RELATIONSHIP OF AGE, WEIGHT AND BODY SURFACE AREA TO WARFARIN MAINTENANCE DOSE REQUIREMENTS

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72458/1/j.1365-2710.1985.tb00722.x.pd

Precision Measurement For Microsurgical Instrument Evaluation

An accurate three-dimensional optical sensing system to track the tip of a microsurgical instrument has been developed for laboratory use. The system is useful for evaluation of microsurgical instrument designs and devices for accuracy enhancement (both robotic devi:es and active hand-held instrument), as well as for assessment and training of microsurgeons. It can also be used as a high-precision input interface to micro-surgical simulators. Tracking is done by illuminating the workspace at an infrared wavelength and using optical sensors to find the position of a small reflective ball at the instrument tip. The RMS noise per coordinate is presently 1 micron. Sample results are presented

A micro motion sensing system for micromanipulation tasks

An optical-based motion sensing system has been developed for real-time sensing of instrument motion in micromanipulation. The main components of the system consist of a pair of position sensitive detectors (PSD), lenses, an infrared (IR) diode that illuminates the workspace of the system, a non-reflective intraocular shaft, and a white reflective ball attached at the end of the shaft. The system calculates 3D displacement of the ball inside the workspace using the centroid position of the IR rays that are reflected from the ball and strike the PSDs. In order to eliminate inherent nonlinearity of the system, calibration using a feedforward neural network is proposed and presented. Handling of different ambient light and environment light conditions not to affect the system accuracy is described. Analyses of the whole optical system and effect of instrument orientation on the system accuracy are presented. Sensing resolution, dynamic accuracies at a few different frequencies, and static accuracies at a few different orientations of the instrument are reported. The system and the analyses are useful in assessing performance of hand-held microsurgical instruments and operator performance in micromanipulation tasks