Abstract
Article: Bioeffects Reference Tool May Not Improve Sonographers’ Monitoring of Mechanical and Thermal Indices in Obstetric Sonography Examinations
Authors: Dora DiGiacinto, MEd, RDMS, RDCS, Jennifer Bagley, MPH, RDMS, RVT, Stacie Cook, BSMIRS, RDCS, and Michael Anderson, PhD
Category: Ob/Gyn
Credit: 1.0 SDMS CME Credit
Objectives: After studying the article entitled “Bioeffects Reference Tool May Not Improve Sonographers Monitoring of Mechanical and Thermal Indices in Obstetric Sonography Examinations,” you will be able to:
Determine the need to monitor the output displays on a regular basis
Describe the machine settings that most affect the output displays
Explain the recommended limits for the output displays.
No bioeffects have been documented in the fetus (to date) when the TI is kept below
2 3 4 5
Nelson et al have suggested in a publication that for obstetric scans that will take less than 30 minutes, the TI should be kept less than
0.3 0.5 0.7 1.0
Multiple surveys of physicians have reported in the literature that the location of the TI and MI displays were known by
Fewer than 18% Fewer than 30% Approximately 30% to 50% More than 50%
Prior to 1992, the Food and Drug Administration–approved exposure limit for fetal examinations was
17 milliwatts/cm2 94 milliwatts/cm2 430 milliwatts/cm2 720 milliwatts/cm2
All surveyed sonographers in the present study knew where the TI/MI were displayed on their machines, and according to the postsurvey, _____ % limited scan time based on the TI.
0% 10% 25% 50%
According to the 2009 guidelines of the British Medical Ultrasound Society, whenever possible, the TI for obstetric scans should be kept below
0.2 0.7 1.0 3.0
Animal studies have shown that congenital anomalies can be produced when the tissue temperature is raised 4°C above core temperature for a period longer than
2 minutes 3 minutes 5 minutes 10 minutes
After 10 weeks’ gestation, the appropriate thermal index to monitor is
None; the MI should be monitored TIS TIC TIB
In the postsurvey responses, the greatest increase in recognition of machine settings that can affect TI/MI was for
Power/intensity and frequency Power/intensity and duty factor Number of focal zones and frequency Number of focal zones and duty factor
A survey by Bagley et al reported in 2011 showed that sonographers’ monitoring of the TI/MI and their knowledge of bioeffects were
Not correlated Mildly correlated Strongly correlated Completely correlated
Footnotes