I. Introduction
PACS (picture archiving and communication system) means image archiving and communication system. It is a system applied in the imaging department of the hospital. Its main task is to convert all kinds of medical images (including MRI, CT, ultrasound, various X-ray machines, various infrared instruments, microscopes and other equipment generated images) Through various interfaces (analog, DICOM, network), it is stored in a large amount in a digital way, and can be called back to use quickly under a certain authorization when needed, and some auxiliary diagnosis and management functions are added at the same time. It plays an important role in transferring data between various imaging devices and organizing and storing data.
PACS takes the realization of digital storage and diagnosis of medical images as its core task, acquires images from medical imaging equipment (such as CT, CR, DR, MR, DSA, RF, etc.), centrally stores and comprehensively manages medical images and patient-related information, and establishes digital work process. The system can realize a series of functions that meet the daily work of the imaging department, such as examination appointment, patient information registration, computer reading, electronic report writing, film printing, data backup, and due to the digital storage of images, users can use image processing and measurement technology to assist diagnosis , Find data conveniently and quickly or use the network to transmit data to clinical departments. It can also be seamlessly connected with the hospital's HIS and LIS, so that the hospital's internal information is highly shared, and it also lays the foundation for telemedicine, greatly improving work efficiency and improving Hospital market competitiveness; In addition, the system also provides statistical functions, and detailed reports enable hospital managers to grasp the usage and work quality of various equipment in a timely and accurate manner, providing a reliable basis for scientific decision-making. This manual introduces the installation, startup, functions, and operation of the software in detail.
2. Composition of PACS system
The original meaning of PACS refers to the archiving and transmission of medical images. The basic components of PACS system include: digital image acquisition, communication and network, medical image storage, medical image management, and various workstations.
(1) Image acquisition workstation
If PACS is compared to an assembly line for goods transmission, the image acquisition link is where the goods are acquired. The image acquisition workstation is responsible for receiving the images of one or more devices and sending these images to the image archiving server or other places. In computer terminology, the image acquisition workstation is the external interface of PACS, and it is an interface specially for receiving medical images, and it can also be called an image gateway. The acquisition workstation not only collects numbers, but also other media such as video, sound and text, so don’t mistakenly think that the image acquisition workstation is only for images, it’s just a habitual name.
The image acquisition workstation is a very important part of PACS. Compared with other workstations, the image acquisition workstation has a large amount of information and calculation, and has high requirements on its performance and reliability. Some new image inspection equipment, such as 256-slice or even 512-slice CT, are being installed in large and medium-sized hospitals in large quantities. The amount of images generated by each scanning part of the equipment routinely reaches hundreds of pieces, and all these images must be collected through image acquisition. The workstation performs processing and forwards to the archive server, so the computing intensity and I/O load of the image acquisition workstation are quite high.
(2) Image transmission
Medical images are generated by image inspection equipment, and are initially stored on the operating workstation of the equipment, then transmitted to the archiving server through the acquisition workstation, and then transmitted to the image reading workstation, printing workstation and other equipment through the archiving server. For the imagery data itself, this is basically a one-way process. If the image reading workstation marks the image, when the mark information is stored in the image file, the modified file needs to be transmitted back to the archive server. In this case, the image transmission is bidirectional.
(3) Management and archiving server
In the whole PACS structure, the management and archiving server is at the center, it is the gathering point of all image and report data, and it is also the central service point. The current PACS architecture basically belongs to the server/client model. The server is at the center of the system and generally gathers the main data and services, and the client obtains the required data and services by accessing the server. The main role of the management and archiving server is archiving and management. Simply understood, it is a server that stores images and other data and has the function of providing these images to doctors. Since the management and archiving server needs to provide concurrent massive data services to hundreds of clients, it puts high demands on the server, especially the storage and I/O of the server. Improper configuration will affect the overall system Performance.
(4) Application server
The application server is based on the management and archiving server, and provides a certain kind of specialized service related to PACS externally. The main application servers are:
1. The Web image server can provide the function of querying and viewing DICOM images in the form of the Web.
2. The web report server can provide image reports in the form of web. It may be necessary to convert DICOM images to common Internet image formats such as JPG, or to provide structured reports in standard XML format.
3. The remote image consultation server provides remote image transmission and interactive consultation functions.
4. The radiotherapy image server provides suitable images for the radiotherapy system.
5. Education and scientific research servers provide dedicated search, transmission and image reading servers for medical teaching and scientific research.
