Since the 1980s since the application of digital subtraction angiography (DSA) technology, people gradually from the past continuous fluoroscopy, random point film, rapid film changer, film film movie and other cumbersome, complex imaging means to get rid of, and the use of today's digital fluoroscopy, digital cinema, DSA, and other advanced technologies, so that angiographic room from a single radiology diagnostic room gradually to the well-equipped, Strict management of the interventional operating room. In order to ensure the smooth progress of interventional surgery, the interventional operating room should be equipped with cardiovascular angiography, high-pressure injector, mobile ultrasound machine and other equipment.
Cardiovascular angiography machine
Modern cardiovascular angiography machine is indispensable equipment for interventional surgery, it is usually composed of X-ray system and computer system. (A) X-ray system high-quality image quality must have a high-performance X-ray machine, in order to enable the patient to get accurate and thorough treatment, therefore, high-performance X-ray machine must have the following characteristics: 1. High power: interventional surgery, it must be repeated, many times in a row of exposure, which requires the X-ray machine can be repeated in a very short period of time to output a sufficiently large amount of power, so as to obtain a satisfactory X-ray image. Now more than 1200mA, 150kV X-ray machine. 2. The capacity of X-ray bulb tube is large and the focus is small: in order to get satisfactory cardiovascular contrast image, under the condition of satisfying the capacity, the smaller the focus of X-ray tube is, the smaller the penumbra is, and the image clarity is good. 3. The pressure from the high-voltage generator should be smooth: in order to ensure the consistent quality of each image, in addition to the consistency of each irradiation parameter, it is also necessary to ensure that there is a high KV value of constancy. 4. Short exposure time: cardiovascular angiography requires many to dozens of consecutive exposures within 1 second, and each exposure time is very short. 5. Two sets of hosts: when cardiography, it is required to do positive, lateral or bilateral oblique projection at the same time, and bidirectional photography should be synchronized, and the two sets of hosts are easy to adjust the irradiation parameters separately, so as to get satisfactory cardiac images and shorten the examination time. X-ray system mainly includes X-ray bulb, image intensifier, high voltage generator, console, TV system, C-arm, catheter bed. 1. X-ray bulb: the main place to produce X-ray, must have high power (50 ~ 150kW), high thermal capacity, small focus (0.4 ~ 1.2mm) of the rotating X-ray bulb, in order to produce high kilovolt, short pulse X-ray, can obtain more than 50 frames per second quality images. 2. Grating and Filter Plate: The control grating can limit the irradiation field of X-rays to reduce scattered rays, while the filter plate can effectively eliminate soft rays and improve the quality of X-rays. Both can limit the generation of low-energy X-rays, reduce the formation of gray mist, while reducing the radiation dose to both patients and doctors. 3. High-voltage generator: In order to ensure the stability of the output voltage, now more than three-phase AC 12 pulses or medium high-voltage generator and other ripples smoother X-ray high-voltage generator. 4. Image intensifier: it receives X-rays that penetrate the examination site and magnify it 0.6 to 10,000 times so that the camera to obtain a brighter image, the size of its field of view varies, can be 6 inches, 9 inches, 11 inches, 14 inches and other specifications, the larger the diameter, the larger the scope of the examination can be displayed. Usually the size of the field of view can be adjusted to adapt to the size of the inspection site, to obtain the best image. 5. TV camera: it is the image resolution of the largest part of the impact, the resolution matrix up to l024 × l024 parties can be image intensifier on the image of the complete conversion of video signals to enter the computer system. 6. X-ray console: it can control the switch of the X-ray machine, focus size selection and adjustment of various technical parameters. 7. "C"-shaped arm: mainly the base of the X-ray tube, control it can realize vertical and horizontal and any aspect of the multi-angle projection, in order to fully display the lesion, conducive to surgery. 8. Catheterization bed: divided into suspended bed and floor bed, it can make multi-directional movement in the horizontal plane, which is conducive to the patient's transportation and surgical procedures. 9. High-resolution monitor: its resolution up to 1024 × 1024 matrix, the general operating room and control room, each 1 to 2 units, for the acquisition of images and processing image monitoring.
(2) computer system
1. computer console: control and coordination of the completion of the steps of imaging, and can access a variety of digital technology applications, digital image adjustment and post-processing. 2. Computer: it is the TV camera to obtain the analog signal into a digital signal, after high-speed computing, amplification and adjustment to obtain high-quality digital images, and complete the processing of digital images, storage, playback and transmission, which is the advantage of digital images. 3. Analog / digital converter (D / A): it is the television camera to obtain the analog signal into binary digital and through the computer central processor for its processing, to obtain digital signals. Can be lossless amplification and post-processing, transmission and storage. 4. Digital, analog converter (A/D): it is the processed digital signal and then converted to analog signals to different grayscale dot matrix composition for diagnostic use of the video image. 5. Central Processing Unit (CPU): it is the core of the entire device, its role is to deal with the digital logic operations in the system, and issue instructions for the operation of each program. High-performance DSA system and its equipment has a very fast processing speed of the CPU. 6. Memory (hard disk): It is used to store the DSA system programs and data, generally divided into the main memory and auxiliary memory. When the main memory is not enough or failure, auxiliary memory to supplement and replace to complete the normal work. 7. Keyboard: It is the bridge between the operator and the machine. Through it, the operator can enter the patient's general information into the computer, and through it to call a variety of programs and image processing. (C) commonly used digital technology 1. digital subtraction angiography (DSA): digital subtraction angiography technology is through the machine and equipment will be un-imaging images and has been imaging images were digitized, and then by the computer to match the subtraction, converted to only blood vessel images and eliminate the surrounding tissue structure of the technology. the application of the DSA technology, so that people with less radiation dose and the amount of contrast medium to obtain more clear image The application of DSA technology allows more clear images to be obtained with less radiation dose and contrast medium to meet the evolving clinical needs. The commonly used methods are pulse mode, continuous mode, time interval difference mode and ECG trigger mode, which can be selected according to the patient's condition, lesion site and special requirements, in order to better detect the lesion. 2. Digital Fluoroscopy: After digitizing ordinary fluoroscopic techniques, the images can be framed, replayed and stored. The application of pulse technology can reduce the X-ray dose exponentially, usually by 1/2 or l/3 factor, which can make the operator and the patient to receive the amount of radiation and the examination time is significantly reduced. 3. Digital film: the past film technology is the image projected on the movie film, if you want to watch it must first be processed through the darkroom to watch through the projector, due to many human factors, the image quality can not be guaranteed, and can not be imaged to watch the effect immediately after the preservation of time is limited. The application of digital technology is the image stored on the hard disk, without the need for many intermediate links, removed many unstable factors, and can be increased to 50 frames of exposure speed, and even 75 frames per second, immediately replay, stable and reliable quality of the image can be preserved for a long time.
