VTT Technical Research Centre of Finland Ltd. Espoo, Finland
www.vttresearch.com/media/news
In the future, selected illnesses will be quickly and painlessly diagnosed by the optical analysis of isotopes contained in exhaled air. VTT Technical Research Centre of Finland developed its first prototype device for this purpose. With the device, it’s possible to determine painlessly and with absolute certainty whether a patient’s stomach troubles are caused by Helicobacter. The certainty of the device is based on its ability to measure not only carbon-13 (13C), but also oxygen-18 (18O) in exhaled air.
The Helicobacter pylori or Helicobacter can cause several problems in the upper gastrointestinal tract, such as ulcers and gastritis. According to estimates, 30 to 40% of the population in developed countries has the infection. Diagnosis of the bacteria is unpleasant for the patient, as it requires a biopsy using gastroscopy, which currently means that the patient has to swallow a tube that is then used to take a sample from the stomach. The accuracy of the procedure depends on the skills of the person performing the procedure, and getting a diagnosis may take several days.
The exhaled-air diagnostic device is based on a technology developed by VTT’s MIKES Metrology — optical absorption spectroscopy in a multipass chamber with the sample volume reduced to just 40 microliters, which is less than ten-millionths of an adult’s lung capacity. The gas inside the chamber can quickly be exchanged because of the extremely small sample volume. As a result, the entire breathing cycle of the patient can be rapidly analyzed by the same device.
Diagnosis methods based on respiratory air are a growing trend. In addition to the Helicobacter, respiratory air can be used to analyze a person’s energy consumption and weight loss, early-stage Type 2 diabetes, and blood poisoning (sepsis) that causes considerable expenses to hospitals, and is one of the main causes of mortality after surgery.
VTT is planning follow-up projects to expand the device for diagnosing other illnesses. The device can be used to analyze proteins and various chemicals, as well as oxygen-17. In addition, because the device measures completely safe, stable isotopes, it can also be utilized by the food industry.
The analyzer has possible applications in the monitoring of surgery patients and unconscious patients, because it can operate next to the patient around the clock. Accurate and specific data can be obtained from each breathing cycle.
VTT’s prototype includes a computer, a pump, and optics, and is operated with a single button. It communicates wirelessly with tablets and smartphones. The result of the measurement is displayed immediately.
Current commercial devices based on exhaled-air analysis give a result with 95 to 98% reliability, which means the results must often be confirmed with gastroscopy. VTT’s device has the benefit of eliminating false positives from the analyses. According to a study published in 2014, 100% analysis accuracy can be achieved when oxygen-18 and carbon-13 are both analyzed from exhaled air. The current commercial exhaled-air analyzers only perform the analysis on carbon-13.
How it Works
Carbon dioxide is composed of carbon atoms with different masses. The origin of the gas can be determined by measuring these carbon isotopes. Helicobacter is detected in exhaled air when the carbon-12 of a urea molecule is artificially replaced by carbon-13. This replacement is done by means of a harmless pill containing the urea chemical, which is swallowed by the patient. If there are Helicobacter in the stomach, they will break down the urea molecules into carbon dioxide molecules that will then enter the patient’s system, eventually traveling via the lungs into the exhaled air.
The device developed by VTT analyzes the ratio between carbon-13 and carbon-12 in exhaled air. When the carbon-13 ratio in exhaled air increases after taking the pill, it has been shown with 97% certainty that the patient is suffering from Helicobacter that can be treated with drugs. The difference in VTT’s device is that it also analyzes the ratio of oxygen-18 in the exhaled air, which guarantees a 100% certainty.
Spectrometry based on the analysis of isotopes has thus far been widely applied in medical analysis, because carbon-13 is relatively easy to measure with a nondispersive optical device. Detecting oxygen-18 is more difficult due to its significantly weaker absorption, and spectrally, it is located between the main isotope and carbon-13. Its detection requires mid-infrared lasers that did not enter the market until recent years.
