title: [Examination of patient dose reduction in cardiovasucular X-ray systems with a metal filter].
abstract: In interventional X-ray for cardiology of flat panel digital detector (FPD), the phenomenon that exposure dose was suddenly increased when a subject thickness was thickened was recognized. At that time, variable metal built-in filters in FPD were all off. Therefore, we examined whether dose reduction was possible without affecting a clinical image using metal filter (filter) which we have been conventionally using for dose reduction. About 45% dose reduction was achieved when we measured an exposure dose at 30 cm of acrylic thickness in the presence of a filter. In addition, we measured signal to noise ratio/contrast to noise ratio/a resolution limit by the visual evaluation, and there was no influence by filter usage. In the clinical examination, visual evaluation of image quality of coronary angiography (40 cases) using a 5-point evaluation scale by a physician was performed. As a result, filter usage did not influence the image quality (p=NS). Therefore, reduction of sudden increase of exposure dose was achieved without influencing an image quality by adding filter to FPD.
authors.affiliation: Department of Radiological Technology, Showa University Fujigaoka Hospital.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Yasuda
authors.forename: Kyouichi
authors.initials: K
authors.lastname: Kato
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Tanabe
authors.forename: Koushi
authors.initials: K
authors.lastname: Sakiyama
authors.forename: Yushi
authors.initials: Y
authors.lastname: Uchiyama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakazawa
mesh_terms: D017023:Coronary Angiography / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008670:Metals; D011829:Radiation Dosage
chemical_list: D008670:Metals