D:-60 cm

Correct Answer:- Option-B
Question29:-Which is false with regard to 6MV photon beam 7

A:-Depth of maximum dose = 1.5 cm

B:-10 cm PDD = 61%

C:-Small penumbra

D:-Homs {beam intensity off-axis) due to flattening filter design is approximately 9%

Correct Answer:- Option-B
Question30:-With regard to composition of Lipowitz metal which is wrong

A:-13.3% tin

B:-50% bismuth

C:-3+6.7% lead

D:-10% cadmium

Correct Answer:- Option-C
Question31:-With regard to radiation treatment of patients with cardiac pacemakers which is wrong

A:-Pacemaker-implanted patients should never be treated with a betatron.

B:-Always keep the pacemaker outside the machine-collimated radiation beam, both during treatment and when taking
portal films

C:-Before treatment, estimate and record the dose {from scatter) to be received by the pacemaker. The total
accumulated dose should not exceed approximately 1 Gy

D:-If treatment with these quidelines is not possible the physician should consider having the pacemaker either
temporarily of permanently moved 0610೧ 1726180೧

Correct Answer:- Option-C
Question32:-With respect to interaction of electron beam with bone which is false 7

A:-The isodose contours in the shadow of the bone are shifted proximally

B:-Dose outside {inside) the bone-water interface increases {decreases) by approximately 15% as a result of loss of
side scatter equilibrium

C:-The lateral dimension of the region having its dose perturbed by the bone increases with depth

D:-Maximum dose increase expected as a result of back scattered electrons is 5% and the maximum dose increase
expected inside bone and in adjacent exit tissue is approximately 7%

Correct Answer:- Option-B
Question33:-Wrong about hot spot as per ICRU Report 62

A:-Volume outside PTV

B:-It receives dose >100% of specified PTV dose

C:-15mm diameter

D:-At least 2 *em”(2)" in a section

Correct Answer:- Option-D
Question34:-The difference between the volume enclosed by the external contour of the patient and that of the CTVs and
OARs on the slice that have been imaged is

A:-Treated volume

B:-PRV

C:-Modified PTV

D:-None of the above

Correct Answer:- Option-D
Question35:-Which of the followi is not correct for Rando phantoms 7

A:-They are used for determining the radiation absorption and reflection characteristics of the human body or a specific
organ

B:-The phantom is made of human tissue-equivalent materials to work with only णि x-rays

C:-The bones in the phantom are real human bones and the same cavities are present as in the human body

D:-Phantom slice are 2.5 cm thick each. There are 3x 3 *cm”2" dosimetric spaces in each slice for TLD

Correct Answer:- Option-B
Question36:-What is the flexure dose 7

A:-Alpha/beta x 0.1

B:-Alpha/beta x 0.2

C:-Alpha/beta x 0.37

D:-Alpha/beta x 0.63

Correct Answer:- Option-A
Question37:-Which of the following match-ups is not correct conceming tissue and organ response to radiation 7

A:-Michalowski-flexible vs. hierarchical and alpha by beta ratio

B:-Rubin and Casarett-proliferation kinetics