What is the difference between X-ray diagnostic system and DR?

Similar to DR equipment, medical X-ray machines are both used for radiological examination in medical diagnosis, and both use the physical penetration effect of rays to see through and examine the internal tissues of the human body, so as to quickly diagnose diseases and give timely treatment.

The difference between medical X-ray machine and ar machine is that the traditional medical X-ray machine can't directly display the image on the screen after shooting the film, and it needs film to display it. The time interval from shooting to film release is relatively long. Ar machine is a digital high-frequency intelligent X-ray machine, and DR machine directly replaces the function of film with matrix, which can be displayed on the computer monitor after shooting. This advantage greatly saves the time of diagnosis. Secondly, the medical X-ray machine is different from the DR machine in terms of imaging effect. The signal of medical X-ray machine is lost during shooting, while the imaging effect of DR machine is clearer. DR machine does not need consumables, and it benefits for life once invested. Therefore, hospitals at all levels are now more inclined to DR machines and gradually eliminate traditional medical X-ray machines.

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 technologies CR and DR have developed rapidly in recent years, which enables people to obtain images satisfying diagnosis with lower X-ray radiation dose than before.

First, the working principle of CR and DR

1.Cr (Computed Radiography) is also called indirect digital X-ray imaging technology, and its main principle is to use stored phosphor to image. Japan's Fuji Company introduced the first clinical CR in 198 1, and then Kodak Company of the United States and Akefa Company of Germany successively introduced their own CR products, which absorbed X-rays by IP plating composed of phosphor crystals. The IP board looks like a 1 ordinary intensifying screen. It is composed of a substrate and phosphor materials, and the outer layer is protected. Then it is protected by a cassette, which can be taken like an ordinary X-ray cassette. After X-ray exposure, the IP board stores the X-ray image information in the crystal, and then sends it to the IP board for reading and displaying, and the read X-ray image information is sent to the computer system. After the image information is read and displayed, the information stored on the IP board disappears and the imaging board can be reused. Advantages: The exposure dose of (1)CR is smaller than that of conventional photography; (2) The requirements of photographic conditions are lower than those of film, and there is almost no "waste film"; (3) When CR is adopted, the X-ray equipment does not need to be greatly changed, and the shooting process is unchanged from the original X-ray film photography; (4) Image post-processing function can improve the accuracy and range of image diagnosis.

2. The working principle of DR DR(Digitalradiography) is also called digital photography. Early DR used CCD (Digital Coupler) with intensifying screen and optical lens to obtain digital X-ray images, which was somewhat similar to the working mode of image intensifier and CCD. This technology is considered as the first generation of disaster recovery technology.

At present, the widely used DR mainly uses flat panel detector (FPD) to scan and directly read the image signals generated by X-rays. The imaging principle is that X-ray signals are first converted into visible light, which is gathered by a algae film layer (TFT) composed of photodiodes, and then directly read by a special reading circuit and sent to a computer system for processing. At present, flat-panel probes are divided into 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 tube and bracket, flat panel detection port, system control port, etc. Compared with the traditional X-ray signal, DR system has the advantages of CR. The X-ray receiver is used to replace the traditional intensifying screen and film for plane detection, which realizes the digitization of X-ray signals, with high dynamic range, spatial resolution and density resolution, low exposure dose, and can obtain X-ray images for doctors to watch at any time. There is almost no loss of image quality in image transmission, storage and amplification, and the imaging speed is much faster than that of traditional film X-ray system.

Second, the performance comparison of CR and DR.

In view of these two different systems, this paper analyzes the system function, image quality, control and use, software function and so on.

1. System function comparison: CR is improved from the traditional X-ray film shooting device. It replaces the original film cassette with IP board, which has little change from the existing X-ray shooting system. After X-ray exposure, the IP board stores the image information on the IP board and sends the IP board (similar to a cassette) to the reading equipment for reading, which can transform the existing equipment. DR is a completely digital product, which has completely changed the traditional X-ray film photography process. After X-ray exposure, the flat panel detector (FPD) will immediately convert X-ray signals into digital signals and send them to the computer for processing. This equipment is a brand-new digital X-ray machine.

2. Image quality comparison: the spatial resolution of image Cr >; 3.5LP/mm，DR & gt3.6 LP/mm； Density resolution CR >2 12 gray scale, DR>2 14 gray scale, FPD shows the information of DR >: In the IP board of CR, the modulation transfer function MTF of DR is higher than that of CR.

3. Operation and use: At present, CR and DR are widely used in hospitals. According to incomplete statistics, each patient needs an average of 7.5 points per person for traditional X-ray photography, 6 points per person for CR photography and 2.5 points per person for DR photography. CR can be used together with the original X-ray system suitable for X-ray plain film photography, especially for complex posture photography in ICU, emergency room and other special departments, while DR system,

4. Software functions: The software functions of CR and DR are similar to those of different models of equipment from different manufacturers. They all use quality control module and post-processing technology to ensure the quality and stability of images. Automatic exposure control (AEC) is adopted for disaster recovery. The main principle is to measure the X-ray dose transmitted through the patient during irradiation by setting different detectors (ionization chambers). When the dose required for image acquisition is reached, the X-ray system is automatically turned off to ensure the consistency of the whole image. After quickly obtaining the digital image, the image can be digitally optimized immediately. You don't need to know the quality of the image after the film is developed, so the probability of the patient retaking because of the image problem is greatly reduced, and the patient also avoids receiving unnecessary X-ray irradiation and reduces the radiation dose received. Through AEC technology and various processing modes on its workstation, the imaging quality is stable, the operation is simplified, and manual adjustment is not needed. The reference value of chromium exposure index (EI) is an important parameter affecting quality. Different parts adopt different EI and EVP values to achieve the goal of high quality images. Because the shooting process is not directly related to the later image processing, it needs some projection technology and experience to obtain a better image, and the operability of the equipment and the stability of image quality are worse than DR.

Third, the similarities between CR and Dr.

* * * The same point is that X-ray image information is converted into digital image information, and its exposure latitude has great advantages over screen film system, thus allowing technical errors in photography, and even in some parts where exposure conditions are difficult to grasp, good images can be obtained; CR and DR can perform various image post-processing, window width and window level adjustment, image mosaic and distance, area and density measurement according to clinical needs, providing technical support for detailed observation, before and after comparison and quantitative analysis in image diagnosis. In addition, they also effectively solve the problem of image archive management and transmission, and can save image data by burning on CD, which has the characteristics of low cost and good economic benefits.

In a word, according to the practice of using CR and DR in the radiology department of Weifang People's Hospital, CR and DR systems have both characteristics and individuality, differences and connections, and each has its own advantages and disadvantages. In a long time, it will be a pair of parallel developing systems, and CR is still a convenient digital photography transition equipment for small and medium-sized hospitals. After more than ten years of development, DR photography technology has entered a mature stage, its technical performance has been continuously improved, and its price has been greatly reduced, which has reached an acceptable level for ordinary patients and will provide a better way for the development of medical imaging.