Dose reduction in skeletal and chest radiography using a large-area flat-panel detector based on amorphous silicon and thallium-doped cesium iodide: technical background, basic image quality parameters, and review of the literature

Völk, Markus; Hamer, Okka W.; Feuerbach, Stefan; Strotzer, M.

doi:10.1007/s00330-004-2243-2

Cited by 41 publications

(20 citation statements)

References 28 publications

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“…Portanto, sempre que possível devem-se priorizar métodos diagnósticos reconhecidamente inócuos ao feto, como US e RM. Existem evidências de que o uso de radiografias digitais também reduziria a quantidade de radiação ionizante absorvida pela paciente (29,30) . Doenças do trato urogenital, como urolitíase e infecções urinárias complicadas com pielonefrite, podem afetar com freqüência a gestante.…”

Section: Exames Radiológicos Durante a Gestaçãounclassified

Exames radiológicos na gestação

D'Ippólito

Medeiros

2005

Radiol Bras

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Gestantes podem precisar ser submetidas a exames radiológicos para um diagnóstico preciso e conduta correta. Nestes casos a exposição à radiação ionizante e seus efeitos sobre o feto são motivo de preocupação para a paciente e o seu médico. Na verdade, a maioria destes exames é segura e não oferece risco significativo ao feto. No entanto, é importante que o radiologista conheça estes riscos potenciais para poder orientar adequadamente todos os envolvidos no atendimento. Unitermos: Radiação ionizante; Gestação; Tomografia computadorizada; Exame radiológico.X-ray examinations during pregnancy. X-ray examinations may be necessary during pregnancy for an accurate diagnosis and adequate treatment administration. In these cases, the exposure to ionizing radiation and its effects on the fetus are a major concern to the patient and to the clinician. In fact, most of these examinations are safe and do not represent a significant risk to the fetus. However, the radiologist must know the potential risks to be able to instruct all personnel involved in the care of the patient. Key words: Ionizing radiation; Pregnancy; Computed tomography; X-ray studies. Atualização feto, permite medir os riscos e justificar a utilização de determinados métodos radiológicos em benefício da gestante. Resumo DEFINIÇÃO E MENSURAÇÃO DA RADIAÇÃO IONIZANTEQualquer discussão a respeito dos efeitos da radiação ionizante prescinde de uma clara compreensão sobre o que é a radiação ionizante e como esta é medida (dosimetria). Podemos definir a radiação ionizante como ondas eletromagnéticas de alta energia (raios X ou raios gama) que, ao interagirem com a matéria, desencadeiam uma série de ionizações, transferindo energia aos átomos e moléculas presentes no campo irradiado e promovendo, assim, alterações físico-químicas intracelulares (7) . Para se entender os efeitos relacionados à exposição à radiação ionizante deve-se definir as grandezas físicas utilizadas para quantificá-la. Com o objetivo de se medir a energia depositada por um feixe de fótons de alta energia (raios X ou raios gama) em um tecido biológico e os seus efeitos sobre este tecido, foi criada a grandeza "dose absorvida". A dose absorvida de radiação é a energia depositada por quilograma de tecido e é expressa em "rad" ("radiation absorbed dose", ou dose de radiação absorvida). Pelo sistema internacional de medidas utiliza-se a unidade "gray" (Gy), que equivale a 100 rad. Ela é adotada para qual- INTRODUÇÃOExames de diagnósticos por imagem são freqüentemente realizados durante a gestação para avaliar afecções maternas preexistentes, inerentes à gravidez ou relacionadas ao feto. Os métodos mais difundidos são aqueles com pouco ou nenhum efeito sobre o feto, tais como a ultra-sonografia (US) e, mais recentemente, a ressonância magnética (RM)(1-3) . Os exames radiológi-cos são geralmente relegados a um segundo plano e eventualmente descartados ou adiados, em virtude da apreensão gerada pelos potenciais riscos à saúde do feto; no entanto, um diagnóstico postergado ou perdido, em função da não...

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Section: Exames Radiológicos Durante a Gestaçãounclassified

Exames radiológicos na gestação

D'Ippólito

Medeiros

2005

Radiol Bras

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“…The recent introduction of flat-panel detectors brings new possibilities of dose reduction with still acceptable image quality owing to a higher DQE [10,11]. The DQE is a parameter that basically describes the capability of the system to use the incoming information of the photon fluency distribution for the formation of the image.…”

Section: Discussionmentioning

confidence: 99%

Reducing dose in urography while maintaining image quality—a comparison of storage phosphor plates and a flat-panel detector

et al. 2005

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The introduction of new flat-panel detector technology often forces us to accept too high dose levels as proposed by the manufacturers. We need a tool to compare the image quality of a new system with the accepted standard. The aim of this study was to obtain a comparable image quality for two systems-storage phosphor plates and a flat-panel system using intravenous urography (IVU) as a clinical model. The image quality figure was calculated using a contrast-detail phantom (CDRAD) for the two evaluated systems. This allowed us to set a dose for the flat-panel system that gave equivalent image quality to the storage phosphor plates. This reduced detector dose was used in an evaluation of clinical images to find out if the dose reduction from the phantom study indeed resulted in images of equal clinical image quality. The image quality was assessed using image criteria of the European guidelines for IVU with visual grading analysis. Equivalent image quality in image pairs was achieved at 30% of the dose. The CDRAD contrast-detail phantom makes it possible to find dose levels that give equal image quality using different imaging systems.

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“…The highest DQE values, however, are obtained with indirect converting flat detectors based on CsI [12,26]. Observer studies demonstrate that the high DQE values reached with the indirect converting flat detectors based on CsI correlate with (1) superior image quality (provided comparable system conditions are given) [31,32], and (2) the potential to reduce dose without loss of image quality [33,34], when compared to other technologies. DQE is largely governed by the absorption properties of the converter material.…”

Section: Modulation Transfer Functionmentioning

confidence: 94%

Flat detectors and their clinical applications

Spahn

2005

Eur Radiol

111

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Diagnostic and interventional flat detector X-ray systems are penetrating the market in all application segments. First introduced in radiography and mammography, they have conquered cardiac and general angiography and are getting increasing attention in fluoroscopy. Two flat detector technologies prevail. The dominating method is based on an indirect X-ray conversion process, using cesium iodide scintillators. It offers considerable advantages in radiography, angiography and fluoroscopy. The other method employs a direct converter such as selenium which is particularly suitable for mammography. Both flat detector technologies are based on amorphous silicon active pixel matrices. Flat detectors facilitate the clinical workflow in radiographic rooms, foster improved image quality and provide the potential to reduce dose. This added value is based on their large dynamic range, their high sensitivity to X-rays and the instant availability of the image. Advanced image processing is instrumental in these improvements and expand the range of conventional diagnostic methods. In angiography and fluoroscopy the transition from image intensifiers to flat detectors is facilitated by ample advantages they offer, such as distortion-free images, excellent coarse contrast, large dynamic range and high X-ray sensitivity. These characteristics and their compatibility with strong magnetic fields are the basis for improved diagnostic methods and innovative interventional applications.

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Dose reduction in skeletal and chest radiography using a large-area flat-panel detector based on amorphous silicon and thallium-doped cesium iodide: technical background, basic image quality parameters, and review of the literature

Cited by 41 publications

References 28 publications

Exames radiológicos na gestação

Exames radiológicos na gestação

Reducing dose in urography while maintaining image quality—a comparison of storage phosphor plates and a flat-panel detector

Flat detectors and their clinical applications

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