You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.
23 February 2010Optoacoustic 13C-breath test analyzer
The composition and concentration of exhaled volatile gases reflects the physical ability of a patient. Therefore, a breath
analysis allows to recognize an infectious disease in an organ or even to identify a tumor. One of the most prominent
breath tests is the 13C-urea-breath test, applied to ascertain the presence of the bacterium helicobacter pylori in the
stomach wall as an indication of a gastric ulcer. In this contribution we present a new optical analyzer that employs a
compact and simple set-up based on photoacoustic spectroscopy. It consists of two identical photoacoustic cells
containing two breath samples, one taken before and one after capturing an isotope-marked substrate, where the most
common isotope 12C is replaced to a large extent by 13C. The analyzer measures simultaneously the relative CO2
isotopologue concentrations in both samples by exciting the molecules on specially selected absorption lines with a
semiconductor laser operating at a wavelength of 2.744 μm. For a reliable diagnosis changes of the 13CO2 concentration
of 1% in the exhaled breath have to be detected at a concentration level of this isotope in the breath of about 500 ppm.