Medical x-ray machine and DR equipment is the same point is that they are used in medical diagnosis of radiology examination, they are the use of: the physical penetration effect of the ray, can be for the body's internal tissues for fluoroscopy, inspection, so as to quickly diagnose the sick situation, give timely treatment.
Medical x-ray machine and ar machine is the difference between the traditional medical x-ray machine after filming can not be directly displayed on the screen, the need for film can be displayed. From the shooting to the film out of the time interval is relatively long. The ar machine is a digital high-frequency intelligent x-ray machine, DR machine with a matrix directly instead of the function of the film, after shooting can be displayed on the computer monitor, this advantage greatly saves a diagnosis of time. Secondly, from the imaging effect, medical X-ray machine and DR machine is also different, medical x-ray machine in the shooting process signal loss, while the DR machine imaging effect is more clear. DR machine without consumables, an investment, lifelong benefit. Therefore, hospitals at all levels are now more favorable to the DR machine, gradually eliminating the traditional medical x-ray machine.
What is the difference between medical CR and DR? : Medical imaging technology is one of the most active research fields in medical diagnostic radiology, and X-ray imaging technology is the main technology of medical imaging. Digital X-ray imaging technology CR, DR has developed very rapidly in recent years, making it possible to obtain images that satisfy diagnosis using a lower dose of X-ray radiation than previously.
I. CR and DR working principle
1. CR (ComputedRadiography) is also known as indirect digital X-ray imaging technology, the main principle is the use of stored phosphor imaging, the Japanese Fuji company in 1981 launched the first CR for clinical applications, followed by the United States, Kodak, Germany, AGFA companies have launched their own CR Products, it uses phosphor crystalline composition of the imaging plate (Plated) that is, the IP plate absorbs X-ray information, IP plate sensitization to form latent images, and then scanned into digital signals into the computer system for image processing. IP plate looks like an ordinary sensing screen, composed of substrate and phosphor material, plus a layer of protection on the outside, and then with the dark box loaded with the protection of the dark box can be taken like an ordinary X-ray dark box. The IP board stores the X-ray image information in the crystal after X-ray exposure, and then sends the IP board to the readout device to read out the X-ray image information and send it to the computer system. After the image information is read out and displayed, the information stored on the IP board disappears and the imaging board can be reused again. Advantages: (1) CR exposure dose compared with conventional radiography, the exposure agent is smaller than conventional film; (2) photography conditions require lower than film, almost no "waste"; (3) the use of CR, X-ray equipment without major changes, the filming process and the original X-ray film photography has not changed much; (4) image Post-processing function, can improve the accuracy and scope of image diagnosis.
2. The working principle of DR (Digitalradiography) is also called digital photography, the early DR is the use of sensing screen coupled with optical lens CCD (digital coupler) to obtain digital X-ray images, a little similar to the image intensifier plus CCD working method, this technology is considered the first generation of DR technology.
Now commonly used DR is mainly used flat-panel detection port (FPD) on the X-ray image signals generated by scanning and direct readout, the imaging principle is the first X-ray signal into visible light through the photoelectric 2 electrodes composed of algal film layer (TFT) for the aggregation of the specialized readout circuit to send a direct read-out of the computer system for processing. At present, the flat detection port is divided into two types of indirect conversion digital photography (IDDR) represented by amorphous silicon and direct conversion digital photography (DDR) represented by amorphous selenium.
The composition of DR generally includes high-voltage generator, X-ray bulb tube and bracket, flat plate detection port, system control port and other components. Compared with conventional X-ray signals, the advantages in addition to the advantages of CR, DR system is a flat plate detection of the X-ray receiving device instead of the traditional sensing screen and film, the realization of the digitalization of the X-ray signal, the dynamic range of the signal, the spatial resolution and density resolution is high, the exposure dose is low, and can be obtained at any time for the doctor to view the X-ray image. There is almost no loss of image quality in the processing of image transmission, storage and magnification, and the imaging speed is much faster than the traditional film X-ray system.
