Projection-domain reconstruction of patient-specific panoramic images from CBCT projection data

Abstract

Background

Panoramic radiography is widely used in dental diagnostics; however, conventional systems require a dedicated panoramic scan, increasing radiation exposure and limiting adaptation to patient-specific anatomical variability. Cone-beam computed tomography (CBCT) provides volumetric information that may potentially replace separate panoramic acquisitions.

Purpose

This study proposes CT2Pano, a projection-domain reconstruction method that generates patient-specific panoramic images directly from CBCT projection data without requiring an additional panoramic scan.

Methods

The CT2Pano algorithm automatically detects teeth from CBCT images and estimates a patient-specific dental arch curve using Bézier curve optimization. Based on the extracted arch, a virtual panoramic scan trajectory is defined and panoramic projections are extracted from the corresponding CBCT projections. Geometric correction combined with subpixel rebinning compensates for magnification variations caused by the fixed rotation center of the CBCT systems. The final panoramic image is reconstructed using a shift-and-add (SAA) method that enhances structures within the focal trough while suppressing out-of-plane structures.

Results

Simulation and phantom experiments demonstrate that CT2Pano generates panoramic images with anatomical fidelity comparable to conventional panoramic imaging systems. The method effectively compensates for geometric distortion and maintains image quality even in the presence of metal artifacts or patient misalignment.

Conclusions

CT2Pano enables patient-specific panoramic reconstruction directly from CBCT projection data, eliminating the need for an additional panoramic scan. By operating in the projection domain, the proposed framework preserves measurement information while reducing radiation exposure and improving imaging workflow efficiency, highlighting its potential for CBCT-based panoramic imaging in dental diagnostics.