| EFFECTS ON THE ENLARGEMENT RATIOS DUE TO CHANGES OF HEAD POSTURE ON LATERAL HEADFILMS |
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| 측두 규격방사선사진 촬영시 두부의 위치변화가 확대율에 미치는 영향 |
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서영훈, 최영철 |
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경희대학교 치과대학 소아치과학교실 |
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| Abstract |
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This study was designed to evaluate the effects of angulation changes of head posture on the enlargement ratios of a lateral headfilm depending on the vortical or horizontal rotation of the objects. A device was constructed to measure regional changes of enlargement ratios. The device was held within the cephalostat and cephalograms recorded at each measured degrees of the device tilting, vertically and horizontally. The enlargement ratios of the horizontal, vertical, and angular measurements on the films taken at each tilted angulations were obtained and compared with those on the films taken without rotation. In summary, the enlargement ratios of the horizontal linear measurements were decreased during horizontal rotations. The enlargement ratios of vortical measurements of the right side on the film were increased and those of the left side were decreased by the horizontal rotations. Enlargement ratios of horizontal measurements were affected further than those of vertical measurements by the same angular changes of the horizontal rotations. Therefore, a disruption of parallelism between the object's midsagittal plane and the film could result in distortion of the image while vertical rotation around the object's porionic axis would not significantly affect the enlargement ratios on the headfilm. |
| Key Words:
Lateral cephalometric radiography, Enlargement ratio, Error, Linear measurement, Angular measurement |
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