The Modular Design Of Exhaled Breath Detecting E-Nose Instrument Intended For Screening Of Lung Cancer

As is known to all, lung cancer has been proved to be the leading cause of death caused by all kinds of tumor. It is a novel diagnostic method of the detection of human breath with advantages of non-invasive, unmarked, fast and low cost. The thesis proposes a modular design of an electronic nose instrument based on customized array of metal-oxide semiconductor sensors with the purpose of exhaled breath detection. The electronic nose can detect several categories of lung cancer specific volatile organic compounds with high sensitivity and low detection limit of ppb level. That the sensitivity and specificity could be further improved for the screening of lung cancer by the MOS-SAW hybrid electronic noses' system has been verified through the clinical study.To begin with, the thesis presents a few cases which successfully detetct the human diseases through analysis of exhaled breath. It has also summarized a number of recent advances in the research of instrumentation intended for the breath diagnosis of lung cancer. Next, the thesis introduces the research work within three main modules of the electronic nose in detail.1. The module of detector. The sensitive mechanism and mathematical model of single MOS sensor have been studied before the introduction of its different structure types, signal detecting circuits, new features and applications of semiconductor gas sensor. The formation of sensors'array and its packaging chamber in the module has also been studied.2. The modules of airway and circuit. The enrichment & desorption unit has been introduced along the discussion about pre-concentration materials, which is recognized as the main part within the airway structure. And the circuits for acquisition of sensors'signal, control of airway structure components, and design of user interface have been studied, which are closely related to the functions of airway in the module. A series of novel sampling methods have been investigated aiming at the analysis of exhaled breath based on the above-mentioned hardware modules. A novel type of electronic nose with GC-MOS-SAW structure has been under testing experiments.3. The module of embedded software. It is devised on the basis ofμC/OSⅡand becomes another module of the instrument. This thesis presents two solutions for the instrumental graphical user interface using both the simulation platform and the touch panel as well.Finally, series of calibrating experiments and clinical tests are introduced in this thesis, which are supported by hospitals, including Sir Run Run Shaw Hospital and the No.1 Hospital of Zhejiang Province. The sensitivity of 93.62% and specificity of 90.48% are obtained through the analysis of 47 lung cancer patients and 42 healthy controls using the MOS-SAW hybrid electronic noses'system. Basically, it can be convinced that this hybrid system is qualified for the clinical diagnosis for lung cancer patients. In combination with network, the hybrid system has the great potential to be a fast screening instrumental technology intended for high risk group of lung cancer.