  A new approach for continuous and non-invasive monitoring of the glucose
concentration in human epidermis has been suggested recently. This method is
based on photoacoustic (PA) analysis of human interstitial fluid. The
measurement can be performed in vitro and in vivo and, therefore, may form the
basis for a non-invasive monitoring of the blood sugar level for diabetes
patients. It requires a windowless PA cell with an additional opening that is
pressed onto the human skin. Since signals are weak, advantage is taken of
acoustic resonances of the cell. Recently, a numerical approach based on the
Finite Element (FE) Method has been successfully used for the calculation of
the frequency response function of closed PA cells. This method has now been
adapted to obtain the frequency response of the open cell. Despite the fact
that loss due to sound radiation at the opening is not included, fairly good
accordance with measurement is achieved.
