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RTT Science Fall 24 > Exam 3 > Flashcards

Exam 3 Flashcards

1
Q

In a _____ CT scanner, the x-ray tube rotates continuously around the patient as the patient travels through the gantry.

A

helical/spiral

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2
Q

DRR stands for

A

digitally reconstructed radiograph

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3
Q

When the isocenter is marked on the patient, 3 sets of marks are created. What is the correct configuration of these marks? (where do the BBs go on the patietns body)

A

2 side marks and 1 anterior mark

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4
Q

T or F: Image reconstruction occurs only after a scan is completed

A

True

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5
Q

DRRs can be created from the CT scans after a process called:

A

reconstruction

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6
Q

As the display field of view increases, the resulting radiation dose to the patient:

A

is not affected

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7
Q

Which of the following are functions of the patient table? (2)

A

-transports the patient through the gantry
-contributes to patient safety

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8
Q

Window level (WL) refers to: (2)

A

-image brightness
-the midpoint in a range of CT numbers

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9
Q

The standard format used to transfer images from diagnostic imaging computers to treatment planning computers is defined by:

A

DICOM

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10
Q

Image noise can be reduced by:

A

increasing mAs

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11
Q

When using x, y and z coordinates to determine the tumor’s isocenter, the y coordinate indicates the isocenter’s:

A

depth

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12
Q

The number for bone is:

A

1000

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13
Q

The CT number for water is:

A

0

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14
Q

A name for a value that represents a specific shade of gray on the CT image is:

A

CT number

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15
Q

Compared to barium used for regular fluoroscopy procedures, the barium used for CT procedures is:

A

less dense

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16
Q

The most common images used for radiation therapy treatment planning are acquired in what plane?

A

axial

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17
Q

In which plane are CT slices originally obtained?

A

axial

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18
Q

Interpolation is directly affected by:

A

pitch

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19
Q

The z-axis refers to the _____ plane

A

axial

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20
Q

Why are diagnostic CTs not optimal for treatment planning?

A

small bore

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21
Q

The contrast given during CT simulation will highlight specific organs to further help create the treatment plan by (2)

A
  • highlight the area to be treated
  • highlight critical structures to be avoided
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22
Q

The ability to differentiate small details in patient anatomy is referred to as:

A

spatial resolution

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23
Q

In multidetector CT scanning, what determines slice thickness?

A

image reconstruction parameters

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24
Q

4D treatment planning incorporates _________ in addition to regular treatment planning

A

respiratory motion

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25
Q

The mathematical unit that describes shades of gray on a CT image is:

A

a Hounsfield unit

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26
Q

Before the development of CT imaging, radiation therapy simulation was performed by
a conventional simulator using:

A

fluoroscopy

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27
Q

___ is associated with a 3D representation of tissue volume?

A

voxel

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28
Q

Patient MRI screening form should include: (3)

A

-allergies
-pregnancy
-implants, devices, objects

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29
Q

What is not a common contrast injection reaction?

A

dyspnea

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30
Q

During the CT simulation, the mA needs to be increased to create a change in the image quality, this will also lead to:

A

an increased patient dose

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31
Q

Patients at high risk of gastrointestinal perforation should be given what type of contrast medium?

A

Gastrografin

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32
Q

T or F: Radiopaque nonionic contrast agents are considered safe for pregnant patients

A

True

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33
Q

The scan field of view (SFOV) is determined by the:

A

CT technologist before the scan begins

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34
Q

What is the effect of increased image noise?

A

decreased contrast resolution

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35
Q

What is the term that describes the average level of shades of gray present on a CT image?

A

window level

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36
Q

Adverse reactions to iodinated contrast administration most commonly appear:

A

within 30 minutes of administration

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37
Q

All of the following are goals of CT simulation except to:

A

determine if a tumor is benign or malignant

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38
Q

Typically, a scout image for prostate CT simulation should show the:

A

diaphragm to mid femurs

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39
Q

The contrast most commonly used for MRI’s is ____________ based.

A

Gadolinium-based

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40
Q

The window width (WW) determines the:

A

image contrast

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41
Q

What is the typical patient
positioning for a prostate
CT simulation?

A

supine

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42
Q

Patients taking metformin
should stop taking the
medication _____ hours after
IV contrast media injection

A

48

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43
Q

An advantage of a DRR
over a conventional
radiograph is that DRR
images:

A

can be reconstructed in multiple planes

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44
Q

Which of the following
would normally NOT be
used to administer
contrast with a power
injector?

