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.
1. Composition of PACS system
The medical imaging system is composed of PACS system and RIS system, and provides an interface with HIS (HL7 or other types).
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.
2. Introduction of main functions
Information appointment registration
Support the management of patients, inspection items, applicant doctors, application documents, equipment and other information. And it supports checking patient queuing management function;
Support large screen queue display and voice call;
Provide functions such as appointment adjustment, queue management, and lagging processing; support priority arrangement for emergency applications.
image review
The system uses DICOM and non-DICOM formats to acquire image data, and collects the original DICOM data of images through communication;
Support static and dynamic image data collection;
Support multiple acquisition methods such as perspective acquisition and exposure acquisition;
Support conversion of image data from non-DICOM image devices into DICOM standard data.
Support reading DCMDIR files, displaying and opening associated DICOM files;
Display a variety of image file formats, and can be converted into DICOM format;
Support multi-screen and vertical screen display; support dynamic image movie playback, frame-by-frame roaming and freezing;
Support to display multiple images on the same screen, and customize the display matrix;
Support to display multiple dynamic movie images of the same patient examined by different examination equipment on the same screen;
Support image display in check mode, compare mode and print mode;
Support multi-screen display of different sequences of images of the same patient or images of different patients;
Support to display images of patients in different positions and different equipment on the same screen;
Support image comparison between different patients.
report management
The system supports the report writing interface to display the list of patients classified by inspection items;
Provide writing, modifying and auditing functions of graphic reports, and support authority management;
Support recording and reporting modification traces;
Support various types of report filing, such as scientific research reports, typical medical records, etc.;
Provide editing and modification functions for report templates;
Provide report printing function and support custom printing format.
Query and statistics
The system provides patient examination information query, disease analysis and statistical functions;
Support checking positive rate and reporting error rate statistics;
Support equipment workload and doctor workload statistics;
Image post-processing and reconstruction
· MPR\CPR (3D multi-planar reconstruction)
·VRT (3D Volumetric Reconstruction)
· SSD (3D Surface Reconstruction)
VE (Virtual Endoscopy)
MIP (Maximum Intensity Projection)
MinIP (Minimum Intensity Projection)
CalSCore (cardiac image coronary calcium score)
Image storage function
The system provides online, near-line and offline storage methods;
supports long-term storage management and short-term storage management of image data;
supports uncompressed (raw data) or lossless compression storage of images;
supports storage of data in different life cycle stages according to data types On a suitable storage device, it can meet the real-time needs of doctors for images and information;
provide standard DICOM disc recording function, and support recording and saving of stored data;
Support automatic dump function between different image storage servers.
Image management and query functions
The system uses a database to manage images and data;
Support multiple ways to query patient information, including patient name, medical card number, hospitalization number, examination number, ID number, examination department, examination doctor and imaging equipment, etc.;
Support the establishment of a patient ID number and image content and storage location comparison table in the database;
Support the archiving of data and images of each patient's examination and physical examination;
Support numbering and archiving of CD-ROM data in chronological order, which is convenient for retrieval and transmission;
Support image recall, dump, delete and image migration functions.
Image processing and measurement functions
The system supports window width and window level presets, continuous adjustment of window level and histogram, image equalization, image smoothing and edge enhancement; support for
contrast adjustment, positive and negative image rotation, image black and white inversion, image horizontal and vertical flipping, Grayscale conversion and rotation at any angle, etc.;
support filtering, sharpening, playback, and color drawing, etc.;
support data measurement and calculation of ROI value, length, angle, and area;
support digital subtraction, stepless zooming, and partial magnification;
support text and graphic marking; query and save DICOM header information;
support for dumping and saving of different image formats;
support automatic application of corresponding preset window width and window level according to inspection items.
Three, PACS system 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.
4. 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.