Tx Planning Quizzes Flashcards by Justice Scales

visibile mass to included lymphadenopathy and metastasis

GTV

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subclinical malignant diseases

CTV

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To include all geometric variations (ITV+SM)

PTV

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volume to include motion (CTV+IM)

ITV

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normal tissue at risk of radiation damage

OAR

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tissue that recieves a dose thatis considered significant in relation to normal tissue tolerance

IrV

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T/F: isodose levels are modified by changing the energy, field size, beam arrangements, and beam modifiers to produce a desired dose distribution.

True

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As source size increases the penumbra ________

increases

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as SSD increases the penumbra _________

increases

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as depth increases the penumbra _________

decreases

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T/F: some MLC’s create a lot of penumbra when the leaves are mounted on diverging carriages

false

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what is the most often used type of DVH graph?

a. cumulative
d. differential
c. superlative

a. cumulative

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which DVH graphs the volume of a strucuture receiving dose within a specified dose interval?

a. cumulative
d. differential
c. superlative

d. differential

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normaliziation point is the point chosen by the planner where the ____% isodose line is placed

100

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which energy would give the most skin sparring?

a. 6 MeV
b. 20MeV
c. 6MV
d. 18MV

d. 18MV

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does dose falloff more rapidly with photons or electrons?

electrons

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

better

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

a. MLC leaf size
b. weight
c. field size
d. material

a. MLC leaf size

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

a. Tspine
b. prostate
c. brain
d. mantle

a. Tspine

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a disadvantage of a parallel opposed treatment planning technique is

a. entry and exit dose
b. cold spots
c. weighting
d. complexity

a. entry and exit dose

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an advantage of using a four field technique is:

a. max dose doubles
b. max dose increases
c. max dose decreases
d. max dose stays the same

c. max dose decreases

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what does VMAT stand for?

volumetric modulated arc therapy

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a commonl used treatment site that uses a matching field technique is:

a. larynx
b. craniospinal
c. brain
d. prostate

b. craniospinal

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

shielding

allows normal dose distribution to be applied to the treated area whereas to even out the dose distribution

compensation

allows for a tilt in the radiation isodose curves

wedge filtration

where the distribution of the beam is altered by reducing the cetral exposure area relative to the peripheral

flattening

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

wedge angle

T/F: the wedge factor is the ratio of the doses with and without the wedge inserted at a specified depth

true

which type of wedge uses the motion of the collimator jaw or leaves during treatment delivery to modify the dose distribution a. enhanced dynamic wedge b. enhanced motorized wedge c. physical wedge d. motorized wedge

a. enhanced dynamic wedge

T/F: MLC's can create island blocks

false

cerrobend blocks are compsoed of: a. Pb, tin, cadmium, bismuth b. Au, Pb, Ca, Bi c. Al, tin, Pb, Copper d. Pb, cerro

a. Pb, tin, cadmium, bismuth

the melting point for cerrobend is a. 100 degrees b. 158 degrees c. 165 degrees d. 212 degrees

b. 158 degrees

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? a. cerrobend b. compensators c. bolus d. flattening filters

b. compensators

bolus is used primarily to: a. skin sparring b. limit Dmax c. block dose to certain areas d. bring dose to the surface for treating superficial lesion

d. bring dose to the surface for treating superficial lesion

as electron energy increase, skin dose _____

increases

practical range

engery/2

80% isodose line

energy/3

90% isodose line

energy/4

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

MeV/2 in mm of Pb

T/F: data registratio and fusion are the geometric alignment of images with one another

true

T/F: axial scanning provides better resolution but helical scanning is faster and delivers less dose

true

T/F: CT scans are used to create DRR's

true

disadvantages of using MRI include all of the following except - soft tissue imaging - lack of signal from bone - distrotions - no relation to electron density - artifacts

-soft tissue imaging

T/F: PET scans provide information about physiology rather than anatomy

true

most common PET radionuclide is a. DFG b. FDG c. GFD d. T99

b. FDG

what are the 2 main types of image registrations? a. vexing and convexing b. formable and sharp c. rigid and deformable d. cumulative and recordable

c. rigid and deformable

what is the main advantage for using deformable registration? a. speed of registration b. patient position does not have to be the same c. patient position must be the same d. computer memory used

b. patient position does not have to be the same

IMRT stands for?

intensity modulated radiation therapy

what best describes an IMRT treatment? a. delivers non uniform fluence from the same beam angles to generate a conformal dose distribution b. delivers non uniform fluence from different beam angles to generate a conformal dose distribution c. delivers a uniform fluence from different beam angles to generate a non confomal dose distribution d. delivers uniform fluence from different beam angles to gerneate a non uniform dose distribution

b. delivers non uniform fluence from different beam angles to generate a conformal dose distribution

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

beamlets

what type of planning concept does IMRT use

inverse

IMRT is delivered most commonly using

MLC's

T/F: when treating using IMRT and using a step and shoot technique the leaves do not more when the beam is on

true

VMAT stands for

volumetric modulated arc therapy

T/F: when treating using VMAT technique radiation is delivered to the target while simultaneously moving the MLC's and the gantry

true

T/F: SRS treatment is usually given in 5 fractions

false

SBRT stands for

sterotactic body radiation therapy