Positive positioning thermocouple positioner.

Designed and Build by John L. Sokol in 1988 at the Stanford Medical School

Notice there are 2 stepper motors, these were controlled via the Parallel port of a 10 Mhz 286 system running DOS and Turbo Pascal v5.
A custom stepper controller was built for this.   The code operated the positive positioner drum (right) and the take up rollers (left) together in sync
 to allow very rapid movement and quick settling times 2 second for 10 Cm Travel using Teflon coated Copper constantine thermocouple or
 the Luxtron fiber optic probes.   Also notice the Luer Lock connectors at the end of the tubes that allowed the thermocouples (this white fibers at the ends of the tubes) to be clipped directly to the ends of stainless steel trocars that had been implanted into a patient.
This device was used in about 20 live human cancer treatments.
 
 
 

Thermocouple Scanner hooked into an ultrasound absorbing "Phantom" to measure power vs. position from 1 & 2 Mhz Ultrasound Transducers.

Another photo of the front of the device.
The front roller is 2 rollers.  The lower roller, not visible, is a copper rod covered in heat shrink tubing and is directly connected to the stepper motor.
The Top roller is free and held in place by 2 spring loaded ball bearings. There are set screws that adjusted the tension on the springs allowing the
right amount of slip against the teflon or plastic fibers used for temperature sensing.