| 摘要 |
PURPOSE:To obtain the tomogrphic image of the head or jaws of a patient having good quality, and no break and no overlap, by allowing the vertical plane motion mechanism of the rotation center of an arm for supporting an X-ray source and a film holder to make only circular motion, and rendering rotation moment constant using a weight to eliminate the effect of gravity. CONSTITUTION:This device consists of an X-ray tube 1, having a focus F, an X- ray film 2, the curved section 3 of the teeth line-shaped bow of a patient, a rotary arm for supporting the tube 1 and the holder 5 of the film 2 on both its ends, a one- dot-dashed line 4 showing X-ray beams, a planet gear 6, a rotating center shaft 7, a sun gear 8, its center shaft 9, a balancing arm 10, a weight 11, etc. The arm 10 passing the denters of the geas 6, 8 supporting the tube 1 and the holder 5 of the film 2 is turned at A:B and moved as shown in the figure, thus permitting the film 2, the tube 1, and the weight 11 to be balanced, each to move like the one-dot- dashed line 3D, and a good quality tomogrph free from breaks and overlaps to be obtained. |