(5) Image reading workstation
The image reading workstation is a tool for doctors in the inspection department (clinical department) to browse images, write reports, and look up patient-related information. Its main functions are:
1. Acquire high-speed images and transmit image data from an archive server.
2. It is seamlessly connected with HIS and RIS, and can obtain the data of RIS and HIS.
3. Provide image services that conform to the DICOM standard.
4. Able to display and operate various types of medical images, such as CR, DR, CT, MRI, DSA, US, CD, etc.; can display and play various dynamic images, such as ultrasound, DSA, etc.
5. Various image processing tools.
6. Graphic report writing tools, customizable report templates.
7. Inquiry function, supports name, examination number, application department, disease name, date and other inquiry items, and supports simple and patient-centered inquiry.
8. Laser film printing, CD burning function.
9. Support professional display output and multi-screen display.
3. PACS system process
The PACS process begins with the patient registering with the HIS (registered registration) or with the RIS for examination registration. Then the patient enters the examination room, and the technician conducts the examination, then reads the film, writes the report, and files the image and graphic report.
1. The clinician enters the electronic examination application form in the doctor workstation and sends the application form to the RIS system.
2. In the RIS of the imaging examination department, the information of the electronic examination application form is reserved, reviewed, and priced and confirmed.
3. RIS communicates with the interface engine of PACS, and transmits HL7 messages including personal information and inspection information to the other party.
4. The PACS interface engine notifies the archive server that there are new checks that need to be scheduled.
5. When the patient arrives at the examination department, the examination equipment requests the worklist from the PACS interface engine.
6. For DICOM devices that support the worklist, the electronic application form is directly sent to the imaging device, and the patient is selected in the imaging device, and the examination is arranged directly. The collected images are automatically sent to PACS; for imaging devices that do not support worklist, basic patient information needs to be entered in the device.
7. The technician performs inspection operations, sends the obtained DICOM images to the acquisition workstation, and completes quality control and other operations at the acquisition workstation.
8. After the image acquisition workstation receives the image, it sends the image to the PACS storage server. If there is a cache server in the applying department, the images will also be sent to the cache server of the department at the same time.
9. The diagnostic imaging doctor consults the examination images as needed.
10. If the diagnostic imaging doctor modifies or marks the image, he will notify the archive server to update the information and upload the updated image.
11. The diagnostic imaging doctor writes the examination report on the PACS diagnostic workstation.
12. PACS interface engine sends information to HIS/RIS to notify update check status.
13. Clinicians obtain images and examination reports as one of the basis for diagnosis.
What has been described above is the current routine image inspection process. With the rapid development of digital imaging equipment and information technology, as well as changes in clinical diagnosis and treatment needs, some links in the imaging inspection system have changed from time to time. Different imaging tests in different hospitals will also be different. For emergency patients, the imaging department will quickly issue an emergency report to the doctor for emergency treatment, and the final formal inspection report will be delivered to the clinical department according to the standard process.
PACS system software selection
At present, in terms of software architecture selection of PACS system, there are mainly two forms of C/S and B/S.
C/S architecture, that is, Client/Server (client/server) architecture, reasonably allocates computing tasks to the client and server, reduces the communication overhead of the entire system, and can make full use of the advantages of the hardware environment at both ends. In the PACS system of C/S structure, the client (medical image display workstation) needs to install the application program. In order to query data and retrieve images. The C/S architecture is commonly used in the local area network, so the information security is higher. Because the client has more computing content, the transmission of network data is reduced, the operation speed is faster, and the interface is more flexible and friendly. But all clients must install the same operating system and software, which is not conducive to the software system and expanding the scope of application at any time.
B/S architecture, that is, Client/Sever (client/server) architecture. Under this architecture, the user interface is completely implemented through the World Wide Web browser, part of the budget is implemented on the client's browser, but the main calculation is implemented on the server side. In the PACS system of B/S structure, the medical image display workstation only needs to open a World Wide Web browser such as IE to query data and retrieve images. The B/S architecture is often used in wide area networks, so the information security is weak, but it is conducive to the release of information; the client can use it as long as it has a browser, so the operating system is usually not limited, and there is no need to install software, which affects the performance of the client computer. Low requirements, easier software upgrades.