模拟医学教育(Simulation Based Medical Education,SBME)是利用医学模拟技术创设高仿真模拟病人和临床情景来代替真实的病人进行临床医学教学实践。与传统的以患者为基础的培训相比,它具有真实性、安全性、可重复性、多样性、可控性等...模拟医学教育(Simulation Based Medical Education,SBME)是利用医学模拟技术创设高仿真模拟病人和临床情景来代替真实的病人进行临床医学教学实践。与传统的以患者为基础的培训相比,它具有真实性、安全性、可重复性、多样性、可控性等特点。血液透析是终末期肾脏病患者延续生命的重要治疗方法。具有较强的专科性,技术要求高、风险大,操作中不仅包含临床医学方面的知识,还涉及医学工程学、物理学等多学科的知识。此外,治疗过程中可能出现低血压、痉挛、空气栓塞、水污染甚至心脏骤停等并发症。因此,在血液透析操作培训中,需要针对复杂情况进行更高级别的训练。此外,高保真血液透析模拟器还可提供实时生理变化的演变,并根据所模拟的场景发出适当的反应。使得受训者可以训练和掌握一系列临床技能,为经常发生和不经常发生的临床情况做好准备。加深受训者对血液透析理论知识的理解和对实际操作的感性认识,提高受训人员思考和解决问题的能力。展开更多
A 3D ultrasound thermal model with a 3D finite element representation for modeling the thermal diffusion effects for hepatic ablation induced by spherical-section ultrasound phased array was developed. The model was f...A 3D ultrasound thermal model with a 3D finite element representation for modeling the thermal diffusion effects for hepatic ablation induced by spherical-section ultrasound phased array was developed. The model was first validated against available published measured data in rat liver. Using the validated model,effects of blood perfusion and heating schemes on lesion formation were studied for both single focus and split-focus intensity patterns. It was shown that for single focus sonication pattern the short-duration(～2 s) and high-intensity(～1250 W/cm2) heating scheme can completely reduce the cooling effect of the blood perfusion. The lesion shape and size were significantly altered by perfusion for split-focus pattern even with a rapid heating scheme when the focus spacing was larger than 2.4 mm. Underdosed areas might be present between two foci. Prolonging ex-posure time or shortening focus spacing can reduce the cool region between two foci. In addition,the influences of thermal and acoustic parameters were also studied. When the therapy depth is short(<5 cm) ,the lesion size monotonically increases with increasing attenuation coefficient that ranges from 5.4 to 11 Np/(m?MHz) .展开更多
The mechanical behavior of non-Newtonian fluids can be modeled by several constitutive differential equations. The Oldroyd model is viewed as one of the successful models for describing the response of a subclass of p...The mechanical behavior of non-Newtonian fluids can be modeled by several constitutive differential equations. The Oldroyd model is viewed as one of the successful models for describing the response of a subclass of polymeric liquids, in particular the non-Newtonian behavior exhibited by these fluids. In this paper, we are concerned with the study of the unsteady flows of an incom-pressible viscoelastic fluid of an Oldroyd-B type in a blood vessel acting on a Brownian force. First we derive the orientation stress tensor considering Hookean dumbbells on Brownian configuration fields. Then we reformulate the three-dimensional Oldroyd-B model with the total stress tensor which consists of the isotropic pressure stress tensor, the shear stress tensor, and the orientation stress tensor. Finally we present the numerical simulations of the model and analyze the effect of the orientation stress tensor in the vessel.展开更多
文摘模拟医学教育(Simulation Based Medical Education,SBME)是利用医学模拟技术创设高仿真模拟病人和临床情景来代替真实的病人进行临床医学教学实践。与传统的以患者为基础的培训相比,它具有真实性、安全性、可重复性、多样性、可控性等特点。血液透析是终末期肾脏病患者延续生命的重要治疗方法。具有较强的专科性,技术要求高、风险大,操作中不仅包含临床医学方面的知识,还涉及医学工程学、物理学等多学科的知识。此外,治疗过程中可能出现低血压、痉挛、空气栓塞、水污染甚至心脏骤停等并发症。因此,在血液透析操作培训中,需要针对复杂情况进行更高级别的训练。此外,高保真血液透析模拟器还可提供实时生理变化的演变,并根据所模拟的场景发出适当的反应。使得受训者可以训练和掌握一系列临床技能,为经常发生和不经常发生的临床情况做好准备。加深受训者对血液透析理论知识的理解和对实际操作的感性认识,提高受训人员思考和解决问题的能力。
基金Project (No. 2003CB716103) supported by the National Basic Research Program (973) of China
文摘A 3D ultrasound thermal model with a 3D finite element representation for modeling the thermal diffusion effects for hepatic ablation induced by spherical-section ultrasound phased array was developed. The model was first validated against available published measured data in rat liver. Using the validated model,effects of blood perfusion and heating schemes on lesion formation were studied for both single focus and split-focus intensity patterns. It was shown that for single focus sonication pattern the short-duration(～2 s) and high-intensity(～1250 W/cm2) heating scheme can completely reduce the cooling effect of the blood perfusion. The lesion shape and size were significantly altered by perfusion for split-focus pattern even with a rapid heating scheme when the focus spacing was larger than 2.4 mm. Underdosed areas might be present between two foci. Prolonging ex-posure time or shortening focus spacing can reduce the cool region between two foci. In addition,the influences of thermal and acoustic parameters were also studied. When the therapy depth is short(<5 cm) ,the lesion size monotonically increases with increasing attenuation coefficient that ranges from 5.4 to 11 Np/(m?MHz) .
基金supported by the Basic Science Research Program through the National Research Foundation (NRF) of Korea funded by the Ministry of Education, Science and Technology (MEST) (Grant No. 2009-0074305)
文摘The mechanical behavior of non-Newtonian fluids can be modeled by several constitutive differential equations. The Oldroyd model is viewed as one of the successful models for describing the response of a subclass of polymeric liquids, in particular the non-Newtonian behavior exhibited by these fluids. In this paper, we are concerned with the study of the unsteady flows of an incom-pressible viscoelastic fluid of an Oldroyd-B type in a blood vessel acting on a Brownian force. First we derive the orientation stress tensor considering Hookean dumbbells on Brownian configuration fields. Then we reformulate the three-dimensional Oldroyd-B model with the total stress tensor which consists of the isotropic pressure stress tensor, the shear stress tensor, and the orientation stress tensor. Finally we present the numerical simulations of the model and analyze the effect of the orientation stress tensor in the vessel.
