Ralco R 302F/A, Инструкция по эксплуатации

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MTR302/A - R302F/A - R302L/A DHHS
MANUALE ISTRUZIONI / INSTRUCTION MANUAL
Modello/Model R302/A
Calibration
2
R30
2/A
- Cali
bration
Ralco
srl
Collimator to Focal Spot Alignment (Primary Shutter Cut-Off)
Inspect the four images of the four collimator shutters which form the edges of the x-ray field.
A definitely indistinct edge indicates that the primary shutter, close to the focal spot, is the one
forming the line, rather than the outermost shutter.
To correct the condition, use the four mounting/centering adjustment screws to shift the
collimator in the direction of the indistinct line.
Repeat the test film exposure after making the adjustment.
L
IGHT
F
IELD TO
X-
RAY
F
IELD
A
LIGNMENT
EN 60601-1-3 par 29.202.9
Misalignment of the light field/ x-ray field in either the X (cross table) or Y (long table) direction
must not exceed 2% of the FFD. In this case, it would be less than 20 mm (0.80"). If the test
film shows that the light field (shadows of the markers) matches the x-ray field ( shadow of the
collimator shutters) to within the diameter of one marker and, if the diameter is less than 20 mm
(1.80"), then alignment complies with the regulations.
Greater precision than this is possible. Recommended maximum deviation is one fourth. it is
important that the greatest degree of congruency possible is achieved.
If misalignment is detected in both X and Y directions, check that spacing from the focal spot
to the collimator mounting surface is 80 mm (3.14") +/- 1 mm. If spacing needs to be adjusted,
repeat the test film exposure after the adjustment.
If the collimator mount spacing is correct, but adjustment is still necessary proceed as follows:
• Place the test film on the face of the cassette over the white paper.
• Place the cassette in the position originally marked.
• Check the correct position of the film by the shadows cast by the markers.
• Using the images of the collimator shutters as the references for the shape and size of the
x-ray field, adjust the light field to match.
• If adjustment is necessary, adjust the travel of the light-field in the transversal, vertical and
longitudinal displacements.
L
IGHT
F
IELD
C
ALIBRATION
Longitudinal Alignment (Long)
• Remove part of the cover - See Chapter -
C
OVER
R
EMOVAL
.
• If the light-field needs to be moved laterally, loosen (not remove) the fixing screws
A.
T
HE HEEL EFFECT WILL CAUSE THE FIELD TOWARD THE CATHODE TO BE
SLIGHTLY LESS SHARP THAN ON THE OTHER THREE SIDES
.
THIS IS NORMAL
AND CANNOT BE CORRECTED BY ADJUSTMENT
.
IN ADDITION
,
AN X
-
RAY TUBE
OF
12 °
OR LESS TARGET ANGLE WILL PRODUCE AN ASYMMETRICALLY SHAPED
FIELD WHEN A LARGE FIELD SIZE IS USED AT SHORT FFD
(
SID
),
BECAUSE
OF ANODE CUT
-
OFF EFFECT
.
THIS IS NORMAL AND MAY NOT BE CORRECTED
BY ADJUSTMENT
.
DO NOT TOUCH THE DISSIPATOR WITH YOUR HANDS
;
IT COULD BE
HOT AND CAUSE SEVERE BURNS
.