PROCEEDINGS ARTICLE | March 12, 2010
Proc. SPIE. 7629, Medical Imaging 2010: Ultrasonic Imaging, Tomography, and Therapy
KEYWORDS: Liver, Tumors, Tissues, Ultrasonography, Control systems, Kinematics, Ultrasonics, Transducers, Acoustics, Thermal modeling
Steerability in percutaneous medical devices is highly desirable, enabling a needle or needle-like instrument to avoid
sensitive structures (e.g. nerves or blood vessels), access obstructed anatomical targets, and compensate for the
inevitable errors induced by registration accuracy thresholds and tissue deformation during insertion. Thus, mechanisms
for needle steering have been of great interest in the engineering community in the past few years, and several have been
proposed. While many interventional applications have been hypothesized for steerable needles (essentially anything
deliverable via a regular needle), none have yet been demonstrated as far as the authors are aware. Instead, prior studies
have focused on model validation, control, and accuracy assessment. In this paper, we present the first integrated
steerable needle-interventional device. The ACUSITT integrates a multi-tube steerable Active Cannula (AC) with an
Ultrasonic Interstitial Thermal Therapy ablator (USITT) to create a steerable percutaneous device that can deliver a
spatially and temporally controllable (both mechanically and electronically) thermal dose profile. We present our initial
experiments toward applying the ACUSITT to treat large liver tumors through a single entry point. This involves
repositioning the ablator tip to several different locations, without withdrawing it from the liver capsule, under 3D
Ultrasound image guidance. In our experiments, the ACUSITT was deployed to three positions, each 2cm apart in a conical pattern to demonstrate the feasibility of ablating large liver tumors 7cm in diameter without multiple parenchyma punctures.
