Towards improvements in radiographic growth measurement of long leg bones in children

The problem of determining and correcting measurement errors in radiological estimates of the bone lengths and differential growth of children's legs is discussed. Sources of possible measurement error are first classified as being physiological, psychophysical, or psychological. The extent of the contribution of each of the identified sources of error to the overall measurement error is then estimated by experiments using a bone phantom and specially constructed test fixtures. Procedures are specified for reducing significant contributors to the overall error. In particular, the problem of radiolucency of bone cartilage is treated by combining a mammographic x-ray technique with computer processing of the radiogram. Also, suggestions are made as to how to reduce the human error. A description of the special purpose scanning system built for use in the computer processing studies is included. The scanning system offers the unique advantage of digitizing an 11 by 11 inch radiogram, or smaller subsections, with virtually any prespecified resolution.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat