Homework 1

Question 1

for polyenergetic (heterogeneous) beams

a. HVL1 is equivalent to HVL 2
b. HVL1 is greater than HVL2
c. HVL2 is greater than HVL1

Answer 1

c. HVL2 is greater than HVL1

Question 2

x-ray beam quality is representative of

a. all of the above
b. the number of photons
c. the quantity of the photons
d. the energy of the photons

Answer 2

d. the energy of the photons

Question 3

which measurement would not be used as an indication of the energy of a megavoltage photon beam?

a. depth of max dose
b. HVL
c. TPR at 20 cm/TPR at 10 cm
d. PDD at 10 cm

Answer 3

b. HVL

Question 4

the term for the monoenergetic beam which matches the attenuation of a polyenergetic beam is called the

a. most probable energy
b. effective energy
c. mean energy
d. average energy

Answer 4

b. effective energy

Question 5

which of the following photon beams has the highest quality?

a. 22 MHz
b. 3 GHz
c. 23 mHz
d. 10 Hz

Answer 5

b. 3 GHz

Question 6

when measuring HVL, good geometry includes

a. a small measuring chamber
b. a narrow x-ray beam
c. absorber material close to the detector
d. a circular treatment beam

Answer 6

b. a narrow x-ray beam

Question 7

the energy measurement most commonly used for x-ray beams between 50 keV and 200 keV is

a. peak energy
b. half value layer
c. average energy
d. most probable energy

Answer 7

b. half value layer

Question 8

the best material for measuring HVL

a. depends on the x-ray energy
b. is aluminum
c. is a combination of copper and aluminum
d. is copper

Answer 8

a. depends on the x-ray energy

Question 9

what is the energy, in MeV, of a photon with a frequency of 4.34x10^21 Hz?
h= 4.15x10^-15 eVs

Answer 9

18