| 摘要 |
PURPOSE:To prevent the formation of an artifact by providing plural small- visual field collimator parts and one large-visual field collimator part. CONSTITUTION:When a collimator ring 3 rotates by 360 deg., data on the number of incident gamma rays at each peripheral position is obtained at every position. Data required to reconstitute a tomographic image of the whole of a large visual field 5 are collected by the large-visual field collimator part 31 which is rotated by 360 deg., and the small-visual field collimator parts 32 are rotated by 360 deg. respectively to collect data of small visual fields 4 of the respective collimator parts 32. Therefore, the collimator parts 32 collect data by repeating the operation by as many times as the parts, so data which have high sensitivity and small statistical variation are obtained. Consequently, an image of the whole of the large visual field 5 covering an examinee 6 is obtained and a high-sensitivity image of parts of small visual fields 4 are obtained. Then, data in the large visual field 5 covering the whole of the examinee are used to reconstitute the image, so no artifact is generated even if there is an intense ray source outside the small visual fields 4. |
