Optical coherence tomography for margin definition of basal cell carcinoma before micrographic surgery-recommendations regarding the marking and scanning technique.

BACKGROUND/PURPOSE: Mohs Micrographic Surgery (MMS) is the preferred therapeutic treatment for high-risk basal cell carcinoma (BCC). Optical Coherence Tomography (OCT) is a non-invasive imaging technique that enables the diagnosis of BCC. We thought to determine the margins of BCCs with OCT, prior to MMS, to reduce the number of surgical steps. METHODS: Different permanent markers were tested on the skin regarding line width, resistance against disinfection and brightness in the OCT image. The visible tumor margins of BCCs were defined by dermoscopy, adding a safety margin of 2 mm and labeled using the selected pen, causing a signal shadow in OCT. Scans of the center and of entire margin were performed. If parts of the BCC were visible outside the margin, another 2 mm were added and the scan was repeated until the tissue outside the labeling looked tumor free. RESULTS: Eight out of ten BCCs were totally excised in a single stage when margin delineation was done by OCT. Macroscopic margins were enlarged after OCT scanning in four patients, saving further stages of MMS. CONCLUSION: OCT may help to better define the microscopic dimensions of BCCs and therefore reduce the number of stages of MMS.

How long does protection last?--in vivo fluorescence confocal laser scanning imaging for the evaluation of the kinetics of a topically applied lotion in an everyday setting.

BACKGROUND: Confocal laser scanning microscopic imaging is well established as a helpful diagnostic tool in dermatology. With a new generation of multi-wave laser confocal microscopes now, in addition to the reflection mode, examinations with fluorescent agents are possible in vivo and ex vivo. Gathering details on the physical, chemical and kinetic features of different fluorophores in different vehicles in healthy skin in vivo will be of interest for therapeutic as well as cosmetic dermatology. OBJECTIVES: Objective of this study was to determine the kinetics of the protective function of a topically applied, fluorescent-containing lotion in a 24 h everyday setting in healthy volunteers using fluorescence confocal laser scanning microscopy imaging. MATERIAL AND METHODS: Fifteen volunteers received a standardized application of a sodium fluoresceine containing lotion. At several time points of a 24 h interval confocal laser imaging in the multi-wave mode was performed. Fluorescence was measured by a semiquantitative score and by one based on the intensity of light. RESULTS: CLSM images in the depths of the stratum corneum and of the upper epidermis of all 15 panelists showed a detectable fluorescence after 30 min and 4 h and after 24 h, a partial fluorescence was still visible in 10 of 15 persons. Similar results were achieved using a semiquantitative score and by measuring the intensity of light. CONCLUSION: Sodium fluoresceine as a safe and efficient fluorophore for in vivo fluorescence CLSM was able to visualize the kinetics of a topically applied protective lotion and was able to be detected for up to 4 h in all panelists and even up to 24 h in two-thirds of the healthy volunteers showing the long duration of the fluorescence on the skin surface, even in an everyday setting.

Multiwavelength shearography for quantitative measurements of two-dimensional strain distributions.

We report on the development of a multiwavelength speckle pattern shearing interferometer for the determination of two-dimensional strain distributions. This system is based on simultaneous illumination of the object with three diode lasers that emit at different wavelengths between 800 and 850 nm. Wavelength separation and image acquisition were performed with a special optical arrangement, including narrow-bandpass filters and three black-and-white cameras. The shearographic camera with a variable shearing element, in combination with the appropriate illumination geometry, permitted us to isolate all six displacement derivatives from phase-stepped fringe patterns. The optical system and the measurement procedure were validated with two different experiments. First, the shearographic sensor head was used for the determination of in-plane displacements, and, second, in-plane strain distributions of an aluminum block caused by temperature expansion were measured.

Additive-Subtractive Two-Wavelength ESPI Contouring by Using a Synthetic Wavelength Phase Shift.

The addition correlation of two speckle fields by simultaneousillumination at different wavelengths is used for object contouring ina Twyman-Green-type interferometer. Fringe visibility is enhancedwhen the stochastic speckle background intensity obtained from areference plane modulation is subtracted. We calculate the contourphase map by using a phase-shift algorithm in the syntheticwavelength. A comparison with a sequential illumination, phasedifference method based on a laser wavelength phase shift isgiven. The test setup does not need to be stable on aninterferometric scale, and therefore a method is provided that lendsitself to applications in noisy environments.