Ultrasound-Guided Robot for Flexible Needle Steering

David Kennedy

Background

• Various clinical procedures require needle insertion:– Biopsies– Local Anesthesia– Blood sampling– Prostate brachytherapy– Ablation

• Many done free-hand.

Ultrasound System

• Includes:– Robot designed insertion system– Image processing algorithms– Tissue stiffness system

Virtual Spring Model

• Needle displacement and tissue response can be modeled as virtual springs distributed along the needle.

Needle Tip Detection

• Image subtraction• Center of mass

Tissue Stiffness System

• speckle tracking algorithm• block matching algorithm• Added together create the tissue stiffness

system used in the virtual spring model

Controlled Needle Insertion

• Tracking error can be minimized by the following control system.

Experiment Setup

Results

• Open-loop vs. Closed-loop vs. Closed-loop with updated tissue stiffness

• The closed-loop with updated tissue stiffness had the least error of a maximum 1mm.

• Improvement from the free-hand range of 6-8mm.

Benefits

• Cut Imaging costs and radiation exposure compared to CT and MRI for brachytherapy

• Improves accuracy and precision for procedures, increasing its success.

Work Cited• Neubach, Z.; Shoham, M.; , "Ultrasound-Guided Robot for

Flexible Needle Steering," Biomedical Engineering, IEEE Transactions on , vol.PP, no.99, pp.1-1, 0 URL:http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5223650&isnumber=4359967 [Impact Factor (2007): 1.677]

• "Biopsy." Wikipedia, the free encyclopedia. Web. 21 Feb. 2010. <http://en.wikipedia.org/wiki/Biopsy>.

• "Brachytherapy." Wikipedia, the free encyclopedia. Web. 21 Feb. 2010. <http://en.wikipedia.org/wiki/Brachytherapy>.