Principles and Applications of DICOM mpps

Principle and Application of DICOM mpps

 

Introduction

The medical imaging Archiving and Communication System (PACS) has developed rapidly in recent years. The purpose is to comprehensively address the acquisition, display, storage, transfer and management of medical images. PACS is a computer network for Digital Management of Medical images. the data exchange standard protocol is a prerequisite for information transmission, and the medical digital image transmission (DICOM) standard is the first widely accepted global medical digital imaging and communication standard. To resolve the differences between image data formats and transmission modes between Image devices and PACS vendors, the American radiology Society {ACR) and the National Electronics Manufacturers Association (SCN) in 1985, a medical digital imaging and communication standard (d1g1_imaging and communication in medicine, DICOM) was jointly established to facilitate the exchange of standardized images and related information. Currently, DICOM has been widely supported, but its main application is to store medical images (c-Store service), transmission, query, and related image processing are printed on amine tablets, but applications in the equipment business information management system and Workflow Management Service are quite slow. Recently, dicom mwl (modality worklist) has been gradually applied. It can be used to automatically input patient information, reducing the need for technicians to re-enter patient information on the device console, this greatly reduces the workload of repeated information input and the probability of human error. However, when and when the imaging device starts the examination. and check some events occurred during the operation, how to notify the corresponding workflow manager of the Information closely related to the daily business process management, usually PACS and RIS (Radiology Information System ), the PACS/RIS system can promptly and accurately know what tests are being performed, when they are completed, and when images have been collected for query and retrieval, this is an essential part of the business management process of the PACS/RIS system.

The mpps service is defined in DICOM protocol (device operation procedure step modality completion Ming procedure step ). Using the mpps service, imaging devices can transmit various status information during inspection execution to the PACS/RIS system to improve and enhance workflow management.

1 mpps Principle

In a complete routine inspection process, the patient first registers and makes an appointment after entering the hospital, then goes to the relevant department for examination, completes the services such as visiting, checking the collected image, and then the image

Transfer to the PACS system for reading and diagnosis, then produce a report, and sometimes print the film. After the examination is complete, the patient leaves.

Based on the time relationship, the I of a check process (from left to right ):

Information Interaction Between the PACS/RIS system and the device mainly includes: before the device check, the DICOM modality worklist function is used to obtain the registered patient information from the RIS.

The DICOM mpps function sends the check status to the PACS/RIS system. After the check is completed, the device sends the image to the PACS system for storage management through the DICOM Storage function. 1.

 

1.1 mpps and MWL

MWL and mpps are the main means for business management information interaction between devices and information systems defined in DICOM. in practical applications, MWL and mpps are often integrated, mpps is also called an extension of MWL. MWL transmits information from the information system to the device, while mpps transmits the status information of the device inspection to the information system. After the doctor selects the worklist item to obtain the patient information to be checked, the image is collected (it contains scheduled procedure step, SPS), and at the end of the collection graph, you can use the mpps service to transmit various current statuses of devices performing tasks, as shown in figure 1.

Mpps is a real execution process (scheduled med). The steps are not exactly the same as those of scheduled, and are often different. In actual situations, it may be related to several actual operations.

For task managers, such as RIS, who are in need of management and monitoring, they need to know the status of the current task, which requires the execution device to effectively provide the status value of the task. When an image starts to be collected, the imaging device sends a message to the task manager, indicating that a task starts, that is, an image is collected for a patient, if an unexpected termination occurs during the operation, you must notify the Process Manager through the message. If the normal collection process is completed without exceptions, the Process Manager is notified to complete this task. Now, the system can query and request images from devices.

1.2 mpps service process

In DICOM, two primitives are used to complete the service: N-create and N-set. The service process is as follows:

● The device selects the scheduled task from the worklist and starts image collection. The N-create primitive is used to notify the workflow manager to create the task.

The mpps instance is in the starting status.

● After receiving the request, the workflow manager creates the instance and sets the corresponding status. After the request is successful, the workflow manager returns the correct response. If the request fails

The error message is returned. The device is associated with this service.

● The device receives confirmation from the workflow manager. When the image collection ends, use the n-set primitive to notify the workflow manager that this mpps ends.

● The workflow manager receives a change notification, performs corresponding operations, and returns a response.

● Close the connection between the device and workflow.

In this way, RIS can be executed in a timely manner, provide necessary conditions for workflow management, and effectively strengthen management. For example, RIS can perform related query operations when an image is notified via mpps that it has been collected. Managers (or technicians) can also use these status information for integrity verification. For example, after confirming that the examination is complete, the PACS system can obtain the relevant images.

2 mpps implementation

Mpps can be divided into two roles: SCP and SCU. The former uses the Workflow Management Terminal, usually PACS/RIS. This document uses RIS as the workflow manager, which is used on the device where the workflow is executed.

Like other network communication services such as storage and query, mpps establishes a connection based on TCP to complete message interaction. Its service framework is as follows:

You can create an mpps instance and update its status in two different links.

 

2.1 create an instance

When the device starts collecting images after obtaining the task, it notifies RIS of this event, and at the time of notification, it needs to determine an mpps instance

Example. In DICOM protocol, the N-create primitive is used to provide this service.

In this request, both the newly created mpps instance UID and the status of the mpps instance are included, that is, in progress.

After receiving this request, RIS creates an instance and sets its status to in progre ss. A confirmation response is returned after the request is successful.

2.2 Transfer status

After Image Acquisition starts, either the collection process is abnormal or the process is completed normally. Use discontinued and complete

Two statuses.

The device uses the n-set service primitive to notify the RIS end. The object set in this request is marked with the created mpps instance uid. After receiving the request, the ris end of the mpps SCP updates the status value of the specified instance. If it is normal, a successful response is returned to confirm that the service is complete.

Mpps management status information is described by attributes (,) in mpps IOD. All statuses are initialized by the device. There are three statuses:

In progre ss: The device starts the task.

Discontinued: indicates the cancellation or unsuccessful termination: the device cannot complete the operation after the mpps starts. Device notification is to reschedule or cancel the related process.

Complete indicates that the acquisition of the composite SOP instance has been completed successfully, and SCU has provided all the values required for mpps.

3 conclusion

Mpps is an important function of workflow and business management. IHE defines a complete Workflow Framework of the medical information system. Based on this framework, it can be used to design and implement digital hospitals that integrate his, PACs, and RIS. The DICOM Standard defines services such as MWL, mpps, and SPS for workflow management. These services are links between his, PACs, RIS, and devices. Currently, this application is still in its infancy in China. With the continuous development of the PACS system, workflow management has become the development trend of PACS in the future. How to better integrate PACS, RIS, and imaging devices to achieve workflows that meet hospital business functions, so as to better meet the needs of daily business work, it is an important part of implementing full-featured digital radiology, and also the focus of PACS system development in the next few years.