DICOM PS3.4 2024b - Service Class Specifications

Z.4.2 C-GET Operation

SCUs of the Composite Instance Retrieve Without Bulk Data Service shall generate retrievals using the C-GET operation as described in PS3.7. The C-GET operation allows an application entity to instruct another application entity to transfer SOP Instances without the Attributes as described in Section Z.1.3 to the initiating application entity using the C-STORE operation. Support for the C-GET service shall be agreed upon at Association establishment time by both the SCU and SCP of the C-GET in order for a C-GET operation to occur over the Association. The C-STORE Sub-operations shall be accomplished on the same Association as the C-GET operation. Hence, the SCP of the Query/Retrieve Service Class serves as the SCU of the Storage Service Class.

Note

The Application Entity that receives the stored SOP Instances is always the originator of the C-GET operation.

Z.4.2.1 C-GET Service Parameters

Z.4.2.1.1 SOP Class UID

The SOP Class UID identifies the Query/Retrieve Information Model against which the C-GET is to be performed. Support for the SOP Class UID is implied by the Abstract Syntax UID of the Presentation Context used by this C-GET operation.

Z.4.2.1.2 Priority

The Priority Attribute defines the requested priority of the C-GET operation and corresponding C-STORE sub-operations with respect to other DIMSE operations being performed by the same SCP.

Processing of priority requests is not required of SCPs. Whether or not an SCP supports priority processing, and the meaning of the different priority levels shall be stated in the Conformance Statement of the SCP. The same priority shall be used for all C-STORE sub-operations.

Z.4.2.1.3 Identifier

The C-GET request shall contain an Identifier. The C-GET response shall conditionally contain an Identifier as required in Section C.4.3.1.3.2.

Note

The Identifier is specified as U in the definition of the C-GET primitive in PS3.7 but is specialized for use with this service.

Z.4.2.1.3.1 Request Identifier Structure

An Identifier in a C-GET request shall contain:

  • the Query/Retrieve Level (0008,0052) that defines the level of the retrieval

  • SOP Instance UID(s) (0008,0018)

  • Conditionally, the Attribute Query/Retrieve View (0008,0053). This Attribute may be included if Enhanced Multi-Frame Image Conversion has accepted during Association Extended Negotiation. It shall not be included otherwise.

Query/Retrieve Level (0008,0052) shall be IMAGE.

Specific Character Set (0008,0005) shall not be present.

The Keys at each level of the hierarchy and the values allowable for the level of the retrieval are defined in the SOP Class definition for the Query/Retrieve Information Model.

Z.4.2.1.4 Status

Table Z.4-1 defines the Status Code values that might be returned in a C-GET response. General Status Code values and fields related to Status Code values are defined for C-GET DIMSE Service in PS3.7.

Table Z.4-1. C-GET Response Status Values for Composite Instance Retrieve Without Bulk Data

Service Status

Further Meaning

Status Codes

Related Fields

Failure

Refused: Out of resources - Unable to calculate number of matches

A701

(0000,0902)

Refused: Out of resources - Unable to perform sub-operations

A702

(0000,1020)

(0000,1021)

(0000,1022)

(0000,1023)

Error: Data Set does not match SOP Class

A900

(0000,0901)

(0000,0902)

Failed: Unable to process

Cxxx

(0000,0901)

(0000,0902)

Cancel

Sub-operations terminated due to Cancel Indication

FE00

(0000,1020)

(0000,1021)

(0000,1022)

(0000,1023)

Warning

Sub-operations Complete - One or more Failures or Warnings

B000

(0000,1020)

(0000,1021)

(0000,1022)

(0000,1023)

Success

Sub-operations Complete - No Failures or Warnings

0000

(0000,1020)

(0000,1021)

(0000,1022)

(0000,1023)

Pending

Sub-operations are continuing

FF00

(0000,1020)

(0000,1021)

(0000,1022)

(0000,1023)


Some Failure Status Codes are implementation specific.

An SCP implementation shall assign specific Failure Status Codes by replacing each 'x' symbol with a hexadecimal digit in the range from 0 to F. An SCP implementation wishing to differentiate between causes of "Failed: Unable to process" Failure Meaning shall assign those causes specific Status Code Values within valid range specified in Table Y.4-2.

An SCU implementation shall recognize any Failure Status Code within the value range specified in Table Y.4-2 as an indicator of the Failure Meaning stated in the table. There is no requirement for an SCU implementation to differentiate between specific Status Codes within the valid range.

Z.4.2.1.5 Number of Remaining Sub-Operations

Inclusion of the Number of Remaining Sub-operations shall be as specified in Section C.4.3.1.5

Z.4.2.1.6 Number of Completed Sub-Operations

Inclusion of the Number of Completed Sub-operations shall be as specified in Section C.4.3.1.6

Z.4.2.1.7 Number of Failed Sub-Operations

Inclusion of the Number of Failed Sub-operations shall be as specified in Section C.4.3.1.7

Z.4.2.1.8 Number of Warning Sub-Operations

Inclusion of the Number of Warning Sub-operations shall be as specified in Section C.4.3.1.8.

DICOM PS3.4 2024b - Service Class Specifications