Slicer IGT : Workflow based design Andinet Enquobahrie, PhD Kitware Inc.

Objective Create KWWidgets wizard skeleton for IGT applications in Slicer Identify the major steps in IGT procedure and translate these steps into wizard interfaces

Major steps 1.Initialization 2.Loading preoperative data 3.Calibration 4.Registration 5.Intrapoperative procedure

Initialization Initialization step includes establishing communication with Navigation system and/or tracking device Endoscope External tracking software – For example, setup communication with IGSTK using OpenIGT link Robot control computer if a robot is used in the surgical procedure.

Loading Preoperative Data Preoperative data includes Images ( such as CT, MRI data ) Models Calibration data for tracker/robot tools Surgical planning ( developed preoperatively )

Calibration This step includes Calibration of camera (Endoscope) and probe Calibration of tracker tools – For example, Pivot calibrations Calibration of robot tools

Registration In this step, transformations between different coordinate systems are established Register preoperative image with the navigation system’s reference frame ( i.e. Patient-Image registration ) If robot is available, register robot coordinate system with the navigation system reference frame.

Registration (Cont’d) Different registration algorithms will be made available – ICP – Landmark/fiducial registration If registration is computed using an external guidance system, then the transformation parameters will be uploaded to Slicer. (For example, StealthLink)

Intraoperative procedure During the procedure – Start Tracking – If robot is available, transmit commands to robot to get it to the right mode – Gather pose information of tracker/surgical tools and update the display

Action Items 1.Create IGT module 2.Design wizard interfaces for each major step 3.Wire the state machine transitions 4.Implement the first few steps (Initialization and load preoperative data steps)