F.8 Modality Performed Procedure Step Retrieve SOP Class
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## F.8 Modality Performed Procedure Step Retrieve SOP Class

### F.8.1 DIMSE Service Group

The DIMSE Services shown in Table F.8.1-1 are applicable to the Modality Performed Procedure Step IOD under the Modality Performed Procedure Step Retrieve SOP Class.

Table F.8.1-1. DIMSE Service Group

DIMSE Service Element | Usage SCU/SCP
--- | ---
N-GET | M/M

The DIMSE Services and Protocols are specified in PS3.7. If the Modality Performed Procedure Step Object is no longer available the Request Primitive will be answered with a Failure Status message "No Such Object Instance".

### F.8.2 Operations

The Application Entity that claims conformance to this SOP Class as an SCU shall be permitted to invoke the following operations and the Application Entity that claims conformance as an SCP shall be capable of providing the following operations.

#### F.8.2.1 Get Performed Procedure Step Information

This operation allows an SCU to get information about a specific real-world Performed Procedure Step that is represented as a Modality Performed Procedure Step Retrieve SOP Instance by a Modality Performed Procedure Step Retrieve SCP. The operation is performed on a Modality Performed Procedure Step IOD. This operation shall be invoked through the DIMSE N-GET Service used in conjunction with the appropriate Modality Performed Procedure Step Retrieve SOP Instance.

The same SOP Instance UID is shared by all three Modality Performed Procedure Step SOP Classes. This means that the SOP Instance created and set using the services of the Modality Performed Procedure Step SOP Class can be retrieved using its SOP Instance UID within the service of the Modality Performed Procedure Step Retrieve SOP Class. Changes in its state can be notified by using its SOP Instance UID within the service of the Modality Performed Procedure Step Notification SOP Class. The SOP Class UID specified in the DIMSE N-GET request primitive shall be the UID of the Modality Performed Procedure Step Retrieve SOP Class.

The Modality Performed Procedure Retrieve Step SOP Instance UID shall not be used to identify a SOP Instance of the Study Component Service Class.

### Note

An Application Entity may support the SCU role of the Modality Performed Procedure Step Retrieve SOP Class in order to obtain information about Performed Procedure Steps created by other Application Entities.

##### F.8.2.1.1 Modality Performed Procedure Step Retrieve IOD Subset Specifications

The Application Entity that claims conformance to this SOP Class as an SCU may choose to interpret the Attribute values maintained by the SCP that the SCU receives via the operation of this SOP Class. The Application Entity that claims conformance as an SCP to this Modality Performed Procedure Step Retrieve SOP Class shall support the subset of the Modality Performed Procedure Step Retrieve Attributes specified in Table F.8.2-1.

Table F.8.2-1. Modality Performed Procedure Step Retrieve SOP Class N-GET Attributes

