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Procedures: 3. Treatment Dose and Prescription (EQUATIONS) > Treatment Prescription > Flashcards

Treatment Prescription Flashcards

Prescription

1
Q

T/F:
Total doses change depending on the location of the tumor and the organs at risk (OARs) surrounding the tumor

A

TRUE

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2
Q

what are 2 reasons listed in Laura Nappi book total doses may change?

A
  • depending on location of tumor
  • organs at risk surrounding the tumor
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3
Q

the following doses are example of Curative or Palliative?

180-200 cGy to a total dose of 5400-6000 cGy

A

Curative

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4
Q

the following doses are example of Curative or Palliative?

300 cGy to a total dose of 3000 cGy

A

Palliative

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5
Q

define a “boost” and or “cone-down field”

A

a smaller field, that can give a higher dose

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6
Q

what is the most common fractionation schedule?

A

once a day, for five days a week, for several weeks

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7
Q

T/F:
the amount of fractions DOES NOT vary with the total tumor dose

A

FALSE
the total amount of fractions DOES vary with the total tumor dose… it would have to, since dose is delivered each fraction

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8
Q

what does BID mean?

A

twice a day

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9
Q

what is the shorthand verbiage for “twice a day”?

A

BID

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10
Q

what is MINIMUM number of hours that must occur between each radiation fraction delivered to any patient?

A

6 hours

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11
Q

how is beam energy selected for treatments?

A

it is chosen depending on the thickness of the patient and depth of the tumor

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12
Q

tumors in areas of the BODY that are THICKER use __lower//higher__ beam energies?

A

higher

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13
Q

most treatments of pelvic tumors use what energy?

A

15x

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14
Q

most treatments of brain tumors use what energy?

A

6x

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15
Q

tumors in areas of the BODY that are not really thick use __higher//lower__ energies?

A

lower

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16
Q

different beam energies have differnt depths for _______

A

dmax

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17
Q

what is dmax?

A

depth of maximum dose

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18
Q

T/F:
different beam energies DO NOT have different depths for dmax

A

FALSE

they very much do have different depths for dmax depending on beam energy level

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19
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“two protons and two neutrons, also known as a helium nuclei, is released from an unstable heavy nuclei as it decays”

A

alpha particles

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20
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

-no mass and no charge
-manmade
-interaction occurs near nucleus

A

xrays

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21
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“electromagnetic radiation, known as photons”

A

xrays

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22
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

-negatively charged (negatron) or positively charged (positron)
-travel further and penetrate farther than others

A

beta particles

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23
Q

which penetrate farther? - beta or alpha particles

what about when compared to gamma rays and xrays?

A

BETA

– gamma and xrays penetrate farther than beta (..thus farther than alpha too)

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24
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

-has a charge, a heavy mass, and a high LET
-travels short distances but creates a lot of damage in that distance
-common in atomic numbers greater than 82

A

alpha particles

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25
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“electrons released by the nucleus”

A

beta particles

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26
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“photons naturally emitted from a nucleus”

A

gamma

-why there is live source in gamma pods, etc

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27
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

-cosmic rays
-terrestrial radiation
-radionuclides in the human body

A

natural background radiation

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28
Q

what does GTV stand for?

A

Gross Tumor Volume

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29
Q

what does CTV stand for?

A

Clinical Target Volume

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30
Q

what does PTV stand for?

A

Planning Target Volume

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31
Q

what does ITV stand for?

A

Internal Target Volume

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32
Q

what does OAR(s) stand for? - what are some examples

A

Organs at Risk
- heart
- lens of eye
- bladder
- rectum
- femoral head

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33
Q

the following is describing what treatment volume?
(ie. GTV, PTV, etc…)

“accounts for the CTV, plus motion of the tumor caused by breathing or involuntary motions”

A

ITV
Internal Target Volume

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34
Q

the following is describing what treatment volume?
(ie. GTV, PTV, etc…)

“is the tumor volume that is visible or can be palpated”

A

GTV
Gross Tumor Volume

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35
Q

the following is describing what treatment volume?
(ie. GTV, PTV, etc…)

“is the CTV, and an area around CTV to give a margin for uncertainties”

–> what are examples of said uncertainties?

