B.4.2.2.3 Association Initiation Policy
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##### B.4.2.2.3 Association Initiation Policy

###### B.4.2.2.3.1 Activity - Worklist Update

###### B.4.2.2.3.1.1 Description and Sequencing of Activities

The request for a Worklist Update is initiated by user interaction, i.e., pressing the buttons "Worklist Update"/"Patient Worklist Query" or automatically at specific time intervals, configurable by the user. With "Worklist Update" the automated query mechanism is performed immediately on request, while with "Patient Worklist Query" a dialog to enter search criteria is opened and an interactive query can be performed.

The interactive Patient Worklist Query will display a dialog for entering data as search criteria. When the Query is started on user request, only the data from the dialog will be inserted as matching keys into the query.

With automated worklist queries (including "Worklist Update") the EXAMPLE-INTEGRATED-MODALITY always requests all items for a Scheduled Procedure Step Start Date (actual date), Modality (RF) and Scheduled Station AE Title. Query for the Scheduled Station AE Title is configurable by a Service Engineer.

Upon initiation of the request, the EXAMPLE-INTEGRATED-MODALITY will build an Identifier for the C-FIND request, will initiate an Association to send the request and will wait for Worklist responses. After retrieval of all responses, EXAMPLE-INTEGRATED-MODALITY will access the local database to add or update patient demographic data. To protect the system from overflow, the EXAMPLE-INTEGRATED-MODALITY will limit the number of processed worklist responses to a configurable maximum. During receiving the worklist response items are counted and the query processing is canceled by issuing a C-FIND-CANCEL if the configurable limit of items is reached. The results will be displayed in a separate list, which will be cleared with the next worklist update.

EXAMPLE-INTEGRATED-MODALITY will initiate an Association in order to issue a C-FIND request according to the Modality Worklist Information Model.

Figure B.4.2-3. Sequencing of Activity - Worklist Update

A possible sequence of interactions between the Workflow AE and a Departmental Scheduler (e.g., a device such as a RIS or HIS that supports the Modality Worklist SOP Class as an SCP) is illustrated in the Figure above:

1. The Worklist AE opens an association with the Departmental Scheduler

2. The Worklist AE sends a C-FIND request to the Departmental Scheduler containing the Worklist Query attributes.

3. The Departmental Scheduler returns a C-FIND response containing the requested attributes of the first matching Worklist Item.

4. The Departmental Scheduler returns another C-FIND response containing the requested attributes of the second matching Worklist Item.

5. The Departmental Scheduler returns another C-FIND response with status Success indicating that no further matching Worklist Items exist. This example assumes that only 2 Worklist items match the Worklist Query.

6. The Worklist AE closes the association with the Departmental Scheduler.

7. The user selects a Worklist Item from the Worklist and prepares to acquire new images.

###### B.4.2.2.3.1.2 Proposed Presentation Contexts

EXAMPLE-INTEGRATED-MODALITY will propose Presentation Contexts as shown in the following table:

Table B.4.2-21. Proposed Presentation Contexts for Activity Worklist Update

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name List | UID List
Modality Worklist Information Model - FIND | 1.2.840.10008.5.1.4.31 | Implicit VR Little Endian | 1.2.840.10008.1.2 | SCU | None
Explicit VR Little Endian | 1.2.840.10008.1.2.1

###### B.4.2.2.3.1.3 SOP Specific Conformance for Modality Worklist

The behavior of EXAMPLE-INTEGRATED-MODALITY when encountering status codes in a Modality Worklist C-FIND response is summarized in the Table below. If any other SCP response status than "Success" or "Pending" is received by EXAMPLEINTEGRATED-MODALITY, a message "query failed" will appear on the user interface.

