ARDMS SPI Ultrasound Bioeffects and Safety 4

Question 1

The FDA regulatory limit for spatial-peak temporal-average intensity (ISPTA.3) for fetal/obstetric ultrasound is:

Accepted Answer

72 mW/cm²

Answer

The FDA limits ISPTA.3 to 72 mW/cm² for fetal and neonatal cephalic applications to protect the developing fetus.

Question 2

When scanning directly over fetal bone in the third trimester, which Thermal Index should be displayed?

Accepted Answer

TIB (Bone Thermal Index)

Answer

TIB (Bone Thermal Index) is used when the beam is focused at or near fetal bone, which absorbs more ultrasound energy and can heat adjacent tissue significantly.

Question 3

Which operator action would most effectively reduce thermal bioeffect risk without eliminating diagnostic utility?

Accepted Answer

Reducing output power and using gain controls to compensate image brightness

Answer

Reducing output power lowers acoustic energy deposition, while compensating with receive gain maintains image quality without additional thermal risk.

Question 4

Non-thermal mechanical bioeffects of ultrasound include all of the following EXCEPT:

Accepted Answer

Protein denaturation from elevated tissue temperature

Answer

Protein denaturation is a thermal effect caused by temperature rise, not a non-thermal mechanical effect; cavitation, streaming, and microstreaming are all mechanical in nature.

Question 5

The Output Display Standard (ODS) requires that real-time MI and TI values be displayed on the monitor when they exceed:

Accepted Answer

MI > 0.5 or TI > 0.5

Answer

The ODS mandates display of MI and TI when either exceeds 0.5, alerting operators that exposure is approaching levels warranting attention.

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI - ARDMS Sonography Principles and Instrumentation Practice Test

ARDMS SPI Ultrasound Bioeffects and Safety 4