Ultrasound effects

biological effects on ultrasound

1. BIOLOGICAL EFFECTS OF ULTRASOUND 1

2. CONTENTS INTRODUCTION TYPES OF BIOLOGICAL EFFECTS OF ULTRASOUND THERMAL EFFECTS NON THERMAL EFFECTS TYPES OF CAVITATION STABLE CAVITATION INERTIAL CAVITATION OTHER BIOLOGICAL EFFECTS THERMAL ABLATION SONOPORATION 2

3. INTRODUCTION Ultrasound is a high frequency mechanical waves that are above the human being range(>20,000Hz) They are produced by converting the electrical energy into mechanical energy. When transmission is through biological tissues and under certain conditions, they may cause biological effects. 3

4. TYPES 4

5. THERMAL EFFECTS Thermal effects result from the passage of ultrasound waveforms, with transformation of acoustic energy into heat. This constitutes the major potential adverse effect of obstetric ultrasound, with several reports existing of the deleterious effects of heat on embryos/fetuses in the animal model. This seems to occur when temperature rises 1.5°C above physiological levels. Thermal effects depend on the type of tissue exposed, the duration of exposure, ultrasound mode, and the distance between tissue and emission source . 5

6. NON THERMAL EFFECTS MECHANICAL Mechanical effects result from the alternating pressures that are generated. The main effect occurs because of the interaction between ultrasound waves and gas bubbles present in tissues. 6

7. NON THERMAL EFFECTS(Contd..) CAVITATION Sound waves generate movement in and around gas bubbles, which can affect the surrounding tissues and lead to cavitation. These bubbles generally of a micron 10 -6 m diameter. The bubbles increases and decreases in pressure alternatively. 7

8. TYPES OF CAVITATION There are two types of cavitation: STABLE CAVITATION INERTIAL (NON-STABLE) CAVITATION 8

9. STABLE CAVITATION Stable cavitation describes the steady oscillation of the size of microbubbles as the pressure changes at the focal point It can induce moderate changes at the cellular level, such as increasing cell membrane permeability to drugs and other molecules. It also causes mechanical damage , membrane rupture , and sometimes cell lysis. 9

10. INERTIAL CAVITATION Inertial cavitation occurs when the transmitted power is high enough to cause a violent collapse of microbubbles that destroys the tissue This type of cavitation can be used to create mechanical “lesions” such as those created by histotripsy. It causes genetic damage in vitro . 10

11. Other Biological Effects Applying focused ultrasound to living tissue results in other effects like tissue destruction, localized drug delivery, or a range of other effects. Tissue Destruction : Tissue destruction is one of the most common applications of focused ultrasound 11

12. THERMAL ABLATION The most clinically advanced bioeffect of focused ultrasound, produces cell death in a targeted area with minimal damage to the surrounding tissue Tissue damage can be accurately controlled using a range of focused ultrasound transducers with different sonication sizes. 12

13. SONOPORATION Cell membranes often prevent large molecules such as drugs and genes from entering cells and taking effect This effect, known as sonoporation, can increase the efficacy of drugs and genes in precise areas in the body 13

14. REFERENCES https://www.glowm.com/article/heading/vol-5--surveillance-of-fetal-wellbeing--effects-of-ultrasound-on-biological-tissues-and-cells/id/411403# Bioeffects_Paper_July_2015.pdf https://www.slideshare.net/muthuu978/ultrasound-therapy https://www.slideshare.net/shatham/bioeffect-of-ultra-sound 14

15. THANK YOU 15