Comparison of saddle and helical trajectories of a mobile cone beam computed tomography scanner with online calibration correction - Archive ouverte HAL
Communication Dans Un Congrès Année : 2024

Comparison of saddle and helical trajectories of a mobile cone beam computed tomography scanner with online calibration correction

Résumé

In cone-beam computed tomography (CBCT), the conebeam (CB) artefact causes object-dependent image distortions away from the central plane. Non-circular trajectories such as saddles or helices can mitigate the CB artefact, but are challenging to execute with scanners not specifically designed for non-circular scanning. In this work, we made use of a recently available mobile robotic CBCT scanner (mobile ImagingRing, medPhoton, Salzburg, Austria) which allows sinusoidal motion perturbation of several degrees of freedoms during a source and detector rotation, coupled with infrared (IR) motion tracking to measure the geometry of each trajectory. We scanned a disk phantom designed to highlight CB artefacts with circular, saddle and helical trajectories executed by driving motion with wheels. We computed an incompleteness metric, tan(ψ), and correlated it with the region free from CB artefacts in the images. Using a separate cylindrical phantom, we additionally computed the modulation transfer function at 10 percent (MTF 10 ) to assess the accuracy of the calibration correction. We found regions free of CB artefacts of up to 190 mm in the superior-inferior direction for the saddle trajectory, and of 120 mm to 140 mm for the helical trajectory. MTF 10 was 1.39 lp/mm, 0.98 lp/mm and 1.03 lp/mm for the circular, saddle and helical trajectories with IR tracking, while without IR tracking the saddle and helical trajectories had MTF 10 less than 0.4 lp/mm.
Fichier principal
Vignette du fichier
wei2024a.pdf (3.42 Mo) Télécharger le fichier
Origine Accord explicite pour ce dépôt

Dates et versions

hal-04753338 , version 1 (25-10-2024)

Identifiants

  • HAL Id : hal-04753338 , version 1

Citer

Chengtao Wei, Simon Rit, Matthieu Laurendeau, Philipp Steininger, Felix Ginzinger, et al.. Comparison of saddle and helical trajectories of a mobile cone beam computed tomography scanner with online calibration correction. Proceedings of the XXth International Conference on the use of Computers in Radiation therapy (ICCR), Jul 2024, Lyon, France. ⟨hal-04753338⟩
17 Consultations
5 Téléchargements

Partager

More