ARDMS SPI Ultrasound Bioeffects and Safety 3

Question 1

The term 'derated' intensity (e.g., ISPTA.3) in ultrasound safety refers to intensity that has been adjusted for:

Accepted Answer

Assumed tissue attenuation of 0.3 dB/cm/MHz

Answer

Derated values apply a standardized attenuation of 0.3 dB/cm/MHz to account for tissue absorption when reporting intensities in safety standards.

Question 2

Which statement about ultrasound bioeffects in diagnostic imaging is most accurate based on current evidence?

Accepted Answer

No confirmed hazardous bioeffects exist at diagnostic levels, but prudent use is advised

Answer

No independently confirmed hazardous bioeffects have been established at diagnostic exposure levels, yet prudent minimization of exposure (ALARA) remains the standard of care.

Question 3

Acoustic streaming in ultrasound refers to:

Accepted Answer

Steady unidirectional fluid flow induced by acoustic radiation force

Answer

Acoustic streaming is a mechanical bioeffect where sustained radiation pressure drives fluid in a net directional flow, independent of the Doppler effect.

Question 4

Which transducer characteristic most directly influences the potential for heating at the transducer face?

Accepted Answer

Transducer efficiency (electroacoustic conversion)

Answer

Poor electroacoustic conversion efficiency means more electrical energy is dissipated as heat at the transducer face rather than converted to acoustic energy.

Question 5

In the context of obstetric ultrasound, TIS (Soft Tissue Thermal Index) is preferred over TIB (Bone Thermal Index) during which trimester?

Accepted Answer

First trimester, before ossification is significant

Answer

TIS is used in the first trimester when fetal ossification is minimal; TIB becomes more relevant later when bone absorbs more ultrasound energy and heats significantly.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Ultrasound Bioeffects and Safety 3