Attribute Name | Tag | Requirement Type (SCU/SCP)
--- | --- | ---
Specific Character Set | (0008,0005) | 3/1C (Required if an extended or replacement character set is used)
Performed Procedure Step Relationship
Scheduled Step Attributes Sequence | (0040,0270) | 3/1
>Study Instance UID | (0020,000D) | -/1
>Referenced Study Sequence | (0008,1110) | -/2
>>Referenced SOP Class UID | (0008,1150) | -/1
>>Referenced SOP Instance UID | (0008,1155) | -/1
>Accession Number | (0008,0050) | -/2
>Issuer of Accession Number Sequence | (0008,0051) | -/3
>>Local Namespace Entity ID | (0040,0031) | -/3
>>Universal Entity ID | (0040,0032) | -/3
>>Universal Entity ID Type | (0040,0033) | -/3
>Placer Order Number/Imaging Service Request | (0040,2016) | -/3
>Order Placer Identifier Sequence | (0040,0026) | -/3
>>Local Namespace Entity ID | (0040,0031) | -/3
>>Universal Entity ID | (0040,0032) | -/3
>>Universal Entity ID Type | (0040,0033) | -/3
>Filler Order Number/Imaging Service Request | (0040,2017) | -/3
>Order Filler Identifier Sequence | (0040,0027) | -/3
>>Local Namespace Entity ID | (0040,0031) | -/3
>>Universal Entity ID | (0040,0032) | -/3
>>Universal Entity ID Type | (0040,0033) | -/3
>Requested Procedure Code Sequence | (0032,1064) | -/3
>>Code Value | (0008,0100) | -/1
>>Coding Scheme Designator | (0008,0102) | -/1
>>Code Meaning | (0008,0104) | -/1
>Requested Procedure Description | (0032,1060) | -/2
>Requested Procedure ID | (0040,1001) | -/2
>Scheduled Procedure Step ID | (0040,0009) | -/2
>Scheduled Procedure Step Description | (0040,0007) | -/2
>Scheduled Protocol Code Sequence | (0040,0008) | -/2
>>Code Value | (0008,0100) | -/1
>>Coding Scheme Designator | (0008,0102) | -/1
>>Coding Scheme Version | (0008,0103) | -/3
>>Code Meaning | (0008,0104) | -/3
>>All other Attributes from Scheduled Protocol Code Sequence |  | -/3
Patient's Name | (0010,0010) | 3/2
Patient ID | (0010,0020) | 3/2
Issuer of Patient ID | (0010,0021) | 3/3
Issuer of Patient ID Qualifiers Sequence | (0010,0024) | 3/3
>Universal Entity ID | (0040,0032) | 3/3
>Universal Entity ID Type | (0040,0033) | 1C/1C Required if Universal Entity ID (0040,0032) is present.
>All other Attributes of Issuer of Patient ID Qualifiers Sequence |  | 3/3
Patient's Birth Date | (0010,0032) | 3/2
Patient's Sex | (0010,0040) | 3/2
Referenced Patient Sequence | (0008,1120) | 3/2
>Referenced SOP Class UID | (0008,1150) | -/1
>Referenced Instance UID | (0008,1155) | -/1
Admission ID | (0038,0010) | 3/3
Issuer of Admission ID Sequence | (0038,0014) | 3/3
>Local Namespace Entity ID | (0040,0031) | -/3
>Universal Entity ID | (0040,0032) | -/3
>Universal Entity ID Type | (0040,0033) | -/3
Service Episode ID | (0038,0060) | 3/3
Issuer of Service Episode ID Sequence | (0038,0064) | 3/3
>Local Namespace Entity ID | (0040,0031) | -/3
>Universal Entity ID | (0040,0032) | -/3
>Universal Entity ID Type | (0040,0033) | -/3
Service Episode Description | (0038,0062) | 3/3
Performed Procedure Step Information
Performed Station AE Title | (0040,0241) | 3/1
Performed Station Name | (0040,0242) | 3/2
Performed Location | (0040,0243) | 3/2
Performed Procedure Step Start Date | (0040,0244) | 3/1
Performed Procedure Step Start Time | (0040,0245) | 3/1
Performed Procedure Step ID | (0040,0253) | 3/1
Performed Procedure Step Status | (0040,0252) | 3/1
Performed Procedure Step End Date | (0040,0250) | 3/2
Performed Procedure Step End Time | (0040,0251) | 3/2
Performed Procedure Step Description | (0040,0254) | 3/2
Performed Procedure Type Description | (0040,0255) | 3/2
Procedure Code Sequence | (0008,1032) | 3/2
>Code Value | (0008,0100) | -/1
>Coding Scheme Designator | (0008,0102) | -/1
>Coding Scheme Version | (0008,0103) | -/3
>Code Meaning | (0008,0104) | -/3
Comments on the Performed Procedure Step | (0040,0280) | 3/3
Performed Procedure Step Discontinuation Reason Code Sequence | (0040,0281) | 3/2
>Code Value | (0008,0100) | -/1
>Coding Scheme Designator | (0008,0102) | -/1
>Coding Scheme Version | (0008,0103) | -/3
>Code Meaning | (0008,0104) | -/3
Image Acquisition Results
Performed Series Sequence | (0040,0340) | 3/2
>Performing Physician's Name | (0008,1050) | -/2
>Protocol Name | (0018,1030) | -/1
>Operators' Name | (0008,1070) | -/2
>Series Instance UID | (0020,000E) | -/1
>Series Description | (0008,103E) | -/2
>Retrieve AE Title | (0008,0054) | -/2
>Referenced Image Sequence | (0008,1140) | -/2
>>Referenced SOP Class UID | (0008,1150) | -/1
>>Referenced SOP Instance UID | (0008,1155) | -/1
>Referenced Non-Image Composite SOP Instance Sequence | (0040,0220) | -/2
>>Referenced SOP Class UID | (0008,1150) | -/1
>>Referenced SOP Instance UID | (0008,1155) | -/1
>All other Attributes from Performed Series Sequence |  | -/3
Modality | (0008,0060) | 3/1
Study ID | (0020,0010) | 3/2
Performed Protocol Code Sequence | (0040,0260) | 3/2
>Code Value | (0008,0100) | -/1
>Coding Scheme Designator | (0008,0102) | -/1
>Coding Scheme Version | (0008,0103) | -/3
>Code Meaning | (0008,0104) | -/3
>All other Attributes from Performed Protocol Code Sequence |  | -/3
All other Attributes from Radiation Dose Module and Billing and Material Code Module |  | 3/3

### Note

1. Attributes (0040,1006) Placer Order Number/Procedure and (0040,1007) Filler Order Number/Procedure were previously defined in DICOM. They are now retired (see PS3.3-1998).

