What is the difference between DR and CR?

Brothers upstairs, if I am not wrong, the poster is asking about the DR of medical devices, so your answer is wrong, okay, let me give you the correct answer: < /p>

DR:

Digital Radiography, direct digital X-ray photography system.

DR consists of detector, image processor, image display, etc. The X-ray signal transmitted through the human body is detected and acquired, and a digital image is directly formed. The digital image data is transmitted to the computer, displayed on the monitor, and can also be post-processed. The main DR detectors currently used are amorphous silicon detectors and amorphous selenium detectors. There is little difference in the image acquisition effects of the two detectors. Others include multifilament proportional chamber detectors, which are air detectors. There is also a CCD detector. Amorphous silicon detectors and amorphous selenium detectors are both called flat panel detectors.

1. Read the film directly through a professional monitor without developing the film, which greatly saves film costs (except for patients with special needs);

2. This can be eliminated after DR upgrade There are various worries such as taking the wrong picture, taking the wrong picture or the patient's body movement resulting in poor picture effect. The doctor can quickly see the impact on the result and retake the picture.

3. The display of bone structure, articular cartilage and soft tissue is better than traditional X-ray imaging, and it can also perform quantitative analysis of mineral salt content; it is easy to display mediastinal structures such as blood vessels and trachea; it is also suitable for nodular The detection rate of lesions is higher than traditional X-ray imaging; it is better than traditional X-ray images in observing calcium-containing lesions such as intestinal pneumatosis, pneumoperitoneum and stones; tomography is better than X-ray tomography; gastrointestinal double contrast imaging Digital images are superior to traditional X-ray imaging in showing small gastric areas, minimal lesions, and intestinal mucosal folds.

4. The imaging process of DR The imaging process of DR is a digital imaging process. X-ray detectors will convert and digitize X-ray energy through the human body. The entire X-ray imaging process, including X-ray collection, conversion, quantification, transmission, processing, display, etc., is a digital information processing process. The digital photography mode has changed the basis for the formation of image information. The carrier of X-ray signals is no longer a screen/film system, but is replaced by many types of X-ray detectors. X-ray detectors use different signal collection principles to capture images representing the human body. The X-ray intensity distribution of information is collected, converted, stored, processed and displayed in digital mode.

CR:

Computed X-ray imaging (CR)

Traditional X-ray imaging is to record the image information on film through X-ray photography. After the development and fixation process, the image can be displayed on the photo. Computed radiography (CR) is different. The image information of X-ray photography is recorded on the image plate (IP). It is read by the reading device and a digital image is calculated by the computer. After conversion by a digital/analog converter, a grayscale image is displayed on the screen. CR and DR described in DSA are both digital imaging.

CR imaging principles and equipment

CR imaging requires the steps of recording, reading, processing and displaying image information. Its basic structure is shown in Figure 1-6-1. Recording of image information: Use an IP made of a barium fluoride bromide compound crystal (BaFX: Eu2+, X=CI. Br. I) containing trace amounts of europium (Eu2+) to replace , making the IP photosensitive and forming a latent image. X-ray image information is recorded by IP. IP can be reused up to 20,000-30,000 times.

Reading of image information: The latent image on the IP is read with a laser scanning system (Figure 1-6-2) and converted into a digital signal. The laser beam accurately and uniformly scans the entire IP moving at a constant speed. The exhaustive fluorescence excited by the laser on the IP is collected by the automatically tracking light collector, converted into electrical signals by the photoelectric converter, amplified, and converted into digital image information by the analog/digital converter. After scanning by IP, a digital image can be obtained.

Processing of image information

The digital signal of the image is processed by the image processing system, which can arbitrarily change the characteristics of the image within a certain range. This is where CR is superior to X-rays. The image characteristics on X-rays cannot be changed. The main functions of image processing include: grayscale processing, window level processing, digital subtraction angiography processing and X-ray absorption rate subtraction processing, etc.

Grayscale processing

Through the adjustment of the image processing system, the digital signal can be converted into black and white image contrast, and selection can be made within the range that the human eye can distinguish to achieve the best visual effects. This facilitates observing different tissue structures. For example, two optimal images of the chest can be obtained showing the lungs and mediastinum respectively.

Window level processing

Set a certain digital signal as 0, that is, the center, so that the tissue structure within a certain gray scale range can obtain the best result based on the difference in X-ray absorption rate. It provides the best display and can enhance the processing of these digital signals. Window level processing can improve image contrast and help display tissue structures, such as trabeculae.

Digital subtraction angiography processing: Select one frame in a series of angiography CR images as a negative (mask) and perform digital subtraction processing to obtain a DSA image.

X-ray absorptivity subtraction processing

Use two different X-ray photography conditions to take pictures, and select any one of the frames as a negative for subtraction to eliminate certain tissues. For example, subtraction processing of the chest can eliminate the image of the ribs to facilitate observation of the lung fields.

Image display and storage: The digital image is converted by a digital/analog converter and displayed on the screen as a grayscale image visible to the human eye. The image on the screen can be observed and analyzed. It can also be photographed on film with a multi-frame optical camera. A laser camera can be used to record the digital signal of the image directly on the film, which can improve the image quality. The laser camera is integrated with the automatic film processor, which can reduce operating procedures.

CR's digital image information can also be stored on tapes, disks and optical disks for long-term storage.

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