医学影像诊断学----1.ppt

Diagnostic of Ultrasonography
ZHANG MEI
Foundations of Ultrasonography
Historical perspective of sound
In 1947, made one of the earliest applications of ultrasound to medical diagnosis.
In 1948, developed the first ultrasound scanner
In 1954,echocardiographic techniques were developed by and in Sweden.
In 1962,the development of the contact static scanner in North America.
In 1972,the new revolutionary gray-scale imaging and improved resolution real-time scanners were developed
Clinical choice of imaging technique
plication
one→many (convenient)
No damage → less damage → more damage
(safe)
Low expense→high expense (cheap)
Compared with CT&MRI
灰阶超声成像(grey scale ultrasonic tomography)。
Advantage: Not expensive as CT&MRI,sectional imaging,real-time,no radiation
Disadvantage: Contrast and spatial resolution of imaging is not as good as CT&MRI.
Qualities of a Sonographer
Intellectual curiosity
Perseverance to obtain high-quality images
Ability to conceptualize 2D images into a 3D format
Quick-thinking and analytic capabilities
Good physical munication skills
Dedication
Basic ultrasound principles
Ultrasound:f>20,000Hertz(Hz)
A wave is a propagation of energy that moves back and forth or vibrates at a steady waves are mechanical oscillations that are transmitted by particles in a gas,liquid or solid medium.
Compared with Audible sound
Common:essential qualities; a kind of mechanical vibration; longitudinal wave; spread in elasticity medium; a kind of energy convert
Difference: high frequency of wave, short wavelength, spread along straight line, good directivity