title: Radiation dose and physical image quality in 128-section dual-source computed tomographic coronary angiography: a phantom study.
abstract: One-hundred-and-twenty-eight-section dual X-ray source computed tomography (CT) systems have been introduced into clinical practice and have been shown to increase temporal resolution. Higher temporal resolution allows low-dose spiral mode at a high pitch factor during CT coronary angiography. We evaluated radiation dose and physical image qualities in CT coronary angiography by applying high-pitch spiral, step-and-shoot, and low-pitch spiral modes to determine the optimal acquisition mode for clinical situations. An anthropomorphic phantom, small dosimeters, a calibration phantom, and a microdisc phantom were used to evaluate the radiation doses absorbed by thoracic organs, noise power spectrums, in-plane and z-axis modulation transfer functions, slice sensitivity profiles, and number of artifacts for the three acquisition modes. The high-pitch spiral mode had the advantage of a small absorbed radiation dose, but provided low image quality. The low-pitch spiral mode resulted in a high absorbed radiation dose of approximately 200 mGy for the heart. Although the absorbed radiation dose was lower in the step-and-shoot mode than in the low-pitch spiral mode, the noise power spectrum was inferior. The quality of the in-plane modulation transfer function differed, depending on spatial frequency. Therefore, the step-and-shoot mode should be applied initially because of its low absorbed radiation dose and superior image quality.
authors.affiliation: Department of Quantum Medical Technology, Faculty of Health Sciences, Kanazawa University, Kanazawa, Japan. matsuk@mhs.mp.kanazawa-u.ac.jp
authors.forename: Kosuke
authors.initials: K
authors.lastname: Matsubara
authors.forename: Haruka
authors.initials: H
authors.lastname: Koshida
authors.forename: Keita
authors.initials: K
authors.lastname: Sakuta
authors.forename: Tadanori
authors.initials: T
authors.lastname: Takata
authors.forename: Junsei
authors.initials: J
authors.lastname: Horii
authors.forename: Hiroji
authors.initials: H
authors.lastname: Iida
authors.forename: Kichiro
authors.initials: K
authors.lastname: Koshida
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Ichikawa
authors.forename: Osamu
authors.initials: O
authors.lastname: Matsui
mesh_terms: D055424:Cardiac-Gated Imaging Techniques; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D015900:Radiography, Dual-Energy Scanned Projection; D015898:Tomography Scanners, X-Ray Computed