Interventions under video-augmented X-Ray guidance: Application to needle placement

Abstract

The camera augmented mobile C-arm (CAMC) has been introduced in [12] for the purpose of online geometrical calibration. Here, we propose its use for an augmented reality visualization. Introducing a double mirror system [11] the optical axes of both imaging systems (Xray and optical) can be aligned. With this property both images can be merged or co-registered by only a planar transformation. This allows a real-time augmentation of X-ray and CCD camera images. We show that the needle placement procedure can be performed under this augmented reality visualization instead of fluoroscopy. Only two single X-ray images from different unknown C-arm positions are needed to align the needle to a target structure labeled by the surgeon in both X-ray images. The actual alignment is done by the surgeon while she/he sees the alignment of the needle to the target structure on video images co-registered with the X-ray image. Preliminary experimental results show the power of CAMC for medical augmented reality imaging. It also shows that this imaging system can provide surgeons with new possibilities for image guided surgery. In particular it reduces the X-ray exposures to both patient and physician.