Recently, Radio Frequency Ablation (RFA) is becoming a popular therapy for 
various cancers such as liver, breast, or lung cancer. RFA is one kinds of 
thermal therapy. However, it has been often reported about excessive ablation or 
non-ablation due to difficult control of ablation energy. In order to solve 
these difficulties, we have been proposed robotized RF-ablation system for 
precise cancer treatment. We have been tried to control heat energy by control 
of electromagnetic-wave frequency. In this paper, we reported about relation 
among electrical impedance of lung, lung's internal air volumes, and heat energy 
by use of electromagnetic-wave. In case of RFA for lung cancer, heat energy 
depends on electrical impedance and lung's internal air volumes. Electrical 
impedance has the dependence of electromagnetic-wave frequency and the 
dependence of lung's internal air volumes. Therefore, firstly we considered 
about fractional calculus model between lung's internal air volumes and 
electrical impedance. Secondly, we measured electric impedance frequency 
characteristic of lung with change of lung's internal air volumes. The measured 
and modeled results showed that use of fractional calculus realized high 
accurate model for electrical impedance of lung. And, from the results of 
numerical analysis of heat energy, it is supposed that control of 
electromagnetic-wave frequency has a small effectiveness for lung tissue 
ablation even if lung includes abundant air.