F.7.2 Operations

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

F.7.2.1 CREATE Modality Performed Procedure Step SOP Instance

This operation allows an SCU to create an instance of the Modality Performed Procedure Step SOP Class and provide information about a specific real-world Performed Procedure Step that is under control of the SCU. This operation shall be invoked through the DIMSE N-CREATE Service.

Note : The modality should inform the Information System as soon as possible that the performance of the Procedure Step has been started by sending the N-CREATE Service Request. This allows an SCP of the Modality Worklist SOP Class (if supported) to update the Modality Worklist. Some of the attribute values are already known at the beginning of the Procedure Step, they are required to be sent in the N-CREATE command. Other mandatory attributes are known only at the end of the Performed Procedure Step, they are assigned a value in the N-SET command.

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-CREATE and N-SET request primitives shall be the UID of the Modality Performed Procedure Step SOP Class.

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

F.7.2.1.1 Modality Performed Procedure Step Subset Specification

The Application Entity which claims conformance to this SOP Class as an SCU must provide all Required Attributes as specified in Table F.7.2-1. Optional Attributes maintained by the SCP may be provided as well. The Application Entity which claims conformance as an SCP to this SOP Class shall support the subset of the Modality Performed Procedure Step Attributes specified in Table F.7.2-1.

Table F.7.2-1 MODALITY PERFORMED PROCEDURE STEP SOP CLASS N-CREATE, N-SET AND FINAL STATE ATTRIBUTES

Attribute Name Tag Req. Type N-CREATE (SCU/SCP) Req. Type N-SET (SCU/SCP) Requirement Type Final State (See Note 1)
Specific Character Set (0008,0005) 1C/1C (Required if an extended or replacement character set is used) Not allowed
Performed Procedure Step Relationship
Scheduled Step Attribute Sequence (0040,0270) 1/1 Not allowed
>Study Instance UID (0020,000D) 1/1 Not allowed
>Referenced Study Sequence (0008,1110) 2/2 Not allowed
>>Referenced SOP Class UID (0008,1150) 1/1 Not allowed
>>Referenced SOP Instance UID (0008,1155) 1/1 Not allowed
>Accession Number (0008,0050) 2/2 Not allowed
>Issuer of Accession Number Sequence (0008,0051) 3/3 Not allowed
>>Local Namespace Entity ID (0040,0031) 1C/1C Required if Universal Entity ID (0040,0032) is not present; may be present otherwise Not allowed
>>Universal Entity ID (0040,0032) 1C/1C Required if Local Namespace Entity ID (0040,0031) is not present; may be present otherwise. Not allowed
>>Universal Entity ID Type (0040,0033) 1C/1C Required if Universal Entity ID (0040,0032) is present. Not allowed
>Placer Order Number/Imaging Service Request (0040,2016) 3/3 Not allowed
>Order Placer Identifier Sequence (0040,0026) 3/3 Not allowed
>>Local Namespace Entity ID (0040,0031) 1C/1C Required if Universal Entity ID (0040,0032) is not present; may be present otherwise Not allowed
