Question 1: Which one of the following radioisotope is not used as
permanent implant ?
A) Iodine-125
B) Palladium-103
C) Gold-198
D) Caesium-137
Answer: D) Caesium-137
Question 2: The technique employed in radiotherapy to counteract the
effect of tumor motion due to breathing is known as ?
A) Arc technique
B) Modulation
C) Gating
D) Shunting
Answer: C) Gating.
Question 3: At t=0, there are 6 x 1023 radioactive atoms of a substance,
which decay with a disintegration constant (lambda) equal to 0.01/sec. What
would be the initial decay rate ?
A) 6 x 1023
B) 6 x 1022
C) 6 x 1021
D) 6 x 1020
Answer: C) 6 x 1021