RERC is one of the pioneering research groups that has been on the cutting edge of using 3-D laser technology to rapidly scan and generate accurate 3-D models of limbs, feet, & torso for use in CAD/CAM software to produce better fitting prosthetics and orthotics.

Casting vs. Scanning
The standard method of casting human limbs, feet, etc. has many drawbacks. It is very subjective. How tightly the plaster wraps are wound varies between prosthetists and from one cast to another. This affects volume and shape of the resulting model. Prosthetists will often modify the cast while it is drying on the patient by pressing on the cast in certain areas. This is also very subjective and variable. Prosthetists will often attempt to transfer landmarks to the cast by marking the patient with a pen. Movement during casting can shift these landmarks. It is very time consuming for both the prosthetist and the patient. Wrapping and drying can easily take one hour. Then the prosthetist has to cut off the cast to remove it and attempt to bring the seam back together without altering the shape or volume. He then must pour plaster into the cast and wait for it to harden, then cut the cast off (destroying the ability to make another copy).

Scanning is fast (from 3.5 to 10 secs), reliable, and repeatable. Anatomical landmarks placed on the skin are read by the scanner and precisely attached to the resulting electronic 3-D model of the subject. This model is easily stored and can be retrieved at any time in the future for use in a CAD/CAM socket design modification program.

Scanners
Working with leading optical scanning manufacturers such as Cyberware, RERC has developed high accuracy scanners for use in the field of prosthetics & orthotics. The BelowKnee Prosthetic Optical Digitizer was specifically developed by Cyberware for the RERC to quickly and accurately scan the residual limbs of below knee amputees. RERC developed custom operator software to easily scan, detect and identify landmarks, and save the resulting electronic 3-D model to a file that can be read into leading Socket Design CAD/CAM application packages. A number of BK scanners are currently being field tested at VA stations across the country.

The LowerLimb Optical Digitizer has the same advantages as the BK scanner but was designed for patients with amputations above the knee. To properly design an AK socket the lateral hip and the area between the legs on the amputated side must be accurately characterized. The Lower Limbs digitizer's unique head design with tilted viewing angles allows these areas to be scanned. The extended travel of the heads also allows for the scanning of an entire leg for the design of braces and orthoses.

The 3-D Pedorthic Optical Digitizer is a unique scanner that creates accurate 3-D models of the whole foot and ankle. The scanner can mimic current foot casting practices in that it can scan while the foot is on platforms with various heel heights as well as on a flat surface. Imbedded force transducers measure the total weight as well as the relative position of the weight distribution. This information is displayed in real time to the subject. Goal weights and positions can be set so that the patient can dynamically control the amount of body weight and relative positioning during the foot scan. Small landmarks are also easily transferred to electronic 3-D models. This file can be input into RERC's custom Pedorthic CAD/CAM system to design lasts, insoles, and shoe upper patterns used to manufacture of footwear.

The Whole Body Optical Digitizer uses four optical scan heads with a custom made system of uprights and servo motors to control scan head movement. The digitizer is capable of scanning the whole body in one scan and can be used for custom body braces, equipment fitting and possible applications to clothing and uniform fitting.