抄録
The main point of the X-ray laryngostroboscopy (X-ray stroboscopy) which was first developed. by Saito is that the trigger pulse for the strobo light of the laryngostroboscope is used as the external trigger for the pulse X-ray radiation of the pulse X-ray angiography system.
The critical defect of the X-ray stroboscopy of human phonations from the frontal plane was that the vibratory image of the vocal cord was masked by the overlapped image of the cervical vertebrae.
This defect was, first in the world, completely resolved by recent development of the digital subtraction X-ray stroboscopy. This is a combined system of the laryngostroboscope and the digital subtraction angiography system. Clear vibratory images of only the vibrating portion of human vocal cords in the frontal plane can be extracted by the digital subtraction of the image of the cervical vertebrae.
The essential principle of the vibration of human vocal cords during phonation is the travelling wave phenomenon whose wave crest travells from the lower portion to the upper portion of the vocal cord continuously.
