ARDMS SPI Study Guide 2023/2024 with complete solutions

ARDMS SPI Study Guide 2023/2024 with complete solutions Continuous wave Doppler has a duty factor of 100% CW Doppler is always transmitting sound making its duty factor 100% The spatial pulse length is defined as: the product of the wavelength and the number of cycles in a pulse? SPL = wavelength x cycles What term and philosophy relates the amount of exposure time for the sonographer and patient during a diagnostic ultrasound examination? ALARA - As Low As Reasonably Achievable What term is defined as the body's pathologic response to illness, trauma or severe physiologic or emotional stress? Shock The inertia of the medium describes its: Density. Inertia is described by Newton's principle - an object at rest will stay at rest. An object in motion stays in motion, unless acted on by an outside force. Greatest attenuation would occur at: long distance with high frequency A 3MHz sound beam travels through two media. It attenuates 5 dB in medium A and 6 dB in medium B. Total attentuation is 11 dB Attenuation simply adds up as sound travels. What would you do to create a wave with the highest possible intensity? Highest intensity would occur with a short distance and low frequency. Lowest Attenuation is found at lowest frequency, with the shortest path length. What results in the most attenuation? most attenuation occurs at the high frequency and long distance. Which media has the greatest attenuation and the slowest speed? Air Air Bone & Lung Soft Tissue Water What type of wave is sound? Mechanical and Longitudinal wave The speed of sound in soft tissue: 1540 m/s The unit for wavelength: Distance (mm) Enhancement is caused by: weakly attenuating structures Lowest attenuating to highest attenuation Fat-Muscle-Bone-Air List propagation speed from lowest to highest Air-Fat-Muscle-Bone Which of these media has the lowest attenuation and the greatest speed? bone tendon lung fat air Air Bone & Lung Soft Tissue Water Bone is more stiff than air (remember ↑ stiffness, ↑ speed) What describes the physics of refraction mathematically? Snell's Law What is a reflection arising from a rough boundary? Non-specular Specular reflection is from a smooth reflector (like mirrors). They return in one direction. Whereas, non-specular is diffuse or scatter, reflection from a rough boundary. When time-of-flight is measured, we can determine the ________? Reflector Depth A sound pulse travels from the transducer to location A, reflects off of it, and returns to the transducer in 130 μs. How deep is location A? Location A is 10 cm from the transducer Total travel distance would be 20 cm Which of the following would be considered the narrowest part of a sound beam?