Rationale and Objectives. To detect the growth in lesions, it is necessary to ensure that the apparent changes in size are above the noise floor of the system. By introducing a fiducial reference, it may be possible to detect smaller changes in lesion size more reliably.Materials and Methods. We suspend three precision spheres with a precision structure built from a popular children s building toy. We measure the distances between the centroids of the structures three ways, namely with a high-precision mechanical method, micro computerized tomography, and medical computerized tomography.Results. The three methods are in agreement, and also agree with the design values for the structure. It is also possible to pick a threshold so that the three spheres have their nominal volumes in the medical computerized tomography images.Conclusion. The use of volumetric measures allows the determination of lengths to much less than a pixel size using materials which have x-ray properties within the range of the human body. A suitable structure may be built with a very small parts cost.
Citation: Academic Radiology
Pub Type: Journals