High-pressure injector
The application of high-pressure injector can ensure that in a relatively short period of time according to a certain pressure, flow rate will be required to inject the contrast agent into the patient's cardiovascular centralized, high-concentration filling the examined area, in order to ingest the image of a high contrast, the process of imaging, can be matched with the exposure of the X-ray machine, so as to increase the accuracy of the photography and success rate. Modern high-pressure apparatus is mostly controlled by microcomputer, which has the advantages of miniaturization, high control precision, stable operation and intelligent operation. (I) Structure and function of the main structure of the high pressure injector are: 1. Multi-axis movement injection head: it draws a certain concentration of contrast agent into the injection barrel (disposable), the total amount of contrast agent in the barrel is detected by the microcomputer and heated up to the body temperature, and its multi-axis system can be matched with the position of the catheter head for the directional movement, so as to ensure the smooth progress of the contrast. 2. Console: it is the center of the high pressure injector and controls all injection parameters and procedures. 3. Mobile stand: The method can be ceiling suspended, catheter bed standing type and floor type. According to the user's habits and the structure of the room to choose one, usually more convenient and practical floor type. (B) injection parameters to obtain a satisfactory contrast image must be based on the location of the catheter head, the diameter of the catheter and the size of the lesion, the blood flow running time to select the appropriate parameters. Commonly used parameters are: 1. delay time: according to the needs of the lesion, control the timing of contrast injection into the body, divided into exposure delay and injection delay two ways. 2. 2. Dose per injection: that is, the amount of contrast agent injected at each imaging, not to be confused with the total amount. It is generally measured in milliliters. 3. Injection flow rate: It is the amount of contrast agent injected into the catheter per unit time, usually expressed in ml/s. The injection flow rate set each time is the upper limit of the substantial injection flow rate, that is, the actual injection volume may not necessarily reach the set value, but it can limit its flow rate to further increase and play a protective role. 4. Injection pressure: It refers to the pressure required per unit area when the contrast agent reaches the blood vessel at a specific flow rate. The injection pressure is set at an upper limit each time to provide some protection and is usually expressed in PSI (pounds per square inch).
Quality assurance system
DSA system is a large precision instruments, its maintenance, use and management of good and bad will directly affect the results of the examination and treatment. (A) factors affecting the quality of the DSA image in the use of the process, each part of the problem can be caused by the impact of the image. 1. Line part: including the capacity of the machine, the selection of photography conditions, the choice of focus, the size of the exposure rate. 2. Mechanical part: the cooperation between the catheter bed and the bulb tube in the image acquisition process. 3. The performance of the high pressure syringe and its compatibility with the contrast. 4. Image acquisition speed: the degree of signal loss in the digital conversion. 5. Image acquisition quality: including image intensifier and television camera performance, image storage devices (such as disks, tapes, video recorders) and multi-frame camera, laser camera performance, or dry printer performance. 6. Performance of post-processing: such as mask reconstruction, pixel shift, etc. 7. Choice of examination method: e.g. digital movie or digital subtraction. 8. The patient's cooperation during the imaging process: e.g., asking the patient to hold his/her breath, etc. 9. The operation of medical personnel: e.g. the choice of catheter, whether the catheter is inserted into the target organ, etc. (ii) Management of large instruments and equipment and apparatus can ensure the safe operation of the equipment only by establishing strict rules and regulations. 1. The equipment should be tested and maintained by the maintenance company regularly every year. 2. The environment of the machine room should be maintained year-round at a temperature of 20 to 25%, relative humidity of 40% to 70% between the rainy season in the south should be dehumidified to keep the room dry. 3. Regular monthly cleaning and maintenance by the staff of the equipment, maintenance, especially the image intensifier and high-pressure injectors. 4. The room and equipment should be sterilized by ultraviolet light every day to eliminate infection. 5. The equipment should be checked whether it is in the best operating condition when it is turned on. 6. Strictly follow the operating procedures of the equipment. (III): Protection of X-ray radiation in DSA examination With the progress of society and the enhancement of environmental protection consciousness, people pay more and more attention to X-ray radiation protection. 1. X-ray monitoring inside and outside the machine room and dose monitoring for medical staff should be carried out regularly by the environmental monitoring station. 2. Medical personnel should strictly wear protective clothing. 3. Corresponding protective equipment should be installed in the machine room. 4. Try to shorten the irradiation time, narrow the irradiation range and reduce the number of exposures during the examination.