Evaluation of skeletal maturation by comparing the hand wrist radiograph and cervical vertebrae as seen in lateral cephalogram.

Background and Objectives: Aim of this study was to determine the validity of cervical vertebrae radiographic assessment to predict skeletal maturation. Materials and Methods: Left-hand wrist and lateral cephalometric radiographs of 100 Bangalore children aged 8-18 years, divided into 10 groups of 10 subjects each with equal distribution of males and females, were measured. On left-hand wrist radiograph, the classification of Fishman was used to assess skeletal maturation. Cervical vertebrae maturation was evaluated with lateral cephalometric radiograph, using the stages developed by Hassel and Farman. The changes in hand wrist and cervical vertebrae were correlated. Results: Significant association was observed between skeletal maturation indicator stages and cervical vertebrae maturation indicator stages. Correlation coefficient was found to be significant (P<0.0001). Conclusion: The results of the study indicated that the cervical vertebrae maturation and hand wrist skeletal maturation was significantly related.

A comparative evaluation of film and digital panoramic radiographs in the assessment of position and morphology of impacted mandibular third molars.

Background and Objective: Digital photo stimulable phosphor (PSP)-based radiography has many known theoretical advantages over conventional film radiography but its diagnostic efficacy has to be assessed clinically. This study compared the efficiency of conventional film-based panoramic radiographs with that of digital PSP-based panoramic radiographs in the assessment of position and morphology of impacted mandibular third molars. Materials and Methods: We selected a total of 80 impacted mandibular third molars that fulfilled the inclusion and exclusion criteria of this study. Both conventional film-based panoramic radiographs and digital PSP-based panoramic radiographs were taken of all the study samples and the teeth were later surgically removed. Conventional film-based and digital PSP-based panoramic radiographs were compared for their relative efficiencies in the assessment of impaction status, position of tooth, number of roots, root morphology, and proximity to mandibular canal of impacted mandibular third molars. An oral surgeon graded these same factors during/after surgical exploration and this assessment was considered the gold standard. The data obtained were statistically analyzed using descriptive statistics, chi-square test, and McNemar's test. Results: There was no statistically significant difference between conventional film-based radiographic assessment and digital PSP-based panoramic radiographic assessment of impaction status, position of tooth, number of roots, and proximity to mandibular canal of impacted mandibular third molars (P>0.05). However, there was significant difference between the two methods with regard to assessment of root morphology of impacted mandibular third molars (P=0.00). Interpretation and Conclusion : Conventional film-based panoramic radiographs and digital PSP-based panoramic radiographs were comparable in their accuracy in the preoperative study of impacted mandibular third molar with regard to impaction status, tooth position, number of roots, and proximity to the mandibular canal. Digital PSP-based panoramic radiographs were more accurate than conventional film-based panoramic radiographs in the assessment of root morphology of impacted mandibular third molars. Hence, we conclude that digital PSP-based panoramic radiographs can be used as an effective alternative to conventional film-based panoramic radiographs for assessment of position and morphology of impacted mandibular third molars.

Dual-Energy Subtraction Imaging for Diagnosing Vocal Cord Paralysis with Flat Panel Detector Radiography

OBJECTIVE: To investigate the clinical feasibility of dual energy subtraction (DES) imaging to improve the delineation of the vocal cord and diagnostic accuracy of vocal cord paralysis as compared with the anterior-posterior view of flat panel detector (FPD) neck radiography. MATERIALS AND METHODS: For 122 consecutive patients who underwent both a flexible laryngoscopy and conventional/DES FPD radiography, three blinded readers retrospectively graded the radiographs during phonation and inspiration on a scale of 1 (poor) to 5 (excellent) for the delineation of the vocal cord, and in consensus, reviewed the diagnostic accuracy of vocal cord paralysis employing the laryngoscopy as the reference. We compared vocal cord delineation scores and accuracy of vocal cord paralysis diagnosis by both conventional and DES techniques using kappa statistics and assessing the area under the receiver operating characteristic curve (AUC). RESULTS: Vocal cord delineation scores by DES (mean, 4.2 +/- 0.4) were significantly higher than those by conventional imaging (mean, 3.3 +/- 0.5) (p < 0.0001). Sensitivity for diagnosing vocal cord paralysis by the conventional technique was 25%, whereas the specificity was 94%. Sensitivity by DES was 75%, whereas the specificity was 96%. The diagnostic accuracy by DES was significantly superior (kappa = 0.60, AUC = 0.909) to that by conventional technique (kappa = 0.18, AUC = 0.852) (p = 0.038). CONCLUSION: Dual energy subtraction is a superior method compared to the conventional FPD radiography for delineating the vocal cord and accurately diagnosing vocal cord paralysis.