A

PTV
Planning Target Volume

–> uncertain examples = patient motion, penumbra, variations of trt setup

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36
Q

the following is describing what treatment volume?
(ie. GTV, PTV, etc…)

-“is the GTV and the area around it that may have microscopic disease”
-“visible or palpable tumor plus any margin of subclinical disease”

A

CTV
Clinical Target Volume

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37
Q

the following is describing what treatment volume?
(ie. GTV, PTV, etc…)
hint - __________ volume

-“the area that is contained within the isodose curve”

-“generally larger than the target volume, encompasses the additional margins around the target volume to allow for limitations of the treatment technique”

A

Treated Volume (TV)

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38
Q

the following is describing what treatment volume?
(ie. GTV, PTV, etc…)
hint - __________ volume

-“the volume of tissue(s) that is given a large portion of the dose”
-“volume of tissues receiving a significant dose of the specified target dose”

A

Irradiated Volume (IV)

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39
Q

-_________ are organs close to the irradiated area that may effect or limit the dosage delivered
-normal issues in which _______ sensitive to radiation damage may influence treatment planning and/or delivery of a prescribed dose radiation

A

Organs at Risk (OARs)

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40
Q

in the image - label (1) and label (2)

A

(1) PTV
(2) GTV

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41
Q

according to Laura Nappi, what 2 reasons are treatment fields established?

A
  • based on tolerance doses of the nearby organs at risk
  • dose distributions
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42
Q

field orientations are arranged depending on the ______ and ______________ near the tumor

A

on the -location
and -organs at risk near the tumor

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43
Q

T/F:
MLCs and other beam modifiers can be used to further shape the beam

A

TRUE

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44
Q

T/F:
Adequate dose distributions usually require multiple fields

A

TRUE

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45
Q

what type of fields are usually used for a posterior spine field?

A

single fields

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46
Q

Parallel Opposed Portals (POPs) have a hinge angle of what?

A

180 degrees

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47
Q

what are some examples of POPs (Parallel Opposed Portals)

A
  • RT and LT lats
  • AP and a PA
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48
Q

_______ field technique is commonly used for structures within the abdomen, such as the pancreas, bladder, rectum, etc.

A

three-field technique

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49
Q

_____ field technique is commonly used for deep tumors within the pelvis or abdomen

A

four-field technique/four field box

50
Q

for a four-field box/four field technique, how far apart are the fields from one another

hint - in degrees

A

each is 90 degrees apart

51
Q

a wedge pair technique has a hinge angle LESS THAN ______ between two fields

A

LESS than 180

  • so example, an AP and a LT lat –> 90 degrees
52
Q

thick ends of wedges are also known as ____

A

heels

53
Q

the heels of wedges DO or DO NOT face each other for a wedge pair field?

A

wedge heels face each other
–heels together, toes apart

54
Q

a wedge pair technique is commonly used for what type of tumor(s)?

A

superficial tumors

55
Q

a wedge-pair technique requires a wedge to have more/a more even ________________

A

a more even dose distribution

56
Q

rotational fields can also be called ____ therapy

A

ARC therapy

57
Q

the following is describing what type of treatment technique?

“radiation is delivered while the gantry is moving in an arc from one set point to another”

A

-VMAT
-ARC therapy
-Rotational fields

58
Q

for arcs LESS than 360 degrees, what is the treatment planning method called?

hint - starts with a “p”

A

past pointing

59
Q

why would there be an arc treatment that does not go a full 360 degrees/a partial arc?

A

the treatment plans for the beam to trt to a depth FARTHER THAN THE CENTER OF THE TUMOR

60
Q

for arcs that ARE 360 degrees, the beam is set to treat where in regards to the tumor

A

at an exact depth of the center of the tumor

61
Q

how is ARC speed calculated?

