Impact of the automatic tube current modulation (ATCM) system on virtual monoenergetic image quality for dual-source CT: A phantom study. (May 2023)

• Record Type: Journal Article
• Authors: Dabli, D.; Durand, Quentin; Frandon, J.; de Oliveira, Fabien; Pastor, Maxime; Beregi, J.P.; Greffier, J.
• Is Part Of: Physica medica. Volume 109(2023)
• Publication Date: 2023-05
• Subjects: ATCM Automatic tube current modulation -- ADMIRE Advanced Modeled Iterative Reconstruction -- CNR Contrast-to-noise ratio -- CT Computed Tomography -- CTDIvol Volume CT dose index -- DECT Dual-energy CT -- DSCT Dual-source CT -- DICOM Digital imaging and communications in medicine -- FOV Field of view -- fav Average frequency of the noise power spectrum -- mAs Milliampere-seconds -- NPS Noise power spectrum -- ROI Region of interest -- TTF Task-based transfer function -- VMIs Virtual monoenergetic images; Dual-source CT scan -- Dual-energy CT -- Virtual monochromatic images -- Automatic tube current modulation -- Detectability; 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.2023.102574
• Languages: English
• ISSNs: 1120-1797

Abstract

Highlights: The automatic tube current modulation allows reducing the mean CTDIvol . The mAs modulation is similar between DECT and SECT imaging on DSCT platform. VMIs provide better detectability than SECT imaging even when using the ATCM system. Abstract: Purpose: To assess the impact of the automatic tube current modulation (ATCM) on virtual monoenergetic images (VMIs) quality in dual-source CT(DSCT). Materials and methods: Acquisitions were performed on DSCT using the Mercury phantom. The acquisition parameters for an abdomen-pelvic examination with single-energy CT(SECT) and dual-energy CT(DECT) imaging were used. Acquisitions were performed for each imaging mode using fixed mAs and ATCM. The mAs value was set to obtain a volume CT dose index of 11 mGy in fixed mAs acquisitions. This value was used as the reference mAs in ATCM acquisitions. The noise power spectrum and task-based transfer function at 40, 50, 60 and 70 keV levels were computed on VMIs and SECT images. The detectability index (d′) was calculated for a lesion with an iodine concentration of 10 mg/mL. Results: The noise magnitude on VMIs was higher with the ATCM system than with fixed mAs for all energy levels and section diameters of 21, 26 and 31 cm. The noise texture and spatial resolution were similar between the fixed mAs and ATCM acquisitions for both imaging modes. The d' values were lower for all energy levels with ATCM than with fixed mAs acquisitions for 21 and 26 cm diameters by −39.82 ± 9.32%, similar at 31 cm diameter −4.13 ± 0.24% and higher at 36 cm diameter 10.40 ± 6.69%. It was higher on VMIs at all energy levels compared to SECT images. Conclusions: The ATCM system could be used with DECT imaging to optimize patient exposure without changing the noise texture and spatial resolution of VMIs compared to fixed mAs and SECT.