Final

Question 1

Visible mass to include lymphadenopathy and metastasis

Answer 1

GTV

Question 2

Subclinical malignant disease

Answer 2

CTV

Question 3

To include all geometric variations (ITV+SM)

Answer 3

PTV

Question 4

Volume to include motion (CTV+IM)

Answer 4

ITV

Question 5

Normal tissue at risk of radiation damage

Answer 5

OAR

Question 6

Tissue that receives a dose that is considered significant in relation to normal tissue tolerance

Answer 6

IrV

Question 7

Isodose levels are modified by changing the energy, field size, beam arrangements, and beam modifiers to produce a desired dose distribution.

Answer 7

True

Question 8

As source size increases the Penumbra

Answer 8

Increases

Question 9

As SSD increases the penumbra

Answer 9

Increases

Question 10

As SDD increase the Penumbra

Answer 10

Decreases

Question 11

Some MLC’s create a lot of penumbra when the leaves are mounted on diverging carriages

Answer 11

False

Question 12

What is the most often used type of DVH graph?

Answer 12

Cumulative

Question 13

Which DVH graphs the volume of a structure receiving dose within a specified dose interval?

Answer 13

Differential

Question 14

Normalization point is the point chosen by the planner where the ____% Isodose line is placed

Answer 14

100%

Question 15

Which energy would give the most skin sparring?

Answer 15

18MV

Question 16

Does dose falloff more rapidly with photons or electrons?

Answer 16

electrons

Question 17

Does using more beams result in better homogeneity or worse homogeneity?

Answer 17

Better

Question 18

Cerrobend blocks have more field conformality than MLC’s due to the

Answer 18

MLC leaf size

Question 19

Single field treatment techniques are usually used for this type of treatment

Answer 19

T-Spine

Question 20

A disadvantage of a parallel opposed treatment planning technique is

Answer 20

entry and exit dose

Question 21

An advantage of using a four field technique is

Answer 21

max dose decreases

Question 22

What does VMAT stand for?

Answer 22

Volumetric modulated arc therapy

Question 23

A commonly used treatment site that uses a matching field technique is

Answer 23

craniospinal

Question 24

The angle through which an isodose curve is tilted at the central ray of a beam at specified depth(usually 10cm) is called the

Answer 24

wedge angle

Question 25

The wedge factor is the ratio of the doses with and without the wedge inserted at a specified depth.

Answer 25

True

Question 26

Which type of wedge uses the motion of the collimator jaw or leaves during treatment delivery to modify the dose distribution.

Answer 26

Enhanced dynamic wedge

Question 27

MLC's can create island blocks. T or F

Answer 27

False

Question 28

Cerrobend blocks are composed of

Answer 28

Pb, tin, cadmium, bismuth

Question 29

The melting point for cerrobend is.

Answer 29

158 degrees

Question 30

What type of beam modifiers can be used to address tissue irregularities for sloping surfaces but today can also be used for tissue inhomogeneities inside the body

Answer 30

Compensators

Question 31

Bolus is used primarily to

Answer 31

Bring dose to the surface for treating superficial lesions.

Question 32

As electrons energy increases, skin dose

Answer 32

Increases

Question 33

Energy/2

Answer 33

Practical range

Question 34

Energy/3

Answer 34

80% isodose line

Question 35

Energy/4

Answer 35

90% isodose line

Question 36

Pb cutout thickness for on skin electron blocking should be at least

Answer 36

MeV/2 in mm of Pb

Question 37

Data registration and fusion are geometric alignment of images with one another. T or F

Answer 37

True

Question 38

Axial scanning provides better resolution but helical scanning is faster and delivers less dose. T or F

Answer 38

True

Question 39

CT scans are used to create DRR's. T or F

Answer 39

True

Question 40

PET scans provide information about physiology rather than anatomy. T or F

Answer 40

True

Question 41

Most common PET radionuclide is

Answer 41

FDG (fluorodeoxyglucose)

Question 42

What are the 2 main types of image registrations?

Answer 42

Rigid and deformable

Question 43

What is the main advantage for using deformable registration

Answer 43

patient position does not have to be the same

Question 44

What best describes an IMRT Treatment?

Answer 44

Delivers non uniform fluence from different beams angles to generate a non uniform dose distribution

Question 45

IMRT planning assigns non uniform intensities or weights to small subdivisions of beams referred to as:

Answer 45

Beamlets

Question 46

IMRT is delivered most commonly using

Answer 46

MLC's

Question 47

When treating using IMRT and using a step and shoot technique the leaves do not move when the beam is on. T or F

Answer 47

True

Question 48

When treating using VMAT technique radiation is delivered to the target while simultaneously moving the MLC's and the gantry. T or F.

Answer 48

True

Question 49

SRS treatment is usually given in 5 fractions. T or F

Answer 49

False

Question 50

Isodose levels are modified by changing the energy, field size, beam arrangements, beam modifiers, etc., to produce a desired dose distribution

Answer 50

Isodose Distribution

Question 51

Isodose levels are lines that pass-through points of equal dose expressed as a % relative to a reference point

Answer 51

Isodose Level Parameters

Question 52

Two-dimensional graph showing dose delivered to volumes of interest.

Answer 52

Dose Volume Histogram, (DVH)

Question 53

(Most often used) graphs the volume(in the y-axis that receives the corresponding dose or more in the x-axis

Answer 53

Cumulative DVH

Question 54

Graphs the volume of a structure receiving dose within a specified dose interval

Answer 54

Differential DVH

Question 55

Cerrobend blocks have more field conformality than MLC's due to the leaf size. T or F.

Answer 55

True

Question 56

Desired modification in the spatial distribution of radiation by insertion of any material in the beam path

Answer 56

Beam modifiers

Question 57

Eliminates radiation dose to certain parts of an area where the beam is directed

Answer 57

Shielding

Question 58

Allows normal dose to certain parts of an area where the beam is directed

Answer 58

Compensation

Question 59

allows for a tilt in the radiation isodose curves

Answer 59

Wedge

Question 60

Where the distribution of the beam is altered by reducing the central exposure area relative to the peripheral

Answer 60

Flattening

Question 61

Wedges are commonly made of

Answer 61

Pb or Steel

Question 62

Angle between isodose curve and central axis

Answer 62

Wedge angle

Question 63

Ratio of doses with and without the wedge inserted at a specified depth

Answer 63

Wedge factor

Question 64

Disadvantages of MLC's include

Answer 64

Island blocking Jagged field boundary Field matching difficult Penumbra is larger

Question 65

Cerrobend blocks composed of

Answer 65

Bismuth, cadmium, lead, and tin

Question 66

Used to bring dose to the surface for treating superficial lesions

Answer 66

Bolus