Two, CR and DR performance comparison
For these two different systems, now from the system function, image quality, control the use of and software features several aspects of the analysis.
1. Comparison of system functions: CR is in the traditional X-ray film photography device improved, it is the use of IP board instead of the original film cassette, and the existing X-ray filming system has not changed much, IP board in the X-ray exposure, the image information stored in the IP board, IP board (similar to the cassette) to send the readout device to read out the processing can be transformed to the existing equipment. DR is completely digital products, completely changing the image quality, control and use of software features several aspects of analysis.
2. Completely digital products, completely changed the traditional X-ray film photography process, flat panel detector (FPD) by the X-ray exposure instantly after the X-ray signal into digital signals sent to the computer for processing, the equipment is a new set of digital X-ray machine.
2. Comparison of image quality: the spatial resolution of the image CR>3.5LP/mm, DR>3.6LP/mm; density resolution CR>212 grayscale, DR>214 grayscale, DR's FPD displays the information >CR's IP board, DR modulation transfer function MTF is higher than CR.
3. Operation and use: At present, hospitals use CR, DR has been more popular, according to incomplete statistics, the use of X-ray conventional screen film photography per patient an average of 7.5 points / person, the use of CR photography needs 6 points / person, and the use of DR photography needs 2.5 points / person, CR can be used in conjunction with the original suitable for X-ray radiography X-ray machine system, in particular, can be used in the ICU, the emergency room and other special departments of the It is especially suitable for photography of complex positions in special departments such as ICU and emergency room, while DR system is more suitable for fluoroscopy and spot film, photography and all kinds of imaging examinations.
4. Software function: CR, DR software function of different manufacturers of different models of equipment software function is similar, are the use of quality control touch block and post-processing technology to ensure the quality and stability of the image, DR using automatic exposure control technology (Automatic ExposureControl, AEC), the main principle is to set up a different The main principle is to measure the X-ray dose through the patient during exposure by setting different detectors (ionization chambers), and automatically turn off the X-ray system when the dose required for image acquisition is reached, which ensures the consistency of the whole image, and allows the image to be digitally optimized and processed immediately after a digital image is obtained quickly. And do not have to know the image is good or bad only after the film is developed as in the past, the probability of the patient being retaken because of image problems is greatly reduced, and the patient also avoids receiving unnecessary X-ray irradiation and reduces the radiation dose received. The AEC technology, together with the multiple processing modalities on its workstations, enables stable imaging quality and simplified operation without human adjustment and processing.The ExposureIndex (EI) reference value of CR is an important parameter affecting the quality, and different parts of the body use different EI and EVP values to achieve high-quality images. As the filming process is not directly related to the later image processing, to obtain better quality images, it also requires a certain projection technology and experience, equipment operability and stability of image quality than the DR is a little worse.
Three, CR and DR's **** the same point
*** the same point is the X-ray image information into digital image information, its exposure tolerance relative to the screen film system reflects a greater advantage, thus allowing the technical errors in the photo, even in some exposure conditions difficult to master the part, can also obtain a very good image; CR and DR can be based on clinical needs for a variety of CR and DR can perform various image post-processing according to clinical needs, window width and window position adjustment, zoom-in and zoom-out, image splicing as well as distance, area and density measurement, etc., which provide technical support for detailed observation, before-and-after comparison and quantitative analysis in diagnostic imaging; in addition, they also effectively solve the management and transmission of image archives, and can be used in the way of CD-ROM burning to save the image data, which is featured by low cost and good economic benefits.
In short, according to the Weifang People's Hospital Radiology Department to use CR, DR practice that CR and DR systems have both **** and personality, both different and linked, they have their own advantages and disadvantages. In a considerable period of time will be a pair of parallel development of the system, CR is currently in small and medium-sized hospitals is still no less convenient digital photography transition equipment. DR photographic technology has undergone more than a decade of development, has entered a mature stage, technical performance has also continued to improve, the price has been reduced dramatically, has reached the level of the average patient acceptable level, will provide a better way for the development of medical imaging.