Case series about ex vivo identification of squamous cell carcinomas by laser-induced autofluorescence and Fourier transform infrared spectroscopy

Types of spectroscopy and microscopy techniques for cancer diagnosis: a review

Cancer is a life-threatening disease that has claimed the lives of many people worldwide. With the current diagnostic methods, it is hard to determine cancer at an early stage, due to its versatile nature and lack of genomic biomarkers. The rapid development of biophotonics has emerged as a potential tool in cancer detection and diagnosis. Using the fluorescence, scattering, and absorption characteristics of cells and tissues, it is possible to detect cancer at an early stage. The diagnostic techniques addressed in this review are highly sensitive to the chemical and morphological changes in the cell and tissue during disease progression. These changes alter the fluorescence signal of the cell/tissue and are detected using spectroscopy and microscopy techniques including confocal and two-photon fluorescence (TPF). Further, second harmonic generation (SHG) microscopy reveals the morphological changes that occurred in non-centrosymmetric structures in the tissue, such as collagen. Again, Raman spectroscopy is a non-destructive method that provides a fingerprinting technique to differentiate benign and malignant tissue based on Raman signal. Photoacoustic microscopy and spectroscopy of tissue allow molecule-specific detection with high spatial resolution and penetration depth. In addition, terahertz spectroscopic studies reveal the variation of tissue water content during disease progression. In this review, we address the applications of spectroscopic and microscopic techniques for cancer detection based on the optical properties of the tissue. The discussed state-of-the-art techniques successfully determines malignancy to its rapid diagnosis.

Wavelength-dependent DNA Photodamage in a 3-D Human Skin Model over the far-UVC and Germicidal-UVC Wavelength Ranges from 215 to 255 nm

The effectiveness of UVC to reduce airborne‐mediated disease transmission is well established. However, conventional germicidal UVC (~254 nm) cannot be used directly in occupied spaces because of the potential for damage to the skin and eye. A recently studied alternative with the potential to be used directly in occupied spaces is far UVC (200–235 nm, typically 222 nm), as it cannot penetrate to the key living cells in the epidermis. Optimal far‐UVC use is hampered by limited knowledge of the precise wavelength dependence of UVC‐induced DNA damage, and thus we have used a monochromatic UVC exposure system to assess wavelength‐dependent DNA damage in a realistic 3‐D human skin model. We exposed a 3‐D human skin model to mono‐wavelength UVC exposures of 100 mJ/cm², at UVC wavelengths from 215 to 255 nm (5 nm steps). At each wavelength, we measured yields of DNA‐damaged keratinocytes, and their distribution within the layers of the epidermis. No increase in DNA damage was observed in the epidermis at wavelengths from 215 to 235 nm, but at higher wavelengths (240–255 nm) significant levels of DNA damage was observed. These results support use of far‐UVC radiation to safely reduce the risk of airborne disease transmission in occupied locations.

Diagnostic value of autofluorescence laryngoscope in early laryngeal carcinoma and precancerous lesions: A systematic review and meta-analysis

OBJECTIVE

We aim to evaluate the diagnostic value of autofluorescence laryngoscope (AFL) in early laryngeal carcinoma and precancerous lesions. aWe also assess the value of AFL in diagnosis of early laryngeal carcinoma and precancerous lesions in comparison with that of white light laryngoscope (WL).

METHODS

The databases consisting of PubMed, Cochrane Library, Web of science and CNKI were systematically searched to find pertinent literatures of AFL in diagnosing early laryngeal carcinoma and precancerous lesions. We made a quality evaluation of every study we included using the modified Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2). The pooled sensitivities, specificities were calculated using Meta-Disc 1.4. And we estimated the summary receiver operating characteristic curves (SROC) and area under the curves (AUC).

RESULTS

We finally included 23 studies. The results of AFL in diagnosing early laryngeal carcinoma and precancerous lesions showed higher sensitivity of 0.91 (95%CI: 0.89-0.93; χ²=43.78, p = 0.0025) and specificity of 0.80 (95%CI: 0.77-0.82; χ²=130.64, p = 0.000), and the weighted AUC of AFL was 0.948 ± 0.013 (95%CI: 0.921-0.974) and the diagnostic accuracy (Q*) was 0.887 ± 0.018. The sensitivity and specificity of WL were 0.74 (95%CI: 0.70-0.77; χ²=52.40, p = 0.000) and 0.89 (95%CI: 0.87-0.90; χ²=299.22, p = 0.000), and the weighted AUC of WL was 0.835 ± 0.029 (95%CI: 0.777-0.892) and the diagnostic accuracy (Q*) was 0.767 ± 0.027.

CONCLUSION

The meta-analysis and systematic review suggested that AFL had high diagnostic value in early laryngeal carcinoma and precancerous lesions, and its diagnostic value was higher than that of WL. These results indicated that AFL can provide good guidance for the early detection of laryngeal carcinoma and precancerous lesions.

Laser induced autofluorescence lifetime to identify larynx squamous cell carcinoma: Short series ex vivo study

Laser induced autofluorescence (LIAF) lifetime is useful to distinguish between normal laryngeal tissues and squamous cell carcinoma (SCC) based on variations of their biochemical composition and structure alterations. LIAF was collected from samples constituted by pairs of normal and malignant tissue, which were excised from three patients. Exclusion criteria for samples harvest were: (i) macroscopic changes of normal vocal cord observed during surgery; (ii) previous surgical intervention on vocal cord, (iii) patients treated only with chemotherapy or radiotherapy for carcinoma. Inclusion conditions: men, aged 57-68, non-smokers. A pulsed laser diode excited LIAF at 375 nm and 31 MHz repetition rate; beam full-time width at half-maximum was 87 ps at an average power of 0.49 mW. Mean LIAF lifetime for normal tissues was (3.75 ± 0.49) ns and for malignant (4.37 ± 0.85) ns: it is longer in malignant than in normal tissue. Variance analysis made with Fisher's test has shown no significant difference between patients for normal tissues; the same was true for malignant. Though, when malignant tissue was compared to normal for the same patients as well as between patients, a significant difference (significance level of 5%) was evidenced. Time-resolved LIAF may allow better differentiation between normal and malignant tissues in patients diagnosed with larynx SCC.