The production of short-lived radioactive gases for medical studies is discussed with regard to the chemical reactions in suggested targets. The chemistry of target materials was studied by using the technique of radio-gas-liquid partition chromatography to analyze the product gases. Based on the chemistry of the reactions of oxygen-15 in oxygen-nitrogen mixtures, and carbon-11 in boric oxide, targets were designed for the production of oxygen-15-labeled oxygen, oxygen- 15-labeled carbon monoxide, and carbon-11-labeled carbon monoxide in high yields and high radio-chemical purity.