>>Universal Entity ID (0040,0032) 1C/1C Required if Local Namespace Entity ID (0040,0031) is not present; may be present otherwise.. Not allowed
>>Universal Entity ID Type (0040,0033) 1C/1C Required if Universal Entity ID (0040,0032) is present. Not allowed
>Filler Order Number/Imaging Service Request (0040,2017) 3/3 Not allowed
>Order Filler Identifier Sequence (0040,0027) 3/3 Not allowed
>>Local Namespace Entity ID (0040,0031) 1C/1C Required if Universal Entity ID (0040,0032) is not present; may be present otherwise Not allowed
>>Universal Entity ID (0040,0032) 1C/1C Required if Local Namespace Entity ID (0040,0031) is not present; may be present otherwise.. Not allowed
>>Universal Entity ID Type (0040,0033) 1C/1C Required if Universal Entity ID (0040,0032) is present. Not allowed
>Requested Procedure ID (0040,1001) 2/2 Not allowed
>Requested Procedure Code Sequence (0032,1064) 3/3 Not allowed
>>Code Value (0008,0100) 1/1 Not allowed
>>Coding Scheme Designator (0008,0102) 1/1 Not allowed
>>Code Meaning (0008,0104) 1/1 Not allowed
>Requested Procedure Description (0032,1060) 2/2 Not allowed
>Scheduled Procedure Step ID (0040,0009) 2/2 Not allowed
>Scheduled Procedure Step Description (0040,0007) 2/2 Not allowed
>Scheduled Protocol Code Sequence (0040,0008) 2/2 Not allowed
>>Code Value (0008,0100) 1/1 Not allowed
>>Coding Scheme designator (0008,0102) 1/1 Not allowed
>>Coding Scheme Version (0008,0103) 3/3 Not allowed
>>Code Meaning (0008,0104) 3/3 Not allowed
>>All other Attributes from Scheduled Protocol Code Sequence 3/3 Not allowed
Patient’s Name (0010,0010) 2/2 Not allowed
Patient ID (0010,0020) 2/2 Not allowed
Issuer of Patient ID (0010,0021) 3/3 Not allowed
Issuer of Patient ID Qualifiers Sequence (0010,0024) 3/3 Not allowed
>Universal Entity ID (0040,0032) 3/3 Not allowed
>Universal Entity ID Type (0040,0033) 1C/1C Required if Universal Entity ID (0040,0032) is present. Not allowed
>All other attributes of Issuer of Patient ID Qualifiers Sequence 3/3 Not allowed
Patient’s Birth Date (0010,0030) 2/2 Not allowed
Patient’s Sex (0010,0040) 2/2 Not allowed
Referenced Patient Sequence (0008,1120) 2/2 Not allowed
>Referenced SOP Class UID (0008,1150) 1/1 Not allowed
>Referenced Instance UID (0008,1155) 1/1 Not allowed
Admission ID (0038,0010) 3/3 Not Allowed
Issuer of Admission ID Sequence (0038,0014) 3/3 Not allowed
>Local Namespace Entity ID (0040,0031) 1C/1C Required if Universal Entity ID (0040,0032) is not present; may be present otherwise Not allowed
>Universal Entity ID (0040,0032) 1C/1C Required if Local Namespace Entity ID (0040,0031) is not present; may be present otherwise.. Not allowed
>Universal Entity ID Type (0040,0033) 1C/1C Required if Universal Entity ID (0040,0032) is present. Not allowed
Service Episode ID (0038,0060) 3/3 Not allowed
Issuer of Service Episode ID Sequence (0038,0064) 3/3 Not allowed
>Local Namespace Entity ID (0040,0031) 1C/1C Required if Universal Entity ID (0040,0032) is not present; may be present otherwise Not allowed
