Kevin O

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Flexible Workflow usingUPSUnified Procedure
Step

• Kevin ODonnellToshiba Medical Systems

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UPS Goals

• Add Push Workflow Create Workitem
• Request another system to add item to worklist
• Simplify Implementation
• GPWL had NM relation of SPSPPS
• State diagram was very complex
• Add Cancel Request
• Improve Status/Result Monitoring
• Getting PPS feed was awkward required
  configuration and forwarding

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Interesting UPS Features

• Remote create
• Task Locking by performer
• Deletion Locking by watchers
• Subscription-based Monitoring
• Gift Subscriptions
• Push, Pull, and Watch Workflows
• Sub-contracting
• 1-to-1 relationship between SPS and PPS
• 4 SOP Classes operating on 1 IOD

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UPS Architecture

• One object
• Each item on a worklist is a UPS Object
• UPS Object Unified Procedure Step IOD
• Unified contains details of both the requested
  task the performed task
• Four SOP Classes
• UPS Push SOP Class
• UPS Pull SOP Class
• UPS Watch SOP Class
• UPS Event SOP Class

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UPS Object
A UPS Object has its attributes grouped into 4
Modules (this does not affect processing
just for logical organization)
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UPS Object Modules

• Relationship Module
• Patient demographics
• Admission details
• Order details
• Requested Procedure
• Accession
• - Reason for Requested Procedure
• Requesting physician/department
• etc

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UPS Object Modules

• Scheduled Proc. Info. Module
• - Priority
• - Requested perform./completion time
• - Requested resources/location
• - Requested Procedure descrip./codes
• - Requested Processing parameters
• List of Input data IDs
• Input Data Availability Flag
• etc

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UPS Object Modules

• Progress Module
• - UPS State (Scheduled, In-Progress, Completed,
  Canceled)
• Progress Status Numerical (e.g. complete)
• Progress Status Description (e.g. Annealing
  phase complete)
• - Contact information for performer (e.g. phone
  )
• etc

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UPS Object Modules

• Performed Proc. Info. Module
• - Time Performed/completed
• - Performing resources/location
• Performed Procedure descrip./codes
• Performed Processing parameters
• - List of Output data IDs
• etc

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UPS State Diagram
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UPS Pull Workflow
Requester(SCU)
Worklist Manager (SCP)
Create UPS
Subscribe UPS
Query
Performer(SCU)
UPS State Event
Get UPS Contents
Get UPS Contents
UPS
UPS State In-Progress


Set UPS Contents

UPS State Complete
Watcher(SCU)

Subscribe Global
UPS State Event
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UPS SOP Classes
Each UPS Object is managed by a single SCP. 4
SOP Classes exist which can be used to operate on
a UPS object. Each SOP Class supports a few
related operations. SCU/SCP not required to
implement all the SOP Classes. Can implement SOP
Classes based on the operations it needs.
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UPS SOP Classes
UPS Push SOP Class allows SCU systems to
create (push) a new worklist item (i.e.
instance) on a worklist request cancellation of
a worklist item
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UPS SOP Classes
UPS Pull SOP Class allows SCU systems to
query a worklist for matching items take
ownership/control (pull) of a worklist item
modify progress/status/result details for
the worklist item finalize a controlled
worklist item as Completed or Canceled.
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UPS SOP Classes
UPS Watch SOP Class allows SCU systems to
query a worklist for items of interest
subscribe/unsubscribe for change events for
one worklist item subscribe/unsubscribe for
change events for all worklist items get
details for a worklist item request
cancellation of a worklist item
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UPS SOP Classes
UPS Event SOP Class allows SCU systems to
receive change events for worklist items
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UPS Task Locking

• For a UPS in SCHEDULED State
• (SCU does N-ACTION to IN-PROGRESS)
• SCP generates a lock ID
• (SCP returns lock ID to performing SCU)
• For a UPS in IN-PROGRESS State
• N-SET without lock ID is rejected by SCP
• N-ACTION to change state
• Of course, lock ID could be distributed, but be
  careful

