the barrel structure are 18 inches in diameter. The outer ring
is hardened steel with a ring gear attached. The horizontal and
vertical support structures are made from standard extruded aluminum
profile sections. The gantry is equipped with a motor
drive with a worm gear to allow for rotation of the gamma detectors
and the X-ray system in order to obtain multiple projections
for tomographic image reconstruction. An additional
motor is used to translate the animal bed horizontally in and out
of the active areas of the gamma detectors and X-ray system.
The stepper motor driver is a Velmex, Inc. model NF90 that can
control three individual stepper motors. The Velmex driver interfaces
to a G3 Macintosh desktop computer via an RS232 port.