Program including abstracts as pdf available here

P 24
Title
DIAGNOSTIC IMAGE QuALITy VERSuS NOISE LEVEL FOR CbCT
Authors
L Seynaeve 1 , R. Pauwels 1 , JCG. Henriques 1 , C. de Oliveira-Santos 2 , P. Couto Souza 3 ,
FH Westphalen 3 , IRF. Rubira-bullen 4 , P. Pittayapat 1 , H. bosmans 5 , R. bogaerts 6 ,
R. Jacobs 1 , K. Horner 7 , THE SEDENTEXCT Project Consor 8
Affiliations
1 Oral Imaging Center, Faculty of Medicine, University of Leuven, Leuven, BELGIUM, 2 Dept
of Morphology, Stomatology and Physiology, University of São Paulo - Ribeirão Preto School
of Dentistry, Ribeirão Preto, BRAZIL, 3 School of Dentistry, Pontifical Catholic University of
Paraná, Curitiba, BRAZIL, 4 Stomatology Department, Bauru School of Dentistry, University of
São Paulo, Bauru, BRAZIL, 5 Department of Radiology, University Hospitals Leuven, Leuven,
BELGIUM, 6 Department of Experimental Radiotherapy, University Hospitals Leuven, Leuven,
BELGIUM, 7 School of Dentistry, University of Manchester, Manchester Academic Health
Sciences Centre, Manchester, UNITED KINGDOM, 8 Listing of partners on www.sedentexct.eu,
Manchester, UNITED KINGDOM
Body
Objectives: The aim of this study was to investigate image noise and diagnostic image quality
at various exposure levels for different CBCT scanners, to determine the relationship between
technical and clinical imaging parameters, and to define preliminary thresholds or reference
levels for CBCT image quality.
Methods: A homogeneous PMMA phantom and an anthropomorphic skull phantom containing
a human skeleton embedded in polyurethane were used. The phantoms were scanned using
four CBCT devices (3D Accuitomo 170, CRANEX 3D, Galileos Comfort, SCANORA 3D), including
seven exposure protocols. For all protocols, the tube current (mA) was varied within the
selectable range. Using the PMMA phantom, noise was measured as the standard deviation of
grey values and corrected for voxel size. In parallel, an observer study was set up by selecting
eight axial slices from the skull phantom. The slices were presented to five oral radiologists,
providing scores for various anatomical and diagnostic parameters.
Results: Depending on the available exposure range, a linear or hyperbolic relation was seen
between noise and mA. Similarly, a gradual reduction in diagnostic image quality was seen for
reduced exposures, although only small differences in image quality were seen for certain exposure
series. It was found that, depending on the diagnostic application, there is a possibility
for a moderate or large mA reduction while keeping the image quality at an acceptable level.
Conclusion: Compared to default exposures provided by manufacturers, a considerate reduction
in radiation dose is possible for certain patient groups.
Keywords
Cone-Beam Computed Tomography,Radiation Dosage,Computer-Assisted Image Analys
POSTerS
139