Early arriving photon imaging for locating optical endomicroscopy fibres and medical devices

Michael George Tanner, R. K. Henderson, K. Dhaliwal, Robert R. Thomson

Research output: Contribution to conferencePaperpeer-review


Optical fibre based endoscopes are increasingly used for imaging and sensing within the human body without navigational guidance of the miniaturised fibre probe. Meanwhile, medical device placement is a standard procedure in clinic. We demonstrate successful imaging of optical device location with centimetre resolution in clinically relevant models, in a realistically lit environment, achieved through the detection of early arriving photons with a time-resolved single photon detector array.
This prototype has been developed within the UK-EPSRC Proteus project, moving advanced research technologies towards clinical implementation.

Short (~100ps) laser pulses are transmitted from the endoscope tip at 785nm in the “optical window” where attenuation is less severe. Most photons passing through tissue undergo much scattering from the disordered structures providing little location determination of the light source. However, some photons probabilistically undergo less scattering, or travel in an almost straight line, exiting the body sooner than the highly scattered light.

A camera based upon a 32 × 32 array of Single Photon Avalanche Photodiode Detectors (SPADs) is used to image the small number photons exiting the tissue. The time resolution capabilities of such a single photon detector (50ps time bin resolution, 200ps jitter) allows separation of the early arriving photons from the highly scattered light, revealing the endoscope location.

This compact packaged system with aggressive optical filtering is demonstrated in a normally lit room to determine optical endomicroscope location in a whole ventilated ovine lung as well as tissue models including bone structure. At the limit of capabilities of this prototype, demonstration through an entire human torso is shown. System improvements and the potential of the next generation prototype in development will be discussed, offering the potential for real time (sub second) imaging of device location for application in standard medical procedures.

Tanner et al, Biomedical Optics Express 8, 4077 (2017)
Original languageEnglish
Publication statusPublished - Sept 2018
EventPhoton 2018 - Aston University, Birmingham, United Kingdom
Duration: 3 Sept 20186 Sept 2018


ConferencePhoton 2018
Country/TerritoryUnited Kingdom
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