Auto calibration of a cone-beam-CT.

Purpose: This paper introduces a novel autocalibration method for cone-beam-CTs (CBCT) or flat-panel CTs, assuming a perfect rotation. The method is based on ellipse-fitting. Autocalibration refers to accurate recovery of the geometric alignment of a CBCT device from projection images alone, without any manual measurements.

Artefacts in CBCT: a review.

Artefacts are common in today's cone beam CT (CBCT). They are induced by discrepancies between the mathematical modelling and the actual physical imaging process. Since artefacts may interfere with the diagnostic process performed on CBCT data sets, every user should be aware of their presence.

Three-dimensional analysis of bone formation after maxillary sinus augmentation by means of microcomputed tomography: a pilot study.

Purpose: Although many studies have analyzed the suitability of different grafting materials for maxillary sinus augmentation by means of histomorphometry in conventional histologic strains, the three-dimensional (3D) structure and remodeling of these grafts after healing beneath the sinus membrane remain unclear. The aim of the present study was to determine whether microcomputed tomography is a suitable method to evaluate the 3D structure and remodeling of grafts after sinus floor augmentation.

Materials And Methods: Sinus floor augmentation was performed in five patients using autogenous bone (AB) alone, AB and beta-tricalcium phosphate (b-TCP, Cerasorb), AB and b TCP/hydroxyapatite (HA) (BoneCeramic), AB and calcium carbonate (Algipore), and AB and HA (PepGen).

Accurate registration of random radiographic projections based on three spherical references for the purpose of few-view 3D reconstruction.

Precise registration of radiographic projection images acquired in almost arbitrary geometries for the purpose of three-dimensional (3D) reconstruction is beset with difficulties. We modify and enhance a registration method [R. Schulze, D.

The patient with recidivent obscure gastrointestinal bleeding.

Obscure gastrointestinal (GI) bleeding is defined as visible or invisible GI blood loss, the source of which can not be identified by standard endoscopy (oesophagogastroduodenoscopy and colonoscopy). Nowadays, GI bleeding is divided into upper, mid- and lower bleeding. Mid-GI bleeding covers the section from the Treitz ligament to the ileocaecal valve.