Материал: part02

Relational Queries are not supported either as an SCU or SCP.​

F.2 Table of Contents​

A table of contents shall be provided to assist readers in easily finding the needed information.​

F.3 Introduction​

F.3.1 Revision History​

Table F.3.1-1. Revision History​

F.3.2 Audience, Remarks, Terms and Definitions, Basics of DICOM Communication, Abbrevi-​ ations, References​

See example text in Section A.3.​

F.3.3 Additional Remarks for This Example​

ThisdocumentisasampleDICOMConformanceStatementcreatedforDICOMPS3.2.Itistobeusedsolelyasanexampletoillustrate​ howtocreateaDICOMConformanceStatementforanimagestoragesystemsupportingDICOMimages.Thesubjectofthedocument,​ EXAMPLE-QUERY-RETRIEVE-SERVER, is a fictional product.​

F.4 Networking​

F.4.1 Implementation Model​

F.4.1.1 Application Data Flow​

ThedivisionofEXAMPLE-QUERY-RETRIEVE-SERVERintotheseparateDICOMApplicationEntitiesrepresentsasomewhatarbitrary​ partitioning of functionality. For the purpose of this document they are organized in this manner so as to detail their independent lo-​ gical functionality.​

By default all of the defined Application Entities have different AE Titles. However, EXAMPLE-QUERY-RETRIEVE-SERVER can be​ configured so that the QUERY-RETRIEVE-SCP AE and STORAGE-SCU AE share the same Application Entity Title. However, the​ QUERY-RETRIEVE-SCP AE and STORAGE-SCP AE must have separate Application Entity Titles.​

- Standard -​

Figure F.4.1-1. Example-Query-Retrieve-Server DICOM Data Flow Diagram​

The Application Entities detailed in the Application Data Flow Diagram are all Windows NT applications.​

•​TheSTORAGE-SCUAEcansendCompositeSOPInstances.IthandlesrequestsfromtheQUERY-RETRIEVE-SCPAEtotransmit​ Images to a specific DICOM destination. The STORAGE-SCU AE functions as a C-STORE SCU. (Note that in this example Con-​ formance Statement this STORAGE-SCU AE does not allow a Local User to request that images be sent to a Remote AE. If a 'real'​ AE does allow this then this should be mentioned here and in the other appropriate areas of the Conformance Statement).​

•​The QUERY-RETRIEVE-SCP AE can handle incoming query and retrieve requests. It can handle external queries for Patient,​ Study,Series,andImagedata,andalsohandleImageretrievalrequests.TheQUERY-RETRIEVE-SCPAEhandlesretrievalrequests​ by issuing a command to the STORAGE-SCU AE to send the requested Images to the destination specified by the Remote AE.​ The QUERY-RETRIEVE-SCP AE functions as an SCP for C-FIND and C-MOVE requests.​

•​The STORAGE-SCP AE can receive incoming DICOM images and add them to the EXAMPLE-QUERY-RETRIEVE-SERVER​ database. It can respond to external Storage and Verification Requests as a Service Class Provider (SCP) for C-STORE and C-​ ECHO requests. The STORAGE-SCP AE can also handle Storage Commitment Push Model Requests. It can thus be used to​ query whether the EXAMPLE-QUERY-RETRIEVE-SERVER will confirm ownership and responsibility for specific Composite SOP​ Instances. The STORAGE-SCP AE currently only supports image type Composite SOP Instances.​

F.4.1.2 Functional Definition of AEs​

F.4.1.2.1 Functional Definition of STORAGE-SCU Application Entity​

The STORAGE-SCU AE can be invoked by the QUERY-RETRIEVE-SCP AE to trigger the transfer of specific images to a remote​ destination AE. The STORAGE-SCU AE must be correctly configured with the host and port number of any external DICOM AEs that​ are to be C-MOVE retrieval destinations. The Presentation Contexts to use are determined from the headers of the DICOM files to​ be transferred. Some conversion of the DICOM image objects is possible if the original Presentation Context is not supported by the​ remote destination AE or if compression is preferred.​

- Standard -​

F.4.1.2.2 Functional Definition of QUERY-RETRIEVE-SCP Application Entity​

The QUERY-RETRIEVE-SCP AE waits for another application to connect at the presentation address configured for its Application​ EntityTitle.Whenanotherapplicationconnects,QUERY-RETRIEVE-SCPAEexpectsittobeaDICOMapplication.QUERY-RETRIEVE-​ SCP AE will accept Associations with Presentation Contexts for SOP Classes of the DICOM Query-Retrieve Service Class, and​ Verification Service Class. It will handle query and retrieve requests on these Presentation Contexts and respond with data objects​ with values corresponding to the contents of the EXAMPLE-QUERY-RETRIEVE-SERVER database. For C-MOVE requests the​ destinationfortheimageobjectsisdeterminedfromtheDestinationAETitlecontainedintheC-MOVErequest.Whenaretrievalrequest​ is received, the QUERY-RETRIEVE-SCP AE issues a command to the STORAGE-SCU AE to send the specified images to the C-​ MOVE Destination AE.​

