a. Maintenance. The collimator system must be properly maintained to assure
compliance with the Center for Devices and Radiological Health (CDRH) regulations
and useful life. Preventive maintenance is to be performed once every twelve months.
This includes inspection and lubrication of the collimator mechanism. You should also
checkout the system under the following conditions.
Premature electronic component failure.
When the collimator is removed from the tube/housing assembly.
When the collimator has been subjected to any external damage.
b. Operational Checkout Procedures.
(1) Description. The following procedures require the alignment of the
tube/collimator with the SFD and image intensifier be performed and verified as per
paragraph (2) below. If after performing this step it becomes evident the collimator
shutters are still not evenly shown on the edges of the fluoroscopic image, this
procedure should be stopped. Then refer to the alignment procedure in the
manufacturer's technical manual for the X-ray table to correct the problem.
(a) Should difficulty arise in obtaining the desired results of this
procedure or if maintenance has been performed on the table/tower assembly, the
under-table logic PCB calibration procedure described below should be performed.
The "RUN" mode must be selected on the under-table logic PCB while
performing this procedure.
(b) To select the "RUN" mode place switch SW2 in the "0" position.
This places the collimator in "RUN" and the "RUN" message appears in the
alphanumeric display. This is the normal operating mode for the collimator system. It
allows the collimator logic to properly position the collimator head shutters upon
command of the SFD. It also enables the error-detection software of the under-table
logic PCB. If a system error is encountered during operation of the collimator logic, the
message "ERR1" will be displayed in the alphanumeric display. The message typically
indicates the collimator shutters are incapable of driving to their proper position within a
time period of approximately four seconds. Possible causes for this can be blockage of
the shutter mechanism, broken signal leads, or improper calibration. The error code is
display for five seconds, at which time the collimator will again try to adjust itself to the
Upon completion of the calibration procedure, the calibration switch SW2
must be placed in the position 0, RUN, in order for the collimating system to