A new system aiming for more effective thermal treatment of tumor is presented in this paper. It facilitates liquid nitrogen (LN2) cooling and radiofrequency (RF) heating in tissue. The bio-heat transfer model has been built to illustrate temperature transients during the treatment, and the induced bio-thermal effects were analyzed at both the tissue and cellular levels. For accurate predictions, the corresponding inactivation energy Delta H of human breast cancer cells (MAD-MB-231) has been obtained through experimental measurements. The results show that through the alternate cooling and heating, the damage region is significantly increased, which cannot be achieved by either the cooling or heating treatment alone. (C) 2008 Elsevier Ltd. All rights reserved.