Recent developments in CT technology has resulted in a continuing expansion of CT practice. CT has become a major source of exposure in diagnostic radiology. Therefore, the European Union, in an ionizing radiation protection directive, has classified computed tomography as a high dose diagnostic procedure and has pointed to the need to reduce the dose to the patient. Efforts towards dose reduction in CT have been recommended by international organizations. The European Commission (EC) have recommended the setup and the implementation of CT dose guidance levels for the most frequent examinations to promote strategies for the optimization of CT doses. These dose guidance levels should be derived using data from a wide scale survey. Therefore, it is of great interest whether there are dose quantities whose values are easy to obtain, which can correctly reflect the patient dose and allow assessment of the risk associated with the CT examination. The most widely used CT Dose Quantity is the computed tomography dose index (CTDI). Another important dose quantity is the Dose Length Product (DLP), which includes the patient, or the phantom volume irradiated during a complex examination. The main purpose of this study is the measurement of CTDI and DLP during the most frequent CT examinations at the University Hospital of Patras. Also scan lengths used for the same type of examinations will be monitored. For the same types of examinations effective doses will be calculated. Four CT examination was selected because of their frequency, Routine Head, Routine Chest, Routine Abdomen and Cervical Spine. The protocols of these exams were compared with the European Commission’s recommendations. Data were collected from 120 patients, 30 for each examination. Data on the scanning parameters and the patient dose were selected from the CT scanner, a GE LightSpeed 16. Moreover, data were collected about the sex, the age and the weight of the patient undergone the examination. The mean values of CTDIw, DLP and Effective Dose were calculated for each protocol and were compared with the recommendations of European Commission. Moreover, an evaluation of the dose indication of the CT scanner was made. Using a head and a body CT Dose phantom made by PMMA, an ionization chamber and an electrometer, the CTDI was measured for each examination protocol. These values were compared with the indications of CT and the correspondent values published by ImPACT. / Τα τελευταία χρόνια έχει παρατηρηθεί επέκταση της χρήσης του Υπολογιστικού Τομογράφου(ΥΤ). Ο ΥΤ είναι η κυριότερη πηγή ακτινοβολίας ανάμεσα σε όλες τις ακτινοδιαγνωστικές εξετάσεις. Για αυτό το λόγο η Ευρωπαϊκή Ένωση, σε μια κατευθυντήρια οδηγία για την προστασία από ιοντίζουσες ακτινοβολίες σημείωσε την ανάγκη μείωσης της δόσης στον ασθενή. Προσπάθειες για τη μείωση της δόσης από ΥΤ έχουν γίνει από διεθνείς οργανισμούς, οι οποίοι έχουν προτείνει τον καθορισμό επιπέδων αναφοράς για τις πιο συχνές εξετάσεις ΥΤ με σκοπό την ανάπτυξη στρατηγικών για τη μείωση της δόσης από ΥΤ. Τα επίπεδα αναφοράς πρέπει να προκύπτουν από έρευνες μεγάλης κλίμακας. Για αυτό το λόγο οι ποσότητες της δόσης που χρησιμοποιούνται πρέπει να είναι εύκολο να υπολογιστούν, αλλά να αντανακλούν σωστά τη δόση στον ασθενή και να επιτρέπουν τον υπολογισμό του κινδύνου που προέρχεται από τη χρήση της ακτινοβολίας. Η ποσότητα που χρησιμοποιείται ευρέως στη Δοσιμετρία από ΥΤ είναι ο Computed