Optimization of image quality and radiation dose using different cone-beam CT exposure parameters. Issue 116 (July 2019)

• Record Type: Journal Article
• Authors: Yel, Ibrahim; Booz, Christian; Albrecht, Moritz H.; Gruber-Rouh, Tatjana; Polkowski, Christoph; Jacobi, Martina; Lenga, Lukas; Schulz, Martin; Frank, Johannes; Marzi, Ingo; Vogl, Thomas J.; Eichler, Katrin; Kaltenbach, Benjamin
• Is Part Of: European journal of radiology. Issue 116(2019)
• Page Start: 68
• Page End: 75
• Publication Date: 2019-07
• Subjects: CBCT cone–beam computerized tomography -- CTDIVOL volume CT dose index -- DLP dose–length product -- FOV field–of–view -- HU hounsfield unit -- ROI region–of–interest -- SD standart deviation -- SNR signal–to–noise ratio; Cone–beam computed tomography -- Extremities -- Image quality -- Radiation dose reduction; Medical radiology -- Periodicals; Radiology -- Periodicals; Radiologie médicale -- Périodiques; Medical radiology; Periodicals; 616.075705
• DOI: 10.1016/j.ejrad.2019.04.005
• Languages: English
• ISSNs: 0720-048X

Abstract

Abstract: Purpose: To investigate and optimize the impact of different exposure parameters on image quality and radiation dose for a latest generation orthopedic cone-beam CT system. Materials and methods: 110 consecutive scans of the same cadaver forearm were performed before and after the insertion of a distal radius plate on the palmar radius to achieve highest intra-individual comparability. All scans were conducted on a latest generation cone-beam CT scanner (Carestream OnSight 3D Extremity System, Carestream Health, Rochester, NY, USA). Extremity imaging was performed using different combinations of tube voltage (kV) and tube current – exposure time product (mAs). Radiation dose (DLP and CTDIVOL ) was recorded to widely varying combinations. Subjective and objective image quality analysis included a blinded evaluation by five different readers independently using 5–point–Likert scales. Results: Highest radiation dose was achieved using the manufacturers' suggested standard protocol (90-kV and 5.0 mAs with DLP of 111.91 mGy*cm and CTDIVOL of 4.49 mGy), while 70-kV and 2.0 mAs provided the most dose reduction with DLP of 20.34 mGy*cm and CTDIVOL of 0.79 mGy. Regarding subjective image quality, higher tube voltage improved depiction of cortical bone (p ≤ 0.038) and cancellous bone (p ≤ 0.001) as well as overall image quality (p ≤ 0.027). Changes of the tube current – exposure time product did not show significant alterations of image quality (p ≥ 0.063). After plate insertion, only the subjective overall image quality showed reduced subjective perception (p < 0.001). Between the different scan protocols, no relevant changes were observed in the objective image quality analysis (SNR: p ≥ 0.125; CNR: p ≥ 0.086). However, presence of osteosynthesis significantly lowered the mean SNR and CNR (p < 0.001). Conclusion: Even with lowest exposure settings, orthopedic extremity CBCT revealed good overall image quality. The best result regarding subjective image quality was achieved with 85-kV / 4.7 mAs with a dose reduction of 18, 9% compared to the manufacturer's recommended protocol (90-kV and 5.0 mAs).