Polymer helps minimise patient's radiation exposure in novel three-dimensional X-ray imaging process
Instrumentarium Imaging Ziehm of Nuremberg, Germany, has been manufacturing and distributing a successful range of mobile X-ray equipment for 30 years.
Its Ziehm 8000 and Ziehm Vista systems in combination with a novel three-dimensional imaging process, Tact, represent a high-performance technology package for a wide range of applications; from intra-operative radioscopy to vascular surgery examination.
Tact does not require patients to remain completely still during an X-ray procedure, thus eliminating the risk of unusable images and repeat procedures that can increase patients' exposure to radiation.
A high-precision adjustable beam restriction system providing for radiation-free virtual fade-in of image details further minimises radiation exposure.
Image detail is confined by the linear motions of the beam restrictor which are actuated by a set of gear wheels made from Victrex's Peek polymer and driven by an aluminium disk cam.
In close cooperation with Bayerschmidt Kunststoffe, which specialises in high-precision machined components, Ziehm selected Peek polymer for the gear wheels in order to meet the many demanding requirements of this application.
While exposed to an X-ray dose of up to 80rad, the wheels must transmit high mechanical forces at temperatures as high as 80C.
In addition, Peek provides good tribological properties and minimises the dry abrasion in contact with aluminium, which is an essential working requirement in the sterile environment of operating rooms.
The gear wheels are manufactured from Peek polymer stock shapes, supplied by Sustaplast.
Its low and relatively isotropic thermal expansion is a main advantage that allows the wheels to fit precisely and avoids any gaps.
Furthermore Peek polymer allows ease of machining, therefore resulting in gear wheels of the highest precision and closest fit.
