Wei-Chan Lin1,2, Hsueh-Han Wang3, Wen-Lin Hsu4,5, Bi-Hui Cao6, De-Ji Chen6, Chia-Jung Tsai7. 1. 1 Department of Radiology, Cathay General Hospital, Taipei, Taiwan. 2. 2 School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan. 3. 3 Department of Radiology, National Yang-Ming University Hospital, Yilan City, Taiwan. 4. 4 School of Medicine, Tzu-Chi University, Hualien, Taiwan. 5. 5 Department of Radiation Oncology, Buddhist Tzu-Chi General Hospital, Hualien, Taiwan. 6. 6 Department of Radiology, Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China. 7. 7 Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan.
Abstract
OBJECTIVES: To propose an imaging protocol that provides satisfactory image quality for oral examination while minimizing radiation dosage using 320-slice multidetector CT (MDCT). METHODS: An anthropomorphic head phantom was scanned using 320 MDCT with protocols combining different scanning modes: volume scanning (whole or local) vs helical scanning (80- or 64-slice detectors); tube voltage settings (80 kVp, 120 kVp and 135 kVp); and tube current settings (60 mA, 80 mA, 100 mA and 120 mA). A total of six anatomical bone structures and three anatomical soft-tissue structures were assessed using quantitative and qualitative analysis in the three orthographic planes (axial, sagittal and coronal). A figure of merit (FOM) was used to determine the optimal imaging protocol in terms of tube voltage, tube current and scanning mode. RESULTS: The 80-kVp setting had the worst quantitative and qualitative results (both p < 0.001) compared with the 135-kVp and 120-kVp settings, especially for soft-tissue structures. A significant difference was noted for the scores obtained using a tube current between 120 mA and 60 mA by quantitative analysis, but not by qualitative analysis. Volume scans using either whole or local modes had a significantly higher FOM than helical scanning of 80 or 64 slices. CONCLUSIONS: In 320 MDCT, a protocol using 135 kVp, 80 mA and the volume-scanning mode (whole or local) offers adequate visualization of both soft-tissue and bone structures while keeping the radiation dose as low as possible. This may therefore be considered a first choice among a wide selection of scanning protocols for dentomaxillofacial CT.
OBJECTIVES: To propose an imaging protocol that provides satisfactory image quality for oral examination while minimizing radiation dosage using 320-slice multidetector CT (MDCT). METHODS: An anthropomorphic head phantom was scanned using 320 MDCT with protocols combining different scanning modes: volume scanning (whole or local) vs helical scanning (80- or 64-slice detectors); tube voltage settings (80 kVp, 120 kVp and 135 kVp); and tube current settings (60 mA, 80 mA, 100 mA and 120 mA). A total of six anatomical bone structures and three anatomical soft-tissue structures were assessed using quantitative and qualitative analysis in the three orthographic planes (axial, sagittal and coronal). A figure of merit (FOM) was used to determine the optimal imaging protocol in terms of tube voltage, tube current and scanning mode. RESULTS: The 80-kVp setting had the worst quantitative and qualitative results (both p < 0.001) compared with the 135-kVp and 120-kVp settings, especially for soft-tissue structures. A significant difference was noted for the scores obtained using a tube current between 120 mA and 60 mA by quantitative analysis, but not by qualitative analysis. Volume scans using either whole or local modes had a significantly higher FOM than helical scanning of 80 or 64 slices. CONCLUSIONS: In 320 MDCT, a protocol using 135 kVp, 80 mA and the volume-scanning mode (whole or local) offers adequate visualization of both soft-tissue and bone structures while keeping the radiation dose as low as possible. This may therefore be considered a first choice among a wide selection of scanning protocols for dentomaxillofacial CT.
Authors: P Pittayapat; D Galiti; Y Huang; K Dreesen; M Schreurs; P Couto Souza; I R F Rubira-Bullen; F H Westphalen; R Pauwels; G Kalema; G Willems; R Jacobs Journal: Clin Oral Investig Date: 2012-03-01 Impact factor: 3.573
Authors: Robert A Mischkowski; Larry Ritter; Jörg Neugebauer; Timo Dreiseidler; Erwin Keeve; Joachim E Zöller Journal: Quintessence Int Date: 2007-10 Impact factor: 1.677