>Universal Entity ID (0040,0032) 1C/1C Required if Local Namespace Entity ID (0040,0031) is not present; may be present otherwise.. Not allowed
>Universal Entity ID Type (0040,0033) 1C/1C Required if Universal Entity ID (0040,0032) is present. Not allowed
Service Episode Description (0038,0062) 3/3 Not allowed
Performed Procedure Step Information
Performed Procedure Step ID (0040,0253) 1/1 Not allowed
Performed Station AE Title (0040,0241) 1/1 Not allowed
Performed Station Name (0040,0242) 2/2 Not allowed
Performed Location (0040,0243) 2/2 Not allowed
Performed Procedure Step Start Date (0040,0244) 1/1 Not allowed
Performed Procedure Step Start Time (0040,0245) 1/1 Not allowed
Performed Procedure Step Status (0040,0252) 1/1 3/1
Performed Procedure Step Description (0040,0254) 2/2 3/2
Performed Procedure Type Description (0040,0255) 2/2 3/2
Procedure Code Sequence (0008,1032) 2/2 3/2
>Code Value (0008,0100) 1/1 1/1
>Coding Scheme Designator (0008,0102) 1/1 1/1
>Coding Scheme Version (0008,0103) 3/3 3/3
>Code Meaning (0008,0104) 3/3 3/3
Reason For Performed Procedure Code Sequence (0040,1012) 3/3 3/3
>Code Value (0008,0100) 1/1 1/1
>Coding Scheme Designator (0008,0102) 1/1 1/1
>Coding Scheme Version (0008,0103) 3/3 3/3
>Code Meaning (0008,0104) 1/1 1/1
Performed Procedure Step End Date (0040,0250) 2/2 3/1 1
Performed Procedure Step End Time (0040,0251) 2/2 3/1 1
Comments on the Performed Procedure Step (0040,0280) 3/3 3/3
Performed Procedure Step Discontinuation Reason Code Sequence (0040,0281) 3/3 3/3
>Code Value (0008,0100) 1/1 1/1
>Coding Scheme Designator (0008,0102) 1/1 1/1
>Coding Scheme Version (0008,0103) 3/3 3/3
>Code Meaning (0008,0104) 3/3 3/3
Image Acquisition Results
Modality (0008,0060) 1/1 Not allowed
Study ID (0020,0010) 2/2 Not allowed
Performed Protocol Code Sequence (0040,0260) 2/2 3/2
>Code Value (0008,0100) 1/1 1/1
>Coding Scheme Designator (0008,0102) 1/1 1/1
>Coding Scheme Version (0008,0103) 3/3 3/3
>Code Meaning (0008,0104) 3/3 3/3
>All other Attributes from Performed Protocol Code Sequence 3/3 Not allowed
Performed Series Sequence (0040,0340) 2/2 3/1 1 (See note 2)
>Performing Physician’s Name (0008,1050) 2/2 2/2 2
>Protocol Name (0018,1030) 1/1 1/1 1
>Operators’ Name (0008,1070) 2/2 2/2 2
>Series Instance UID (0020,000E) 1/1 1/1 1
>Series Description (0008,103E) 2/2 2/2 2
>Retrieve AE Title (0008,0054) 2/2 2/2 2
>Archive Requested (0040,A494) 3/3 3/3
>Referenced Image Sequence (0008,1140) 2/2 2/2 See F.7.2.2.2.
>>Referenced SOP Class UID (0008,1150) 1/1 1/1
>>Referenced SOP Instance UID (0008,1155) 1/1 1/1
>>Container Identifier (0040,0512) 3/3 3/3
>>Specimen Description Sequence (0040,0560) 3/3 3/3
>>>Specimen Identifier (0040,0551) 1/1 1/1
>>>Specimen UID (0040,0554) 1/1 1/1
>Referenced Non-Image Composite SOP Instance Sequence (0040,0220) 2/2 2/2 See F.7.2.2.2.
>>Referenced SOP Class UID (0008,1150) 1/1 1/1
>>Referenced SOP Instance UID (0008,1155) 1/1 1/1
>All other attributes from Performed Series Sequence 3/3 3/3
All other attributes from Radiation Dose Module and Billing and Material Code Module 3/3 3/3