Tomography Dose Index, CTDI, το Γινόμενο Δόσης Μήκους (Dose Length Product, DLP) το οποίο συνυπολογίζει τον όγκο του ασθενή ή του ομοιώματος που έχει ακτινοβοληθεί κατά τη διάρκεια μιας πλήρους εξέτασης. Ο κύριος σκοπός αυτής της εργασίας είναι η μέτρηση του CTDI και του DLP για τις πιο συχνές εξετάσεις ΥΤ στο Πανεπιστημιακό Γενικό Νοσοκομείο Πατρών. Ακόμα υπολογίζεται το μέσο μήκος εξέτασης και η μέση ενεργός δόση για κάθε εξέταση. Επίσης ελέγχεται η αξιοπιστία των ενδείξεων της δόσης στην κονσόλα του ΥΤ. Επιλέχτηκαν τέσσερις εξετάσεις ΥΤ λόγω της συχνότητας τους, αυτές είναι: η εξέταση κεφαλής, θώρακα, κοιλίας και αυχένα. Τα πρωτόκολλα αυτών των εξετάσεων συγκρίνονται με τις συστάσεις της European Commission. Συνολικά συλλέχτηκαν δεδομένα από 120 ασθενείς, 30 για κάθε εξέταση. Δεδομένα που αφορούσαν τις παραμέτρους της σάρωσης κάθε ασθενή συλλέχτηκαν από την κονσόλα του ΥΤ, ο οποίος είναι ένας GE LightSpeed 16. Επιπλέον συλλέχτηκαν δεδομένα σχετικά με το φύλλο, την ηλικία και το βάρος του ασθενή που υποβλήθηκε σε εξέταση. Υπολογίστηκε η μέση τιμή του CTDIw, του DLP και της ενεργού δόσης για κάθε πρωτόκολλο και συγκρίθηκαν με τα όρια που προτείνει η European Commission σαν DRL. Επιπλέον, έγινε αξιολόγηση της τιμής της δόσης όπως αυτή εμφανίζεται στην κονσόλα του ΥΤ. Για αυτό το λόγο έγιναν μετρήσεις σε ένα ομοίωμα κεφαλής και σε ένα ομοίωμα σώματος κατάλληλο για την δοσιμετρία ΥΤ. Επιπλέον, χρησιμοποιήθηκε ένας θάλαμος ιονισμού και ένα ηλεκτρόμετρο. Έτσι μετρήθηκε η τιμή του CTDI για κάθε πρωτόκολλο χρησιμοποιώντας τις ίδιες παραμέτρους σάρωσης. Οι τιμές που μετρήθηκαν συγκρίθηκαν με τις ενδείξεις του ΥΤ αλλά και με τις τιμές που έχει δημοσιεύσει το Imaging Performance Assessment of CT scanners (ImPACT).

Thesis (MSc (Radiography))--Cape Peninsula University of Technology, 2017. / Background: Metabolic syndrome (MetS) is a clustering of cardiovascular disease (CVD) risk factors which include abdominal obesity, hyperglycaemia, hyper-triglyceridaemia, low HDL-cholesterol and hypertension. This cluster of metabolic deviations is believed to be the primary driver of the double global epidemic of diabetes (DM) and CVD, conditions which account for much of the social and economic global burden of disease. Similar to the global trend, a high prevalence of MetS (62%) and type 2 Diabetes Mellitus (T2DM) (28.2%) has been reported for the South African mixed ancestry population, with CVD risk significantly higher in subjects with DM. The increase in MetS prevalence is driven by the obesity epidemic and anthropometric cut-off values to define MetS for this particular component of the disease has been reported to differ widely between different populations and ethnicities. Currently the waist circumference (WC) cut-off value for MetS diagnosis needs to be determined and validated per ethnic group as opposed to the previously used European derived cut-off values (Alberti et al., 2006; 2009). Validation of the WC cut-off value needs to be against one of the so called gold standards of central obesity measurement, such as Computer Tomography (CT). This technique can measure subcutaneous fat (SAT) and visceral fat (VAT) individually, which is important because VAT has been reported to be associated with MetS and CVD. The current study forms part of a large research group, investigating the prevalence and risk factors for MetS and T2DM in the South African mixed ancestry population.