The comparison of subjective image quality in conventional and digital panoramic radiography.

OBJECTIVE: The purpose of this study was to compare the subjective image quality of (1) regular intensifying screens with medium intensifying screens, (2) regular intensifying screens with digital radiography, and (3) medium intensifying screens with digital radiography for panoramic radiographs. MATERIALS AND METHODS: Forty-five patients participated and a total of 90 radiographs were obtained in the study. The patients were divided into three groups (regular-medium intensifying screen, regular intensifying screen-digital radiography, and medium intensifying screen-digital radiography) that consisted of 15 people each. All radiographs were assessed by three oral radiologists independently. The observers evaluated the images using a 3-point scale (1=well visible, 0=partly visible, -1=not or hardly visible) for anatomical structures and pathological findings that are commonly found on panoramic radiographs. Subjective image quality of the groups and comparison of the observers were assessed by using non parametric Kruskal Wallis and Mann-Whitney U tests. RESULTS: For all groups and observers, no statistically significant difference (p>0.05) was found for both anatomical structures and pathologies and between anatomical structures and pathologies according to the Mann Whitney U test. In comparison with observers, no statistically significant difference (p>0.05) was found for both anatomical structures and pathologies and between anatomical structures and pathologies for all groups according to the Kruskal Wallis test. CONCLUSION: The subjective image quality of medium and regular intensifying screens and conventional and digital panoramic radiographs were found statistically equal in this study.

Detector efficiency for non-helical trajectory of cone beam reconstruction / 生物医学工程学杂志

Using the present cone beam reconstruction formula for general trajectory, we have investigated the issue of detector efficiency for non-helical trajectory. The results reveal that the two factors dominating the detector efficiency are detector geometry and filtering directions. The methods for to higher detector efficiency are proposed, and the reliability and feasibility are tested by simulation results.

Evaluation of the effects of processing delays and protective plastic cases on image quality of a photostimulable phosphor plate system

This ex vivo study evaluated the quality of digital radiographic images obtained with the photostimulable phosphor plate system (Digora) according to the processing delay and maintenance of optical plates in either opaque (supplied with the system) or transparent protective plastic cases during this period. Five radiographs were obtained from the mandibular molar region of a dry human mandible using optical plates. These plates were placed in the protective plastic cases before obtaining the radiographs and were processed immediately or after processing delays of 5, 60 and 120 min, when the case was removed. The results revealed a reduction in image quality when processing was delay 120 min compared to the other times. The opaque case provided better protection to the sensor than the transparent case. In conclusion, a 120-min processing delay for the Digora system caused a reduction in image quality, yet without interfering with the quality of diagnosis. The opaque case supplied by the system's manufacturer provided better protection to the optical plate than the transparent case.

Otimização dos parâmetros de exposição radiográfica através de método computacional para aquisição de imagens de boa qualidade para diagnóstico / A computer-aided method to optimize radiographic exposure parameters to acquire better quality images for diagnosis

Falhas na execução de uma imagem radiográfica ou durante o processamento dos filmes geram interpretações errôneas, repetição do exame, maior exposição dos pacientes à radiação, além de aumentar o tempo clínico e os custos. A seleção correta dos parâmetros de exposição radiográfica proporciona a aquisição de imagens radiográficas com contraste, nitidez, detalhes, densidade óptica e definição das estruturas anatômicas para a realização de laudos radiográficos confiáveis. Assim sendo, neste artigo é apresentado um método computacional que pode auxiliar na seleção dos parâmetros de exposição mais apropriados para um dado exame radiográfico. As densidades ópticas foram simuladas considerando a composição e a espessura dos tecidos da estrutura anatômica, as características do aparelho de raios  X e do sistema écran-filme e os parâmetros de exposição otimizados conforme regras encontradas na literatura. Cinco radiologistas experientes avaliaram imagens radiográficas adquiridas de simuladores antropomórficos com parâmetros de exposição sugeridos pelo método computacional desenvolvido e também parâmetros encontrados na literatura. Após analisarem o contraste (diferença de densidade óptica em áreas adjacentes) e a nitidez (presença de detalhes visíveis tais como linhas estruturais finas, bordas de tecidos ou estruturas de interesse diagnóstico), os radiologistas opinaram que as imagens adquiridas com os parâmetros de exposição sugeridos pelo método computacional proposto proporcionaram um bom diagnóstico. Além disso, os valores de densidade óptica medidos nas imagens radiográficas numa posição correspondente ao centro do campo de radiação também apresentaram uma boa correlação com aqueles calculados pelo método, em torno de 90%. Este método pode se tornar também um valioso recurso didático para treinamento de novos profissionais para o setor radiológico.

