Tests of one Brazilian facial reconstruction method using three soft tissue depth sets and familiar assessors

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Association of 3D Reconstruction and Conventional Radiography for the Description of the Appendicular Skeleton of Chelonoidis carbonaria (Spix, 1824)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Niobium filtration of conventional and high-frequency x-ray generator beams for intraoral radiography. Effects on absorbed doses, image density and contrast, and photon spectra

We have studied the effects of niobium beam filtration on absorbed doses, on image density and contrast, and on photon spectra with conventional and high-frequency dental x-ray generators. Added niobium reduced entry and superficial absorbed doses in periapical radiography by 9% to 40% with film and digital image receptors, decreased the radiation necessary to produce a given image density on E-speed film and reduced image contrast on D- and E-speed films. As shown by increased half-value layers for aluminum, titanium, and copper and by pulse-height analyses of beam spectra, niobium increased average beam energy by 6% to 19%. Despite the benefits of adding niobium on patient dose reduction and on narrowing the beams' energy spectra, the beam can be overhardened. Adding niobium, therefore, strikes the best balance between radiation dose reduction and beam attenuation, with its risks of increased exposure times, motion blur, and diminished image contrast, when it is used at modest thicknesses (30 μm) and at lower kVp (70) settings. © 1995 Mosby-Year Book, Inc.

Construction and test of low cost X-ray tomography scanner for physical-chemical analysis and nondestructive inspections

X-ray computed tomography (CT) refers to the cross-sectional imaging of an object measuring the transmitted radiation at different directions. In this work, we describe the development of a low cost micro-CT X-ray scanner that is being developed for nondestructive testing. This tomograph operates using a microfocus X-ray source and contains a silicon photodiode as detectors. The performance of the system, by its spatial resolution, has been estimated through its Modulation Transfer Function - MTF and the obtained value at 10% of MTF is 661 μm. It was built as a general purpose nondestructive testing device. © 2009 American Institute of Physics.

Wavelets in the computed evaluation of mammographic accreditation phantom images

This paper presents a novel approach to the computed assessment of a mammographic phantom device. The approach shown here is fully automated and is based on the automatic selection of the region of interest, in the use of the discrete wavelet transform (DWT) and morphological operators to assess the quality of the American College of Radiology (ACR) mammographic phantom images. The algorithms developed here have succesfully scored 30 images obtained with different combinations of voltage applied to the tube and exposure and could notice the differences in the radiographs due to the different level of exposure to radiation. © 2013 Springer-Verlag.

Airway space changes after maxillomandibular counterclockwise rotation and mandibular advancement with TMJ Concepts® total joint prostheses: Three-dimensional assessment

This study focused on three-dimensional (3D) airway space changes and stability following simultaneous maxillomandibular counterclockwise rotation, mandibular advancement, and temporomandibular joint (TMJ) reconstruction with custom-made total joint prostheses (TMJ Concepts®). Cone beam computed tomography (CBCT) scans of 30 consecutive female patients with irreversibly compromised TMJs were obtained at the following intervals: T1, presurgery; T2, immediately after surgery; and T3, at least 6 months after surgery. The CBCT volumetric datasets were analysed with Dolphin Imaging ® software to evaluate surgical and postsurgical changes to oropharyngeal airway parameters. The average changes in airway surface area (SA), volume (VOL), and minimum axial area (MAA) were, 179.50 mm2, 6302.60 mm3, and 92.23 mm2, respectively, at the longest follow-up (T3 - T1) (P ≤ 0.001). Significant correlations between the amount of mandibular advancement and counterclockwise rotation of the occlusal plane and 3D airway changes were also found (P ≤ 0.01). The results of this investigation showed a significant immediate 3D airway space increase after maxillomandibular counterclockwise rotation and mandibular advancement with TMJ Concepts total joint prostheses, which remained stable over the follow-up period. © 2013 International Association of Oral and Maxillofacial Surgeons.

Temporomandibular joint condylar changes following maxillomandibular advancement and articular disc repositioning