The purpose of this study is to evaluate the past and recent literature in order to determine the role of pre-operative CT scans in chronic otitis media. We aim to find consensus on the diagnostic ability of CT imaging in various anatomical parts of the middle ear and mastoid, and how this knowledge can affect clinical and surgical management. In context of all literature, there has been mixed results when looking at the sensitivity and specificity of middle ear structures. There was favorable consensus for CT's diagnosis of erosion of the malleus-incus complex, lateral semicircular canal, the facial nerve canal, and presence of soft tissue in the middle ear cavity. There were mixed results with respect to the erosion of tegmen tympani, and sigmoid sinus. Lastly, there was an unfavorable consensus when looking at the erosion of the stapes, oval window, and round window. Various studies conclude that the information gained from CT regarding the condition of the mastoid and middle ear can influence both the type of surgical method used and the success rate by reducing the risk of complications and recurrence of disease. In many studies, the methodology and interpretation of the CT scans are not very well presented. This unfortunately disallows meta-analysis between studies as the number of uncontrolled variables is too large. In the future, we hope that more information is provided as to the method of interpretation as well as the type of CT scanner and dosage. This will allow for a more meaningful result when comparing sensitivities and specificities towards middle ear pathologies, and it will allow for better examination of image quality and usefulness in context of the risk of radiation. Many otologists make routine use pre-operative CT scans in cases of chronic otitis media while others are more selective. In order to reach a consensus, however, more research focused on specific the decision-making process of physicians.

A possibilidade de exploração das imagens oferecida pela tomografia computadorizada cone beam (TCCB) permite investigações mais detalhadas do paciente. Este estudo, empregando alguns destes recursos, se propôs a comparar medidas cefalométricas realizadas sobre telerradiografias convencionais e reconstruções de perfil total e unilaterais obtidas da TCCB. Análises cefalométricas de 30 pacientes foram realizadas por um examinador calibrado sobre as reconstruções da TCCB e as telerradiografias convencionais. A reprodutibilidade dos fatores cefalométricos foi investigada por meio do coeficiente de correlação intraclasse em cada imagem. O método de Bland-Altman foi utilizado para averiguar a performance diagnóstica de cada imagem em relação às medidas de cada fator cefalométrico. O coeficiente de correlação intraclasse evidenciou semelhança de reprodutibilidade entre os exames. Quando os valores dos fatores cefalométricos foram comparados, observou-se forte concordância diagnóstica entre as mensurações realizadas sobre telerradiografias convencionais e imagens reconstruídas por TCCB. Conclui-se que, em pacientes sem assimetrias faciais importantes, a telerradiografia convencional e as reconstruções total e unilaterais a partir da TCCB oferecem desempenho de reprodutibilidade e resultado de análise cefalométrica semelhantes. / The possibility to explore images afforded by the cone beam computer tomography (CBCT) technique allows investigating patients in more detail. The present study uses some of these resources to compare cephalometric measurements obtained from conventional cephalograms and total and half-skull synthesized cone beam computed tomography (CBCT) cephalograms. Cephalometric analyses of 30 clinically symmetric patients; were conducted by a calibrated examiner on conventional and CBCTsynthesized cephalograms. Reproducibility was investigated using the intraclass correlation coefficient. The Bland-Altman analysis was used to assess the agreement of the measurements from each factor obtained by conventional, total, right and left CBCT-synthesized cephalograms. The intraclass correlation coefficient revealed similar levels of reproducibility. When the measurements obtained from conventional and CBCT-synthesized cephalograms were compared, the Bland-Altman analysis showed a strong agreement between them. Half-skull CBCT-synthesized cephalograms offer the same diagnostic performance and equivalent reproducibility in terms of cephalometric analysis as observed in conventional and total CBCT-synthesized cephalograms.

