1. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 1 Ultrasound in Medicine Ch.4 Ultrasound pictures of the body

2. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 2 Applications of US in Medicine: -Are based on the principal of sonar. -The pulses frequency is ranging between (1-5) MHz. -Its average intensity of few m watts/cm 2. -Its mechanical work: -The types : -1- A-Scan (Pulsed scan). 2- B-Scan (2-d view). -3- M-Scan (Motion scan) 4- Doppler effect. vibrating crystal skinwater or a jelly paste (why?) 1-Pulses are transmitted into the body by placing the vibrating crystal in close contact with the skin using water or a jelly paste (why?) To eliminate the air. 2-This increases the transmission of the US into the body and the echoes back to the detector

3. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 3 First: A-Scan (Pulsed scan)  It’s used to obtain the diagnostic information about the depth of the structure in the body by : Measuring the time required to receive the echoes from the various from the body.  The transducer is fixed.  Pulses for A-scan work are a few microseconds long and emitted at 400 to 1000 pulses/sec.

4. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 4 Beaker of water electrical signal

5. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 5  The bases of use US in Medicine is: The partial reflection of sound at the surface between two media that have different acoustical properties.  The amount of reflection depend on: 1- The difference in the acoustical impedances of the two media. 2- 2- The orientation of the surface with respect to the beam.

6. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 6 Problems of ultrasound echos ’ detection :  1-The echoes are very small signals, why?  2-The resolution : is the ability  2-The resolution : is the ability of the equipment to detect separate echoes from two objects close together.   In general, structures smaller than the wave length cannot be resolved. Since :   λ = v/ƒ  better resolution  If the ƒ sound has λ and allows better resolution The absorption The absorption. Small echoes weak reflection and the absorption of the soundly tissue. than ƒ sound.

7. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 7 Fig. (4.2): Weak echoes from deep structures can fee electronically amplified to make them more visible, (a) the transmitted pulse T produces a weak echo R on the CRT. (b) the amount of amplification Increases with time (or distance), (c) The amplification Increases the size of the echo.

8. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 8 Medical Application of A – Scan 1- Detection of Brain tumors (echoencephalography) A tumor on one side of the brain tends to shift the midline toward the other side The abnormal case : If a shift was > 3 mm,,, adult > 2 mm,,, children

9. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 9 2- 2- ophthalmology (daises in the eye). We usually use ƒ up to 20 MHz in the eye ? For 2 reasons : 1- better resolution 1- to obtain better resolution,,, since there is no bone to absorb most of the energy. absorption is not significant 2- The absorption is not significant,,, because the eye is small. The US can provide information about deeper regions of the eye 1-the deeper regions of the eye like : Tumors, foreign bodies, and detachment of the retina. distances in the eye 2-To measure distances in the eye such as lens thickness, the distance to the retina, depth from cornea to lens, and the thickness of the vitreous humor.

10. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 10 Second : B – Scan (Two-Dimensional View)   Is used: 1-To obtain two dimensional views of parts of the body. 2-To provide information about the internal structure of the body. 3-In diagnostic studies of (the eye, liver, breast, heart, and fetus). 4-To detect pregnancy as early as the fifth week and can provide information about (the size, location, and change with time) of a fetus.   Has the same principle of A-Scan except the transducer is moved.   Each echo produces a dot on the oscilloscope.  provide more information less risk  In many cases B-scans can provide more information than x-ray and they present less risk.

11. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 11

12. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 12  in:  large echoes appear brighter than weak echoes in: Grey – scale display  ,where the brightness is directly proportional to the size of the echo.   Its advantage : is successful in detecting tumors such as liver tumors.

13. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 13 M – Scan (Motion Scan)  It  It combines certain features of the A-scan and the B- scan. The transducer is held stationary. the echoes appear as a dots.

14. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 14 Scan of the Heart   The places where the heart can be probed are quite limited because of poor ultrasound transmission through lung tissue and bone.  transducer patient's left side  The usual method is to put the transducer on the patient's left side,,, why? between the ribsover the heart tip itdifferent angles. Because the aim it between the ribs over the heart, and tip it at different angles to explore various regions of the heart.

15. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 15 Medical Application of M – scan : .  mitral valves.   Provide the information about the rate of closing and opening (motion) of the mitral valve is 72 mm/sec.   But in the abnormality case called mitral stenosis (a narrowing of the valve opening). The slope is reduced

16. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 16 The Doppler Effect  The doppler effect :.  The doppler effect : Is the frequency change due to the motion of the source or listener.   Δf = f - f = ± f(u/v)   Where:   Δf is (Shift doppler) the frequency change due to the motion of the source or the listener.   f is the frequency of the sound source. higher pitchtoward a listenerlower pitchaway from him ± f has(+) a higher pitch (frequency) when it is moving toward a listener and (-) a lower pitch when it is moving away from him.   v is the velocity of sound.   u is the velocity of source or listener.

17. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 17 Medical Application of Doppler effect 1- Measurement the velocity of blood.   Is used to measure the velocity of moving objects or fluids within the body such as the blood. This method to measuring blood flow doesn’t require surgery to implant measuring devices. Red blood cells in the arteries.

18. إعداد : أ. بلسم فهد صوفي،،،المصدر:محاضرات د.حنان 18 2- Measurement of fetal heart rate.   is used to detect motion of the fetal heart.