A probe comprising a body portion and a tip portion. The body portion comprises: a first mounting portion comprising a plurality of first carriers, each first carrier being arranged to support an elongate first waveguide, the first carriers being disposed in an equiangular arrangement around a longitudinal axis of the body portion; a plurality of first waveguides, each first waveguide being supported in a respective one of the plurality of first carriers; and a body end fitting at which first ends of the first waveguides are supported in the equiangular arrangement around the longitudinal axis of the body portion such that the first waveguides can transmit electromagnetic radiation signals from an energy source to the body end fitting and/or transmit electromagnetic radiation signals from the body end fitting to a receiver. The tip portion comprises: a second mounting portion comprising a plurality of second carriers, each second carrier being arranged to support an elongate second waveguides, the second carriers being disposed in the equiangular arrangement around a longitudinal axis of the tip portion; a plurality of second waveguides, each second waveguides being supported in a respective one of the plurality of second carriers; and a tip end fitting at which first ends of the second waveguides are supported in the equiangular arrangement around the longitudinal axis of the tip portion; and an elongate conduit for piercing human tissue.