Radiographic images of good quality allow adequate diagnosis. However imperfections in the selection process of exposure parameters, or during the film processing, generate erroneous interpretations or exam repetition, resulting in major exposure of patients to the radiation, and increasing the clinical time and costs. This article presents a computer method that helps the choice of better exposure parameters. The optical densities had been simulated taking into account tissue composition and thickness of the anatomical structure, characteristics of the X-ray equipment and screen-film system, and radiographic exposure parameters optimized according to rules found in literature. Five experienced radiologists evaluated the radiographic images obtained from anthropomorphic phantoms with the exposure parameters suggested by proposed method (named MD), and also with others parameters found in literature. After analyzing the image contrast and sharpness, they declared that the MD images provide a good diagnosis. Besides, the optical density values measured in these radiographic images on the position corresponding to the center of radiation field presented a good agreement (correlation of 90%) with those values calculated by the proposed method. This method can also become a valuable didactic resource for training of new professionals for the radiological sector.

Image quality in partially erased DenOptix® storage phosphor plates

This study aimed at investigating the effect of the partial erasing of DenOptix® system storage phosphor plates on the image quality of digital radiographs. Standardized digital radiographs were acquired of a phantom mandible, using size 2 intraoral DenOptix® storage phosphor plates (n = 10). Subsequently, the active areas of the plates were placed in a viewing box with a constant light intensity of 1,700 lux for 130 seconds to achieve complete erasing (control plate), as well as for 0, 5, 10, 15, 20, 25, 34, 66, and 98 seconds, to compose the experimental group of partially erased plates. The same exposure settings were repeated using the control and experimental plates, which were scanned at a resolution of 300 dpi. Five radiologists independently examined the pairs of digital radiographs obtained with the control and partially erased plates, in random order, and indicated the best image for oral diagnosis. Cochran-Mantel-Haenszel’s chi-square test, at a significance level of 5 percent, was used to compare the percentages of superior quality images in each combination of control and partially erased plates, subjectively assessed. No significant differences were found between radiographic images acquired with control and partially erased plates, except for the combination of 0 second (30 percent) versus 130 seconds (70 percent), p = 0.0047. It can be concluded that, under adequate light intensity conditions, erasing intraoral DenOptix® storage phosphor plates may require time intervals of as little as 5 seconds.

Some considerations about developments of rural digital X-ray radiography systems / 中国医疗器械杂志

A kind of rural digital radiography systems is introduced In this paper, including its design, constructural characteristics, and the implementing methods. Meanwhile time, it is pointed out that detail considerations should be given to the system features, key components selection and clinical workflow. Serviceability and ease of as for developments of rural digital radiography systems are also mentioned.

Reproducibility of pixel values for two photostimulable phosphor plates in consecutive standardized scannings / Reprodutibilidade dos valores de "pixels" de duas placas de fósforo fotoestimuláveis em leituras padronizadas consecutivas

The objective of the present study was to determine the reproducibility of the pixel values obtained with the Digora system (Soredex, Finland). Exposures were standardized, with variation in exposure and scanning time of two photostimulable phosphor plates containing a stepwedge image. The smallest variation in pixel values ranged from 50 to 75 percent, with the widest variations being observed in less dense steps. A significant difference in pixel values was observed in terms of X-ray exposure and scanning times and between the two plates themselves (ANOVA, p < 0.01). Using the present methodology, the reproducibility of pixel values was not satisfactory for the tested white photostimulable plates. This wide variation in digitalization might be influenced by the amount of X-rays that sensitized the plates. It may be important to establish the reproducibility of the pixel values in quantitative studies using digital image.

O objetivo do presente trabalho foi determinar a reprodutibilidade dos valores de "pixels" obtidos com o sistema Digora (Soredex, Finlândia). As exposições foram padronizadas, com variação no tempo de exposição e leitura de duas placas de fósforo fotoestimuláveis contendo a imagem de um penetrômetro. A menor variação nos valores de "pixels" foi de 50 a 75 por cento, sendo as maiores variações oriundas nas faixas mais claras. Uma diferença significante nos valores de "pixels" foi observada em relação ao tempo de exposição e leitura das placas e entre as duas placas (ANOVA, p < 0,01). Utilizando a presente metodologia, a reprodutibilidade dos valores de "pixels" das placas testadas do sistema Digora não foi satisfatória. Essa grande variação na digitalização pode ter sido influenciada pela quantidade de Raios X que sensibilizou as placas. Isso pode ser importante para estabelecer a reprodutibilidade dos valores de "pixels" em estudos quantitativos usando imagem digital.

