UltrasoUnd Physics & instrUmentation - Pegasus Lectures
UltrasoUnd Physics & instrUmentation - Pegasus Lectures
UltrasoUnd Physics & instrUmentation - Pegasus Lectures
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8.3 Transmit Voltages for Various Modalities .................................................................................634<br />
8.4 Ultrasound Modalities in Terms of Cavitation ..........................................................................635<br />
8.5 Theory of FDA Limits ...............................................................................................................636<br />
9. Acoustic Power Measurements ...........................................................................................................636<br />
9.1 Overview of Acoustic Power Measurements ............................................................................636<br />
9.2 The Hydrophone ........................................................................................................................637<br />
9.3 Six Degrees of Freedom ............................................................................................................638<br />
9.4 Beamplots .................................................................................................................................639<br />
10. Output Display Standards ....................................................................................................................641<br />
11. Mechanical Index (MI) ........................................................................................................................641<br />
12. Thermal Indices ...................................................................................................................................642<br />
12.1 Absorption Rates of Various Mediums ......................................................................................642<br />
12.2 Thermal Indices Defined ...........................................................................................................642<br />
12.3 The Three Thermal Indices ........................................................................................................642<br />
12.4 Underestimation of Worst Case .................................................................................................642<br />
13. AIUM Statements Regarding Ultrasound and Bioeffects ...................................................................643<br />
13.1 Acknowledging the AIUM ........................................................................................................643<br />
13.2 How Best to Use the Following Pages ......................................................................................643<br />
13.3 Conclusions Regarding the Safety of Ultrasound......................................................................643<br />
13.4 ALARA Principle ......................................................................................................................644<br />
13.5 Prudent Use................................................................................................................................644<br />
13.6 Safety Concerns Regarding the Use of Ultrasound in Training and Research ..........................645<br />
13.7 Statement Regarding Non-Human Mammalian In Vivo Biological Effects .............................645<br />
13.8 The Mechanical Index and Conclusions Regarding Gas Bodies ...............................................646<br />
13.9 Conclusion Regarding Heat and the Thermal Indices (TIS, TIB, TIC) .....................................648<br />
13.10 Thermal Effects on the Fetus .....................................................................................................650<br />
13.11 The AIUM Statement Regarding “In Vitro” Biological Effects ................................................650<br />
13.12 AIUM Conclusions Regarding Epidemiology for Obstetric Ultrasound ..................................651<br />
14. Conceptual Questions ..........................................................................................................................651<br />
15. Review Sheet For Converting Intensities ............................................................................................653<br />
15.1 Conversion Between Spatial Peak and Spatial Average ............................................................653<br />
15.2 Converting Between the Pulse Average and the Temporal Average ..........................................653<br />
15.3 ...................................................................................................................................................653<br />
16. Hydrophones .......................................................................................................................................655<br />
16.1 Comparison Table ......................................................................................................................655<br />
16.2 Membrane Hydrophones (HMA and HMB)* ............................................................................656<br />
16.3 Capsule “Golden Lipstick” Hydrophones (HGL)* ...................................................................656<br />
16.4 Needle Hydrophones (HNZ and HNV)* ...................................................................................656<br />
16.5 Needle Reflecting Hydrophones (HNR)* ..................................................................................656<br />
CHaPTeR 10 - Contrast and Harmonics<br />
1. Motivation for Contrast Imaging .........................................................................................................659<br />
1.1 Overcoming Too Much Attenuation ..........................................................................................659<br />
1.2 Conventional Approaches ..........................................................................................................659<br />
1.3 Increasing the Acoustic Impedance Mismatch ..........................................................................659<br />
1.4 Increase in Signal Amplitude with Contrast ..............................................................................660<br />
2. Fundamentals of Harmonics ................................................................................................................660<br />
2.1. Motivation for Harmonic Imaging ...........................................................................................660<br />
2.2 Mechanisms that Produce Harmonic Signals ............................................................................661<br />
xxx<br />
<strong>Pegasus</strong> <strong>Lectures</strong>, Inc.
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