W/L Ch 16 Particle Therapy Quiz

Question 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.

Answer 1

d. It needs a complex system to extract the beam energy needed.

Question 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

Answer 2

c. 50 to 250 MeV

Question 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

Answer 3

d. Pencil thin

Question 4

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

a. Nozzle
b. Aperture
c. Compensator
d. Modulator wheel

Answer 4

d. Modulator wheel

A range modulator wheel is used to create the SOBP so that the maximum energy can treat the entire tumor from the most distal edge to the most proximal edge.

Question 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.

Answer 5

d. Conform dose to the tumor.

Question 6

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

a. smearing
b. shaving
c. rotating
d. waxing

Answer 6

a. smearing

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

Question 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 7

a. 1.1

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 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 8

c. Range

Question 9

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

a. Decreases
b. Increases
c. Remains unchanged

Answer 9

b. Increases

Question 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

Answer 10

a. relative stopping power (RSP)

Question 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

Answer 11

b. 180 degrees

Question 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

Answer 12

d. Incorporate simultaneous boosts

Question 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.

Answer 13

c. The patient loses significant weight.

Question 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

Answer 14

b. Performance of manual verification

Question 15

Who discovered the Bragg peak phenomenon?

a. William Bragg
b. Ernest Lawrence
c. Ernest Rutherford
d. Robert Rathburn Wilson

Answer 15

a. William Bragg

Question 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

Answer 16

c. fall-off region (penumbra)

Patch planning utilizes two beams to treat the tumor, each beam treating partial volume of the tumor. There is a thru beam that treats the majority of the tumor and a patch field that matches the sharp distal margin fall-off region at the end of the spread out Bragg peak with the 50% isodose line of the thru beam.

Question 17

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

a. Magnet
b. Nozzle
c. Compensator
d. Accelerator

Answer 17

b. Nozzle

Question 18

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

a. Brass
b. Steel
c. Acrylic
d. Tungsten

Answer 18

c. Acrylic

Question 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

Answer 19

d. 100

Question 20

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

Answer 20

a. Eye

c. Brain