A

MU/degree

62
Q

MU/degree calculates what?

A

ARC speed

63
Q

T/F:
before treating with an ARC, the therapist DOES NOT HAVE TO do a dry run of the gantry rotation to ensure there will be no collisions between the gantry and the patient or table

A

FALSE
- must do dry run, think back to QAs at Kyle and ACC *VMATs
-would do a dry run for new starts or if they got a boost, change in plan etc.

64
Q

what does VMAT stand for?

A

Volumetric-Modulated Arc Therapy

65
Q

describe main difference between VMAT and IMRT

A

IMRT - MLCs move, gantry does not rotate while beam is on

VMAT - MLCs move AND gantry is on continuous rotation while beam is on

66
Q

T/F:
For fixed fields, the gantry DOES move while the radiation beam is delivered

A

FALSE

Gantry DOES NOT move for fixed field; FIXED

-the gantry moves between each field while the beam is off
-the gantry is stationary while the beam is being delivered

67
Q

T/F:
doses from multiple fields ARE always equal

A

FALSE
-doses from different fields CAN BE weighted differently

68
Q

when would one want/use an unequal weighted field?

A

usually used when the tumor dose not lie at mid-depth/mid-line

or when one beam may be going through/obstructing critical structure(s)

69
Q

T/F:
Beam angles can contribute different doses toward the total dose

A

TRUE

70
Q

the following could be an example of what?

AP:PA with weights 2:1 respectfully,
–the AP would deliver 2/3 of dose
–the PA field would deliver 1/3 of dose

A

weighted fields

71
Q

Scenario:

AP:PA with weights 2:1 respectfully.
Answer the following questions

–the AP would deliver how much?
–the PA field would deliver how much?

A

AP = 2/3 of dose
PA = 1/3 of dose

72
Q

isocenter is at ___ cm

A

100

73
Q

we treat electrons to ___ cm

A

100 cm
100 SSD

*SSD = SOURCE TO SKIN DISTANCE!
*TSD = TARGET TO SKIN DISTANCE!

74
Q

what is the max field size of a LINAC?

A

40x40 cm at 100 SSD

75
Q

Photon therapy energies range from about ___ to ___ MV

A

4-35 MV

76
Q

Electron therapy energies range from about ___ to ___ MeV

A

4-22 MeV

77
Q

Photon energy is measured in ___ whereas Electron energy is measured in ______

A

Photon = MV (Megavolt)
Electron = MeV (Mega electron volt)

78
Q

treatment tables can hold up to ____ pounds (lbs)

A

350 lbs

79
Q

T/F:
any changes in a patient’s trt plan must be recognized PRIOR to the patient’s next trt

A

TRUE

80
Q

If a patient’s trt plan is changed, and the change includes a change in field size or shape, must happen?

A
  • patient’s trt plan must be recognized PRIOR to the patient’s next trt
  • NEW FIELD MUST BE IMAGED FOR CONFIRMATION
81
Q

what is being described below -

  • ____ is placed between the radiation source and the patient’s skin
  • it brings dose closer to the skin’s surface and decreases skin sparing
  • will attenuate some of the beam
A

bolus

82
Q

____________ and ___________ are used to alter the isodose distribution based on the patient’s skin contour

A

wedges and compensators

83
Q

____________ are made of a high-density material, like Cerrobend or “poly lead” and are rarely used nowadays and have been replaced by IMRT

A

compensators

84
Q

like compensators, wedges are made of ___high//low__ density material

A

high

85
Q

wedges can be made of ___ or ____ commonly

A

lead or steel

86
Q

newer machines use _______________ to replace the use of physical wedges

A

EDW (Enhanced Dynamic Wedges)

  • internal wedges; dynamic wedges
87
Q

instead of a physical wedge that is placed into the treatment head, an EDW (Enhanced Dynamic Wedge) uses the motion of the ______ to mimic a wedge

A

Y-jaw

88
Q

EDWs change the _______, just like a wedge

A

isodose distribution

89
Q

when are EDWs added to patient’s treatment profile/techniques..?

