PET-CT/Documentation/Modules/GuidedInterventionPETCT

Introduction and Acknowledgements

Authors: Andinet Enquobahrie Kitware, Guillaume Sala, Kitware, Rahul Khare, ChildrensNational
Acknowledgements: This work is supported by NIH grants 2R42CA153488-02A1 and R41CA153488-01 "Improving liver lesion biopsy in the CT suite through fusion with PET images"
Contact: Andinet Enquobahrie, Guillaume Sala

Module Description

The GuidedInterventionPETCT is a workflow-based module that guides the user in a step-by-step interface to realize a guided biopsy after fusing respiratory-compensated PET/CT with images in the interventional CT suite.
In each step of the workflow we prepare the necessary requirements to fulfill the end goal, following a given pipeline: Registration of the different volumes acquired, establishing the connection between the tracking device and Slicer, registration of the coordinate system of the tracking system and the registered volume and live tracking of the needle in Slicer.
This module uses existing modules to accomplish some of the steps:

• OpenIGTLinkIF
• Annotations
• Fiducial Registration
• Volume Reslice Driver
• Pivot Calibration

Use Cases

• 

  Step1: Load Data

• 

  Step2: Registration PET/CT and interventional CT

• 

  Step3: OpenIGTLinkIF

• 

  Step4: Pivot Calibration

• 

  Step5: CT to hardware registration

• 

  Step6: Reslicing with tracker

Panels

Loading Step

The loading step is the first step of the workflow. The user selects the data that is going to be used for the guided biopsy. Read here the instructions to load data into Slicer. MC PET Volume: This combobox allows selecting the motion-compensated PET scans. MC CT Volume: This combobox allows selecting the motion-compensated CT scans. CBCT Volume: This combobox allows selecting the interventional CT Scan. The volumes in these comboboxes will be used to compute the image registration, between the pre-operative PET/CT acquisition and the interventional CT. The fused PET and interventional CT images will guide the biopsy procedure.

Loading data panel

Volume Registration Step

In this step we compute the image registration with the motion-compensation PET/CT and interventional CT. For the time being we have place-holders while the software is developed. Registration Parameters: Registration parameter 1 Registration parameter 2 Registration parameter 3 Start Registration: Push Button to start the registration with the volumes selected in the previous step. At this stage, a result volume is created and all other volumes are deleted from the scene.

Volume Registration panel

OpenIGTLinkIF Step

In this step of the workflow we establish the link between Slicer and the tracking system. To establish this connection we import the OpenIGTLinkIF module of Slicer. For more information about the use of this module please see the OpenIGTLinkIF documentation. One method to establish the connection is using IGSTK: Run the executable OpenIGTLinkTrackerBroadcasting giving a configuration file for the given tracking system (e.g Polaris configuration file, Micron configuration file)

OpenIGTLinkIF panel

Pivot Calibration Step

This section allows the user to run a pivot calibration algorithm on the tracker device (whose connection was establish on the previous step), to do this, we import the existing PivotCalibration module. For more information about the use of this module please see the Pivot Calibration documentation.

Pivot calibration panel

Hardware Registration Step

This step allows the user to run a fiducial registration to transform the registered volume (PET/CT scans with the interventional CT scans) coordinate system to the tracker coordinate system. To run the fiducial registration we need to create two fiducial lists containing respective points in the different coordinate system. At this stage of the workflow two list are generated, the "CTMarkers" to place the fiducials on the registered Volume and the "TrackerMarkers" where the fiducials on the tracker coordinate system will be placed. For more information about the fiducial registration, please see the documentation here. Register: The "Add Fiducial" button allows the user, by clicking on it, to create a new fiducial at the current position of the tracking device, and adding it to the "TrackerMarkers" list Annotation: This is the "Annotation" module where we can see the fiducial lists and manipulate them. The user needs to place the fiducials on the CT volume to be able to run the registration. Start Registration: This button allows the user to call the fiducial registration CLI module with two fiducial lists previously filled.

Hardware registration panel

Tracking Step

This is the last step of the workflow, it uses the Volume Reslice Driver module, to reslice de volume according to the position of the tracker device

Pivot calibration panel