2. Attributes (0040,2006) and (0040,2007) were previously defined in DICOM. They are now retired (see PS3.3-1998).

##### F.8.2.1.2 Service Class User

The SCU uses the N-GET Service Element to request the SCP to get a Modality Performed Procedure Step Retrieve SOP Instance. The SCU shall specify in the N-GET request primitive the UID of the SOP Instance to be retrieved, which is a UID of a Modality Performed Procedure Step SOP Instance. The SCU shall be permitted to request that Attribute Values be returned for any Modality Performed Procedure Step Retrieve SOP Class Attribute specified in Table F.8.2-1. Additionally values may be requested for optional Modality Performed Procedure Step IOD Attributes.

The SCU shall specify the list of Modality Performed Procedure Step Retrieve SOP Class Attributes for which values are to be returned. The encoding rules for Modality Performed Procedure Step Attributes are specified in the N-GET request primitive specification in PS3.7.

In an N-GET operation, the values of Attributes that are defined within a Sequence of Items shall not be requested by an SCU.

The SCU shall be capable of receiving all requested Attribute Values provided by the SCP in response to the N-GET indication primitive. The SCU may request Attribute Values for optional Attributes that are not maintained by the SCP. In such a case, the SCU shall function properly regardless of whether the SCP returns values for those Attributes or not. This Service Class Specification places no requirements on what the SCU shall do as a result of receiving this information.

### Note

In order to accurately interpret the character set used for the Attribute Values returned, it is recommended that the Attribute Value for the Specific Character Set (0008,0005) be requested in the N-GET request primitive.

##### F.8.2.1.3 Service Class Provider

The N-GET operation allows the SCU to request from the SCP selected Attribute values for a specific Modality Performed Procedure Step SOP Instance via a Modality Performed Procedure Step Retrieve SOP Instance. This operation shall be invoked through the use of the DIMSE N-GET Service used in conjunction with the appropriate Modality Performed Procedure Step Retrieve SOP Instance that equals the Modality Performed Procedure SOP Instance. The SCP shall retrieve the selected Attribute values from the indicated Modality Performed Procedure Step SOP Instance.

The SCP shall return, via the N-GET response primitive, the N-GET Response Status Code applicable to the associated request. A Failure Code shall indicate that the SCP has not retrieved the SOP Instance. Contingent on the N-GET Response Status, the SCP shall return, via the N-GET response primitive, Attribute Values for all requested Attributes maintained by the SCP.

##### F.8.2.1.4 Status Codes

The status values that are specific for this SOP Class and DIMSE Service are defined in Table F.8.2-2. See PS3.7 for additional response status codes.

Table F.8.2-2. Response Status

Service Status | Further Meaning | Response Status Code
--- | --- | ---
Warning | Requested optional Attributes are not supported | 0001

### F.8.3 Modality Performed Procedure Step Retrieve SOP Class UID

The Modality Performed Procedure Step Retrieve SOP Class shall be uniquely identified by the Modality Performed Procedure Step Retrieve SOP Class UID that shall have the value "1.2.840.10008.3.1.2.3.4".

### F.8.4 Conformance Requirements

Implementations providing conformance to the Modality Performed Procedure Step Retrieve SOP Class shall be conformant as described in the following sections and shall include within their Conformance Statement information as described below.

An implementation may conform to this SOP Class as an SCU or as an SCP. The Conformance Statement shall be in the format defined in Annex A “DICOM Conformance Statement Template (Normative)”.

#### F.8.4.1 SCU Conformance

An implementation that is conformant to this SOP Class as an SCU shall meet conformance requirements for the operations that it invokes.

##### F.8.4.1.1 Operations

Any Attributes for which Attribute Values may be requested (using the N-GET Service) by the SCU shall be enumerated in the SCU Operations Statement. The SCU Operations Statement shall be formatted as defined in Annex A “DICOM Conformance Statement Template (Normative)”.

#### F.8.4.2 SCP Conformance

An implementation that is conformant to this SOP Class as an SCP shall meet conformance requirements for the operations that it performs.

##### F.8.4.2.1 Operations

Any Attributes for which Attribute Values may be requested (using the N-GET Service) by the SCU shall be enumerated in the SCP Operations Statement. The SCP Operations Statement shall be formatted as defined in Annex A “DICOM Conformance Statement Template (Normative)”.

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