PTAP 1240 - Ultrasound Test Questions with Correct Answers Latest Update

PTAP 1240 - Ultrasound Test Questions with Correct Answers Latest Update ultrasound - Answers -sound waves with a frequency greater than 20,000 hertz -has a thermal/nonthermal effects when applied to the body sound waves enter the body and are attenuated by? - Answers -absorption -reflection -refraction attenuation - Answers gradual decrease in intensity as ultrasound travels through tissue absorption - Answers -some tissues are capable of greater absorption of ultrasound than others -tissue and frequency specific -higher absorption occurs in tissue with a high collagen rate and with higher us frequencies ultrasound energy absorption - Answers best in tendon, ligament, fascia joint capsule and scar tissue reflection of a sound wave - Answers occurs when the wave passes between two tissues and a fraction of the wave "bounces" back refraction - Answers occurs when the US signal is deflected from a straight path and the angle of deflection is away from the transducer coupling agents - Answers gel and water US parameters - Answers -effective radiating area (ERA) -cm2 -beam nonuniformity ratio (BNR)- ratio -intensity- 2 -frequency- MHZ -duty cycle-% effective radiating area (ERA) - Answers -area of the crystal that actually produces sound waves -energy is concentrated near the center -era is always smaller than the total size of the transducer head beam profile - Answers -multiple ways to emerge from the head -energy diverges as it moves away from the source -energy is uniform close to the head (fresnel zone) -becomes less consistent farther away from the head (spatial peak intensity) beam nonuniformity ration (BNR) - Answers -describes amount of variation in the beam -perfect beam would have a BNR of 1:1 ration is between the spatial peak intensity and spatial averaged intensity -high the quality of the crystal, the lower the BMR -lower BNR is more favorable since patients will be less likely to experience hot spots and discomfort during treatment frequency - Answers -selected according to the depth of the tissue to be treated -US delivered at a higher frequency is absorbed more rapidly than US delivered at a lower frequency 3 MHZ - Answers reaches soft tissues 1-2 cm deep 1 MHZ - Answers reaches soft tissues up to 5 cm deep intensity - Answers -measures the quantity of energy delivered per unit area -spatial average intensity: the average intensity of the US input over the area of the transducer; expressed in w/cm2 -selected according to treatment goal -3 MHZ increases tissue temp ~3x faster than 1 MHZ when same duty cycle - Answers portion of treatment time that US is generated during the entire treatment continuous - Answers uninterrupted flow of sound waves; intensity remains constant; 100% used when the goal is to increase tissue temp pulsed - Answers produced by intermittently interrupting the supply of electrical energy to the US head, which causes the sound waves to be discontinuous; 20% most recommended pulsed cycle; used when nonthermal effects desired thermal effects - Answers -increase extensibility of collagen structures -decrease joint stiffness and inflammation -pain relief -increase blood flow -decrease muscle spasms -increased metabolic rate -enhanced immune system response -decreased viscosity of tissue fluids continuous US - Answers -sound waves consist of compression and rarefaction which oscillates particles of material; increases in molecular vibration in the tissue can result in the heat generation -extent of thermal effects is dependent on the intensity, duration and frequency selected