Table B.4.2-22. Modality Worklist C-FIND Response Status Handling Behavior

Service Status | Further Meaning | Error Code | Behavior
--- | --- | --- | ---
Success | Matching is complete | 0000 | The SCP has completed the matches. Worklist items are available for display or further processing.
Refused | Out of Resources | A700 | The Association is aborted using A-ABORT and the worklist query is marked as failed. The status meaning is logged and reported to the user if an interactive query. Any additional error information in the Response will be logged.
Failed | Identifier does not match SOP Class | A900 | The Association is aborted using A-ABORT and the worklist query is marked as failed. The status meaning is logged and reported to the user if an interactive query. Any additional error information in the Response will be logged.
Failed | Unable to Process | C000 - CFFF | The Association is aborted using A-ABORT and the worklist query is marked as failed. The status meaning is logged and reported to the user if an interactive query. Any additional error information in the Response will be logged.
Cancel | Matching terminated due to Cancel request | FE00 | If the query was canceled due to too may worklist items then the SCP has completed the matches. Worklist items are available for display or further processing. Otherwise, the Association is aborted using A-ABORT and the worklist query is marked as failed. The status meaning is logged and reported to the user if an interactive query.
Pending | Matches are continuing | FF00 | The worklist item contained in the Identifier is collected for later display or further processing.
Pending | Matches are continuing - Warning that one or more Optional Keys were not supported | FF01 | The worklist item contained in the Identifier is collected for later display or further processing. The status meaning is logged only once for each C-FIND operation.
* | * | Any other status code. | The Association is aborted using A-ABORT and the worklist is marked as failed. The status meaning is logged and reported to the user if an interactive query. Any additional error information in the Response will be logged.

The behavior of EXAMPLE-INTEGRATED-MODALITY during communication failure is summarized in the Table below.

Table B.4.2-23. Modality Worklist Communication Failure Behavior

Exception | Behavior
--- | ---
Timeout | The Association is aborted using A-ABORT and the worklist query marked as failed. The reason is logged and reported to the user if an interactive query.
Association aborted by the SCP or network layers | The worklist query is marked as failed. The reason is logged and reported to the user if an interactive query.

Acquired images will always use the Study Instance UID specified for the Scheduled Procedure Step (if available). If an acquisition is unscheduled, a Study Instance UID will be generated locally.

The Table below provides a description of the EXAMPLEINTEGRATED-MODALITY Worklist Request Identifier and specifies the attributes that are copied into the images. Unexpected attributes returned in a C-FIND response are ignored.

Requested return attributes not supported by the SCP are set to have no value. Non-matching responses returned by the SCP due to unsupported optional matching keys are ignored. No attempt is made it filter out possible duplicate entries.

Table B.4.2-24. Worklist Request Identifier

Module Name Attribute Name | Tag | VR | M | R | Q | D | IOD
--- | --- | --- | --- | --- | --- | --- | ---
SOP Common
Specific Character Set | (0008,0005) | CS |  | x |  |  |
Scheduled Procedure Step
Scheduled Procedure Step Sequence | (0040,0100) |  |  |  |  |  |
>Scheduled Station AET | (0040,0001) | AE | (S) |  |  | x |
>Scheduled Procedure Step Start Date | (0040,0002) | DA | S |  |  | x |
>Scheduled Procedure Step Start Time | (0040,0003) | TM |  | x |  | x |
>Modality | (0008,0060) | CS | S | x |  |  |
>Scheduled Performing Physician's Name | (0040,0006) | PN |  | x | x | x | x
>Scheduled Procedure Step Description | (0040,0007) | LO |  | x |  | x | x
>Scheduled Station Name | (0040,0010) | SH |  | x |  |  |
>Scheduled Procedure Step Location | (0040,0011) | SH |  | x |  |  |
>Scheduled Protocol Code Sequence | (0040,0008) | SQ |  | x |  |  | x
>Pre-Medication | (0040,0012) | LO |  | x |  | x |
>Scheduled Procedure Step ID | (0040,0009) | SH |  | x |  | x | x
>Requested Contrast Agent | (0032,1070) | LO |  | x |  | x |
Requested Procedure
Requested Procedure ID | (0040,1001) | SH |  | x | x | x | x
Requested Procedure Description | (0032,1060) | LO |  | x |  | x | x
Study Instance UID | (0020,000D) | UI |  | x |  |  | x
Requested Procedure Priority | (0040,1003) | SH |  | x |  |  |
Patient Transport Arrangements | (0040,1004) | LO |  | x |  |  |
Referenced Study Sequence | (0008,1110) | SQ |  | x |  |  | x
Requested Procedure Code Sequence | (0032,1064) | SQ |  | x |  |  | x
Imaging Service Request
Accession Number | (0008,0050) | SH |  | x | x | x | x
Requesting Physician | (0032,1032) | PN |  | x |  | x | x
Referring Physician's Name | (0008,0090) | PN |  | x | x | x | x
Visit Identification
Admission ID | (0038,0010) | LO |  | x |  |  |
Visit Status
Current Patient Location | (0038,0300) | LO |  | x | x |  |
Visit Admission
Admitting Diagnosis Description | (0008,1080) | LO |  | x |  | x |
Patient Identification
Patient Name | (0010,0010) | PN |  | x | x | x | x
Patient ID | (0010,0020) | LO |  | x | x | x | x
Patient Demographic
Patient's Birth Date | (0010,0030) | DA |  | x | x | x | x
Patient's Sex | (0010,0040) | CS |  | x | x | x | x
Patient's Weight | (0010,1030) | DS |  | x |  | x | x
Confidentiality constraint on patient data | (0040,3001) | LO |  | x |  | x |
Patient Medical
Patient State | (0038,0500) | LO |  | x |  | x |
Pregnancy Status | (0010,21C0) | US |  | x |  | x |
Medical Alerts | (0010,2000) | LO |  | x |  | x |
Allergies | (0010,2110) | LO |  | x |  | x |
Special Needs | (0038,0050) | LO |  | x |  | x |

