Identifying differences among various techniques in Imaging - Computer Essay Example
Identifying differences among various techniques in Imaging
The most common filming techniques used in the filed of medicine today are film-screen, computed radiography, and digital radiography - Identifying differences among various techniques in Imaging introduction. These techniques slightly differ in their functionalities, combined with the ease of usage and the quality of images produced.
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Film screen radiography is a conventional radiography technique that utilizes X-ray radiated onto the body of the organism that later on produces output signals convertible to image as captured by cassettes (Rockwood, Green, Bucholz, Heckman, Court-Brown, et al., 2006, p. 356). The discovery of the components of the film screen is very important even in the modern radiography. An example of a component present in modern radiography techniques is the intensifying screen. In the 1990s, film screen cassettes were replaced by alternative X-ray detectors like the photostimulable phosphor plate and the selenium plate (Pettersson, Allison, Schulthess, NICER Institute, Resnick, et al., 1998, p. 206). The optical density, which is one of the characteristics taken into consideration in imaging, is measured sufficiently by the human eye to determine if the optical density is acceptable or not (Allisy-Roberts, Williams, & Farr, 2007, p. 86).
Computed radiography is run in almost similar fashion that is used in film screen radiography. According to Bushberg and his colleagues (2002), this similarity in the handling of the cassettes of these two imaging systems led to the initial success of computer radiography, since users did not find it hard to adapt on the operation of the more advanced system. Both imaging techniques use cassettes that are exposed before the to the reader unit (for computer radiography) or to the film processor (for those using film-screen). The advantage of CR over film screen is that it caters to a larger dynamic range. This only means that the exposure latitude with CR is on a much wider range than the range that the film screen is capable. In this manner, instances of overexposure or underexposure are rare since retakes are avoided. Because of the quality of images produced by CR, it is now commonly used in portable examinations. It is often difficult to obtain portable radiographic images in film-screening. In addition, phototiming is usually not one of its features. CR is often associated with producing images with proper grayscale at high and low exposure levels (p. 297).
The differences between computed and digital radiography is only in an artificial manner. Both techniques need computers for implementation. Digital radiography utilizes amorphous silicon thin-film transistor arrays a detector instead. The signals being produced in this technique are in terms of electrical charge as the transistor amplifies the signal and later stores it as such. The stored electrical charge is then released by applying a high potential. Each row of the detectors is connected to an activating potential and a charge measuring device, which measures the electric charges released. The potential is applied row by row as determinant of its location and time of detection, which corresponds to the pixel from which the electrical charge is detected (Allisy-Roberts, Williams, & Farr, 2007, p. 87).
Digital radiographic image receptors gradually replace screen-film cassettes as the need to convert images to all-digital environment has come into the picture. Still, film screens are tried and tested to produce excellent image quality that is why there are still radiology departments that remain in using the film screen technique. In addition to this disadvantage, digital radiographic images require a large memory for storage, a huge picture archiving and communication systems, and require high luminance and high resolution monitors (Bushberg, Seibert, Leidholdt, and Boone, 2002, p. 293).
Film-screen and computed radiography on the other hand are disadvantageous because of the delay in the production of the image. The delay can reach up to almost one minute that may somehow reduce the patients’ throughput. In contrast, digital radiography systems utilize devices that produce image that can cause only a delay of about 10 seconds since the images production is in situ (Allisy-Roberts, Williams, & Farr, 2007, p. 86).
Allisy-Roberts, P., J. Williams, & R. F. Parr. (2007). Farr’s Physics for Medical Imaging. 2nd ed. Retrieved May 17, 2009, from http://books.google.com/books?id=EHODwuD73XMC&pg=PA86&dq=film+screening+computed+radiography+digital+radiography&as_brr=3#PPA74,M1
Bushberg, J. T., J. A. Seibert, E. M. Leidholdt, & J. M. Boone. (2002). The essential physics of medical imaging. 2nd ed. Retrieved May 16, 2009, from http://books.google.com/books?id=VZvqqaQ5DvoC&pg=PA293&dq=film+screening+computed+radiography+digital+radiography&as_brr=3#PPA284,M1
Pettersson, H., D. Allison, G. K. von Schulthess, NICER Institute, D. Resnick, et al. (1998). The encyclopaedia of medical imaging . Retrieved May 17, 2009, from http://books.google.com/books?id=H7GZKCG7SkoC&pg=PA206&dq=essential+of+film+screen+imaging&as_brr=3#PPA206,M1
Rockwood, C., D. P. Green, R. W. Bucholz, J. D. Heckman, C. M. Court-Brown, et al. (2006). Rockwood and Green’s fractures in adults. 6th ed. Retrieved May 16, 2009, from http://books.google.com/books?id=9XCnfKcv9rcC&pg=PA356&dq=film+screening+computed+radiography+digital+radiography&as_brr=3#PPA356,M1