Methods and systems for shape sensing

A measurement system for assisting in guiding a tubular-shaped medical device in a body, the measurement system comprising:

• a multicore fiber for insertion into a tubular shaped medical device such that a position of a tip of the multicore fiber corresponds with a position near the tip of the tubular shaped medical device, the multicore fiber comprising a plurality of cores, whereby a plurality of Bragg gratings are inscribed in the multicore fiber, the plurality of Bragg gratings being spaced apart from each other and being positioned along a length of the multicore fiber, and
• a measurement device for:
• reading out optical signals obtained of the plurality of cores of the multicore fiber as function of total length of a multicore fiber portion that has been inserted in the body when the tubular shaped medical device comprising the multicore fiber is inserted into the body, and
• deriving, based thereon, shape information of the multicore fiber and for deriving therefrom shape information from the tubular shaped medical device wherein the multicore fiber is inserted,
• wherein deriving shape information comprises obtaining a difference in bending planes between two different subsequent Bragg gratings along the length in the tip of the multicore fiber and using previously recorded optical measurements of the plurality of Bragg gratings.