Gerhard Mu¨ller

Bio: Gerhard Mu¨ller is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 818 citations.

Optical Properties of Circulating Human Blood in the Wavelength Range 400-2500 nm.

Abstract: Knowledge about the optical properties μa,μs, and g of human blood plays an important role for many diagnostic and therapeutic applications in laser medicine and medical diagnostics. They strongly depend on physiological parameters such as oxygen saturation, osmolarity, flow conditions, haematocrit, etc. The integrating sphere technique and inverse Monte Carlo simulations were applied to measure μa,μs, and g of circulating human blood. At 633 nm the optical properties of human blood with a haematocrit of 10% and an oxygen saturation of 98% were found to be 0.210±0.002 mm-1 for μa,77.3±0.5 mm-1 for μs, and 0.994±0.001 for the g factor. An increase of the haematocrit up to 50% lead to a linear increase of absorption and reduced scattering. Variations in osmolarity and wall shear rate led to changes of all three parameters while variations in the oxygen saturation only led to a significant change of the absorption coefficient. A spectrum of all three parameters was measured in the wavelength range 400-2500 nm for oxygenated and deoxygenated blood, showing that blood absorption followed the absorption behavior of haemoglobin and water. The scattering coefficient decreased for wavelengths above 500 nm with approximately λ-1.7; the g factor was higher than 0.9 over the whole wavelength range. © 1999 Society of Photo-Optical Instrumentation Engineers.

Optical properties of human skin, subcutaneous and mucous tissues in the wavelength range from 400 to 2000 nm

Abstract: The optical properties of human skin, subcutaneous adipose tissue and human mucosa were measured in the wavelength range 400–2000 nm. The measurements were carried out using a commercially available spectrophotometer with an integrating sphere. The inverse adding–doubling method was used to determine the absorption and reduced scattering coefficients from the measurements.

A review of indocyanine green fluorescent imaging in surgery

Abstract: The purpose of this paper is to give an overview of the recent surgical intraoperational applications of indocyanine green fluorescence imaging methods, the basics of the technology, and instrumentation used. Well over 200 papers describing this technique in clinical setting are reviewed. In addition to the surgical applications, other recent medical applications of ICG are briefly examined.

Optical properties of skin, subcutaneous, and muscle tissues: a review

Abstract: The development of optical methods in modern medicine in the areas of diagnostics, therapy, and surgery has stimulated the investigation of optical properties of various biological tissues, since the efficacy of laser treatment depends on the photon propagation and fluence rate distribution within irradiated tissues. In this work, an overview of published absorption and scattering properties of skin and subcutaneous tissues measured in wide wavelength range is presented. Basic principles of measurements of the tissue optical properties and techniques used for processing of the measured data are outlined.

Optical properties of normal and cancerous human skin in the visible and near-infrared spectral range.

Abstract: Differences in absorption and/or scattering of cancerous and normal skin have the potential to provide a basis for noninvasive cancer detection. In this study, we have determined and compared the in vitro optical properties of human epidermis, dermis, and subcuta- neous fat with those of nonmelanoma skin cancers in the spectral range from 370 to 1600 nm. Fresh specimens of normal and cancer- ous human skin were obtained from surgeries. The samples were rinsed in saline solution and sectioned. Diffuse reflectance and total transmittance were measured using an integrating sphere spectropho- tometer. Absorption and reduced scattering coefficients were calcu- lated from the measured quantities using an inverse Monte Carlo tech- nique. The differences between optical properties of each normal tissue-cancer pair were statistically analyzed. The results indicate that there are significant differences in the scattering of cancerous and healthy tissues in the spectral range from 1050 to 1400 nm. In this spectral region, the scattering of cancerous lesions is consistently lower than that of normal tissues, whereas absorption does not differ significantly, with the exception of nodular basal cell carcinomas BCC. Nodular BCCs exhibit significantly lower absorption as com- pared to normal skin. Therefore, the spectral range between 1050 and 1400 nm appears to be optimal for nonmelanoma skin cancer detection. © 2006 Society of Photo-Optical Instrumentation Engineers.