Internal or in-scan validation: a method to assess CBCT and MSCT gray scales using a human cadaver.
OBJECTIVE
This study aimed to explore whether cone beam computed tomography (CBCT) and multislice computed tomography (MSCT) can be used to quantify tissue density and to determine if the Hounsfield unit scale is applicable.


METHODS
A clinical MSCT scanner and effective energy adjusted photon beam attenuation references were used to compare the gray scale of CBCT images of the mandible region. A phantom was scanned using axial cadaver slices and 4 different homogeneous reference objects. The consistency of the references' gray values and 12 linear profile lines from both scanner data sets were compared.


RESULTS
The gray values of the 2 scans showed strong correlation with quantified position-dependent differences as an outcome of the validation process.


CONCLUSIONS
The introduced internal, in-scan validation is able to estimate and has a potential to compensate for the differences between MSCT and CBCT protocols. This validation serves as a guide in situations where the users can expect deviations.
Department of Oral and Maxillofacial Surgery, University Hospitals of Oulu; Department of Oral and Maxillofacial Surgery, Southern General Hospital, Glasgow, United Kingdom. Electronic address: bujpet@yahoo.co.uk.
Péter
P
Bujtár
Department of Machine and Product Design, Faculty of Mechanical Engineering, Budapest University of Technology and Economics (BME), Budapest, Hungary.
János
J
Simonovics
Centre for Medical Image Computing (CMIC), University College London, London, United Kingdom.
Gergely
G
Zombori
Department of Human Morphology and Developmental Biology and Department of Anatomy, Histology and Developmental Biology, Semmelweis University, Budapest, Hungary.
Zsolt
Z
Fejer
Department of Oral-Maxillofacial Surgery and Stomatology, Semmelweis University, Budapest, Hungary.
Attila
A
Szucs
Department of Mechatronics, Optics and Engineering Informatics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics (BME), Budapest, Hungary.
Attila
A
Bojtos
Federal Institute of Education, Science, and Technology (IFBA), Salvador, Bahia, Brazil.
Wilson Otto
WO
Batista
Department of Machine and Product Design, Faculty of Mechanical Engineering, Budapest University of Technology and Economics (BME), Budapest, Hungary.
Károly
K
Váradi
Oral and Maxillofacial Surgery, University of Oulu; Biomeditech, Institute of Biomedical Technology, University of Tampere, Tampere, Finland.
George K B
GK
Sándor
D015519:Bone Density; D002102:Cadaver; D002138:Calibration; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D008334:Mandible / Q000000981:diagnostic imaging*; D061330:Multidetector Computed Tomography / Q000379:methods*; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted