Dept. of Electr. & Comput. Eng., State Univ. of New York, Buffalo, NY.
IEEE Trans Med Imaging. 1993;12(2):383-4. doi: 10.1109/42.232270.
In the above-titled work by G. T. Gullberg and G. L. Zeng (ibid., vol.11, no.1, p.91-101, 1992), a fan-beam reconstruction formula of a noncircular scanning locus was derived and extended for half-scan cone-beam reconstruction. However, the reconstruction formula is not exact mathematically unless a necessary condition is satisfied. In this correspondence, the commenters derive this necessary condition and provide a geometrical explanation of the condition.
在 G.T. Gullberg 和 G.L. Zeng 的题为“……”的文章中（同刊，第 11 卷第 1 期，第 91-101 页，1992 年），推导并扩展了扇束重建公式以应用于半扫描锥束重建。然而，除非满足一个必要条件，否则该重建公式在数学上并不精确。在本通信中，评论者推导出这个必要条件，并对该条件提供了几何解释。
