MPPG-2011 Radiology questions

Questions submitted by students of DAMS by memory recall 
Q1 Non ionic iv iodinated contrast agents are better than ionic contrast due to:


[a]reduced rate of adverse reaction 
[b]improve imaging due to increase concentration of contrast in collecting system
[c] both
[d] none

Answer is a)  Non-ionic compounds have a lower rate of adverse reactions, but in IVP their concentration is lower than ionic.

Q2 Minimal ascitis best detected by-


a] USG [b] x ray [c]MRI [d] CT

Answer- A ) USG

Q 3. when x ray or gamma rays enter a material/tissue in its path ,all possible except:
[a] intensity of radiation fall by at least 80%
 [b]radiation may travel without any interaction
 [c] radiation may be completely absorbed by interaction 
[d] the radiation is partially attenuated and result in scattered radiation

Answer- a)
Reference- http://www.sprawls.org/ppmi2/INTERACT/#Photon%20Interactions

As an x-ray beam or gamma radiation passes through an object, three possible fates await each photon, as shown in the figure below:
1. It can penetrate the section of matter without interacting.
2. It can interact with the matter and be completely absorbed by depositing its energy.
3. It can interact and be scattered or deflected from its original direction and deposit part of its energy.


Q4 The highly accurate imaging modality in investigation of ureteric colic
a X ray 
b Spiral ct 
c USG 
d IVU

Answer- Spiral CT

Q5 Cancer cells are LEAST SENSITIVE to Radiotherapy -


a) G1
b) G2
c) M phase
d) Later phase of S phase.

answer-d)
The cell cycle phase also determines a cell's relative radiosensitivity, with cells being most radiosensitive in the G(2)-M phase, less sensitive in the G(1) phase, and least sensitive during the latter part of the S phase.