Establishment And Verification Of Temperature Field Distribution Model Of Pulsed Nd: YAG Laser Irradiation Lips

OBJECTIVETo analyse the pulsed Nd:YAG laser (5w,100 Hz) heat transfer profiles on venous lakes of vermillion lip by observing temperature distribution of the tissue and establish nonlinear biological heat transfer equation and biological model.METHODThrough analyzing the profiles of heat transfer irradiated by pulsed Nd:YAG laser, three-layer fminte element mode was established and the nonlinear partial differential equation of heat transfer was calculated by Matlab software. The biological model was simulated to analyse the temperature response of the venous lakes of vermillion lip after laser irradiation time (2s,3s,5s,7s), and verify the FEM-3 model.RESULTSThe model temperature distribution after pulsed Nd:YAG laser (5w, 100Hz) irradiation varied in different time. The temperature was 40±0.10℃、 42±0.12℃、49 ±0.20℃、 52±0.10℃ (r>0.9, P＜O.05)at the time of 2s、 3s、5s、7s with blood perfusion, However, the temperature was 51±0.12℃、56±0.20℃、77±0.20 ℃.90±0.12℃ r>0.9, P<0.05) at the time of 2s.3s.5s.7s without blood perfusion. The biological model of pulsed Nd:YAG laser irradaition (5w,100 Hz) on venous lakes of vermillion lip showed that the temperature also varied in different time, with 90±0.20 ℃ at the time of 7s.CONCLUSIONfininte element mode model can well predict the biological reaction of vascular lesions after laser treatment.When lasing venous lakes of vermillion lip, irradiation time should not be more than 7s to avoid irreversible thermal damage. Besides, the blood flow can reduce temperature rise, which prompt that we could reduce thermal damage around the treatment area by using circulating cooling device.