Nephrolithiasis can be a painful problem due to presence of kidney stones. Kidney stone is among the common painful disorders of the urinary system. Various imaging modalities are used to diagnose patients with symptoms of renal or urinary tract disease such as plain kidney, ureter, bladder x-ray (KUB), intravenous pyelography (IVP), and computed tomography (CT). As a traditional three-dimensional (3D) nephrolithiasis and kidney stones detection technique, computed tomography (CT) provides detailed cross-sectional images as well as 3D structure of kidney from moving the x-ray beam in a circle around the body. However, the risk of CT scans of the kidney is relatively higher exposure to radiation which is more than regular x-rays. C-arm technique is a new x-ray imaging modality that uses 2D array detector and cone shaped x-ray beam to create 3D information about the scanned object. Both x-ray source and 2D array detector cells mounted on C-shaped wheeled structure (C-arm). A series of projection images are acquired by rotating the C-arm around the patient in along circular path with a single rotation. The characteristic structure of C-arm allows to provide wide variety of movements around the patient that helps to remain the patient stationary during scanning time. In this work, we investigated a C-arm technique to generate a series of tomographic images for nephrolithiasis and detection of kidney stones. C-arm tomographic technique (C-arm tomosynthesis) as a new three dimensional (3D) kidney imaging method that provides a series of two dimensional (2D) images along partial circular orbit over limited view angle. Our experiments were done with kidney phantom which formed from a pig kidney with two embedded kidney stones inside it and low radiation dosage. Radiation dose and scanning time needed for kidney imaging are all dramatically reduced due to the cone beam geometry and also to limitation of angular rotation. To demonstrate the capability of our C-arm tomosynthesis to generate 3D kidney information for kidney stone detection, two groups of tomographic image reconstruction algorithms were developed for C-arm tomosynthesis: direct algorithms such as filtered back projection (FBP) and iterative algorithms such as simultaneous algebraic reconstruction technique (SART), maximum likelihood expectation maximization (MLEM), ordered- subset maximum likelihood expectation maximization (OS-MLEM) and Pre-computed penalized likelihood reconstruction (PPL). Three reconstruction methods were investigated including: pixel-driven method (PDM), ray-driven method (RDM) and distance driven method (DDM). Each method differs in their efficiency of calculation accuracy per computing time. Preliminary results demonstrated the capability of proposed technique to generate volumetric data about the kidney for nephrolithiasis and kidney stone detection by using all investigated reconstruction algorithms. In spite of each algorithms differs in their strategies, embedded kidney stone can be clearly visualized in all reconstruction results. Computer simulation studies were also done on simulated phantom to evaluate the results for each reconstruction algorithm. To mimic kidney phantom, simulated phantom was simulated with two different size kidney stones. Dataset of projection images was collated by using a virtual C-arm tomosynthesis with geometric configuration similar to real technique. All investigated algorithms were used to reconstruct 3D information. Different of image quality functions were applied to evaluate the imaging system and the reconstruction algorithms. The results show the capability of C-arm tomosynthesis to generate 3D information of kidney structures and to identify the size and location of kidney stones with limited amount of radiation dose.

Made available in DSpace on 2014-06-11T19:31:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-22Bitstream added on 2014-06-13T18:06:53Z : No. of bitstreams: 1 zanatta_r_dr_jabo.pdf: 28419186 bytes, checksum: 99fc23beed288698b72ece9e5547815c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A proposta deste estudo foi estabelecer um método de ensino para a disciplina de diagnóstico por imagem veterinária, ao associar o uso de imagens tridimensionais às aulas convencionais de radiologia. Para este fim foram obtidas imagens tridimensionais, por meio de exames de tomografia computadorizada multidetectores, da cabeça de cinco gatos domésticos. Estas imagens foram adicionadas à aula de radiologia da cabeça, onde comumente são apresentadas imagens bidimensionais. A aula foi ministrada para alunos de três instituições de ensino superior, uma federal, uma estadual e outra particular. Após a apresentação, os alunos responderam a um questionário para que fosse possível verificar se o método contribuiu para assimilar com mais facilidade o conhecimento anatômico e radiográfico regional. Dos 100 alunos, 77% acharam o método totalmente satisfatório, 19% satisfatório, 