Purpose To evaluate condylar changes 1 year after bimaxillary surgical advancement with or without articular disc repositioning using longitudinal quantitative measurements in 3-dimensional (3D) temporomandibular joint (TMJ) models. Methods Twenty-seven patients treated with maxillomandibular advancement (MMA) underwent cone-beam computed tomography before surgery, immediately after surgery, and at 1-year follow-up. All patients underwent magnetic resonance imaging before surgery to assess disc displacements. Ten patients without disc displacement received MMA only. Seventeen patients with articular disc displacement received MMA with simultaneous TMJ disc repositioning (MMA-Drep). Pre- and postsurgical 3D models were superimposed using a voxel-based registration on the cranial base. Results The location, direction, and magnitude of condylar changes were displayed and quantified by graphic semitransparent overlays and 3D color-coded surface distance maps. Rotational condylar displacements were similar in the 2 groups. Immediately after surgery, condylar translational displacements of at least 1.5 mm occurred in a posterior, superior, or mediolateral direction in patients treated with MMA, whereas patients treated with MMA-Drep presented more marked anterior, inferior, and mediolateral condylar displacements. One year after surgery, more than half the patients in the 2 groups presented condylar resorptive changes of at least 1.5 mm. Patients treated with MMA-Drep presented condylar bone apposition of at least 1.5 mm at the superior surface in 26.4%, the anterior surface in 23.4%, the posterior surface in 29.4%, the medial surface in 5.9%, or the lateral surface in 38.2%, whereas bone apposition was not observed in patients treated with MMA. Conclusions One year after surgery, condylar resorptive changes greater than 1.5 mm were observed in the 2 groups. Articular disc repositioning facilitated bone apposition in localized condylar regions in patients treated with MMA-Drep. © 2013 American Association of Oral and Maxillofacial Surgeons.

Avaliação da prevalência de canais mandibulares bífidos em tomografia computadorizada por feixe cônico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monitoramento do processo de densificação de compósitos termoestruturais de carbono reforçado com fibras de carbono por tomografia computadorizada e resistividade elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da densidade óssea mandibular por meio de tomografias computadorizadas: Multislice e de feixe cônico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Application of two segmentation protocols during the processing of virtual images in rapid prototyping: ex vivo study with human dry mandibles

The aim of this study was to evaluate the accuracy of virtual three-dimensional (3D) reconstructions of human dry mandibles, produced from two segmentation protocols (outline only and all-boundary lines).Twenty virtual three-dimensional (3D) images were built from computed tomography exam (CT) of 10 dry mandibles, in which linear measurements between anatomical landmarks were obtained and compared to an error probability of 5 %.The results showed no statistically significant difference among the dry mandibles and the virtual 3D reconstructions produced from segmentation protocols tested (p = 0,24).During the designing of a virtual 3D reconstruction, both outline only and all-boundary lines segmentation protocols can be used.Virtual processing of CT images is the most complex stage during the manufacture of the biomodel. Establishing a better protocol during this phase allows the construction of a biomodel with characteristics that are closer to the original anatomical structures. This is essential to ensure a correct preoperative planning and a suitable treatment.

CT study of the performance of reciprocating and oscillatory motions in flattened root canal areas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação de Técnicas de Interpolação de Imagens Digitais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controle de qualidade em equipamentos mamográficos

Nowadays the mammography is the most effective way of revealing early breast cancer. The image in this kind of exam is gotten trough a x-ray sheaf of low energy, however, the suitable visualization of the interesting structures by the radiologist is not always possible due several factors that appears since the mamma composition until the equipments limitation. The regulation 453/98 sets quality control tests and limits of acceptation that guarantee a good development of the mammographys. The purpose of this study is the 3D principle ( Diagnostic, Dose and Dollar), that means, an improved diagnosis, a dose reduction in the patient and a cost decrease for the Institution. In this study was made the quality control tests set by the Regulation in two mammography equipments from Hospital das Clínicas da Faculdade de Medicina de Botucatu (HCFMB - UNESP). The results reached in this research were used in the renovation process of quality stamp in mammography granted by Colégio Brasileiro de Radiologia (CBR) to the diagnosis by image from the HCFMB – UNESP

Controle de qualidade em equipamentos de tomografia computadorizada

The computed tomography, devised by Godfrey Hounsfield and Allan Cormack, is in its fourth decade of the clinical use and has presented to be a very useful tool in the diagnosis of several pathologies. For this reason, its use is increasing each day, due to technological progress since its creation. Due to be more and more utilized, the equipment must be in good operating conditions, because it is subject to variance and wearing, damage the quality of diagnosis. To evaluate whether the performance of the scanner remains constant along the time and the dose received by the patient is within the desired limits, periodic tests of quality control must be performed. For this subject, the regulation 453 (June 01, 1998) was created, which determines the need of the implementation of a program for quality assurance (PGQ), where, in addition to the tests of quality control, are established the necessary measurements for the proper functioning of the equipment, generating a trustworthy diagnosis, reducing the dose for the patient and the costs. In this document, are presented tests of quality control carried out in hospitals of the city of Sao Paulo carried out together with the Technical Section of Applications by Imaging Diagnostic (STADI) of the Institute of Electrotechnics and Energy of the University of São Paulo (IEE/USP)