Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method. Issue 4 (April 2016)

• Record Type: Journal Article
• Authors: Hara, Takanori; Urikura, Atsushi; Ichikawa, Katsuhiro; Hoshino, Takashi; Nishimaru, Eiji; Niwa, Shinji
• Is Part Of: Physica medica. Volume 32:Issue 4(2016)
• Page Start: 625
• Page End: 630
• Publication Date: 2016-04
• Subjects: Temporal resolution -- Helical acquisition mode -- Gantry rotation time -- Pitch factor; Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2016.02.015
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract : Highlights: Temporal resolution (TR) of modern CT scanners was analysed using an impulse method. Scan combinations of pitch factor ( P ) and gantry rotation time ( R ) were assessed. For 320-row ADCT, TR ≈ R (with P < 1.0), whereas TR ≈ 0.5 R (with P > 1.0). For 128-slice DSCT, TR improved with a shorter R and greater P. TR of helical acquisition modes were dependent on not only R but also P . Abstract: Purpose: To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. Methods: To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor ( P ) and gantry rotation time ( R ). Results: The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of <1.0 was almost equal to the gantry rotation time, whereas with pitch factor of >1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 ( R / P = 0.285/1.5) and 0.074 s ( R / P = 0.285/3.2), and the maximum TR values of the 64 × 0.5- and 160 × 0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 ( R / P = 0.275/1.375) and 0.195 s ( R / P = 0.3/0.6), respectively. Conclusion: Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement.