Medical femtosecond laser

Koenig, Karsten

doi:10.1051/jeos/2023032

Cited by 7 publications

(1 citation statement)

References 31 publications

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“…MPT has the best spatial resolution. In fact, with a lateral resolution of 300 nm, MPT provides even better resolution than conventional histology of fixed, stained, and sliced skin sections [6][7] . MPT as a clinical imaging method was introduced in 2003 by two-photon imaging of patients with suspicious pigmented lesions at the University of Jena.…”

Section: Introductionmentioning

confidence: 99%

Multiphoton skin biopsy

König,

Meinke,

Schleusener

et al. 2024

Clinical Biophotonics III

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High-resolution optical in vivo and ex vivo skin biopsies with subcellular resolution and metabolic information can be provided by multimodal multiphoton tomography. We report on the use of an ultracompact air-chilled 50/80 MHz femtosecond fiber laser for two-photon autofluorescence excitation, generation of higher harmonics, fluorescence lifetime imaging, and confocal reflectance imaging. The 18cm long laser head is placed into a 360° imaging head without requiring an optical arm. The tomograph operates efficiently with a total energy consumption of only 240 watts. This energy efficiency enables portability, allowing operation with batteries even in remote areas, with the added convenience of recharging via foldable flexible photovoltaics. Multiphoton and confocal reflectance images of in vivo human skin are presented. Furthermore, rapid, wide-field ("mosaicking"), and deep skin imaging of label-free fresh skin biopsies in a clinical environment is demonstrated.

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Section: Introductionmentioning

confidence: 99%

Multiphoton skin biopsy

König,

Meinke,

Schleusener

et al. 2024

Clinical Biophotonics III

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Differentiation of Tumors of the Upper Respiratory Tract Using Optical Metabolic Imaging

Eggert,

Gaertner,

Rühm

et al. 2024

Lasers Surg Med

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ObjectivesWith over 184,000 new cases and more than 99,000 deaths per year, malignancies of the larynx are a global health problem. Currently, a dedicated screening method enabling a direct onsite diagnosis is missing. This can lead to delayed diagnosis and worse outcomes of the patients. An endoscopic optical method enabling a direct distinction between healthy tissue, dysplastic tissue and cancerous tissue would be an ideal tool for the detection of tumors of the upper aerodigestive tract (UADT). Healthy and tumor cells differ significantly in their metabolic state due to the different metabolic pathways they use (more oxidative phosphorylation in healthy cells, more glycolysis in tumor cells). Optical metabolic imaging (OMI) measuring relative intracellular concentration of NAD(P)H and FAD redox pairs could be a promising approach for early tumor detection and differentiation of suspicious mucosal lesions.MethodsIn this study, a specially designed endoscopic two‐beam two‐photon fluorescence lifetime imaging (FLIM) system was used to perform two‐photon two‐beam FLIM of NAD(P)H and FAD to image the metabolic state in different tissue samples of the UADT. FLIM data sets of 27 tissue samples from 16 patients were recorded directly after surgery ex vivo in a special tissue culture medium at 37°C on a dedicated microscope using multiphoton excitation.ResultsBased on the FLIM measurements of NAD(P)H and FAD, six of the most common indices for the characterization of the cells' metabolism were calculated. Three of them, the ratio of the exponential coefficients (amplitudes) of the short and long lifetime components both for NAD(P)H and FAD (NAD(P)H a1/a2 ratio and FAD a1/a2 ratio) and the fluorescence lifetime redox ratio (FLIRR) enabled differentiation between healthy tissue, benign lesions, dysplastic tissue, and cancer tissue with statistical significance.ConclusionsWe showed by measurements on freshly collected tissue samples that mucosal lesions of the UADT can be differentiated using our newly designed endoscopic FLIM device. In vivo measurements in healthy volunteers were also possible. By means of this technology, differentiation of cancerous, pre‐cancerous, and healthy tissue in the UADT by OMI could be possible. Of six indices used to characterize cell metabolism we calculated, the FLIRR showed the most significant differences between tissue types.

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