Oblique needle segmentation and tracking for 3D TRUS guided prostate brachytherapy

Area of Science:

• Medical Imaging
• Robotics
• Surgical Navigation

Background:

• Brachytherapy requires precise needle placement for effective radiation delivery.
• Oblique needle trajectories pose challenges for traditional imaging and tracking methods.
• Accurate segmentation and tracking are crucial for minimizing off-target radiation exposure.

Purpose of the Study:

• To develop and validate an algorithm for segmenting and tracking brachytherapy needles in three-dimensional (3D) transrectal ultrasound (TRUS) images.
• To assess the algorithm's accuracy in relation to needle insertion distance and angulation.
• To evaluate the feasibility of near real-time needle tracking for clinical applications.

Main Methods:

• Developed a novel algorithm for segmenting and tracking brachytherapy needles in 3D TRUS images.
• Utilized rigid rods simulating needles in agar and chicken breast phantoms.
• Employed a robot with high accuracy as a gold standard for comparison.
• Quantified segmentation and tracking errors based on insertion distance and angulation.

Main Results:

• The algorithm demonstrated high accuracy, with needle tip position errors less than 1 mm at insertion distances >15 mm and 10-degree angulation in agar phantoms.
• Near real-time tracking was achieved, with segmentation and scanning times under 60 ms and 1.2 s, respectively, for insertion distances <55 mm.
• Needle orientation errors were less than 2 degrees (yaw) and 0.7 degrees (pitch) in chicken breast phantoms for up to 20-degree insertion angles and distances >15 mm.

Conclusions:

• The developed algorithm provides accurate segmentation and tracking of brachytherapy needles, even along oblique trajectories.
• The method shows potential for real-time image-guided brachytherapy, enhancing treatment precision.
• The algorithm's performance is dependent on needle insertion distance and angulation relative to the TRUS transducer.