Lesson 1B (Part 2) Flashcards
What is the frequency range for a transabdominal probe?
3-5MHz
What is the frequency range for a transvaginal probe?
5-10MHz
What happens with a higher resolution probe?
Less penetration
When is a transvaginal probes used in pregnancies? (2)
- During the early stages
2. Later pregnancies to asses the cervix
Transperineal US
Correctly evaluates sphincters in patients with fecal incontinence, postpartum and also following surgical repair of obstetric tears
- 3-5MHz probe
Translabial US
Is the most commonly used imaging method in the investigation of women with lower urinary tract symptoms and female pelvic organ prolapse
- 3-5MHz probe
What can transperineal and translabial US do? (2)
- Less intrusive
2. Can provide useful information in later pregnancies
What kind of information does transperineal and translabial US provide? (2)
- Cervix length
2. Fetal head positioning
What must be done to sonogrpahic equipment?
Calibrated and/or serviced routinely
- cleaned appropriately on a per use basis
Who is able to request for an obstetrical US? (3)
- Physicians
- Obstetricians
- Midwives
What is important to do for continual quality patient care?
Provide appropriate documentation
- images of all normal/abnormal areas are documented
- gestational age and measurements
What do all images require in an OB exam? (3)
- Date of the exam
- Appropriate patient identification
- Right and left side of the anatomy
What does most US software contain?
An Obstetrical calculation package
- summarizes important measurements
What AIUM statements does Sonography Canada endorse? (2)
- No independently confirmed adverse effects caused by exposure from present diagnostic ultrasound instruments
- Fetal ultrasound should be performed only when there is a valid medical reason, and the lowest possible ultrasonic exposure settings and should be used to gain the necessary diagnostic information under the ALARA Principle
ALARA
As low as reasonably achievable
- this is the main principle behind all ultrasound examinations and patient safety
What 2 things contribute to patients exposure and need to be minimized?
- Output intensity
2. Exposure time
Minimizing output intensity
Appropriate quality control to maintain appropriate output settings on ultrasound equipment
How do you minimize the output intensity? (4)
- Reducing power settings on the machine
- Using Doppler (higher intensity) only when necessary
- Only when medically necessary
- Perform examinations as efficiently as possible
- minimize repeat examinations
Thermal bioeffects
Some of ultrasound energy is absorbed by the tissue it travels through
What does thermal bioeffetcs cause?
Increase in temperature of the tissues
What can heat affect? (2)
- Chemical reactions
- Molecular bonds
- potential teratogen
Teratogen
Agent causing malformation of embryo
Thermal index
Is a measurement of ultrasound conditions that can change the temperature of a tissue
What does thermal index 1 indicate?
That the tissues may increase in temperature 1°C