2% moderadamente satisfatório, 2% pouco satisfatório. Nenhum aluno considerou o método insatisfatório, validando o método proposto. Como objetivo secundário discutiram-se as imagens tridimensionais obtidas, com enfoque anatomo-clínico, visando tornar mais atrativo o estudo da anatomia radiográfica dos ossos da cabeça. As imagens permitiram a identificação dos ossos e das cavidades da cabeça. Acredita-se que estas possam ser utilizadas no estudo das estruturas frequentemente acometidas por enfermidades em gatos domésticos / The aim of this study was to establish a teaching methodology for diagnostic imaging in veterinary medicine by correlating the use of three-dimensional images to conventional radiology lectures. For this purpose, threedimensional images of the head of five domestic cats were acquired by multi-detector row computed tomography. These images were added to the lecture of radiology of the head, in which two-dimensional images are usually presented. The lecture was presented to students of three different institutions (federal, state and private). After the lecture the students answered a questionnaire to verify if the method contributed for better assimilation of the anatomical and radiographic knowledge. From 100 students, 77% found the method highly satisfactory, 19% satisfactory, 2% moderately satisfactory, 2% poorly satisfactory. None of the students found the method unsatisfactory. Threedimensional images obtained had been discussed with an anatomical and clinical view to make the study of radiographic anatomy of the bones of the head more attractive to students. The images allowed the identification of bones and cavities of the head, being able to be used to study the structures that are frequently affected by diseases in domestic cats

The metal strung harp indigenous to Ireland and Scotland from the Medieval period to the end of the 18th century was widely admired throughout its time period, and is now an important part of the cultural and musical heritage of both of these countries. This type of harp, known as the 'Irish harp', cláirseach, or clàrsach, currently has 18 known surviving instruments, including two sets of fragments. All of these harps are now too fragile to be played, therefore musicians and audiences wishing to explore the performance practice and repertory associated with them must rely on faithful replicas. The extensive knowledge and understanding of the construction of the surviving harps that is crucial to building these replica instruments is currently very limited, however. Although harps of this type enjoyed a long period of use dating back to the Medieval period, most surviving instruments post-date the beginning of the 17th century. Two harps belonging to the National Museum of Scotland, the 'Queen Mary' and 'Lamont', generally dated to circa the 15th century, are understood to be two of the oldest extant examples, making a study of their construction of particular interest. This dissertation presents the results of a comprehensive study of the construction of these two harps. A methodology was developed to address the issue of their uniqueness and fragility by combining the techniques used for non- and minimally destructive analysis of archeological artefacts with non-invasive medical diagnostic imaging. This study has utilized CT-scanning to provide three-dimensional radiography of each harp; XRF and SEM-EDX analysis to identify woods, metals, and pigments; photography and microscopy to record the decorative work, visible damage, repairs, and modifications; and a visual examination to assess the current state of each harp and to identify areas of interest for further analysis. The CT scanning was conducted at the Clinical Research Imaging Centre of Queen's Medical Research Institute, and the remainder of the analysis was conducted at the National Museums Scotland Collections Centre. Staff at both centres kindly facilitated the acquisition of the data for this study. Part I of this dissertation discusses the stringing of the instruments, presenting materials analysis of wire fragments, analysis of the effect of damage to the frames on the length and number of strings, and proposed reconstructions of the 'as-built' string lengths. Possible solutions for the pitch and gamut of each harp are also discussed. The construction of the harps is discussed where it is relevant to understanding the stringing. Part II presents a general discussion of the construction of each harp, including materials, decorative work, modifications, and signs of wear. This section also discusses evidence that may help establish dates of construction and timelines of modifications. Diagrams showing the dimensions of each harp are also presented. The implications of the results of this study for current understanding of these harps are discussed in detail and the methodology employed is discussed in terms of its applicability to future research of other surviving instruments.

