Calibration of a Computer Assisted Orthopedic Hip Surgery Phantom
Daniel S. Sawyer, Nicholas G. Dagalakis, Craig M. Shakarji, Yong Sik Kim
Orthopedic surgeons have identified a need for calibration artifacts (phantoms) to establish the traceability (to the SI unit of length) of measurements performed with Computer Assisted Orthopedic Surgery (CAOS) systems. These phantoms must be lightweight, easy to transport and simple to use. In collaboration with medical professionals, National Institute of Standards and Technology (NIST) researchers have developed a family of novel CAOS phantoms designed to meet the metrology needs of this critical segment of the US healthcare industry. The phantoms function as a surrogate hip joint and pelvis and can be measured with CAOS systems using the same technique employed to measure a patients hip joint and pelvis for replacement surgery. The phantoms contain a mechanical ball joint, which functions as a substitute for a patients hip joint and small holes, referred to as target holes, for receiving the measuring probe of CAOS systems. The location of the mechanical ball joint and the relative positions of the target holes are measured using the CAOS system and the results compared to the known values for these quantities. The results of this comparison are then used to verify the CAOS system performance specifications. In order to determine the known values for the critical dimensions of the phantom, the mechanical ball joint location and target hole positions are measured with a Coordinate Measuring Machine  (CMM), which is more accurate than CAOS Systems. This paper will report on the calibration of the NIST prototype phantom using a CMM & simulation tools at NIST.
Performance Metrics for Intelligent Systems Workshop, PerMIS'08
August 18-21, 2008
2008 Performance Metrics for Intelligent Systems (PerMIS'08) Workshop