Notes: 1. The requirement for the final state is that which applies at the time that the Performed Procedure Step Status (0040,0252) is N-SET to a value of COMPLETED or DISCONTINUED, as described in F.7.2.2.2. It is only described if it is different from the SCP requirement for the N-CREATE.

2. The Performed Series Sequence (0040,0340) may not be empty (zero length) at the time that the Performed Procedure Step Status (0040,0252) is N-SET to a value of COMPLETED or DISCONTINUED. In other words a Series must exist for every Performed Procedure Step, though it may contain no Images or Non-Image Composite objects, if none were created, as described in F.7.2.2.2.

3. 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).

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

5. Only attributes that are specified in a SOP Instance at N-CREATE may later be updated through the N-SET. If an SCU wishes to use the PPS Discontinuation Reason Code Sequence (0040,0281), it must create that attribute (zero-length) during MPPS N-CREATE.

F.7.2.1.2 Service Class User

The SCU shall specify in the N-CREATE request primitive the Class and Instance UIDs of the Modality Performed Procedure Step SOP Instance which is created and for which Attribute Values are to be provided.

Note: This requirement facilitates the inclusion of relevant Attributes in the Composite SOP Instances generated during the Performed Procedure Step.

The SCU shall provide Attribute values for the Modality Performed Procedure Step SOP Class Attributes as specified in Table F.7.2-1. Additionally, values may be provided for optional Modality Performed Procedure Step IOD Attributes that are supported by the SCP. The encoding rules for Modality Performed Procedure Step Attributes are specified in the N-CREATE request primitive specification in PS 3.7.

The SCU shall be capable of providing all required Attribute values to the SCP in the N-CREATE request primitive. The SCU may provide Attribute values for optional Attributes which are not maintained by the SCP. In such case the SCU shall function properly regardless of whether the SCP accepts values for those Attributes or not.

All Attributes shall be created before they can be set. Sequence Attributes shall be created before they can be filled. Sequence Item Attributes shall not be created at zero length.

Note: Not all the attributes that can be created can be set afterwards (see Table F.7.2-1).

The SCU shall only send the N-CREATE request primitive with the value for the Attribute “Performed Procedure Step Status” (0040,0252) set to “IN PROGRESS”.

Notea: 1. It is assumed but not required that the SCU (the modality) received the Study Instance UID within the scope of the Basic Worklist Management SOP Class.

2. If the SCU has grouped multiple Requested Procedures into a single performed step the Study Instance UID (0020,000D) attribute within the Scheduled Step Attributes Sequence (0040,0270) may be the Study Instance UID (0020,000D) for the study that contains all images and non-image composite instances created during performance of the current step. This value may be generated by the SCU and may be the same for all items of the sequence. In addition, the Referenced Study Sequence (0008,1110) may contain the Study Instance UIDs from the Requested Procedures being grouped.

3. If the SCU does not have available Scheduled Procedure Step data applicable to the current step, the SCU may generate a value for the Study Instance UID (0020,000D) attribute within the Scheduled Step Attributes Sequence (0040,0270). This value of the Study Instance UID (0020,000D) may be stored in all mages and non-image composite SOP instances created during performance of this step. All other attributes within the Scheduled Step Attribute Sequence (0040,0270) may be set to zero length for 2/2 requirement types or absent for 3/3 requirement types (see Table F.7.2-1) .

F.7.2.1.3 Service Class Provider

The N-CREATE operation allows the SCU to provide to the SCP selected Attribute values for a specific Modality Performed Procedure Step SOP Instance. This operation shall be invoked through the use of the DIMSE N-CREATE Service used in conjunction with the appropriate Modality Performed Procedure Step SOP Instance.

The SCP shall return, via the N-CREATE response primitive, the N-CREATE Response Status Code applicable to the associated request.

The SCP shall accept N-CREATE request primitives only if the value of the attribute “Performed Procedure Step Status” (0040,0252) is “IN PROGRESS”. If the Performed Procedure Step Status attribute has another value, the SCP shall set the failure status code “Invalid attribute value” (Code: 0106H) with an Attribute List.

Note: The SCP may update the scheduling information on which the Modality Worklist is based, including the values of Study Date (0008,0020) and Study Time (0008,0030) using the earliest corresponding values of Performed Procedure Step Date (0040,0244) and Performed Procedure Step Time (0040,0245), in order to achieve consistency of Study level attributes when multiple procedure steps are performed on different devices.

F.7.2.1.4 Status Codes

There are no specific status codes. See PS 3.7 for response status codes.

F.7.2.2 SET Modality Performed Procedure Step Information

This operation allows an SCU to set Attribute Values of an instance of the Modality Performed Procedure Step SOP Class and provide information about a specific real-world Modality Performed Procedure Step that is under control of the SCU. This operation shall be invoked through the DIMSE N-SET Service.

F.7.2.2.1 Modality Performed Procedure Step IOD Subset Specification

The Application Entity which claims conformance to this SOP Class as an SCU may choose to modify a subset of the Attributes maintained by the SCP. The Application Entity which claims conformance as an SCP to this SOP Class shall support the subset of the Modality Performed Procedure Step Attributes specified in Table F.7.2-1.

The character set used for Attribute Values updated using the N-SET shall be the same as that specified by the N-CREATE Request Primitive.

F.7.2.2.2 Service Class User

The SCU shall specify in the N-SET request primitive the UID of the Modality Performed Procedure Step SOP Instance for which it wants to set Attribute Values.