The above table should be read as follows:

Module Name

  The name of the associated module for supported worklist attributes.

Attribute Name

  Attributes supported to build an EXAMPLEINTEGRATED-MODALITY Worklist Request Identifier.

Tag

  DICOM tag for this attribute.

VR

  DICOM VR for this attribute.

M

  Matching keys for (automatic) Worklist Update. A "S" will indicate that EXAMPLE-INTEGRATED-MODALITY will supply an attribute value for Single Value Matching, a "R" will indicate Range Matching and a "*" will denote wild card matching. It can be configured if "Scheduled Station AE Title" is additionally supplied "(S) " and if Modality is set to RF or SC.

R

  Return keys. An "x" will indicate that EXAMPLE-INTEGRATED-MODALITY will supply this attribute as Return Key with zero length for Universal Matching. The EXAMPLE-INTEGRATED-MODALITY will support retired date format (yyyy.mm.dd) for "Patient's Birth Date" and "Scheduled Procedure Step Start Date" in the response identifiers. For "Scheduled Procedure Step Start Time" also retired time format as well as unspecified time components are supported.

Q

  Interactive Query Key. An "x" " will indicate that EXAMPLE-INTEGRATED-MODALITY will supply this attribute as matching key, if entered in the Query Patient Worklist dialog. For example, the Patient Name can be entered thereby restricting Worklist responses to Procedure Steps scheduled for the patient.

D

  Displayed keys. An "x" indicates that this worklist attribute is displayed to the user during a patient registration dialog. For example, Patient Name will be displayed when registering the patient prior to an examination.

IOD

  An "x" indicates that this Worklist attribute is included into all Object Instances created during performance of the related Procedure Step.

The default Query Configuration is set to "Modality" (RF) and "Date" (date of today). Optionally, additional matching for the own AET is configurable.

###### B.4.2.2.3.2 Activity - Acquire Images

###### B.4.2.2.3.2.1 Description and Sequencing of Activities

After Patient registration, the EXAMPLE-INTEGRATED-MODALITY is awaiting the 1st application of X-Ray Dose to the patient. The trigger to create a MPPS SOP Instance is derived from this event. An Association to the configured MPPS SCP system is established immediately and the related MPPS SOP Instance will be created.

A manual update can be performed with the MPPS user interface where is it possible to set the final state of the MPPS to "COMPLETED" or "DISCONTINUED". In the "Discontinued" case the user can also select the discontinuation reason from a list corresponding to CID 9300 “Procedure Discontinuation Reasons”. A MPPS Instance that has been sent with a state of "COMPLETED" or "DISCONTINUED" can no longer be updated.

The EXAMPLE-INTEGRATED-MODALITY will support creation of "unscheduled cases" by allowing MPPS Instances to be communicated for locally registered Patients.

The EXAMPLE-INTEGRATED-MODALITY only supports a 0-to-1 relationship between Scheduled and Performed Procedure Steps.

EXAMPLE-INTEGRATED-MODALITY will initiate an Association to issue an:

- N-CREATE request according to the CREATE Modality Performed Procedure Step SOP Instance operation or a

- N-SET request to update the contents and state of the MPPS according to the SET Modality Performed Procedure Step Information operation.

