A Steerable Guiding Device: The New Method in Ultrasound Guidance

Breast biopsy navigation system with an assisted needle holder tool and 2D graphical user interface

Objective

This paper proposes the development of a breast biopsy navigation system with an assisted needle holder tool for a coaxial needle and a graphical user interface, which utilizes an optical tracking device to localize the needle position relative to the ultrasound image with the aim to improve performance especially for a new radiologist or an inexperienced group.

Materials and methods

The system consists of an assisted needle holder tool, which as an attachment for the 2D ultrasound transducer and the graphical user interface (GUI) that shows the needle pathway, needle line and warning signs. An optical tracking system is used to track the needle motion, ultrasound image and transform all information to with respect to the technique. The system is evaluated using a phantom made from gel candle. There were nine experienced and eight inexperienced participants who performed the breast biopsy intervention, using three methods: the freehand method, only the needle holder tool guidance, and the whole navigation guidance (GUI + assisted needle holder).

Results

The results demonstrate a success rate of over 90% using only assisted needle holder and the whole system to perform breast biopsy for the experienced and inexperienced groups, whereas for the inexperienced group a success rate of 57.5% was achieved using the freehand method. The use of only assisted needle holder for breast biopsy reduces the time for a procedure in the inexperienced group by 6 s when compared to the freehand method.

Conclusion

The authors believe that this navigation system can be applied in a clinical setting and give an advantage to inexperienced radiologists who must successfully perform clinical breast biopsy.

Laser assisted ultrasound guided aspiration improves procedure time and reduces number of withdrawals

This study evaluated the performance of in-vitro freehand aspiration of a simulated cyst with ultrasound aspiration guided by a newly designed laser assisted (LA) device. The LA device was equipped with an adjustable light source generating a sector light plane. This laser light plane was parallel to and overlapped the ultrasound acoustical plane, to help with needle positioning. Five operators randomly performed 30 freehand or LA ultrasound guided aspirations of a simulated cyst. The frequency was set at 8 MHz and depth at 4 cm. Procedure time and number of syringe withdrawals were statistically compared before and after using the LA device. Both experienced and inexperienced operators required significantly less time to perform the aspiration and had fewer syringe withdrawals when using the LA device. The LA device provides a reference plane in space, allowing the operator to more accurately position and adjust needle direction. Additional in-vivo testing is required to test the clinical practicability.

Laser needle guide for the sonic flashlight

We have extended the real-time tomographic reflection display of the Sonic Flashlight to a laser guidance system that aims to improve safety and accuracy of needle insertion, especially for deep procedures. This guidance system is fundamentally different from others currently available. Two low-intensity lasers are mounted on opposite sides of a needle aimed parallel to the needle. The needle is placed against a notch in the Sonic Flashlight mirror such that the laser beams reflect off the mirror to create bright red spots on the flat panel display. Due to diffuse reflection from these spots, the virtual image created by the flat panel display contains the spots, identifying the projected destination of the needle at its actual location in the tissue. We have implemented our design and validated its performance, identifying several areas for potential improvement.