1-8.
OVER-TABLE COLLIMATOR
a. Maintenance. The collimator system must be properly maintained to assure
both compliance with the Bureau of Radiological Health (BRH) regulations and useful
life. Preventive maintenance is to be performed once every twelve months. This
includes inspection and lubrication of both the cassette tray(s) and collimator
mechanism. Check the collimator if any of the following conditions occurs.
(1)
Lamp replacement.
(2)
Premature electronic component failure.
(3)
When the collimator is removed from the tube/housing assembly.
(4) When the collimator and/or cassette tray have been subjected to
external damage.
b. Operational Checkout Procedures. The following procedures form a
means to check operation of the over-table collimating system. They also form a key
troubleshooting aid by using internal SID and indicated radiation (IR) signals to check
for correct logic PCB and collimator response, followed by use of external signals to
check the wiring. Although some signals are internally simulated, external wiring or
component defects can prevent proper operation by producing false input signals. An
external short circuit to ground for example, on the 40-inch SID switch will prevent the
40-inch indicator from coming ON. During any of the following tests, you must identify
and correct an incorrect indication or operation before continuing with the tests. These
procedures are listed in a specific sequence; altering the sequence will result in
misjudgment and a waste of time.
NOTE:
If you are installing an X-ray system you have legal obligations. Prior to
release of the system to the user, the results of each step must be as defined.
Enter the appropriate data in the spaces provided in the compliance data-log
and retain them for your records as proof these tests were successfully
performed.
c. Equipment Required.
(1) The X-ray tube support and the table must include angulation indicators
to be used for the following tests.
(2)
The X-ray tube-support device also must include SID-indicating means.
(3) Measuring tape or ruler to be used as a backup for the SID indicating
means and as an operational range measurement.
MD0351
1-35