Deck 7: Treatment Delivery Equipment

Question 1

5)Which of the following is (are)true of electron beams?

A) Require a flattening filter to make the electron beam profile symmetric and flat
B) Require a scattering foil to make the electron beam profile symmetric and flat
C) Interact with the transmission target before leaving the exit window
D) a, b, and c
E) b and c

Answer 1

B
When using electron beams, the target is removed and a scattering foil must be used to broaden the pencil-like beam.

Question 2

11)At what rate does the cobalt 60 source decay?

A) 1% per month
B) 2% per month
C) 3% per month
D) 5% per month

Answer 2

A
The cobalt source decays at a rate of 1% per month.The physicist must adjust the dose monthly to accommodate the decay.

Question 3

12)Which of the following limited the use of orthovoltage x-ray machines for radiation therapy?

A) Skin dose tolerance
B) Proton contamination
C) Excessive dose rate
D) Neutron contamination
E) The Nuclear Regulatory Commission requirement

Answer 3

A
Orthovoltage units are limited to treat lesions of 2 to 3 cm.

Question 4

3)Which of the following best describes the major components of a linear accelerator?

A) Power supply, modulator, electron gun, accelerating waveguide, head, beryllium target
B) Power supply, modulator, klystron, electron gun, "D"s, beryllium target
C) Power supply, electron gun, accelerating waveguide, head, doughnut accelerator structure
D) Modulator, klystron, electron gun, accelerator structure, waveguide, bending magnet

Question 5

9)Which of the following is the half-life of a cobalt 60 source?

A) 30 years
B) 1,600 years
C) 5.26 years
D) 74.2 days

Question 6

2)Which of the following is not found inside the head of a linear accelerator?

A) Ion chambers
B) Target
C) Accelerator structure
D) Bending magnet
E) Scattering foil

Question 7

19)Lipowitz metal is composed of which of the following? 

A) Tin, bismuth, lead, and cadmium
B) Lead, tungsten, and tin
C) Tin, bismuth, tungsten, and lead
D) Bismuth, cadmium, and lead

Question 8

18)A Van de Graaff machine __________________.
I)is an electrostatic generator
II)operates at 2 MV
III)operates a 200 kV
IV)uses a doughnut-shaped accelerator structure

A) I and II
B) II and IV
C) III and IV
D) I and IV

Question 9

15)When treating with electrons, the carousel rotates to place a _________________ in the beam to spread it out.

A) collimator
B) cone
C) scattering foil
D) flattening filter

Question 10

6)The electron gun is similar to what part of an x-ray tube?

A) Anode
B) Rotating tungsten target
C) Cathode
D) Power supply

Question 11

8)In treatments using kilovoltage equipment, filters are used to ___________________.

A) filter low-energy x-rays
B) shield the patient from all radiation exposure
C) collimate the beam
D) increase quantity

Question 12

13)The circulator in a linear accelerator does which of the following?

A) Mixes the hot and cold water to get the right temperature
B) Spins the electrons in the right direction
C) Conducts microwaves from the radiofrequency (RF)driver into the klystron
D) Isolates the klystron from reflected microwave power

Question 13

20)When using multileaf collimation, which concerns need to be evaluated?

A) Penumbra between the leaves and the transmission of the leaves
B) Movement of MLCs during the treatment give variations in dose that need to be evaluated along with penumbra between the leaves
C) Movement of MLCs during treatment and interleaf transmission leakage
D) Penumbra at the end of the leaves and interleaf transmission leakage

Question 14

7)A bending magnet in an accelerator may be used to do which of the following?

A) Help deflect microwave power
B) Deflect (bend)the electron beam
C) Gather stray electrons together in a bunch
D) Gather random paper clips

Question 15

10)The photon energy emitted by cobalt 60 is _______ MeV.

A) 1.36 and 1.01
B) .662 and 1.5
C) 1.00 and 1.5
D) 1.17 and 1.33

Question 16

1)When did installation of the first fully isocentric linear accelerator in the United States occur?

A) 1942
B) 1952
C) 1961
D) 1979

Question 17

16)Image-guided radiation therapy (IGRT)can be accomplished with ____________.
I)ultrasound units
II)computed tomography (CT)scanner
III)kV imager
IV)cone beam
V)simulator

A) I, III, and IV
B) II, III, and V
C) I, II, III, and IV
D) III, IV, and V

Question 18

17)Orthovoltage x-ray machines have energies in the range of which of the following?

A) 1 kV to 100 kV
B) 150 kV to 500 kV
C) 200 MeV to 400 MeV
D) None of the above

Question 19

14)Of the following treatment units, which has the least amount of skin sparing?

A) Orthovoltage
B) Cobalt
C) 4 MV beam
D) 10 MV beam

Question 20

4)Which of the following best describes the order in which electron bunches and the resulting x-rays travel through the head of a linear accelerator?

A) Bending magnet, dose chambers, target, flattening filter, wedge
B) Bending magnet, target, dose chambers, primary collimator, wedge, flattening filter
C) Bending magnet, target, primary collimator, flattening filter, wedge, dose chamber
D) Bending magnet, target, primary collimator, flattening filter, dose chamber, multileaf collimator
E) Bending magnet, dose chambers, target, flattening filter, primary collimator, multileaf collimator

Question 21

22)Depth of maximum dose for a 10-MV machine is how far below the skin surface?

A) 0.5 cm
B) 1.5 cm
C) 2.5 cm
D) 5 cm

Question 22

23)Depth of maximum dose for a 6-MV machine is how far below the skin surface?

A) 0.5 cm
B) 1.5 cm
C) 2.5 cm
D) 5 cm

Question 23

24)Depth of maximum dose for a 15-MV machine is how far below the skin surface?

A) 0.5 cm
B) 1.5 cm
C) 2.5 cm
D) 3 cm

Question 24

21)Some of the more common medical accelerator hazards include which of the following?
I)Incorrect dose delivered
II)Dose delivered to wrong area
III)Machine collision
IV)Emergency off malfunction

A) I, II, and IV
B) II, III, and IV
C) I, III, and IV
D) I, II, and III