F.4.1.2.3 Functional Definition of STORAGE-SCP Application Entity​

The STORAGE-SCP AE waits for another application to connect at the presentation address configured for its Application Entity Title.​ Whenanotherapplicationconnects,theSTORAGE-SCPAEexpectsittobeaDICOMapplication.TheSTORAGE-SCPAEwillaccept​ Associations with Presentation Contexts for SOP Classes of the Verification, Storage, and Storage Commitment Service Classes.​ Any images received on such Presentation Contexts will be added to the EXAMPLE-QUERY-RETRIEVE-SERVER database. If a​ Storage Commitment Push Model N-ACTION Request is received then the STORAGE-COMMITMENT-SCP AE will immediately​ check if the referenced Composite SOP Instances are in the EXAMPLE-QUERY-RETRIEVE-SERVER database and return an N-​ EVENT-REPORTNotification.Itwillnever'cache'StorageCommitmentPushModelRequestsandwaitforCompositeSOPInstances​ to be received at a later time.​

F.4.1.3 Sequencing of Real-World Activities​

The only sequencing constraint that exists across all the EXAMPLE-QUERY-RETRIEVE-SERVER Application Entities is the fact that​ a Composite SOP Instance must be received by the STORAGE-SCP AE before Storage Commitment Push Model or Query-Retrieve​ Requests related to this SOP Instance can be successfully handled:​

4.Peer AE Queries for Information related to SOP Instance

5.Return Information related to SOP Instance

6.Peer AE Requests Retrieva l of SOP Instance

7.Images to be sent to C-MOVE Destination AE in Response

8.Images Sent to Peer AE in Response

Figure F.4.1-2. Sequencing Constraints​

NotethattheonlyconstraintisfortheCompositeSOPInstancetobereceivedpriortotheotherevents.Forexample,itisnotnecessary​ for the Storage Commitment Push Model Request to be received prior to receiving Query or Retrieval Requests related to the SOP​ Instance.​

- Standard -​

F.4.2 AE Specifications​

F.4.2.1 STORAGE-SCU Application Entity Specification​

F.4.2.1.1 SOP Classes​

The STORAGE-SCU AE provides Standard Conformance to the following DICOM SOP Classes:​

Table F.4.2-1. SOP Classes for STORAGE-SCU AE​

STORAGE-SCU AE can be configured to use the retired US Image objects (US Image Storage, 1.2.840.10008.5.1.4.1.1.6, and US​ Multi-frame Storage, 1.2.840.10008.5.1.4.1.1.3) rather than the current US SOP Classes for ultrasound images or vice-versa, making​ any necessary changes to make the transformed image objects conformant to the corresponding SOP Class. This is only done if the​ external Storage SCP AE does not support the SOP Instance's original SOP Class.​

By altering the configuration it is possible to support additional or fewer SOP Classes.​

F.4.2.1.2 Association Establishment Policies​

F.4.2.1.2.1 General​

The STORAGE-SCU AE can only form Associations when requested to do so by the QUERY-RETRIEVE-SCP AE. The STORAGE-​ SCU AE can only request the opening of an Association. It cannot accept requests to open Associations from external Application​ Entities.​

The DICOM standard Application Context Name for DICOM is always proposed:​

Table F.4.2-2. DICOM Application Context for STORAGE-SCU AE​

The maximum number of simultaneous Associations is configurable, but is usually limited to a maximum of 10. This configuration​ largely depends on whether relatively quick response to multiple simultaneous C-MOVE Destination AEs is required or maximum​ throughput performance is required. If the latter is the case, then no simultaneous Associations are permitted, in order to reduce disk​ thrashingandthusmaximizethroughput.TheSTORAGE-SCUAEcaninitiatesimultaneousAssociationstoagivenexternalC-MOVE​ Destination AE up to the maximum number configured. There is no separate limit on the maximum number permitted to the same C-​ MOVE Destination AE.​

If the first attempt to open an Association fails then the STORAGE-SCU AE will reschedule the task to attempt it again after a config-​ urable time delay. The number of times to reattempt Association establishment is configurable, with the default being zero.​

- Standard -​

Table F.4.2-3. Number of Associations as a SCU for STORAGE-SCU AE​

TheSTORAGE-SCUAEdoesnotsupportasynchronouscommunication(multipleoutstandingtransactionsoverasingleAssociation).​ All Association requests must be completed and acknowledged before a new operation can be initiated.​

Table F.4.2-4. Asynchronous Nature as a SCU for STORAGE-SCU AE​

Table F.4.2-5. DICOM Implementation Class and Version for STORAGE-SCU AE​

NotethattheSTORAGE-SCUAEandQUERY-RETRIEVE-SCPAEusethesameImplementationClassUID.AllEXAMPLE-QUERY-​ RETRIEVE-SERVER AEs use the same Implementation Version Name. This Version Name is updated with each new release of the​ product software, as the different AE versions are never released independently.​

F.4.2.1.3 Association Initiation Policy​

F.4.2.1.3.1 Activity - Send Images Requested By an External Peer AE​

F.4.2.1.3.1.1 Description and Sequencing of Activity​

The STORAGE-SCU AE will initiate a new Association when the QUERY-RETRIEVE-SCP AE invokes the STORAGE-SCU AE to​ transmit images. The QUERY-RETRIEVE-SCP AE will issue such a command whenever it receives a valid C-MOVE Request. An​ Association Request is sent to the specified C-MOVE Destination AE and upon successful negotiation of the required Presentation​ Context the image transfer is started. In all cases an attempt will be made to transmit all the indicated images in a single Association,​ but this may not always be possible. The Association will be released when all the images have been sent. If an error occurs during​ transmission over an open Association then the image transfer is halted. The STORAGE-SCU AE will not attempt to independently​ retry the image export.​

Note that the STORAGE-SCU AE does not support the unsolicited sending of SOP Instances using the DICOM Storage Service​ Class. It will only send SOP Instances in response to a C-MOVE Request from a peer AE.​

- Standard -​