Download
1 / 45
460 likes | 565 Views
Explore the world of ultrasound in this resource covering principles, history, properties of sound waves, transducers, advantages, and disadvantages of diagnostic ultrasound imaging. Learn about its evolution, applications, and the importance of ergonomics in sonography. Discover the significance of real-time, Doppler, and color flow Doppler imaging. This guide is ideal for students, professionals, and anyone interested in the field of sonography.
E N D
Ultrasound Spring 2009 Student Final
Ultrasound AKA: 1)Diagnostic Medical Sonography 2)Sonography 3) 4) Vascular Sonography 5)Echocardiography
Principles of Diagnostic Ultrasound • NON- ionizing • Uses high frequency sound waves • By giving reflections from parts in the body • ? • Cost effective • ? • Can be imaged in sectional, coronal and oblique planes
What makes a good Sonographer? • Knowledge of detailed anatomy and Pathophysiology • 3D anatomy • Good communication • Be able to work under stress
Poor ergonomic habits Poor equipment design Poor posture 80% have muscloskeletal injuries Shoulder (rotator cuff) ? Neck Lower Back Pain ? Eyesight problems Why? Sustained pressure and force ? Assisting with patient movement ? Inadequate work breaks Overall job stress Repetitive Motion Injuries
Still a Neonate • Fairly new technology compared with x-ray • First used for navy sonar in World War II • 1940’s • US waves transmitted and returned
1947 – Through- Transmission • Used to detect tumors and intracranial lesions • With 2 transducers opposite sides of the head • Called through-transmission
Contact Compound Scanner • 1957 • Tom Brown and Ian Donald • Obstetric techniques
Present Day • Smaller machines • Increased resolution • Real time scanning • Portable • Mobile
Properties of Sound Waves • Acoustic waves • Energy that moves back and forth or vibrates at a steady rate • Audible sound waves • 16,000 – 20,000 cycles/sec • Ultrasound waves • 1- 10 million cycles/sec • _____________ mechanical vibrations through a medium • Transmitted by particles of gas, liquid or solid medium
Piezoelectric Effect • AC applied across piezoelectric crystals • Crystals grow an shrink • Conversion of electrical energy to mechanical energy • US is produced from a transducer by this effect
Acoustic Impedance • Has properties similar to light • Focused, refracted, reflected or scattered • Dependent on the density and elastic properties of medium • Velocity of sound • Sound waves are sent and received • Velocity is different among bone, air and soft tissue • Poor impedance in air • Pitch and sound waves are picked up by computer and produce images: based on depths and speeds
Elements of Transducers • Capable of sending and receiving US
Advantages of US • 1. Ultrasound examinations can be non-invasive • 2. Ultrasound methods are relatively inexpensive, quick and convenient • 3. No harmful effects have been detected • 4. Ultrasound is particularly suited to imaging soft tissues
Disadvantages of US • 1. The major disadvantage is that the resolution of images is often limited. • 2. Ultrasound is reflected very strongly on passing from tissue to gas, or vice versa • 3. Ultrasound also does not pass well through bone
Real Time, Dopplerand Color Flow Doppler • Real time: • Multiple rapid image frames per second • Ex: can see pulsative vascular, cardiac structures, diaphragm motion & peristalsis • Doppler • Frequency change in laminar or turbulent flow in vascular structures • Color Doppler • Assigns a color scale to change in frequency • Red toward transducer and blue away from transducer
