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The Challenge:
A company which produces equipment for
radiation therapy requires a two axis (X-Y) positioner which could precisely position a patient (on a hospital bed) for treatment with radiation.
The operator positions the bed to a pre-determined
location, determined by the physician, under a radiation head. A grid is then established with each grid location 12 mm apart. A radiation stream is applied to the affected tissue at the first
location. Once the dosage is completed, the patient is then re-positioned to the second grid location for the next dose. This process continues until the affected area
is completely treated. While the positioning accuracy requirement is not extremely tight, it must be absolutely reliable with a 100% confidence level.
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The Solution:
An (X-Y) linear positioning system comprised of (2) modified 404XR tables with a travel range of 300 X 300 mm. Modifications include hand crank
drives, tape scale encoders for positive position feedback, and a black anodized finish. The 404 XR series was chosen because of the following characteristics:
- it is completely sealed;
- it is lightweight;
- it has a tape scale encoder option;
- it is easily adapted for a manual handcrank
- it can be easily converted (on site) for motor driven operation.
The first ten units were installed in 1998 and have been
successfully operating with zero maintenance required. Since that time an additional 40 units have been in-stalled and performing with complete reliability.
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