A

perma-cath

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45
Q

When a traditional CT unit
is used for simulation
purposes, what change
must be made to simulate
the position of the patient
on the treatment unit?

A

a board must be placed on the CT table

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46
Q

Images within the therapy
department are shared
and stored through:

A

PACS

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47
Q

MRI interactions with
implants/devices can
result in: (3)

A

-malfunction
-artifacts
-displacement

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48
Q

Ancillary equipment that
must be MRI compatible
is/are: (3)

A

-IV poles
-stretchers
-vital monitors

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49
Q

T or F: An implanted
device that is not MRI
compatible may be
heated causing burns

A

True

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50
Q

To ensure that a patient’s
head is not rotated during
CT simulation of the head,
the side lasers should be
centered to the:

A

anterior tragal notches

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51
Q

The patient should be
aligned with the _____ laser
light when performing a
CT simulation.

A

sagittal

52
Q

Patient screenings for MRI
include all of the
following, except:

A

Physician order

53
Q

MRI screening for
personnel should include
all of the following: (2)

A

-general employee info
-implants, devices, or objects

54
Q

There are ____ MRI safety
zones

A

4

55
Q

Safety line drawn around
the perimeter of the main
magnet of the MRI
scanner…is known as

A

The 5 Gause line

56
Q

When a ferromagnetic
object is rapidly drawn
into the MR is known as
_____________.

A

missle “E”FFECT

57
Q

For CT scanning, as mAs
increase, patient dose
______, and image noise
______.

A

increases;decreases

58
Q

All of the following factors
indicate that a patient is at
increased risk of an
iodinated contrast agent
reaction except:

A

younger than 50 y/o

59
Q

What part of the CT
simulator is often referred
to as the “bore”?

A

gantry

60
Q

The DRR is created from:

A

CT

61
Q

All of the following are
contraindications for using
contrast media
EXCEPT:

A

patients under 50

62
Q

Compared with conventional (axial) CT
scanning, spiral-helical CT has:

A

faster imaging times

63
Q

Spatial resolution can be
improved by using: (2)

A

-small detector sizes
-thin slice thickness

64
Q

As the display field of view (DFOV) decreases:

A

-noise increases
-spatial resolution increases

65
Q

The Hounsfield unit of air is:

A

-1000

66
Q

The 2 most common types of contrast adminstration routes in CT simulation are:

A

oral & intravenous

67
Q

If you want to adjust the brightness of your CT image, you will be adjusting the:

A

window level

68
Q

The daily CT numbers test is performed using a
phantom provided by the:

A

CT scanner vendor

69
Q

When a spiral-helical CT scanner takes a scout
image, the x-ray tube:

A

is stationary

70
Q

Which of the following techniques would be used
for a patient who has trouble holding his or her
breath or has an irregular heartbeat?

A

retrospective gating

71
Q

The CT image made directly through the
reference point corresponds to CT image
number

A

0

72
Q

Which of the following
electromechanical
functions of the CT
scanner are NOT used in
simulation, yet must be
tested as part of a quality
assurance program?

A

gantry tilt

73
Q

The following are true of uncontrolled areas,
except:

A

is monitored by the Radiation Safety Officer

74
Q

T or F: Nuclear Regulatory Commission (NRC) was
created as an independent agency by Congress in 1974 to ensure the safe use of radioactive materials for beneficial civilian purposes while protecting people and the environment

A

True

75
Q

The most common material used for protective barriers is:

A

concrete

76
Q

T or F: Diodes are preferred to use for beam calibration.

A

False

77
Q

T or F: American Association of Physicists in Medicine (AAPM) is advancing medicine through excellence in the science, education and professional practice of all physics; a broad-based scientific and professional
discipline which encompasses physical principles with applications in biology and medicine.

A

False; it’s medical physics

78
Q

Correction factors that may be applied to ionization chambers are as follows: (3)

A

-temperature
-volume
-pressure
(cause ionization)

79
Q

T or F: The National Council on Radiation Protection and
Measurements (NCRP) seeks to formulate and widely disseminate information, guidance and recommendations on radiation protection and measurements which represent the consensus
of leading scientific thinking.

