Main equipment of interventional operating room

Since the application of digital subtraction angiography (DSA) technology in 1980s, people gradually got rid of the complicated imaging methods such as continuous fluoroscopy, random filming, rapid film changer, film film and so on. With the advanced technologies such as digital fluoroscopy, digital film and DSA, the angiography room gradually moved from a single radiology diagnosis room to a fully equipped and strictly managed referral operating room. In order to ensure the smooth progress of interventional surgery, the interventional operating room should be equipped with cardiovascular imaging machine, high-pressure syringe, mobile B-ultrasound machine and other equipment.

Cardiovascular imaging machine

Modern cardiovascular imaging machine is an indispensable equipment for interventional surgery, which usually consists of X-ray system and computer system. (1) A high-quality image quality X-ray system must have a high-performance X-ray machine, so that patients can get accurate and thorough treatment. Therefore, a high-performance X-ray machine must have the following characteristics: 1. High power: Repeated continuous exposures are required during interventional surgery, which requires the X-ray machine to repeatedly output enough power in a short time to obtain satisfactory X-ray images. X-ray machines of 1200mA and 150kV are widely used. 2. The X-ray tube has a large capacity and a small focus: In order to obtain a satisfactory angiocardiographic image, the smaller the focus of the X-ray tube and the smaller the penumbra, the better the image definition. 3. The pressure generated by the high voltage generator should be stable: in order to ensure the consistent quality of each image, besides the consistent irradiation parameters, it is also necessary to ensure a constant high KV value. 4. Short exposure time: The ECG needs to be exposed several times to dozens of times in 1 second, and each exposure time is very short. 5. Two sets of host computers: during cardiac angiography, it is required to take oblique projection on the front, side or both sides at the same time, and the two-way photography should be synchronized. It is easy for two sets of hosts to adjust the irradiation parameters separately, so as to obtain satisfactory cardiac images and shorten the examination time. X-ray system mainly includes X-ray tube, image intensifier, high-voltage generator, console, TV system, C-arm and catheter bed. 1.X-ray tube: an X-ray tube with high power (50 ~ 150 kW), high heat capacity and small focus (0.4 ~ 1.2 mm), which is mainly used to generate X-rays with high kilovolts and short pulses, and can obtain high-quality images of more than 50 frames per second. 2. Grating and filter plate: Controlling the 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 of them can limit the generation of low-energy X-rays, reduce the formation of fog and reduce the radiation dose of both doctors and patients. 3. High voltage generator: In order to ensure the stability of output voltage, three-phase AC 12 pulse or medium high voltage generator and other X-ray high voltage generators with relatively stable ripple are often used. 4. Image intensifier: it receives the X-rays penetrating the inspection site and magnifies them by 0.6 ~ 10000 times, so that the camera can obtain brighter images. Its visual field varies in size, including 6 inches, 9 inches, 1 1 inch, 14 inch and so on. The larger the diameter, the larger the detection range that can be displayed. Usually, the visual field can be adjusted to adapt to the size of the examination site to obtain the best image. 5. TV camera: it is the part that has the greatest influence on image resolution. Only when the resolution matrix reaches l024×l024 can the image on the image intensifier be completely converted into a video signal and input into the computer system. 6.X-ray console: It can control the switch of the X-ray machine, select the focus size and adjust various technical parameters. 7. "C" arm: mainly the base of X-ray tube. By controlling it, we can realize vertical, horizontal and arbitrary multi-angle projection, fully display the lesions and facilitate the operation. 8. Catheter bed: it can be divided into suspended bed and floor bed, which can move in many directions on the horizontal plane, which is beneficial to the handling of patients and the operation. 9. High-resolution monitor: Its resolution can reach 1024× 1024 matrix, and there are 1 ~ 2 monitors in the general operation room and control room for monitoring the collected and processed images.

(2) Computer system

1. computer console: control and coordinate every step of photography, and can call the application of various digital technologies, digital image adjustment and post-processing. 2. Computer: It converts analog signals obtained by TV cameras into digital signals, obtains high-quality digital images through high-speed operation, amplification and adjustment, and completes the processing, storage, playback and transmission of digital images, which is the advantage of digital images. 3. Analog-to-digital converter (D/A): It converts analog signals obtained by TV cameras into binary numbers, which are processed by computer central processor to obtain digital signals. Lossless post-amplification processing, transmission and storage can be carried out. 4. Digital-to-analog converter (A/D): Convert the processed digital signals into analog signals to form diagnostic video images with different gray-scale lattice. 5. Central Processing Unit (CPU): It is the core of the whole equipment, and its function is to process the logical operation of numbers in the system and issue instructions for running various programs. High-performance DSA system is equipped with CPU with fast processing speed. 6. Memory (hard disk): used to store the programs and data of DSA system, generally divided into main memory and auxiliary memory. When the main memory is insufficient or invalid, the auxiliary memory is supplemented and replaced to complete normal work. 7. Keyboard: It is the bridge between the operator and the machine. Through it, the operator can input the general data of patients into the computer, and call various programs and process images through it. (3) Common digital technology 1. Digital Subtraction Angiography (DSA): Digital Subtraction Angiography is a technology that digitally processes non-contrast images and contrast images respectively by machines and equipment, and then matches and subtracts them by computers, and only converts them into blood vessel images to eliminate the surrounding tissue structures. The application of DSA technology enables people to obtain clearer images with less radiation dose and contrast dose to meet the growing clinical needs. The commonly used methods include pulse mode, continuous mode, time interval difference mode and ECG trigger mode. The appropriate mode and sequence can be selected according to the patient's condition, lesion site and special requirements to better find the lesion. 2. Digital perspective: After the ordinary perspective technology is digitized, its images can be fixed, played back or even stored. The application of pulse technology can double the X-ray dose, usually using 1/2 or l/3 coefficient, which can obviously reduce the radiation dose and examination time accepted by operators and patients. 3. Digital film: In the past, film technology was to project images on film. If you want to see it, you must go through a darkroom before you can watch it through the projector. Due to many human factors, the image quality can not be guaranteed, and the effect can not be seen immediately after comparison, so the preservation time is limited. The application of digital technology is to store the image on the hard disk without many intermediate links and remove many unstable factors, which can increase the exposure speed to 50 frames, seconds or even 75 frames/second and play it back immediately. The image quality is stable and reliable, and can be stored for a long time.

