Breath analysis is in use since a long history as a part of medical diagnostics. Idea that some of the diseases are characterised by a specific odour was already known since the Hippocrates time. Modern breath analysis has significantly developed comparing to the discovery of the several hundred different VOCs in the common human breath to more than a thousand different VOCs. Regrettably, lack of specificity and selectivity of the semiconductor sensors lead to complications sensing to differ between those compounds for modern semiconductor. Accordingly, it may be a challenge to give right diagnosis to a patient. To improve such a drawback, a new approach of sensing was provided. Using n- doped semiconductor and the spotlight lamp as an optical irradiation source have shown a possibility to sense different concentrations of acetone vapour. Measured signal maximal increment relative to air in the presence of acetone is 17% (measurement uncertainty 0,72%). It is possible clearly distinguish between healthy and diabetic patients. Thus present way of stimulation may be used to increase level of acetone sensing.