China
Africa
Explore chapters and articles related to this topic
Radiation protection and safety
Published in Ken Holmes, Marcus Elkington, Phil Harris, Clark's Essential Physics in Imaging for Radiographers, 2021
If the examination does proceed the relatively small radiation risk to the patient/fetus will be outweighed by the benefit of the diagnosis and subsequent treatment of potentially life-threatening or serious conditions. These could present a much greater risk to both parties if left undiagnosed. To minimise the risks when examining pregnant women, the radiographer should adopt the following strategies:Use of the highest imaging speed system available, e.g. 800 speed or equivalent settings for computed radiography/direct digital radiographyLimiting collimation to area of interestUse of shielding (can the uterus be shielded without significant loss of diagnostic information?)Use of the minimum number of exposures to establish a diagnosisUse of projections that give the lowest doses
X-ray Vision: Diagnostic X-rays and CT Scans
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
Radiography that produces digital images that can be processed, stored and displayed on computers is called digital radiography. Several technologies are used in digital radiography. One is computed radiography (CR), not to be confused with computed tomography discussed in Section 5.11. In CR a latent image is created on plates coated with so-called storage phosphors, materials such as europium-doped barium fluoride, which exhibit photo-stimulated luminescence. Absorbed x-ray photons excite electrons that are trapped in impurities within the storage phosphor. The distribution of these trapped electrons represents the stored latent image. To convert the latent image into a digital image a scanning laser is used to illuminate the storage phosphor plate. The laser beam causes the trapped electron to escape and emit visible photons, which are guided into a photomultiplier tube.
Viva voce
Published in Tristan Barrett, Nadeem Shaida, Ashley Shaw, Adrian K. Dixon, Radiology for Undergraduate Finals and Foundation Years, 2018
Tristan Barrett, Nadeem Shaida, Ashley Shaw, Adrian K. Dixon
The use of digital / computed radiography to acquire images means that it is no longer necessary to deal with complicated film developing equipment and processes, nor to use expensive and toxic chemicals. In turn this reduces the time taken to perform an image and increases patient through-put. With digital radiography it is also less likely that a non-diagnostic image will be produced (i.e. over- or under-exposed) as post processing means the image contrast can be changed; this theoretically reduces unnecessarily repeated patient radiation exposure. Conversely, a potential disadvantage of this system is that overexposures may be masked; radiographers need to be aware of this and calibration is important. Other advantages specifically related to the PACS system are listed below.
Can adaptive post-processing of storage phosphor plate panoramic radiographs provide better image quality? A comparison of anatomical image quality of panoramic radiographs before and after adaptive processing
Published in Acta Odontologica Scandinavica, 2019
Björn Svenson, Magnus Båth, Reet Karlsson
Panoramic radiography has long been a technique for imaging teeth and jaws [1]. Digital panorama techniques have been developed over the past 10 years, and images can be achieved with either an indirect digital technology such as storage phosphor plate (SPP) technology or direct digital technology such as charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS). There are a number of advantages to digital radiography [2,3], one being that image processing makes it possible to improve image quality [4–7]. It is well known that for the detection of pathological changes diagnostically acceptable representation of normal anatomy is required. Optimal image quality is fundamental to clinical confidence in digital radiography. To achieve this, different techniques have been recommended, such as adjustment of contrast and density, change of kV, and use of filters for the processing of the digital images [8,9]. The effect of image filters for enhancement of the panoramic image quality has been investigated in some studies [7,10,11] and some have applied external image post-processing [4,7,12]. Digital post-processing with sharpening and median filters significantly improved diagnostic image quality [4,7,13] and can improve diagnostic quality significantly in terms of radiographic density and contrast [5].
Dentists’ use of digital radiographic techniques: Part I – intraoral X-ray: a questionnaire study of Swedish dentists
Published in Acta Odontologica Scandinavica, 2018
Björn Svenson, Katri Ståhlnacke, Reet Karlsson, Anna Fält
Basically, there are two types of digital imaging technologies available for intraoral digital radiography, the indirect technique comprising storage phosphor plate (SPP) and the direct technique. The direct technique comprises a charged coupled device (CCD) and complementary metal oxide semiconductor (CMOS), which in this paper will be referred to as solid-state detectors (SSDs). The SPP technology is in a number of countries the most common choice for intraoral digital techniques, and about two-thirds of dentists have chosen an SPP system [2,4,7–9] to replace analogue technology with digital. The quality of the digital images should be at least as good as with film, and in addition, there should be some advantages to using digital technology.
A comprehensive review of the literature on the biological effects from dental X-ray exposures
Published in International Journal of Radiation Biology, 2019
Vinita Chauhan, Ruth C. Wilkins
As digital technologies have evolved over the years, so have dental X-ray image receptors. New technologies are emerging that have the capability to provide improved image quality. For example, digital radiography has become more popular in the past 10 years allowing the viewing of digital images on a computer screen and eliminating the need for traditional film and its associated processing. Under optimized settings, this can lead to shorter exposure times which can translate to lower doses to the patient (Okano and Sur 2010).