High pressure injector

The application of high-pressure injector can ensure that the required contrast agent can be injected into the cardiovascular system of patients at a certain pressure and flow rate in a short time, and the detected part can be filled with high concentration to shoot high-contrast images, which can cooperate with the exposure of X-ray machine in the imaging process, thus improving the accuracy and success rate of photography. Modern high-voltage equipment is mostly controlled by microcomputer, which has the advantages of miniaturization, high control accuracy, stable operation and intelligence. (I) Structure and function The main structure of the high-pressure injector is: 1. Multi-axis mobile injection head: a certain concentration of contrast agent is sucked into the injection cylinder (disposable), and the total amount of contrast agent in the cylinder is detected by microcomputer and heated to body temperature. Its multi-axis system can move in the direction with the position of the catheter head to ensure the smooth imaging. 2. Console: It is the center of the high-pressure injector and controls all injection parameters and procedures. 3. Mobile support: there are three methods: zenith hanging, catheter bed standing and landing standing. You can choose one according to the user's habits and room structure. Generally speaking, floor-standing is more convenient and practical. (II) Injection parameters In order to obtain a satisfactory contrast image, appropriate parameters must be selected according to the position of the catheter head, the diameter of the catheter, the size of the lesion and the blood flow running time. Commonly used parameters are: 1. Delay time: according to the needs of the lesion, the timing of contrast agent injection is controlled, which is divided into two ways: exposure delay and injection delay. 2. Dose per injection: that is, the dose of contrast agent injected during each radiography cannot be mixed with the total amount. Generally in milliliters. 3. Injection flow rate: refers to the dose of contrast agent injected into the catheter per unit time, usually expressed in milliliters per second ... Each set injection flow rate is the upper limit of the actual injection flow rate, that is, the actual injection volume may not reach the set value, but it can limit the further increase of the flow rate and play a protective role. 4. Injection pressure: refers to the pressure required per unit area when the contrast agent reaches the blood vessel at a certain flow rate. The injection pressure set at each time is the upper limit, which can play a certain protective role, usually expressed in PSI (pounds per square inch).

Quality assurance (control) system

DSA system is a large precision instrument, and its maintenance, use and management will directly affect the examination results and treatment effects. (1) Factors affecting the quality of DSA images In the process of use, problems in each link will affect the images. 1. Line part: including the capacity of the machine, the choice of shooting conditions, the choice of focusing, the size of exposure, etc. 2. Mechanical part: the cooperation between catheter bed and bulb in the process of image acquisition. 3. The performance of high-pressure injector and its matching with X-ray photography. 4. Image acquisition speed: the degree of signal loss in digital conversion. 5. Image acquisition quality: including the performance of image intensifiers and TV cameras, image storage devices (such as disks, tapes, video recorders) and multiple cameras, laser cameras or dry printers. 6. Post-processing performance: such as mask reconstruction and pixel shift. 7. Selection of inspection method: such as digital film or digital subtraction. 8. The patient's cooperation during filming: if the patient is required to hold his breath. 9. Operation of medical personnel: such as the choice of catheter, whether the catheter is inserted into the target organ, etc. (II) Management of large-scale instruments and equipment Only by establishing strict rules and regulations can the safe operation of the equipment be guaranteed. 1. The equipment is tested and maintained by the maintenance company regularly every year. 2. The environment of the computer room is kept at 20 ~ 25% all the year round, and the relative humidity is 40% ~ 70%. Dehumidification is needed in the rainy season in the south to keep the room dry. 3. Equipment, especially image intensifiers and high-pressure syringes, should be cleaned and maintained by staff regularly every month. 4. The computer room and equipment should be disinfected with ultraviolet rays every day to prevent infection. 5. Check whether the equipment is in the best running state at startup. 6. Operate in strict accordance with the equipment operation procedures. (Protection of X-ray radiation in DSA examination With the progress of society and the enhancement of environmental awareness, people pay more and more attention to X-ray radiation protection. Therefore, in DSA examination, X-ray radiation should be controlled in the minimum range to prevent accidents. 1. The environmental monitoring station regularly carries out X-ray monitoring inside and outside the computer room and dose monitoring for medical staff. 2. Medical personnel should strictly wear protective clothing. 3. The corresponding protective equipment should be installed in the computer room. 4. Try to shorten the exposure time, narrow the exposure range and reduce the exposure times during inspection.