A New Approach to Ultrasound Guided Radio-Frequency Needle Placement - - PowerPoint PPT Presentation

March 26, 2007

Chair for Computer Aided Medical Procedures & Augmented Reality Department of Computer Science | Technische Universität München

Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

A New Approach to Ultrasound Guided Radio-Frequency Needle Placement

Claudio Alcérreca, Jakob Vogel, Marco Feuerstein, and Nassir Navab

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 2 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Outline

 Introduction  Related Work  Methods  Device Calibration  Needle Placement  Evaluation  Results  Conclusion

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 3 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Introduction

 Tumor Ablation/Radio-Frequency Ablation (RFA)  Minimally invasive  Kill cancer cells in-situ  RFA requires accurate needle placement  Ultrasonography (US)  Non-invasive  Highly available  Simple to use

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 4 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Workflow

 Pre-operative  Diagnosis, based on MRI study using contrast agent.  Planning (Number of needles, time, power, and path)  Intra-operative  Locate lesion and path.  Insert needle into the center of the lesion.  Apply RF.  Remove needles.  Post-operative  Confirm ablation (PET).

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 5 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Related Work

 Ultraguide 1000  Electromagnetic tracking (distortions, cables, lower accuracy)  BrainLAB  Preoperative 3D data (CT, MR, or PET)  Correct registration required  Siemens Corporate Research  Expensive AR equipment (HMD)  In-situ US volume creation

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 6 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: Setup

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 7 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: US Calibration

 Single Wall calibration with Langø‘s extension (incl. time & SOS)

Image Probe Probe OT Image OT

T T T 

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 8 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: US Calibration

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 9 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: Needle Calibration

 Hot-Spot calibration for tip and base

Tip Needle Needle OT Tip OT

T T T 

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 10 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: Setup

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 11 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: RF Needle Placement

 Surgeon selects target in the US View (live image or frozen)

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 12 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: RF Needle Placement

 Surgeon aligns the guidance lines and inserts the needle in the World View

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 13 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: RF Needle Placement

 Alternative perspective: Needle View

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 14 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: RF Needle Placement

 Another perspective: Augmented Reality View

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 15 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Methods: RF Needle Placement

 Distance to the target is color-coded.  Guidance lines help the surgeons to align the needle correctly before the needle is visible in US.  Support for pre-operative volumes.

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 16 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Evaluation

 Euclidean distance from needle tip to segmented tip

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 17 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Results

 Errors measured using a more recent system: 1.1 mm mean, 0.4 mm standard deviation, 1.17 mm RMS

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 18 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Conclusion

 RFA divided into two consecutive tasks:  Surgeons only need to handle one device at a time.  The needle position can be shown relative to live, frozen, or past US measurements  Possible improvements include:  Better lesion segmentation  More complex (deformable) models  Automated registration of pre-operative volumes  Planning and guidance along a safe path

CAMP | Department of Computer Science | Technische Universität München | March 26, 2007 19 Chair for Computer Aided Medical Procedures & Augmented Reality | wwwnavab.cs.tum.edu

Thanks for your attention!