The simplest X-ray table is a horizontal surface with limited motion. The film cassette
tray—the Bucky—is stationary, as is the overhead tube, and the patient is positioned
using the “floating top.” The head-foot movement is generally two feet or less, with sideto-
side motion of about half the head-foot motion. Once the table and patient have been
properly aligned, the top is locked in place using electrically powered brakes. The tabletop
is made of a composite material that allows X-rays to pass through it with little or no
loss, and no additional scatter. Many of these tops have weight limits of 175–200 kilograms.
Damaged tops should be replaced when found, as they could compromise patient
safety by contributing to lock failures, poor film quality, infection, and patient injury.
Powered tables have the head/foot and side/side motions along with multicassette
trays, plus the ability to move the patient from a prone (i.e., horizontal) position to perpendicular
positions. The I/I moves with the angular position so that it is always aligned
with the tube under the table. Because there are motor drives that are used to move the
table and patient to selected angles, it is common for linens to catch in the drive mechanisms.
These should always be covered. When they are not covered, they can present a
major potential for a patient injury. In addition, it can put an unreasonably heavy demand
on the motors and can lead to failures. The locking systems in tilting tables are critical
and should be a major point on any PM program. As with the simple table, the tabletop
is subject to damage from heavy patients and should be inspected closely after a heavy
patient has been on the table. When performing annual PM inspections on the table, the
gearing should be checked for missing teeth and lint accumulation. These two hazards
can contribute to premature failures of the drive motors. When working on tables that are
used for reflux or voiding studies, one should follow universal precautions procedures
for personal protection.