Made available in DSpace on 2014-06-11T19:29:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-25Bitstream added on 2014-06-13T19:38:18Z : No. of bitstreams: 1 trautmann_f_me_sjc.pdf: 1282508 bytes, checksum: f1c7cce5513c5a439cf27f0bb563ed86 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O propósito deste trabalho foi verificar a posição das cabeças da mandíbula nas suas respectivas fossas mandibulares em individuos com diferentes má-oclusões Classe I, II e III. Foram utilizadas tomografias computadorizadas volumétricas de 60 indivíduos em avaliação préortodôntica do sexo masculino e feminino. Com o gabarito preconizado por Pereira (1997), obtivemos medidas lineares dos espaços articulares anterior, posterior e superior de cada ATM. Após análise estatística, concluiu-se que as cabeças da mandíbula nos casos de Classe III do lado esquerdo apresentaram, com significancia estatística, maior deslocamento anterior em relação a fossa mandibular. Os casos de Classe II do lado esquerdo, embora sem significância estatística, apresentaram tendência de maior deslocamento porterior da cabeça da mandíbula enquanto os grupos de Classe I do mesmo lado apresentaram tendência a posição centralizada. Os grupos de Classe I e III do lado direito apresentaram maior tendência de deslocamento centralizado, enquanto os grupos de.Classe II do mesmo lado apresentaram maior tendência de deslocamento posterior porém sem significância estatística / The purpose of this study was to determine the condyle position in their respective mandibular fossa in different individuals with Class I, II and III malocclusions. Cone Beam Computer Tomographies (CBCT) from 60 male and female individuals were taken in the pre-orthodontic treatment. The answer key developed by Pereira (1997) provides us the linear measurements of the anterior, posterior and superior spaces of TMJ. After statistic analysis, we can conclude that the condyle position in Class III individuals on the left side, showed, with statistical significance, more tendency to anterior condyle dislocation in the mandibular fossa. In Class II cases on the left side, although not statistically significant, tended to posterior condyle deviation position. Class I group on the same side showed a tendency towards central position. Class I and III groups on the right side showed a higher tendency to central position, while Class II groups in the same side showed a higher tendency to posterior position, but without statistical significance

Made available in DSpace on 2014-06-11T19:29:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-06Bitstream added on 2014-06-13T20:19:07Z : No. of bitstreams: 1 matai_cvb_me_sjc.pdf: 1230516 bytes, checksum: a6fc95904a3af2e656ac9e3c2960bfaf (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As tomografias computadorizadas (TC) tridimensionais (3D) solucionaram em grande parte as inconveniências da sobreposição de acidentes anatômicos laterais comuns (dependendo da direção de incidência dos raios X) nas radiografias realizadas com o indivíduo em perfil. Também eliminou-se a sobreposição de imagens comuns a métodos radiográficos 2D. O propósito neste trabalho foi comparar a precisão das mensurações 3D na identificação de estruturas craniofaciais e ampliar o conhecimento da classe odontológica sobre o uso da Tomografia computadorizada 3D cone beam’ (TCCB) como ferramenta de auxílio no diagnóstico das estruturas faciais. Foram utilizados cinco crânios secos, pertencentes à Disciplina de Anatomia da Faculdade de Odontologia de São José dos Campos – UNESP. Os crânios foram fixados em relação central dos côndilos com máxima intercuspidação dos dentes. Todos os crânios apresentaram seus pontos cefalométricos demarcados com identificadores metálicos e escaneados no tomógrafo cone beam Newtom, sendo que todas as medidas lineares foram comparadas com as medidas in situ mensuradas com o auxílio do paquímetro digital. Após validação do erro do operador, os dados obtidos foram comparados e submetidos a estatística descritiva e à análise de Wilcoxon. Os resultados mostraram que 40% das medidas tiveram uma diferença menor que 0,16mm, 85% apresentaram acurácia abaixo do valor de 0,58mm e que menos de 3% das medidas tiveram diferença de valores acima de 1mm. O teste de Wilcoxon não encontrou nenhuma diferença estatisticamente significante entre os métodos. Concluímos que a TCCB é um método preciso para obtenção de medidas linear de estruturas do crânio quando comparada as mesmas mensurações realizadas in situ(AU) / The three-dimensional (3D) computed tomography (CT) overcame many of the hassles of overlapping anatomical accidents common in lateral radiographs taken with the individual in profile. Also