Figure B.4.2-4. Sequencing of Activity - Acquire Images

A possible sequence of interactions between the Workflow AE and a Departmental Scheduler (e.g., a device such as a RIS or HIS that supports the MPPS SOP Class as an SCP) is illustrated in Figure B.4.2-4:

1. The Worklist AE opens an association with the Departmental Scheduler

2. The Worklist AE sends an N-CREATE request to the Departmental Scheduler to create an MPPS instance with status of "IN PROGRESS" and create all necessary attributes. The Departmental Scheduler acknowledges the MPPS creation with an N-CREATE response (status success).

3. The Worklist AE closes the association with the Departmental Scheduler.

4. All images are acquired and stored in the local database.

5. The Worklist AE opens an association with the Departmental Scheduler.

6. The Worklist AE sends an N-SET request to the Departmental Scheduler to update the MPPS instance with status of "COMPLETED" and set all necessary attributes. The Departmental Scheduler acknowledges the MPPS update with an N-SET response (status success).

7. The Worklist AE closes the association with the Departmental Scheduler.

###### B.4.2.2.3.2.2 Proposed Presentation Contexts

EXAMPLE-INTEGRATED-MODALITY will propose Presentation Contexts as shown in the following table:

Table B.4.2-25. Proposed Presentation Contexts for Real-World Activity Acquire Images

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name List | UID List
Modality Performed Procedure Step | 1.2.840.10008.3.1.2.3.3 | Implicit VR Little Endian | 1.2.840.10008.1.2 | SCU | None
Explicit VR Little Endian | 1.2.840.10008.1.2.1

###### B.4.2.2.3.2.3 SOP Specific Conformance for MPPS

The behavior of EXAMPLE-INTEGRATED-MODALITY when encountering status codes in an MPPS N-CREATE or N-SET response is summarized in Table B.4.2-26. If any other SCP response status than "Success" or "Warning" is received by EXAMPLEINTEGRATED-MODALITY, a message "MPPS update failed" will appear on the user interface.

Table B.4.2-26. MPPS N-CREATE / N-SET Response Status Handling Behavior

Service Status | Further Meaning | Error Code | Behavior
--- | --- | --- | ---
Success | Success | 0000 | The SCP has completed the operation successfully.
Failure | Processing Failure - Performed Procedure Step Object may no longer be updated | 0110 | The Association is aborted using A-ABORT and the MPPS is marked as failed. The status meaning is logged and reported to the user. Additional information in the Response will be logged (i.e., Error Comment and Error ID).
Warning | Attribute Value Out of Range | 0116H | The MPPS operation is considered successful but the status meaning is logged. Additional information in the Response identifying the attributes out of range will be logged (i.e., Elements in the Modification List/Attribute List)
* | * | Any other status code. | The Association is aborted using A-ABORT and the MPPS is marked as failed. The status meaning is logged and reported to the user.

The behavior of EXAMPLE-INTEGRATED-MODALITY during communication failure is summarized in the Table below:

Table B.4.2-27. MPPS Communication Failure Behavior

Exception | Behavior
--- | ---
Timeout | The Association is aborted using A-ABORT and MPPS marked as failed. The reason is logged and reported to the user.
Association aborted by the SCP or network layers | The MPPS is marked as failed. The reason is logged and reported to the user.

Table B.4.2-28 provides a description of the MPPS N-CREATE and N-SET request identifiers sent by EXAMPLE-INTEGRATED-MODALITY. Empty cells in the N-CREATE and N-SET columns indicate that the attribute is not sent. An "x" indicates that an appropriate value will be sent. A "Zero length" attribute will be sent with zero length.

