A Low-Cost Fiducial Reference Phantom for Computed Tomography.
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. We suspend three precision spheres with a precision structure built from pieces 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. 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. The use of volumetric measures allows the determination of lengths to much less than the voxel 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.
Photon Physics Group National Institute of Standards and Technology, Gaithersburg, MD 20899-8410.
Zachary H
ZH
Levine
Photon Physics Group National Institute of Standards and Technology, Gaithersburg, MD 20899-8410.
Steven
S
Grantham
Large-Scale Coordinate Metrology Group National Institute of Standards and Technology, Gaithersburg, MD 20899-8211.
Daniel S
DS
Sawyer
Department of Electrical and Computer Engineering Cornell University, Ithaca, New York 14853.
Anthony P
AP
Reeves
Weill Medical College Cornell University, New York, New York 10065.
David F
DF
Yankelevitz
Coordinate Measuring Machine; centroid; dimensional reference; medical phantom; second moment tensor; tomography