Mechanical arm bests freehand for new breast biopsy technique

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Researchers have developed a new breast biopsy technique that could lead to decreased procedure times and reduced patient discomfort and morbidity, according to a study in the June issue of American Journal of Roentgenology. Moreover, less operator experience is required for a successful breast biopsy using a needle guidance system than using a freehand technique.

The technique uses a mechanical arm to guide the needle for the biopsy and has a braking system to allow for accurate placement of the needle and to avoid needle motion.

Breast biopsy procedures, using both methods, were performed on phantoms during the study. The system was attached to an ultrasound transducer, and biopsy needles were inserted through the guidance arm. Both experienced and inexperienced radiologists performed ultrasound-guided biopsy on simulated breast lesions with and without the guidance system. Success rates were scored on the basis of the presence of lesions in the core biopsy samples. The biopsy procedures were analyzed using procedure time and total needle tip travel distance before firing.

"Our results showed that biopsy success rates were greater when using our new guidance system," said the study's lead author Aaron Fenster, MD, who performed the study at Roberts Research Institute, the University of Western Ontario and London Health Sciences Centre in London, Ontario, Canada. "We also showed that experienced and inexperienced radiologists performed a biopsy significantly faster when using our needle guidance system."

The success rate using the needle guidance system was 95.9 percent compared to a success rate of 91.3 percent using the freehand technique. Using the freehand technique, experienced radiologists had a procedure time of approximately 31 seconds. Using the needle guidance system, experienced radiologists had a procedure time of approximately 10 seconds.

The researchers concluded that breast biopsies performed on test lesion phantom showed "marked improvement with needle guidance over freehand techniques."

"Procedure times and needle tip movement were reduced for all participants-both inexperienced and experienced operators-when using our system. With the promise of reduced necessary experience to perform biopsy and of potentially reduced morbidity, we believe that our guidance system will enable physicians to diagnose early-stage carcinomas more efficiently and accurately," Fenster and colleagues wrote.

"The system we designed is a prototype and is required to be redesigned for routine clinical use. Tests with human subjects are planned for the fall of 2009," they wrote.