New comprehensive surgical procedures for the correction of severe craniofacial anomalies have resulted in a need for precise anatomical information for presurgical planning. The extreme variability in expressivity of these anomalies has served to make this need particularly urgent. This, in turn, has led to requests for increasing numbers of torrographic scans for assessment of these patients. Both standard and computed tomograms are used for this purpose. Unfortunately, there is an extreme paucity of information on comparative radiation dose levels and comparative image quality among these methods and their use may, in some instances, place patients at undue risk. For purposes of the current study, a phantom head was constructed which allowed the measurement of the Threshold Quality Factor (TQP) as a function of radiation dose. Quantitative results obtained from this phantom and from cadaver heads on three CT units (CT/T GE, Delta 50, and EMI 5005) and from one standard tomographic unit (CM Stratomatic) were compared in terms of dosimetry, quantified image quality, and subjective clarity of anatomical landmarks. Based on findings in this study, it is suggested that a diagnostic hierarchy could be formulated which would significantly reduce the total radiation levels to which specific types of patients are exposed.

Date Published: 27 December 1977
PDF: 9 pages
Proc. SPIE 0127, Application of Optical Instrumentation in Medicine VI, (27 December 1977); doi: 10.1117/12.955964

Published in SPIE Proceedings Vol. 0127:
Application of Optical Instrumentation in Medicine VI
Joel E. Gray; William R. Hendee, Editor(s)