Infrared Fluorescence-Based Cancer Screening Capsule for the Small Intestine

Abstract

Infrared fluorescence endoscopy (IRFE), in conjunction with an infrared fluorescent-labelling contrast agent, is a well known technique used for efficient early-stage cancer detection. In this paper we present a cost-effective (< $500) screening capsule prototype, which is able to detect infrared (IR) fluorescence emitted by indocyanine green (ICG) fluorophore dye. Rather than image, the capsule works as a high-sensitivity fluorometer that records fluorescence levels throughout the small intestine. The presented mixed-signal system has a small size, consumes very little power (≈ 6.3 mA) and does not require an external belt and hardware for data collection. By determining fluorescence levels in the intestine, rather than collecting images, we avoid the need for labour intensive video analysis. The whole system is contained within a compact ingestible capsule, that is sized so as to come into close contact with the intestine walls during peristalsis. Ex-vivo experiments, on ICG-impregnated swine intestine, have shown that the prototype system is able to detect low concentrations of ICG in the nanomolar and micromolar region, which is required to detect early cancer in the small intestine.

Simultaneous Energy and Data Wireless Transfer Attenuation in Biological Channel of Deep Implantable Medical Devices: Characteristic Analysis and Modeling

“…With the development of modern medicine and electronic technology, implantable medical devices have been widely used in modern medicine [1][2][3][4][5]. However, implantable medical devices face common challenges in the areas of energy supply and data transmission.…”

Gastrointestinal diagnosis using non-white light imaging capsule endoscopy

“…Because of this potential, there is considerable research interest in the use of AFI 6 with conventional endoscopy, so it was logical that the integration of AFI with CE would be explored to improve the 7 diagnostic capabilities of CE. The integration of AFI CE has led to the development of several prototype imaging 8 devices such as those being created by the Cummings group 81 , and has also contributed use of fluorescence as a 9 sensing modality as evidenced by the work of Demosthenous et al 82 and Nemiroski et al 83 filtering out light other than that owing to fluorescence emission. 25…”

“…Rawhani capsule, were created for gastrointestinal diagnosis by Demosthenous et al 82 and Nemiroski et al 83 . 6…”

“…These devices detect light with photo-diodes rather than SPAD imagers. Demosthenous et al 82 used their CE device 7…”

“…for instance, at low concentrations, such as those expected in small cancers, the optimum excitation wavelength is 13 780 nm. Increasing the concentration causes a second absorption wavelength to appear at 708 nm 82,87 . 14 Demosthenous and colleagues designed their autonomous system for use with 780nm wavelength excitation, as the 15 deeper tissue penetration depth at this wavelength is more suitable for detecting small cancers 88,89 and the rate of 16 false positives arising from endogenous fluorophores within surrounding tissue that emit light in the ultraviolet and 17 other parts of the visible spectrum is reduced 90 .…”