Teaching Plan Name:LU Chuan Academic Year:2012-2013 Term :2 Date:March 18 Period:3-4 Textbook Diagnostic Imaging Content Foundations of 2 Objectives Tomphysics instrumentation,transducers of ultrasound Key points Sound Reflections,Acoustic Impedance,Doppler Effect Por Piezoelectric Effeet Content for lfstudy Interventional ultrasound Teaching equipment multimedia Related knowedge Physics of urasound Teaching methods Heuristic method /discuss Outlinesrequrements and time llo What is Ultrasound? 5 Sound Wave A wave is a propagation energy that moves back and forth or vibrates at a steady rate. Sound wave are mechanical oscillations that are transmitted by particles in a gas liquid,orsolid Wave are generated over a period of time.The time required to produce each cycle depends on the nd is char err to the "om o6时prude of the时m日d e wave is 00000 oscillation/see=1megahertz(1MHz)1 Teaching Plan Name：LU Chuan Academic Year：2012-2013 Term :2 Date：March 18 Period：3-4 Textbook Diagnostic Imaging Specialty and Stratification 2010MBBSAutumn (international students) Content Foundations of sonography 1 Teaching hours 2 Objectives To master the physics, instrumentation, transducers of ultrasound Key points Sound Reflections, Acoustic Impedance, Doppler Effect Points difficult to understand Piezoelectric Effect Content for self study Interventional ultrasound Teaching equipment multimedia Related knowledge Physics of ultrasound Teaching methods Heuristic method /discuss Outlines, requirements and time allocation What is Ultrasound? U ltrasound refers to sound waves beyond the audible range Generated by an external source, ultrasound is the transmission of high-frequency mechanical vibrations greater than 20 kilohertz (kHz) through a medium. Diagnostic application of ultrasound use frequency of 3.5-10MHz Basics-Physics For Successful Scanning In order to obtain the best image possible, basic fundamentals of ultrasound wave physics must be understood and applied。 Sound Wave A wave is a propagation energy that moves back and forth or vibrates at a steady rate. Sound wave are mechanical oscillations that are transmitted by particles in a gas, liquid, or solid medium. Wave are generated over a period of time. The time required to produce each cycle depends on the frequency of the transducer. This time interval is the period of the wave. As frequencies become higher, the pulse duration decrease, yielding a decrease in the depth of field. Frequen cy Sound is characterized according to its frequency .In ultrasound ,frequency refers to the number of oscillations per second performed by the particles of the medium in which the wave is propagation. 1 oscillation/sec =1 hertz(1Hz) 1000 oscillation/sec = 1 kilohertz (1kHz) 1,000,000 oscillation/sec = 1 megahertz(1MHz) 5’