Cavitation-enhanced back projection for acoustic rib detection and attenuation mapping

Area of Science:

• Medical Physics
• Biomedical Engineering
• Acoustic Imaging

Background:

• High-intensity focused ultrasound (HIFU) offers minimally invasive cancer treatment.
• Thoracic cage interference obstructs HIFU beams in upper abdominal therapies, causing off-target heating.
• Phased array transducers require apodization based on beam path analysis to mitigate complications.

Purpose of the Study:

• To develop and validate a novel rib detection method for HIFU.
• To enable real-time optimization of HIFU therapy in the presence of thoracic obstructions.
• To improve the safety and efficacy of intercostal HIFU procedures.

Main Methods:

• A new rib detection technique utilizing cavitation-enhanced ultrasonic reflections was developed.
• The method was validated on porcine tissue samples containing ribs.
• Apodization laws were compared between the proposed method and traditional image analysis.

Main Results:

• Apodization laws derived from the proposed method showed ~90% similarity to those from image analysis.
• The method provided data on acoustic attenuation between transducer elements and the focal point.
• Experimental confirmation was achieved using a polymer phantom.

Conclusions:

• The cavitation-enhanced ultrasonic reflection method effectively detects ribs for HIFU planning.
• This technique can potentially be implemented in real-time for intercostal HIFU therapy.
• The approach enhances the precision and safety of HIFU by accounting for anatomical obstructions.