DISTANCE OF 1 M SID CANNOT BE DETERMINED, USE THE SID VALUE CLOSEST
TO ONE METER AND CALCULATE THE MEASUREMENT TOLERANCES AS THE APPROPRIATE
PERCENTAGES OF THE DISTANCE.
IF THE X-RAY BEAM CANNOT BE POSITIONED VERTICALLY USE CLAMPS, MASKING TAPE,
OR OTHER MATERIAL AS REQUIRED TO POSITION THE X-RAY TUBE AND IMAGE RECEPTOR.
THE X-RAY TUBE AND THE IMAGE RECEPTOR MUST BE SET OUT AT THE SPECIFIED
SID DISTANCE PERPENDICULARLY TO THE X-RAY TUBE AS DESCRIBED IN THE FOLLOWING
PROCEDURE.
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