Modeling of light propagation in skin, and an application to noninvasive diagnostics

Diabetics would greatly benefit from a device capable of providing continuous noninvasive monitoring of their blood glucose levels. At present, diabetics rely on pricking their finger to obtain a blood sample which in turn is placed upon a test strip. Life long finger pricking is often accompanied by chronic infections and pain during the lancets prick. Moreover, to significantly reduce longer-term secondary effects of diabetes such as retinopahy, nephropathy or neuropathy on the one hand and to reduce the risk of unnoticed suffering from hypoglycemia on the other hand a more frequent or even continuous monitoring of blood glucose swings is needed. In the past decade several attempts have been made to measure the glucose content of blood in a more compliant fashion. These endeavors will gain importance in the near future. Already nowadays, diabetes ranges among the top civilization deseases, about 10 of all U.S. citizens are living with this diagnosis, European citizens will make up in the future. Many techniques have been suggested for continuous monitoring of glucose, ranging from implanted electrochemical sensors to noninvasive optical methods. So far none of these methods have proven to be sensitive or specific enough for commercial use. The method proposed in this thesis deals with an effect which is based upon changes of the light scattering coefficient in the upper dermal regions of skin induced by glucose dissolved in the interstitial fluid. We will focus on the identification of this coefficient in vivo. As we want to probe our tissue with decoherent light of a single wavelength in the near infrared regime, the physical process is properly described by the radiative transfer equation. The modeling has to face the task of mapping a special measurement setting as well as spatial and temporal varying skin optical properties to a proper boundary value problem formulation for the radiative transfer equation and an effective

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Universität Heidelberg

Year

2001

Author dc:creator

• Volz, Dietmar

Contributors dc:contributor

• Jäger, Willi

Repository record source_url

http://www.ub.uni-heidelberg.de/archiv/1877

OAI identifier oai:identifier

oai:archiv.ub.uni-heidelberg.de:1877