eliminated the overlap of images common to 2D radiographic methods. The purpose of this study was to compare the accuracy of 3D measurements in the identification of craniofacial structures and expanding the knowledge of the class on the use of dental computed tomography 3D cone beam (CBCT) as a tool to aid in the diagnosis of facial structures. The tests were in situ, on a five dry skulls, belonging to the Discipline of Anatomy, São José dos Campos Dental School- UNESP. The skulls were fixed on the central condyle with maximum intercuspation teeth. All of than had their skulls cephalometric points marked with metal identifiers and scanned with Newtom cone beam tomography. Linear measurements were compared with measures in situ measured using the digital caliper. After validation of operator error, the data were compared and subjected to descriptive statistics and analysis of Wilcoxon. The results showed that 40% have had a difference of less than 0.16 mm, 85% were below the accuracy of 0.58 mm and less than 3% of the difference in values were over 1 mm. The test of Wilcoxon found no statistically significant difference between the methods. We conclude that CBCT is a precise method for identifying and measuring the linear skull’s structures when compared the same measurements performed with digital caliper in situ(AU)

Orientador: Adriano Marotta Araújo / Banca: Jefferson Luis OshiroTanaka / Banca: Horácio Faig Leite / Resumo: As tomografias computadorizadas (TC) tridimensionais (3D) solucionaram em grande parte as inconveniências da sobreposição de acidentes anatômicos laterais comuns (dependendo da direção de incidência dos raios X) nas radiografias realizadas com o indivíduo em perfil. Também eliminou-se a sobreposição de imagens comuns a métodos radiográficos 2D. O propósito neste trabalho foi comparar a precisão das mensurações 3D na identificação de estruturas craniofaciais e ampliar o conhecimento da classe odontológica sobre o uso da Tomografia computadorizada 3D "cone beam' (TCCB) como ferramenta de auxílio no diagnóstico das estruturas faciais. Foram utilizados cinco crânios secos, pertencentes à Disciplina de Anatomia da Faculdade de Odontologia de São José dos Campos - UNESP. Os crânios foram fixados em relação central dos côndilos com máxima intercuspidação dos dentes. Todos os crânios apresentaram seus pontos cefalométricos demarcados com identificadores metálicos e escaneados no tomógrafo cone beam Newtom, sendo que todas as medidas lineares foram comparadas com as medidas in situ mensuradas com o auxílio do paquímetro digital. Após validação do erro do operador, os dados obtidos foram comparados e submetidos a estatística descritiva e à análise de Wilcoxon. Os resultados mostraram que 40% das medidas tiveram uma diferença menor que 0,16mm, 85% apresentaram acurácia abaixo do valor de 0,58mm e que menos de 3% das medidas tiveram diferença de valores acima de 1mm. O teste de Wilcoxon não encontrou nenhuma diferença estatisticamente significante entre os métodos. Concluímos que a TCCB é um método preciso para obtenção de medidas linear de estruturas do crânio quando comparada as mesmas mensurações realizadas in situ(AU) / Abstract: The three-dimensional (3D) computed tomography (CT) overcame many of the hassles of overlapping anatomical accidents common in lateral radiographs taken with the individual in profile. Also eliminated the overlap of images common to 2D radiographic methods. The purpose of this study was to compare the accuracy of 3D measurements in the identification of craniofacial structures and expanding the knowledge of the class on the use of dental computed tomography 3D cone beam (CBCT) as a tool to aid in the diagnosis of facial structures. The tests were in situ, on a five dry skulls, belonging to the Discipline of Anatomy, São José dos Campos Dental School- UNESP. The skulls were fixed on the central condyle with maximum intercuspation teeth. All of than had their skulls cephalometric points marked with metal identifiers and scanned with Newtom cone beam tomography. Linear measurements were compared with measures in situ measured using the digital caliper. After validation of operator error, the data were compared and subjected to descriptive statistics and analysis of Wilcoxon. The results showed that 40% have had a difference of less than 0.16 mm, 85% were below the accuracy of 0.58 mm and less than 3% of the difference in values were over 1 mm. The test of Wilcoxon found no statistically significant difference between the methods. We conclude that CBCT is a precise method for identifying and measuring the linear skull's structures when compared the same measurements performed with digital caliper in situ(AU) / Mestre