Biophysics Flashcards
What is the frequency of transvaginal USS
7.5MHz
(5 - 7.5 MHz)
USS in early pregnancy, embryonic pole seen but heartbeat not visible. What is the likely gestation?
5 weeks
Gestational sac visible 4+3
Yolk sac visible 5 - 5+3
Embryonic pole visible 5+3 - 6/40
At what HCG should a pregnancy be visible on USS
1000
When can Hysterosalpingography be done?
In the first 10 days of the proliferative phase (first part of cycle)
What day can a FHR first be seen?
Day 22
When the CRL is 10mm, what is the likely gestation?
7 weeks
When the CRL is 30mm, what is the likely gestation?
10 weeks
Proton relaxation occurs in which imaging
MRI
What word is used to describe areas appearing dark in ultrasound?
Anechoic
With regard to MRI scanning what is the SI unit measure of strength of magnetic field?
Tesla
The difference between the peak and the base line of ultrasound wave is called?
Amplitude
Diathermy plate partially detached with burn near it - aetiology?
Current density concentrated in smaller area where plate was attached
ECG: Regular, tachycardia, NN QRS, absent p wave.
Supraventricular tachycardia
In ECG which lead reflects the inferior wall of heart?
II, III, aVF
T wave inversion is a sign of what electrolyte imbalance?
Hypokalaemia
6/40 with PVB. USS foetal pole with CRL of 4mm, no foetal heart action. Diagnosis?
Non viable pregnancy
(different from booklet)
My notes say at 6/40 and CRL >2mm expect to see the FH
Piezoelectric used in
USS
In ECG, T wave represents
Ventricular repolarization
Cauterization of large area with appearance of smoke
Fulguration
There are 3 components of interaction of ultrasound with the tissue medium: absorption, scattering, and the third one is -
Reflection
cervical cancer; RT by gamma-emitting isotopes containing Casieum 137 on her vagina. This type of therapy is …
Brachytherapy
What type of Laser is Neodymium: YAG laser?
solid laser
Areas appear dark or black in ultrasound?
Anechoic
What is the unit of ionizing radiation dose in RT?
Gray
Which element is impacted by MRI
hydrogen
In which test is there the maximum radiation exposure?
Hystero contrast salpingography
Hysterosalpingogram
Lap and dye test
Hysterosalpingogram
What is Axial resolution?
Axial resolution is the ability to see the two structures that are side by side as separate
Achieved with higher frequency, high resolution, low penetration (like with TVUS)
How does USS cause tissue damage?
Thermal - TIS - soft tissue (T1)
Thermal - TIB - bone (T2/3)
Cavitation - MI (mechanical)
What is the SI unit of diathermy power?
Power: Watts
Contrast:
Frequency is measured in Hertz
6/40
Gestational sac 23mm
Foetal pole 4mm
(No FH)
Gestational sac 4+3 (3mm)
Yolk sac 5 to 5+3 (3mm) (GS10mm)
Embryonic pole 5+3 - 6 (3mm) (GS16mm)
Gestational sac is appropriate for 6/40
At CRL >2mm, expect to see an FH
So not clear re FH in this one
How many mGrays are delivered to maternal breast tissue during CTPA
? 20 mGrays
Electrosurgery frequency
Cutting / coagulation using high frequency electrical current
300kHz to 3MHz
What USS probe should be used in obese patients
Low frequency
Low resolution
gives
High penetration
(like a trans abdo mode)
What unit measures radiation dose e.g. from CXR/CT
mSv
mili sievert
One small square on ECG = how many seconds
0.04 seconds
Normal variations seen in ECG of a pregnant person
Lead III - TWI and Q waves
aVF - Q waves
What is the contrast dye used in MRI scans?
Gaudolinium
What is the SI unit for the activity of radioactive decay?
becquerel (Bq)
