## 4 Conclusions  
The influence of each dynamic tissue property on HIFU hyperthermia is studied independently based on the reported experimental data of dynamic tissue properties. The findings in the present study suggest that the acoustic pressure is insensitive to the dynamic tissue properties. The numerical results also show that the dynamic acoustic absorption coefficient significantly affects the temperature and thermal damage zone; on the contrary, the dynamic non-linearity parameter has almost no effect on the temperature and thermal damage zone. It is found that the thermal damage zone for dynamic \(W_{b,liver}\) is smaller than that for constant \(W_{b,liver}\), and the influence of a dynamic sound speed, dynamic specific heat capacity, and dynamic density on the thermal damage zone is slight. It is also worth mentioning that the maximum focal temperature for dynamic \(K_{liver}\) is lower than that for constant \(K_{liver}\), but the thermal damage zone is almost the same for dynamic \(K_{liver}\) and constant \(K_{liver}\). Among all of the individual dynamic tissue properties, the dynamic acoustic absorption coefficient has the greatest influence on the temperature and thermal damage zone. Knowing the influence of each dynamic tissue property is beneficial to our deep understanding of the principle of HIFU therapy. Besides studying the influence of each individual dynamic tissue property, the simulation considering all of the dynamic tissue properties to explore the comprehensive influence on HIFU hyperthermia is performed. The numerical results show that the maximum focal temperature and thermal damage zone for simulation using all of the dynamic tissue properties increase, compared with those for simulation using constant tissue properties, implying that the simulation using constant tissue properties underestimates the focal temperature and thermal damage zone compared with the simulation using all of the dynamic tissue properties. Moreover, it is interesting to point out that the thermal energy absorbed by the tissue for simulation using all of the dynamic tissue properties is greater than that for simulation using dynamic \(\alpha_{liver}\), but the maximum focal temperature and thermal damage zone for simulation using all of the dynamic tissue properties decrease, compared with those for simulation using dynamic \(\alpha_{liver}\). Consequently, when doctors develop a more accurate clinical protocol for HIFU treatment planning, it is necessary to consider all of the dynamic tissue properties to assess the size of thermal damage zone, so as not to damage normal tissue.  
[PERSON] conceived and designed the research idea and the framework; [PERSON] and [PERSON]. ([PERSON]) performed the simulations; [PERSON] and [PERSON]. ([PERSON]) wrote the paper; [PERSON], [PERSON] and [PERSON] analyzed the data, [PERSON] and [PERSON]. ([PERSON]) modified the paper.  
This work is partially supported by the National Nature Science Foundation of China (No. 11474090, 11774088, 11174077, 61502164), Hunan Provincial Natural Science Foundation of China (No. 2016)J3090), Scientific Research Fund of Hunan Provincial Education Department (No. 16B155), Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province, Science and Technology Research Program of Chenzhou City (No. CZ2014039) and Research Program of Xiangnan University (No. 2014 XJ63).  
The authors declare no conflict of interest.