Because patient collection was retrospective, two CBCT units were used: (1) NewTom VG (Quantitative Radiology), with exposure parameters of 110 kVp and 2–3 mA and an FOV of 15 cm × 15 cm; and (2) i-CAT FLX (Imaging Sciences International, Inc.), with exposure parameters of 120 kVp and 5 mA and an FOV of 16 cm × 13 cm. The voxel size was 0.3 × 0.3 × 0.3 mm3. The CT images were acquired by a 64-row spiral CT scanner (Philips Inc., Andover, MA, USA) at 120 kVp, 230 mA, and 1.0 mm layer thickness. The CT resolution was set to 512 × 512 × 236, and the voxel size was 0.4 × 0.4 × 1 mm3.
In total, 50 independent CBCT and 42 paired CT and CBCT (268 MM in total) were collected in this retrospective study for model training, validating and blind testing. The CT was considered as the reference.
In total, 50 independent CBCT and 42 paired CT and CBCT (268 MM in total) were collected in this retrospective study for model training, validating and blind testing. The CT was considered as the reference.