Digital Subtraction X-ray Stroboscopy on Human Phonation (the 2nd report)

Abstract

Digital subtraction X-ray stroboscopy is a combined laryngostroboscopic and digital subtraction angiographic system.
Clear vibratory images of only the vibrating portions of human vocal cords in the frontal plane obtained by digital subtraction of the image of the cervical vertebrae were first reported in this journal.
However, the previous system had two major defects, regarding the size and the quality of images acquired with digital subtraction.
The size of the acquired image of the vocal folds was too small since the image size is inversely proportionate to the diameter of the image intensifier, which in this case was large. The quality was not satisfactory because of the inclusion of black lateral-striped shadows due to the difference in the number of X-ray pulses during electrical scanning with a television camera between the contrast images.
Fundamental improvement in these areas has been achieved by newly adopting an image intensifier with a 4.5 inch diameter (half the size of the previous device) and a CCD digital television camera.