Table B.4.2-28. MPPS N-CREATE / N-SET Request Identifier

Attribute Name | Tag | VR | N-CREATE | N-SET
--- | --- | --- | --- | ---
Specific Character Set | (0008,0005) | CS | "ISO_IR 100" or "ISO_IR 144" |
Modality | (0008,0060) | CS | RF |
Referenced Patient Sequence | (0008,1120) | SQ | Zero length |
Patient's Name | (0010,0010) | PN | From Modality Worklist or user input (all 5 components). The user can modify values provided via Modality Worklist. |
Patient ID | (0010,0020) | LO | From Modality Worklist or user input. The user can modify values provided via Modality Worklist. |
Patient's Birth Date | (0010,0030) | DA | From Modality Worklist or user input. The user can modify values provided via Modality Worklist. |
Patient's Sex | (0010,0040) | CS | From Modality Worklist or user input. The user can modify values provided via Modality Worklist. |
Distance Source to Detector (SID) | (0018,1110) | DS | Zero length | x
Image Area Dose Product | (0018,115E) | DS | Zero length | x
Study ID | (0020,0010) | SH | From Modality Worklist or user input. The user can modify values provided via Modality Worklist. |
Performed Station AE Title | (0040,0241) | AE | MPPS AE Title |
Performed Station Name | (0040,0242) | SH | From configuration |
Performed Location | (0040,0243) | SH | From configuration |
Performed Procedure Step Start Date | (0040,0244) | DA | Actual start date |
Performed Procedure Step Start Time | (0040,0245) | TM | Actual start time |
Performed Procedure Step End Date | (0040,0250) | DA | Zero length | Actual end date
Performed Procedure Step End Time | (0040,0251) | TM | Zero length | Actual end time
Performed Procedure Step Status | (0040,0252) | CS | IN PROGRESS | DISCONTINUED or COMPLETED
Performed Procedure Step Discontinuation Reason Code Sequence | (0040,0281) | SQ | Zero length | If Performed Procedure Step Status (0040,0252) is "DISCONTINUED" then a single item will be present containing a user-selected entry drawn from CID 9300 “Procedure Discontinuation Reasons”.
Performed Procedure Step ID | (0040,0253) | SH | Automatically created but can be modified by the user. |
Performed Procedure Step Description | (0040,0254) | LO | From Modality Worklist or user input. The user can modify the description provided via Modality Worklist. |
Performed Procedure Type Description | (0040,0255) | LO | Zero length |
Performed Protocol Code Sequence | (0040,0260) | SQ | Zero length | Zero or more items
Scheduled Step Attributes Sequence | (0040,0270) | SQ | If 1st dose applied results in an Instance |
> Accession Number | (0008,0050) | SH | From Modality Worklist or user input. The user can modify values provided via Modality Worklist. |
> Referenced Study Sequence | (0008,1110) | SQ | From Modality Worklist |
>> Referenced SOP Class UID | (0008,1150) | UI | From Modality Worklist |
>> Referenced SOP Instance UID | (0008,1155) | UI | From Modality Worklist |
> Study Instance UID | (0020,000D) | UI | From Modality Worklist |
> Requested Procedure Description | (0032,1060) | LO | From Modality Worklist |
> Scheduled Procedure Step Description | (0040,0007) | LO | From Modality Worklist |
> Scheduled Protocol Code Sequence | (0040,0008) | SQ | From Modality Worklist |
> Scheduled Procedure Step ID | (0040,0009) | SH | From Modality Worklist |
> Requested Procedure ID | (0040,1001) | SH | From Modality Worklist |
Performed Series Sequence | (0040,0340) | SQ | if 1st dose applied results in an instance | One or more items
> Retrieve AE Title | (0008,0054) | AE | x | x
> Series Description | (0008,103E) | LO | x | x
> Performing Physician's Name | (0008,1050) | PN | x | x
> Operator's Name | (0008,1070) | PN | x | x
> Referenced Image Sequence | (0008,1140) | SQ | One or more items | One or more items
>> Referenced SOP Class UID | (0008,1150) | UI | x | x
>> Referenced SOP Instance UID | (0008,1155) | UI | x | x
> Protocol Name | (0018,1030) | LO | x | x
> Series Instance UID | (0020,000E) | UI | x | x
> Referenced Standalone SOP Instance Seq. | (0040,0220) | SQ | Zero length (SOP classes not supported) | Zero length (SOP classes not supported)
Total Time of Fluoroscopy | (0040,0300) | US | Zero length | Total time
Total Number of Exposures | (0040,0301) | US | Zero length | Number of exposures
Entrance Dose | (0040,0302) | US | Zero length | Entrance dose
Exposed Area | (0040,0303) | US | Zero length | Exposed area
Film Consumption Sequence | (0040,0321) | SQ | Zero length | Zero or more items
> Medium Type | (2000,0030) | CS |  | x
> Film Size ID | (2010,0050) | CS |  | x
> Number of Films | (2100,0170) | IS |  | x

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