The SCU shall be permitted to set Attribute values for any Modality Performed Procedure Step SOP Class Attribute specified in Table F.7.2-1. The SCU shall specify the list of Modality Performed Procedure Step SOP Class Attributes for which it wants to set the Attribute Values. The SCU shall provide, with one or more N-SET request primitives, the attribute values specified in Table F.7.2-1. The encoding rules for Modality Performed Procedure Step Attributes are specified in the N-SET request primitive specification in PS 3.7. The SCU shall only set Attribute Values which are already created with an N-CREATE request.

The SCU shall not send N-SET request primitives for a Modality Performed Procedure Step SOP Instance after a N-SET request primitive with a value for the attribute “Performed Procedure Step Status” (0040,0252) is “COMPLETED” or “DISCONTINUED” has been sent.

If Sequences are included in a N-SET command, all Items of a Sequence are to be included in the command and not only the Items to be updated.

Once the Modality Performed Procedure Step Status (0040,0252) has been set to “COMPLETED” or “DISCONTINUED” the SCU shall no longer modify the Modality Performed Procedure Step SOP Instance, and shall not create new Composite SOP Instances as part of the same Modality Performed Procedure Step SOP Instance.

Note: A Modality that wishes to continue or resume creating Composite SOP Instances may create a new Modality Performed Procedure Step.

Before or when Modality Performed Procedure Step Status (0040,0252) is set to “COMPLETED” or “DISCONTINUED” the SCU shall have created or set all the Attributes according to the requirements in the Final State column of Table F.7.2-1.

Before or when Modality Performed Procedure Step Status (0040,0252) is set to “COMPLETED” or “DISCONTINUED” the SCU shall have sent to the SCP a list of all Image SOP Instances and all Non-Image Composite SOP Instances created during the Procedure Step in Referenced Image Sequence (0008,1140) and Referenced Non-Image Composite SOP Instance Sequence (0040,0220) respectively.

Notes: 1. The intent is that a completed or discontinued Modality Performed Procedure Step entity will contain a complete list of all the Images and Non-Image Composite SOP Instances that were created.

2. The distinction between the list of images and non-images is present for historic reasons only, and has no semantic significance.

The Modality Performed Procedure Step Status (0040,0252) shall not be set to “COMPLETED” or “DISCONTINUED” if the list contains neither Image references nor Non-Image Composite SOP Instance references, unless no such Instances were created.

F.7.2.2.3 Service Class Provider

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

The SCP shall return, via the N-SET response primitive, the N-SET Response Status Code applicable to the associated request. Contingent on the N-SET Response Status, the SCP shall update the Referenced Performed Procedure Step Attributes.

The SCP shall accept N-SET request primitives only if the value of the already existing attribute “Performed Procedure Step Status” (0040,0252) is “IN PROGRESS”. If the already existing Performed Procedure Step Status attribute has another value, the SCP shall set the failure status code “Processing failure” (Code: 0110H) with a Specific Error Comment (see Section F.7.2.2.4).

The SCP may itself modify any Attributes of the Modality Performed Procedure Step SOP Instance only after the “Performed Procedure Step Status” (0040,0252) has been set to “COMPLETED” or “DISCONTINUED”.

Notes: 1. Such coercion of Attributes by the SCP may be necessary to correct, for example, patient identification information or incorrectly selected scheduling information. Such an operation is not permitted to the SCU by the requirements described in Table F.7.2-1, which might create a new Modality Performed Procedure Step SOP Instance to achieve the same objective.

2. Under exceptional circumstances, it may be necessary for the SCP to itself set the Performed Procedure Step Status (0040,0252) to COMPLETED or DISCONTINUED, for example if the Modality has failed. When the Modality recovers, subsequent N-SETs may fail.

F.7.2.2.4 Status Codes

The specific error comment which may be returned as a status code in a N-SET-RSP is defined in Table F.7.2-2. See PS 3.7 for additional response status codes.

Table F.7.2-2

N-SET STATUS

Service Status Further Meaning Status Code Error Comment (0000,0902) Error ID (0000,0903)
Failure Processing Failure 0110H Performed Procedure Step Object may no longer be updated A710