Active ultrasound tracking method for prostate brachytherapy using acoustic needle prototype and sonomicrometry

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Surgical Navigation

Background:

• Prostate brachytherapy requires precise placement of radioactive seeds.
• Accurate real-time tracking of brachytherapy needles is crucial for optimal treatment delivery.
• Existing methods may have limitations in achieving high accuracy and precision for needle guidance.

Purpose of the Study:

• To evaluate sonomicrometry for measuring displacements of an active ultrasound-tracked needle.
• To assess the linearity, accuracy, and precision of sonomicrometry in tracking needle motion.
• To determine the feasibility of triangulating the needle's 3D position relative to an intra-rectal ultrasound probe for prostate brachytherapy.

Main Methods:

• Developed an active ultrasound-tracked needle prototype with a piezoelectric tracking sensor.
• Utilized sonomicrometry to measure the time-of-flight (ToF) of ultrasound signals.
• Employed a simulated intra-rectal ultrasound probe with sensors for 3D tracking and triangulation algorithms.

Main Results:

• Sonomicrometry demonstrated strong linearity (R ≥ 0.999) in displacement measurements.
• High accuracy (mean difference ≤ 0.55 mm) and precision (≤ 0.22 mm) were achieved compared to a reference.
• 3D spatial tracking using triangulation algorithms showed close overlap with ground-truth video data.

Conclusions:

• Sonomicrometry is a promising technique for measuring needle displacements and triangulating spatial position.
• The developed active ultrasound-tracked needle shows potential for prostate brachytherapy applications.
• Further development is needed for automated triggering, real-time tracking, and commercial viability.