Cupping correction for partial rotation dental conebeam CT

Maryam Rahbaran; Nancy L. Ford

doi:10.1117/12.2608906

4 April 2022 Cupping correction for partial rotation dental conebeam CT

Maryam Rahbaran, Nancy L. Ford

Proceedings Volume 12036, Medical Imaging 2022: Biomedical Applications in Molecular, Structural, and Functional Imaging; 120361D (2022) https://doi.org/10.1117/12.2608906
Event: SPIE Medical Imaging, 2022, San Diego, California, United States

Abstract

Dental cone beam computed tomography (CBCT) offers a variety of fields of view (FOV), ranging from the entire craniofacial complex down to an individual tooth. To manage the radiation dose to the patient, partial rotation scanning is often used. However, the images suffer from non-uniformities related to attenuation of the beam as it crosses the patient anatomy and the uneven radiation field due in part to scattered radiation. We have modelled the cupping artifact in the maxillofacial field of view and applied a correction to improve uniformity in the image. We applied this correction to smaller fields of view. Images were obtained using a Carestream 9300 CBCT system of the SEDENTEX image quality phantom and 2 anthropomorphic skull phantoms. The maxillofacial FOV (17x11 cm² ) was used with clinical settings for an average adult (90 kVp, 4 mA, 6.4 s) and reconstructed with 0.25 mm voxel spacing. In MATLAB, we modeled the 2D surface across a uniform section of the SEDENTEX phantom with a polynomial fit to find an offset that could be added to reduce the cupping artefact. This offset was then applied to the images of the anthropomorphic and SEDENTEX phantoms for 17x11 cm² , 10x10 cm² , 10x5 cm² and 8x8 cm² FOVs. The offset was cropped for the 10x10 cm² , 10x5 cm² and 8x8 cm² FOVs. For all images, the uniformity was improved. From this study, we conclude that a single correction matrix can be used for all 4 FOVs on this machine to improve image quality.

Conference Presentation

Citation Download Citation

Maryam Rahbaran and Nancy L. Ford "Cupping correction for partial rotation dental conebeam CT", Proc. SPIE 12036, Medical Imaging 2022: Biomedical Applications in Molecular, Structural, and Functional Imaging, 120361D (4 April 2022); https://doi.org/10.1117/12.2608906

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