A

planned in the treatment planning process

90
Q

a ____________ is used in larger fields like TBI (Total Body Irradiation) and eliminates skin sparing

A

beam spoiler

91
Q

describe a “beam spoiler”

A

-solid plastic tray
-increases dose to skin! without decreasing the penetration of beam!!

92
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“high LET particulate radiation, positively charged, which consists of 2 protons & 2 neutrons (helium nuclei) released during nuclei decay”

A

alpha particles

93
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“electrons released by the nucleus”

A

beta particles

94
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“electromagnetic radiation (photons) produced when a fast electron stream hits a target”

A

xrays

95
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

“high energy, electromagnetic radiation emitted from decaying isotopes, used in brachytherapy”

A

gamma rays

96
Q

the following is describing what radiation type?
hint - choose from xrays, beta particles, alpha particles, gamma rays, or natural background radiation

-no mass, no charge, emitted during nuclear decay

A

gamma rays

97
Q

T/F:

gamma rays and xrays penetrate FURTHER THAN alpha particles and beta particles

A

TRUE

98
Q

label the tumor volumes in the image below -

A
  1. GTV
  2. CTV
  3. PTV
  4. TV (Tumor volume)
  5. IV (Irradiated volume)
99
Q

for any LIVE source (ex. brachy, or Colbalt) we set ____ NOT MU.

A

set Time for LIVE sources … cause half-lives

100
Q

field size is determined where?

A

AT ISOCENTER

101
Q

extended distance is Isocentric OR Non-isocentric

A

NON-ISOCENTRIC

102
Q

label the angles -

A
  1. LAO
  2. Left lat
  3. LPO
  4. RPO
  5. Right lat
  6. RAO
103
Q

when a jaw is closed at 0, and the other jaw is not… what is this called?

A

Half Beam Block

104
Q

draw how a HINGE angle should be -

A
105
Q

illustrate the WEDGE angle -

A
106
Q

T/F:

you CAN have a LT medial tangent and a RT lateral tangent

A

FALSE

you can only have a LT medial tangent and a LT lateral tangent … depends on side your treating… so RT would go with RT

*breast usually

107
Q

label which is medial tangent and which is lateral tangent -

A
  1. medial tang
  2. lateral tang
108
Q

out of the following - which are included on the prescription and which are included on the treatment plan

-bolus
-bolus thickness
-wedges
-blocks
-MLCs

A

prescription –> bolus and bolus thickness

treatment plan –> wedges, MLCs, blocks

109
Q

TBI treatments have large or small fields? - that typically require what?

A

LARGE

  • a beam spoiler
110
Q

field size is created by what?

A

2 pairs of secondary asymm. collimator jaws (X and Y)

and further shaped using MLCs or custom blocks

111
Q

____ document field parameters

A

DRRS

112
Q

the physical radiation field size is delineated at the ___% isodose line

A

50%

113
Q

target depth is establish using ___ imaging

A

3D

114
Q

target ____ determines the energy of the beam and the type of treatment

A

depth

115
Q

______ tumors are typically treated with electrons and ____ tumors with photons

A

-superficial tumors

-deeper tumors

116
Q

______ _______ can also be called,
-patient separation
-intra-field distance
-inner-field distance (IFD)

A

patient thickness

117
Q

patient thickness is measured how?

A

with calipers

118
Q

…a ruler with one sliding leg and the other stationary is called __________

A

calipers

119
Q

T/F:

SSD changes at different gantry angles when using SAD technique

A

TRUE

120
Q

which technique has more room for error?

SAD or SSD

A

SSD

121
Q

Low energy beams have what type of scatter?

What about High energy beams?

A

Low energy beams = back scatter

High energy beams = peak scatter

Procedures: 3. Treatment Dose and Prescription (EQUATIONS) (3 decks)

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