Biophysics

Question 1

What is the frequency of transvaginal USS

Answer 1

7.5MHz

(5 - 7.5 MHz)

Question 2

USS in early pregnancy, embryonic pole seen but heartbeat not visible. What is the likely gestation?

Answer 2

5 weeks

Gestational sac visible 4+3
Yolk sac visible 5 - 5+3
Embryonic pole visible 5+3 - 6/40

Question 3

At what HCG should a pregnancy be visible on USS

Answer 3

1000

Question 4

When can Hysterosalpingography be done?

Answer 4

In the first 10 days of the proliferative phase (first part of cycle)

Question 5

What day can a FHR first be seen?

Answer 5

Day 22

Question 6

When the CRL is 10mm, what is the likely gestation?

Answer 6

7 weeks

Question 7

When the CRL is 30mm, what is the likely gestation?

Answer 7

10 weeks

Question 8

Proton relaxation occurs in which imaging

Answer 8

MRI

Question 9

What word is used to describe areas appearing dark in ultrasound?

Answer 9

Anechoic

Question 10

With regard to MRI scanning what is the SI unit measure of strength of magnetic field?

Answer 10

Tesla

Question 11

The difference between the peak and the base line of ultrasound wave is called?

Answer 11

Amplitude

Question 12

Diathermy plate partially detached with burn near it - aetiology?

Answer 12

Current density concentrated in smaller area where plate was attached

Question 13

ECG: Regular, tachycardia, NN QRS, absent p wave.

Answer 13

Supraventricular tachycardia

Question 14

In ECG which lead reflects the inferior wall of heart?

Answer 14

II, III, aVF

Question 15

T wave inversion is a sign of what electrolyte imbalance?

Answer 15

Hypokalaemia

Question 16

6/40 with PVB. USS foetal pole with CRL of 4mm, no foetal heart action. Diagnosis?

Answer 16

Non viable pregnancy

(different from booklet)
My notes say at 6/40 and CRL >2mm expect to see the FH

Question 17

Piezoelectric used in

Answer 17

USS

Question 18

In ECG, T wave represents

Answer 18

Ventricular repolarization

Question 19

Cauterization of large area with appearance of smoke

Answer 19

Fulguration

Question 20

There are 3 components of interaction of ultrasound with the tissue medium: absorption, scattering, and the third one is -

Answer 20

Reflection

Question 21

cervical cancer; RT by gamma-emitting isotopes containing Casieum 137 on her vagina. This type of therapy is …

Answer 21

Brachytherapy

Question 22

What type of Laser is Neodymium: YAG laser?

Answer 22

solid laser

Question 23

Areas appear dark or black in ultrasound?

Answer 23

Anechoic

Question 24

What is the unit of ionizing radiation dose in RT?

Answer 24

Gray

Question 25

Which element is impacted by MRI

Answer 25

hydrogen

Question 26

In which test is there the maximum radiation exposure? Hystero contrast salpingography Hysterosalpingogram Lap and dye test

Answer 26

Hysterosalpingogram

Question 27

What is Axial resolution?

Answer 27

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)

Question 28

How does USS cause tissue damage?

Answer 28

Thermal - TIS - soft tissue (T1) Thermal - TIB - bone (T2/3) Cavitation - MI (mechanical)

Question 29

What is the SI unit of diathermy power?

Answer 29

Power: Watts Contrast: Frequency is measured in Hertz

Question 30

6/40 Gestational sac 23mm Foetal pole 4mm (No FH)

Answer 30

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

Question 31

How many mGrays are delivered to maternal breast tissue during CTPA

Answer 31

? 20 mGrays

Question 32

Electrosurgery frequency Cutting / coagulation using high frequency electrical current

Answer 32

300kHz to 3MHz

Question 33

What USS probe should be used in obese patients

Answer 33

Low frequency Low resolution gives *High penetration* (like a trans abdo mode)

Question 34

What unit measures radiation dose e.g. from CXR/CT

Answer 34

mSv mili sievert

Question 35

One small square on ECG = how many seconds

Answer 35

0.04 seconds

Question 36

Normal variations seen in ECG of a pregnant person

Answer 36

Lead III - TWI and Q waves aVF - Q waves

Question 37

What is the contrast dye used in MRI scans?

Answer 37

Gaudolinium

Question 38

What is the SI unit for the activity of radioactive decay?

Answer 38

becquerel (Bq)