title: Prototype heel effect compensation filter for cone-beam CT.
abstract: The prototype cone-beam CT (CBCT) has a larger beam width than the conventional multi-detector row CT (MDCT). This causes a non-uniform angular distribution of the x-ray beam intensity known as the heel effect. Scan conditions for CBCT tube current are adjusted on the anode side to obtain an acceptable clinical image quality. However, as the dose is greater on the cathode side than on the anode side, the signal-to-noise ratio on the cathode side is excessively high, resulting in an unnecessary dose amount. To compensate for the heel effect, we developed a heel effect compensation (HEC) filter. The HEC filter rendered the dose distribution uniform and reduced the dose by an average of 25% for free air and by 20% for CTDI phantoms compared to doses with the conventional filter. In addition, its effect in rendering the effective energy uniform resulted in an improvement in image quality. This new HEC filter may be useful in cone-beam CT studies.
authors.affiliation: Department of Medical Physics, National Institute of Radiological Sciences, Chiba 263-8555, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Mori
authors.forename: Masahiro
authors.initials: M
authors.lastname: Endo
authors.forename: Kanae
authors.initials: K
authors.lastname: Nishizawa
authors.forename: Mari
authors.initials: M
authors.lastname: Ohno
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Miyazaki
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tsujita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Saito
mesh_terms: D004867:Equipment Design; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods*