Quantitative Performance Evaluation of Mobile Cone-Beam CT for Head and Neck Imaging

Abstract

Cone-beam computed tomography (CBCT) has become increasingly popular in dental and maxillofacial imaging due to its accurate 3D information, minimal radiation dose, and low machine cost. In this paper, we propose the newly developed mobile CBCT scanner which combines the benefits of CBCT and mobility to extend its applications to head and neck imaging and allow faster access to a patient at various clinical sites. With the large area detector, only a single rotation is needed to reconstruct the field-of-view of almost the entire head. Our filtered back-projection reconstruction and artifact reduction algorithms were based on a graphics processing unit to speed up the calculations. The quantitative performance was evaluated in terms of radiation doses and image quality. The radiation doses were measured using both CT dose index and dose area product (DAP) and compared with other CBCT and multi-slice CT (MSCT) machines. Then, we analyzed image quality using the standard cone-beam phantom. The effective doses radiated from the proposed mobile CBCT machine were within the range of 0.1–0.2 mSv, while the normalized DAP measurements were within the range of 46–144 mGy cm², which are significantly below the achievable dose of 250 mGy cm². The overall image quality of the proposed scanner was mostly comparable to other MSCT and CBCT scanners. Geometric accuracy of the reconstructed images provided the errors less than 0.16 mm or 0.12%. Due to low radiation dose, high accuracy and adequate image quality as compared to others, the proposed mobile CBCT has high potential for diagnosis and treatment planning in head and neck applications.