Abstract: A system comprises a medical device configured to be positioned at least partially within a scattering medium, the medical device comprising at least one optical fibre or other waveguide having a plurality of light-emitting regions arranged along at least part of the length of the at least one optical fibre or other waveguide; a pulsed light source configured to transmit pulsed light into a proximal end of the at least one optical fibre or other waveguide, such that the pulsed light is guided along the at least one optical fibre or other waveguide to the light-emitting regions and emitted by the light-emitting regions into the scattering medium; at least one detector configured to receive photons of the pulsed light that have passed through the scattering medium; and a processor configured to: select signals corresponding to at least some of the received photons; determine a respective location of each of the light-emitting regions based on the selected signals; and determine a path of at least part of the me

Abstract: A method of determining a location of an optical fibre positioned at least partially inside a scattering medium, the method comprises transmitting pulsed light into the scattering medium, receiving, by a detector, photons of the pulsed light that have passed through the scattering medium, selecting signals corresponding to some of the received photons, wherein the selecting is based on a time of arrival of the received photons; and determining a location of the optical fibre based on the selected signals.