Analysis of the automatic brightness controlling for x-ray imaging systems / 中国医疗器械杂志

In this paper, the question about automatic brightness control for x-ray imaging systems based on CCD camera is discussed, and the structure and principle of an auto brightness control loop are analyzed along with the working procedure of the x-ray imaging system. A kind of digital brightness controller about a typical device and the designing idea of the computer brightness intelligent control software is introduced.

Actualización en el uso del sistemas pantalla-película en radiología convencional / Update in screen-film systems use in conventional radiology

En la mayoría de los Servicios y Centros Radiológicos de nuestro país se utilizan los sistemas detectores de pantalla-película de fósforos de tierras raras con emisión de luz verde y película sencible a la misma; sin embargo, en algunos Centros del Sistema Público de Salud aún se utilizan pantalla película convencionales de tungstato de calcio, que emite luz azul, con película sencible a este color (por ej: en el Hospital San Juan de Dios, Peumo, Quillota, Puerto Natales, San José de Maipo). El objetivo del presente artículo es proporcionar a los profesionales herramientas que les permitan optimizar el empleo de los sistemas detectores, que son elementos accesorios de gran importancia de la abtención de imágenes radiográficas de alta calidad diagnóstica, logrando además disminuir la dosis de irradiación al paciente y una mayor duración del tubo de rayos X, entre otras características

Niveles lipídicos y calcificaciones coronarias detectadas por radioscopia con intensificador de imágenes TV en una población asintomática / Lipidic levels and fluoroscopyc detection of coronary artery calcification in asymptomatic subjects

Es sabido que la detección precoz de la arterosclerosis coronaria disminuye el riesgo de infarto. Con tal motivo se estudiaron 104 pacientes, de 52 años de edad promedio, mediante radioscopia TV. De acuerdo a los resultados de la calcificación coronaria CC y al número de territorios involucrados se clasificaron los pacientes en varios grupos, concluyendo que la radioscopia TV es un método de alta sensibilidad, bajo costo, rapidez y seguridad para la detección de CC

Estudos baseados nas técnicas de angiografia / Study based in angiography techniques

Este trabalho baseia-se em levantamentos radiométricos feitos nos modos de fluoroscopia e grafia, considerando medidas de feixe primário e secundário, com o objetivo da avaliação das taxas de exposição a que estão submetidos o paciente, o médico, o anestesista e demais membros da equipe executora de exames de radiologia vascular periférica.

Dispositivo de sensoriamento do feixe de raios-x para determinaçäo do centro do campo de radiaçäo / Sensing dispositive of x-ray bundle for determination of the radiation field center

As características do ponto focal do tubo de raios-X são o fator limitante da capacidade de resolução espacial em muitos sistemas radiográfios, e variam consideravelmente quando observadas em diferentes pontos de campo de radiação. Desta forma, é importante não somente conhecer estas características, como também a posição exata a partir da qual foram medidas. Neste trabalho, estamos propondo um novo dispositivo eletrônico para localização do raio central do cone de radiação, a fim de possibilitar um perfeito alinhamento dos objetos de teste utilizados na avaliação do ponto focal com eixo de referência.

Processamento para simulaçäo da nitidez de imagens radiográficas para diversos sistemas de registro da imagem / Processing to clearness simulation of radiographic images to several image register system

Este trabalho descreve um método para prever a influência do sistema de registro sobre a nitidez de imagens radiográficas por simulação computacional, procurando apresentar previamente a imagem a ser obtida para cada tipo de filme ou combinação écran-filme usada durante a exposição.

This work describes a method aimed to predict the influence of the record system on radiographic images sharpness by computer simulation. This method is intended to previously show the image to be obtained for each type of film or screen-film combination used during the exposure. l

Determinaçäo do tamanho do ponto focal de tubos de raios-x: digitalizaçäo direta vs avaliaçäo óptica / Determination of the size of focal point of x-rays tube: direct digitalization versus optical evaluation

Neste trabalho é discutida uma metodologia comparativa entre técnicas convencionais de midição das dimensões do ponto focal de tubos de raios-X e uma nova técnica utilizando recursos para aquisição digital de imagens. São apresentados resultados de medições com ambos os métodos.

This work shows a comparative methodology between standard techniques for evaluation of X-ray tubes focal spots and a newer one which uses digital resources for image acquisition. Results from measurements by using both methods are presented