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Pull Workflow
SCP
SCU
Give me a list of tasks that need to be done
(C-FIND)
UPS
UPS
UPS
UPS
I will do that one (N-ACTION Set to IN-PROGRESS)
Record these details in the UPS (N-SET attribute
values)
I am finished (N-ACTION Set to COMPLETE)
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Pull Workflow 3D Workstation
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Comparison to Modality Worklist

• MWL is like UPS Pull-mode, except
• UPS combines SPS and MPPS in a single object
• UPS has extra features
• UPS will not generally replace MWL
• MWL does its (limited) job reasonably well
• MWL has a large install base
• UPS might supplement MWL for specific
  applications that need its features
• e.g. Push Workflow for X-Ray clinics

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Push Workflow
SCU
SCP
Please perform this task(N-CREATE with these
attribute values)
UPS
Notify me about progress for that task(N-ACTION
Subscribe)
I have started to do that task (N-EVENT it is
IN-PROGRESS)
I have updated details in the UPS (N-EVENT)
I am finished (N-EVENT it is COMPLETE)
Give me the result details of the task(N-GET
these attribute values)
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Push Workflow X-Ray Clinic
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Watch Workflow

• No central controller
• Workstation watches flow of N-EVENTsSystem A
  did X, System B did Y
• Workstation decides Hmmm, I think I will do
  this
• Workstation internally creates a UPS
• Interested Subscribers are notified of
  Workstation activity via N-EVENT N-GET details
  as needed
• Examples
• CAD workstation sees N-EVENT that Mammo Acq. is
  complete decides to do CAD processing
• Reporting station sees N-EVENT that CAD is
  complete decides to queue reading worklist for
  that study

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Example Implementation Groupings
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Deletion Locks Reliable Watchers

• Reliable Watcher (SCU)
• Problem SCP might delete a completed UPS before
  SCU gets needed details
• (e.g. due to Network latency or outage)
• Missing a UPS could prevent Watcher from
• monitoring completion
• extracting details
• creating subsequent UPS Instances,
• referencing UPS 1 outputs as UPS 2 inputs
• Mechanism
• SCU Sets a Deletion Lock flag during subscription
• SCP cant delete UPS with outstanding Deletion
  Locks
• SCU removes Deletion Lock after retrieving final
  state of UPS
• SCP free to delete UPS after all deletion locks
  removed
• SCP documents how it handles orphans

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Requesting Cancel
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Current DICOM Status

• Sup 96 (UPS)
• Officially published as Frozen for Trial Use
• Sup 74 (Radiotherapy Treatment Delivery Workflow)
• Officially published as Frozen for Trial Use
• Defines Treatment Delivery Objects
• Documents use of UPS for RT
• UPS references instances of RT Beams Delivery
  Instruction
• Treatment Delivery System (SCU) pulls work from
  the Treatment Management System (SCP)
• Z.3.1.2 gives detailed example of UPS usage,
  specifying both the task and input objects
• Sup 124 (Softcopy Display Mgt.)
• Under development
• Defines Display management/callibration Tasks
  Results
• Uses UPS to push Display Calibration jobs (with
  Task description) convey Results

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Current IHE Status

• IHE Radiation Oncology
• Planning to test Sup 74 workflow using UPS
• IHE Mammography
• expressed interest in UPS features (not
  committed yet)
• UPS could help handle complex cases such as
• Multi-pass Acquisition
• Callbacks
• CAD
• Reading Worklists
• IHE Radiology
• no plan to replace Modality Worklist for
  acquisition workflow
• will consider UPS when re-visiting Reporting
  Workflowand Post-processing Workflow
• may profile Sup 124 when its ready

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Questions?

• www.dclunie.com
• gt DICOM Status
• gt Sup 96