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1.
Phys Med ; 24(2): 117-21, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18291697

RESUMO

I-ImaS (Intelligent Imaging Sensors) is a European project aiming to produce real-time adaptive X-ray imaging systems using Monolithic Active Pixel Sensors (MAPS) to create images with maximum diagnostic information within given dose constraints. Initial systems concentrate on mammography and cephalography. In our system, the exposure in each image region is optimised and the beam intensity is a function of tissue thickness and attenuation, and also of local physical and statistical parameters in the image. Using a linear array of detectors, the system will perform on-line analysis of the image during the scan, followed by optimisation of the X-ray intensity to obtain the maximum diagnostic information from the region of interest while minimising exposure of diagnostically less important regions. This paper presents preliminary images obtained with a small area CMOS detector developed for this application. Wedge systems were used to modulate the beam intensity during breast and dental imaging using suitable X-ray spectra. The sensitive imaging area of the sensor is 512 x 32 pixels 32 x 32 microm(2) in size. The sensors' X-ray sensitivity was increased by coupling to a structured CsI(Tl) scintillator. In order to develop the I-ImaS prototype, the on-line data analysis and data acquisition control are based on custom-developed electronics using multiple FPGAs. Images of both breast tissues and jaw samples were acquired and different exposure optimisation algorithms applied. Results are very promising since the average dose has been reduced to around 60% of the dose delivered by conventional imaging systems without decrease in the visibility of details.


Assuntos
Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Algoritmos , Fenômenos Biofísicos , Biofísica , Feminino , Humanos , Arcada Osseodentária/diagnóstico por imagem , Mamografia/instrumentação , Mamografia/estatística & dados numéricos , Radiografia Dentária/instrumentação , Radiografia Dentária/estatística & dados numéricos
2.
Dentomaxillofac Radiol ; 35(3): 147-51, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16618846

RESUMO

OBJECTIVE: To survey end-user opinions on dental digital sensor characteristics for the design of a new X-ray imaging sensor. MATERIALS AND METHODS: 100 questionnaires were sent out to dentists and dental radiologists. The questionnaire consisted of six parts related to dental sensors. A: Details about the respondent; B: Prioritization of most important aspects of digital sensors; C: Rating advantages and D: disadvantages of digital sensors; F: Dental features that need to be enhanced by digital sensors; G: End-user comments. RESULTS: Fifty-six questionnaires were returned. Contrast resolution and imaging time were assessed as the most and the least important aspects, respectively. Aspects considered as advantages by approximately 80% of respondents were: optimal contrast resolution, increased specificity, increased discrimination between diseased and healthy tissue, increased sensitivity, lower dose to the patient by more than 20%; as a disadvantage, increased patient dose was given. Dental features considered important by over 80% of the respondents were for intraoral radiographs: the visibility of caries, periapical, periodontal, and bone lesions; for panoramic radiographs: reduction of ghost images, image sharpness and bone. Bone and soft tissues on cephalograms and bone on temporomandibular joint (TMJ) tomograms were mentioned by over 70%. CONCLUSION: The most desired characteristic for a new sensor is contrast resolution. Dose saving is not considered as important unless it is more than 20%. Examination time is not a major issue. Caries, periapical and periodontal, and bone lesions for intraoral radiographs, reduction of ghost images, image sharpness and bone for panoramic radiographs were the most frequently mentioned dental features that should be enhanced by digital sensors.


Assuntos
Radiografia Dentária Digital , Ecrans Intensificadores para Raios X , Artefatos , Meios de Contraste , Odontólogos , Humanos , Projetos Piloto , Doses de Radiação , Radiologia , Inquéritos e Questionários
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