Deck 16: Particle Therapy

Question 1

6)Internal target motion can be accounted for by _____________ the compensator used in proton therapy.

A) smearing
B) shaving
C) rotating
D) waxing

Answer 1

A
Smearing is a process that modifies the compensator design to take into account internal motion of the tumor and setup uncertainties.

Question 2

7)Protons have an accepted relative biological effect (RBE)value of which of the following?

A) 1.1
B) 2.5
C) 3.0
D) 4.0

Answer 2

A
Protons have an accepted RBE value of 1.1, whereas carbon's RBE can range between 3 and 5 in the Bragg peak region.

Question 3

8)The water equivalent thickness (WET)of an immobilization device used during proton therapy can affect which of the following attributes of the beam?

A) Linear energy transfer
B) Symmetry
C) Range
D) Energy

Answer 3

C
Special attention must be given to the type and thickness of the material used in an immobilization device.Minimizing the water equivalent thickness is important because it affects the penumbra and range.

Question 4

9)In an SOBP proton beam, as depth increases, linear energy transfer (LET)does what?

A) Decreases
B) Increases
C) Remains unchanged

Question 5

16)Patch planning is an approach used when matching two proton fields together based on their __________.

A) energy
B) field size
C) fall-off region (penumbra)
D) field range

Question 6

10)Hounsfield units should be converted to correct for particle ___________ when using computed tomography (CT)for proton therapy planning?

A) relative stopping power (RSP)
B) nonuniformity
C) energy fluctuation
D) Bragg peak

Question 7

5)An acrylic or wax compensator may be necessary during proton therapy to do which of the following?

A) Collimate the beam.
B) Scatter the protons.
C) Increase surface dose.
D) Conform dose to the tumor.

Question 8

1)The tumor types treated in the earliest years of proton therapy included those in or near which of the following? (Select two.)

A) Eye
B) Spine
C) Brain
D) Liver

Question 9

19)Although several heavy particles may be used therapeutically, proton therapy represents _____% of the particle therapy market in the United States.

A) 60
B) 75
C) 88
D) 100

Question 10

2)What are the typical therapeutic proton beam energies?

A) 6 to 25 MeV
B) 10 to 50 MeV
C) 50 to 250 MeV
D) 300 to 500 MeV

Question 11

3)What is the shape of the proton beam as it passes through the transport system?

A) Divergent
B) Conical
C) Fan-shaped
D) Pencil thin

Question 12

12)Which of the following is one common characteristic for uniform and nonuniform scanning systems that they both are able to do?

A) Can also be called intensity modulated proton therapy
B) Geometrically cover the tumor volume with one beam
C) Deliver a uniform dose throughout the tumor with one beam
D) Incorporate simultaneous boosts

Question 13

18)Custom compensators used in proton therapy are often made of which of the following?

A) Brass
B) Steel
C) Acrylic
D) Tungsten

Question 14

14)Which of the following is the most reliable method for verifying beam clearance before a patient is treated?

A) Utilization of three-dimensional (3D)room models
B) Performance of manual verification
C) Use of room blueprints and computer plans
D) Robust review of treatment plans

Question 15

11)Most small footprint proton systems have gantry rotation capabilities up to which of the following?

A) 90 degrees
B) 180 degrees
C) 270 degrees
D) 360 degrees

Question 16

4)The spread out Bragg peak (SOBP)is created by which of the following?

A) Nozzle
B) Aperture
C) Compensator
D) Modulator wheel

Question 17

17)The proton beam is focused and shaped by devices in which of the following?

A) Magnet
B) Nozzle
C) Compensator
D) Accelerator

Question 18

13)What do the results of a clinical study completed at MD Anderson indicate regarding when adaptive planning is strongly indicated?

A) The first week of therapy is completed.
B) The first day of therapy is completed.
C) The patient loses significant weight.
D) A high Z prosthesis is in the beam path.

Question 19

1)What is one disadvantage of today's synchrocyclotron over the cyclotron?

A) It needs energy degraders.
B) It can generate variable beam energies.
C) It has less current producing longer treatment times.
D) It needs a complex system to extract the beam energy needed.

Question 20

15)Who discovered the Bragg peak phenomenon?

A) William Bragg
B) Ernest Lawrence
C) Ernest Rutherford
D) Robert Rathburn Wilson