| 摘要 |
<p>PURPOSE:To reduce a shift quantity of a measured CT value by furnishing an apparatus with a phantom removably, which is photographed together with a top plate which supports a subject or a member analogous to the top plate. CONSTITUTION:When a water phantom is photographed for a calibration, an initialization photographing is carried out under a condition that the water phantom 10 and a top plate-like member 13 are arranged on a slice plane in a photographing zone S. A measured CT value, a reference for the calibration, is not the value for the phantom 10 alone but a value of taking the top plate- like member 13 into account. Therefore, when a real photographing, wherein a subject 3 and a top plate 6 for supporting it are arranged in the photographing zone S, is carried out after finishing the water phantom photographing and removing the water phantom 10 and the top plate-like member 13, there is no influence due to the existence of top plate. A problem that a shift quantity of a measured CT value is larger than that of an actual CT value is improved by the aforementioned method, and the shift quantity of measured CT value is reduced, resulting in an easy preparation of a correct CT image as a diagnostic information.</p> |
