Mechatronically guided micro navigation for soft tissue needle insertion
The insertion of needles represents an interesting alternative for minimally invasive and focusses diagnosis and therapy in soft tissues, e.g., including biopsies or brachytherapy. However, needle insertion often causes substantial soft tissue deformation, which can result in a misplacement of the needle relative to the tissue. In a first project phase, we realized a mechatronic setup to prove feasibility of high resolution optical navigation from within the needle. Using fiber optic components integrated into the needle, we obtain high resolution optical coherence tomography images of the tissue surrounding the needle. Particularly, it is possible to detect even small deformations of the tissue and to estimate the relative motion between needle and tissue. In a second project phase the resulting tissue model will be extended to include elastic tissue properties and even higher resolution spatial information. One objective is to estimate the information needed to model and predict the needle-tissue interaction from within the needle. In combination with the mechatronic needle driving, this will form the basis for a precise control of the needle motion accounting for tissue deformation. Another aspect regards the possible differentiation of different tissues. For example, the elastic tissue properties are also related to the type of tissue, e.g., tumor tissue is often less elastic. To also consider structural differences in the tissue, we will first integrate optical coherence microscopy into a needle probe. A longer term objective is using the morphological and mechanic tissue model for localization and treatment planning.