DR film is a direct digital radiography system.
It is composed of an electronic dark box, scanning controller, system controller, image monitor, etc. It is a direct digital radiography in the broad sense that X-ray photons are directly converted into digital images through the electronic dark box.
And the narrow sense of the direct digital photography that is DDR, usually refers to the use of flat panel detector image direct conversion technology of digital radiography, is the true sense of the direct digital radiography system.
DR and CR **** the same point is the X-ray image information into digital image information, its exposure tolerance relative to the ordinary screen-enhanced film system reflects certain advantages: CR and DR due to the use of digital technology, a wide dynamic range, both have a wide exposure tolerance, thus allowing technical errors in the photographic, even in some of the exposure conditions are difficult to master the part, can also obtain a very good CR and DR can perform various image post-processing according to clinical needs, such as various image filters, window width and window position adjustment, zoom roaming, image splicing, and distance, area, density measurement and other rich functions, which provide technical support for the observation of details, before and after comparisons, and quantitative analysis in image diagnosis. The performance comparison of the two is as follows:
1. Imaging principle: DR is an X-ray direct conversion technology, which utilizes selenium as an X-ray detector, with fewer imaging links; CR is an X-ray indirect conversion technology, which utilizes an image plate as an X-ray detector, with more imaging links relative to DR.
2, image resolution: DR system without optical scattering caused by image blur, its clarity is mainly determined by the size of the pixel size; CR system due to its own structure, when subjected to X-ray irradiation, the phosphorus particles in the image plate so that the X-ray there is scattering, caused by the blurring of the latent image; in the reading latent image of the process, the excitation light of the laser scanner in the image plate through the deep part of the image produced by the scattering along the path of the formation of excited fluorescence, making the latent image blurred. path to form excited fluorescence, blurring the image, reducing the image resolution, so the shortcomings of the current CR system is mainly poor time resolution, can not meet the dynamic organs and structures of the display.
3. DR is the future direction of development, but at present, the structure of the DR electronic dark box 14 in × 17 in (1 in=2.54 cm) consists of 4 pieces of 5 in × 8 in, each piece of the seam due to the limitations of the process can not be done without a seam, and once a piece of damage will lead to the four pieces of the replacement, not only the cost is expensive, but also need to modify existing X-ray machine equipment, while CR is relatively expensive. The cost of CR is relatively low, and multiple X-ray machines can be used at the same time, without changing the existing equipment.
4, CR system is more suitable for X-ray plain film photography, its non-specific models can be matched with more than one conventional X-ray camera, and is more suitable for complex parts and position of the X-ray photography; DR system is more suitable for fluoroscopy and point film photography and a variety of imaging examinations, due to the single machine working flux limitations, it is not easy to replace the large hospitals in the conventional X-ray photography equipment for multi-machine work at the same time, but it is more suitable for small medical units and clinics in a However, it is more suitable for small medical units and clinics for the purpose of multi-purpose. In fact, CR and DR systems will be a pair of parallel systems for quite some time.