Premium
Quasimonochromatic x‐ray computed tomography by the balanced filter method using a conventional x‐ray source
Author(s) -
Saito Masatoshi
Publication year - 2004
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1819553
Subject(s) - x ray , tomography , computed tomography , physics , computed radiography , medical imaging , nuclear medicine , medical physics , optics , computer science , radiology , medicine , image quality , computer vision , image (mathematics)
A quasimonochromatic x‐ray computed tomography (CT) system utilizing balanced filters has recently been developed for acquiring quantitative CT images. This system consisted of basic components such as a conventional x‐ray generator for radiography, a stage for mounting and rotating objects, and an x‐ray line sensor camera. Metallic sheets of Er and Yb were used as the balanced filters for obtaining quasimonochromatic incident x rays that include the characteristic lines of the W K α doublet from a tungsten target. The mean energy and energy width of the quasimonochromatic x rays were determined to be 59.0 and 1.9 keV , respectively, from x‐ray spectroscopic measurements using a high‐purity Ge detector. The usefulness of the present x‐ray CT system was demonstrated by obtaining spatial distributions of the linear attenuation coefficients of three selected samples—a 20 cm diameter cylindrical water phantom, a 3.5 cm diameter aluminum rod, and a human head phantom. The results clearly indicate that this apparatus is surprisingly effective for estimating the distribution of the linear attenuation coefficients without any correction of the beam‐hardening effect. Thus, implementing the balanced filter method on an x‐ray CT scanner has promise in producing highly quantitative CT images.