Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. X:X | DOI: 10.5507/bp.2024.004

Comparison of dose length product and image quality of a biphasic whole-body polytrauma CT protocol with and without the automatic tube voltage selection

David Girsa¹, Karin Kremenova², Jiri Lukavsky³, Lucie Sukupova⁴, Hana Malikova¹

¹ Department of Radiology and Nuclear Medicine, Third Faculty of Medicine, Charles University in Prague and Faculty Hospital Kralovske Vinohrady; Second Faculty of Medicine, Charles University in Prague, Czech Republic

² Department of Radiology and Nuclear Medicine, Third Faculty of Medicine, Charles University in Prague and Faculty Hospital Kralovske Vinohrady, Prague, Czech Republic

³ Institute of Psychology, Czech Academy of Sciences, 110 00 Prague, Czech Republic; Department of Psychology, Faculty of Arts, Charles University in Prague, Czech Republic

⁴ Director's Department, Institute for Clinical and Experimental Medicine, Prague, Czech Republic

Background and Aims: A significant source of man-made radiation is now linked to medical devices especially X-ray imaging based ones like CT scans which expose the body to cumulative ionizing radiation and thus attendant cancer risks. The aim of this study was to determine whether using a combination of Automatic Tube Current Modulation (ATCM) and Automatic Tube Voltage Selection (ATVS) during two-phase whole-body CT (2PWBCT) examinations would reduce the radiation dose while preserving the image quality.

Patients and Methods: This was a prospective, observational, single-centre study of 127 adult patients who had undergone the 2PWBCT polytraumatic protocol. All were examined on a Somatom Drive scanner (Siemens). The patients were divided into two groups: ATCM only (42 patients) and ATCM +ATVS (85 patients). Patients' arm positions during examination and the examination dose length product (DLP) values were recorded, as well the standard deviations (SD) of the density in reference areas on CT scans for the image quality assessment. The DLP values and image quality in the groups were compared using ANOVA.

Results: Mean Total DLP (in mGy*cm): ATCM only: 3337 +/-797, ATCM+ATVS: 3402 +/-830; P=0.674. No effect of arm position (P=0.586). Mean density SD values in reference areas (in HU) in ATCM only: 49 +/-45, 15 +/-6, 9 +/-2, 12 +/-4, 10 +/-3, in ATCM+ATVS: 48 +/-45, 17 +/-6, 11 +/-3, 15 +/-6, 12 +/-4. SD values was higher in ATCM+ATVS group (P<0.001).

Conclusion: Combination of ATVS and ATCM in polytraumatic 2PWBCT leads to no significant radiation load reduction compared with ATCM only but does lead to a slight degradation of image quality. The radiation load is significantly reduced if the patient has their arms behind the head when scanning, regardless of the activation of ATVS.

Keywords: whole body CT, polytrauma, automatic tube current modulation, automatic tube voltage selection, dose length product

Received: October 26, 2023; Revised: December 27, 2023; Accepted: February 15, 2024; Prepublished online: March 4, 2024