MRI-guided frameless biopsy robotic system with the inclusion of unfocused ultrasound transducer for brain cancer ablation

Abstract

Background: A magnetic resonance image (MRI) guided robotic system dedicated for brain biopsy was developed. The robotic system carries a biopsy needle and a small rectangular unfocused, single element, planar ultrasonic transducer which can be potentially utilized to ablate small and localized brain cancer.

Materials and methods: The robotic device includes six computer-controlled axes. An agar-based phantom was developed which included an olive that mimics brain target. A rectangular ultrasonic transducer operated at 4 MHz was used.

Results: The functionality of the robotic system was assessed by means of ultrasound imaging, MRI imaging, and MR thermometry, demonstrating effective targeting. The heating capabilities of the ultrasonic transducer were also evaluated.

Conclusions: A functional MRI-guided robotic system was produced which can perform frameless brain biopsy. In the future, if a tumour is proven malignant, the needle can be pulled-out and a small ultrasonic transducer can be inserted to ablate the tumour.

Keywords: MRI; ablation; biopsy; brain; ultrasound.