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Biophotonic endoscopy: a review of clinical research techniques for optical imaging and sensing of early gastrointestinal cancer.

Coda S, Siersema PD, Stamp GW, Thillainayagam AV - Endosc Int Open (2015)

Bottom Line: In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients.However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology.Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

View Article: PubMed Central - PubMed

Affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Imperial College London, London, United Kingdom ; Photonics Group, Department of Physics, Imperial College London, London, United Kingdom ; Endoscopy Unit, Department of Gastroenterology, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom ; Department of Endoscopy, North East London NHS Treatment Centre, Care UK, London, United Kingdom.

ABSTRACT
Detection, characterization, and staging constitute the fundamental elements in the endoscopic diagnosis of gastrointestinal diseases, but histology still remains the diagnostic gold standard. New developments in endoscopic techniques may challenge histopathology in the near future. An ideal endoscopic technique should combine a wide-field, "red flag" screening technique with an optical contrast or microscopy method for characterization and staging, all simultaneously available during the procedure. In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients. However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology. This review describes some of the most recent applications of biophotonics in endoscopic optical imaging and metrology, along with their fundamental principles and the clinical experience that has been acquired in their deployment as tools for the endoscopist. Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

No MeSH data available.


Related in: MedlinePlus

Jablonski diagram showing electronic energy levels of ground (E0) and excited (E1) states and both radiative (Γ) and nonradiative (κ) decay pathways in a fluorescent molecule. b After a short pulse of light, fluorescence emitted from the sample decays away over a period of nanoseconds as excited molecules return to their ground state. Fluorescence lifetime imaging microscopy (FLIM) produces images by using the fluorescence lifetime determined at each pixel to provide image contrast, displayed through a false-color scale, between tissues or different components within the tissue that have different fluorescence decays.
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FI158-3: Jablonski diagram showing electronic energy levels of ground (E0) and excited (E1) states and both radiative (Γ) and nonradiative (κ) decay pathways in a fluorescent molecule. b After a short pulse of light, fluorescence emitted from the sample decays away over a period of nanoseconds as excited molecules return to their ground state. Fluorescence lifetime imaging microscopy (FLIM) produces images by using the fluorescence lifetime determined at each pixel to provide image contrast, displayed through a false-color scale, between tissues or different components within the tissue that have different fluorescence decays.

Mentions: A fluorophore in the excited electronic state may also return to the ground state by a number of nonradiative processes (i. e., without the emission of fluorescence). Thus, fluorescent light from a sample does not instantaneously cease the moment that the excitation light is extinguished; rather, it decays away over a period of nanoseconds as excited fluorophore molecules in the sample return to their ground state. This period is referred to as fluorescence lifetime (τ), and the energy transfer is schematically illustrated with the classic Jablonski diagram (Fig. 3 a). The key point is that different fluorophores decay at different rates, and this parameter can be mapped at every pixel in an image in order to produce a fluorescence lifetime image (Fig. 3 b). Typical fluorescence lifetimes are of the order of picoseconds (10‑12 seconds) to nanoseconds (10‑9 seconds).


Biophotonic endoscopy: a review of clinical research techniques for optical imaging and sensing of early gastrointestinal cancer.

Coda S, Siersema PD, Stamp GW, Thillainayagam AV - Endosc Int Open (2015)

Jablonski diagram showing electronic energy levels of ground (E0) and excited (E1) states and both radiative (Γ) and nonradiative (κ) decay pathways in a fluorescent molecule. b After a short pulse of light, fluorescence emitted from the sample decays away over a period of nanoseconds as excited molecules return to their ground state. Fluorescence lifetime imaging microscopy (FLIM) produces images by using the fluorescence lifetime determined at each pixel to provide image contrast, displayed through a false-color scale, between tissues or different components within the tissue that have different fluorescence decays.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4612244&req=5

FI158-3: Jablonski diagram showing electronic energy levels of ground (E0) and excited (E1) states and both radiative (Γ) and nonradiative (κ) decay pathways in a fluorescent molecule. b After a short pulse of light, fluorescence emitted from the sample decays away over a period of nanoseconds as excited molecules return to their ground state. Fluorescence lifetime imaging microscopy (FLIM) produces images by using the fluorescence lifetime determined at each pixel to provide image contrast, displayed through a false-color scale, between tissues or different components within the tissue that have different fluorescence decays.
Mentions: A fluorophore in the excited electronic state may also return to the ground state by a number of nonradiative processes (i. e., without the emission of fluorescence). Thus, fluorescent light from a sample does not instantaneously cease the moment that the excitation light is extinguished; rather, it decays away over a period of nanoseconds as excited fluorophore molecules in the sample return to their ground state. This period is referred to as fluorescence lifetime (τ), and the energy transfer is schematically illustrated with the classic Jablonski diagram (Fig. 3 a). The key point is that different fluorophores decay at different rates, and this parameter can be mapped at every pixel in an image in order to produce a fluorescence lifetime image (Fig. 3 b). Typical fluorescence lifetimes are of the order of picoseconds (10‑12 seconds) to nanoseconds (10‑9 seconds).

Bottom Line: In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients.However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology.Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

View Article: PubMed Central - PubMed

Affiliation: Section of Gastroenterology and Hepatology, Department of Medicine, Imperial College London, London, United Kingdom ; Photonics Group, Department of Physics, Imperial College London, London, United Kingdom ; Endoscopy Unit, Department of Gastroenterology, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom ; Department of Endoscopy, North East London NHS Treatment Centre, Care UK, London, United Kingdom.

ABSTRACT
Detection, characterization, and staging constitute the fundamental elements in the endoscopic diagnosis of gastrointestinal diseases, but histology still remains the diagnostic gold standard. New developments in endoscopic techniques may challenge histopathology in the near future. An ideal endoscopic technique should combine a wide-field, "red flag" screening technique with an optical contrast or microscopy method for characterization and staging, all simultaneously available during the procedure. In theory, biophotonic advances have the potential to unite these elements to allow in vivo "optical biopsy." These techniques may ultimately offer the potential to increase the rates of detection of high risk lesions and the ability to target biopsies and resections, and so reduce the need for biopsy, costs, and uncertainty for patients. However, their utility and sensitivity in clinical practice must be evaluated against those of conventional histopathology. This review describes some of the most recent applications of biophotonics in endoscopic optical imaging and metrology, along with their fundamental principles and the clinical experience that has been acquired in their deployment as tools for the endoscopist. Particular emphasis has been placed on translational label-free optical techniques, such as fluorescence spectroscopy, fluorescence lifetime imaging microscopy (FLIM), two-photon and multi-photon microscopy, second harmonic generation (SHG) and third harmonic generation (THG) imaging, optical coherence tomography (OCT), diffuse reflectance, Raman spectroscopy, and molecular imaging.

No MeSH data available.


Related in: MedlinePlus