DIAGNOSTIC EFFECT OF “COMBINATION ZONOGRAPHY” IN THE MAXILLOFACIAL REGION

Abstract

Zonography is one of tomography with very narrow exposure angle from 0°to 20°, while conventional tomography which has widely applied for roentgen diagnosis in dento-maxilo-facial region is ordinarily used about 30°to 60°exposure angle.
The latter has great benefit to detect diseases occurred in craniofacial region as cross sectional image.
However, abnormal changes in detailed structures are often hidden by severe blurring shadow arising from dense structures outside the tomographic plane.
The puropose of present study is to analyze the image formation of zonogram which can be aid above mentioned fault of tomography continuously to the former report.
Authors attempted to combined several zonographies with different exposure angles and to exposed on a film for improving the image quality of conventional zonography.
We called this special technique “Combination Zonography” to compare with conventional zonography.
The results from our study were as follows.
1. Combination zonography has characteristic blurring effect differed from neither conventional zonography nor tomography.
2. The image quality is extremely good because of its effective blurring compared with conventional zonography.
3. The best zonographic combination angle is experimentally 5°+10°+15°three revolutions.
4. Combination zonography may not get only true cross sectional image like conventional tomography, but the former is much better both on contrast and sharpness than the latter.