A

True

80
Q

OSL crystals are excited
by:

A

Light

81
Q

TLD’s store the information for:

A

weeks

82
Q

OSL’s are made of:

A

Aluminum Oxide (Al2O3)

83
Q

T of F: Diodes provide real-time readings

A

True

84
Q

Gas-filled detectors include all of the following, except:

A

Scintillation detectors

85
Q

Proportional counters are typically used for ___________.

A

Neutrons

86
Q

TLD’s are accurate within +/-______%

A

5

87
Q

Materials used for primary barriers include all the following except:

A

cerrobend

88
Q

T or F: Primary Barrier is directly hit by the useful
radiation beam

A

True

89
Q

OSL’s store information for

A

Year

90
Q

TLD’s crystals light up when exposed to:

A

heat

91
Q

T or F: Geiger Mueller Counters measure the amount of radiation

A

False

92
Q

At the completion of a prostate seed implant, the
room is surveyed using a ____________.

A

geiger mueller counter

93
Q

Radiation area:
>/= ___rem
In ___ (time)
At ___ cm

A

person can receive greater than or
equal to 0.005 rem (.05 mSv or 5 mrem) in 1 hour @ 30
cm from the source

94
Q

High radiation area:
>/= ___ rem
___ (time)
At ___ (cm)

A

posted when a person can receive greater than or
equal to 0.1 rem (1 mSv) in 1 hour @ 30 cm from the
soucre

95
Q

Very high radiation area:
> ___ rad
In ___ (time)
At ___ (Meters)

A

posted when a person can receive more than 500
rads(5 cGy) in 1 hour @ 1 meter from the source

96
Q

Caution: Radioactive
materials

A

posted in areas where sources of radiation are used
and/or stored

97
Q

Shielding for neutron contamination must be
considered at energies of ____________.

A

> 10 MV

98
Q

T or F: Signage for radiation areas include a
radiation symbol with 3 blades that are marroon
or black on a yellow background.

A

Flase

99
Q

Medicare and medicaid require the following
accreditation from the following:

A

-The Joint Commission (TJC)
-American College of Radiology (ACR)
-American College of Radiation Oncology (ACRO)

100
Q

Average concrete thickness for secondary
barrier = _______ for beams with energies of 15 - 18
MV.

A

1 meter

101
Q

MRI zone 1:

A
  • Safest
  • Pulic can acess freely
  • No hazards by magnet
102
Q

MRI zone 2:

A
  • Buffer (between 1 and 3)
  • Patient acess with supervision
  • Generally no hazards from magnet
103
Q

MRI zone 3:

A
  • Restricted with physical barrier
  • Only patients who did interview can acess with supervision
104
Q

MRI zone 4:

A
  • Magnet room, only acessable by passing zone 3
105
Q

5 gausse and below is considered ___ for public

A

safe

106
Q

Above what gausse line can interfere with implated devices

A

5

107
Q

MRI screening includes (3)

A
  • Printed form
  • Review of printed screening form
  • Verbal inteview
108
Q

GFR can happen in patients ___ years or older

A

60

109
Q

General patient related information during MRI screening include (4)

A
  • age
  • height
  • weight
  • sex
110
Q

What is occupational rad dose

A

1rem/1year

111
Q

Public rad dose is
- yearl
- weakly

A
  • 0.5rem/1year
  • 0.1/weekly
112
Q

energies above ___mV need shielding for possible ___ contamination

A
  • 10mv
    -neutron
113
Q

Materials used for barriers include (4)

A
  • lead
  • tugnsten
  • aluminium
  • concrete (most common)
114
Q

Primary concrete barries is ___ meters

A

2

115
Q

Primary barrier is hit by ___ beam while secondary barrier is hit by ___

A
  • Primary
  • Scatter
116
Q

Mazeless vaults characteristics (2)

A
  • least square footage
  • Thicker walls
117
Q

Mini maze characteristics

A
  • reduced square footage and shielding requirements
118
Q

Maze vault characteristics

A
  • Blance of square footage and shielding
119
Q

Ionization chamber meters measrue:

A

Electrical signal

120
Q

Ionization chamber meters are accurate within ___% +/-

A

2%

121
Q

Cutie pies are

A

portable ion chambers

122
Q

What is used to calibrate external beam radiation machines?

A

Farmers chamber

123
Q

Geiger-muller detector detects

A

low levels of radiation and contamination

124
Q

Diodes give ___ time readings

A

real

125
Q

Neutron detectors used in ___ and ___ therapy greater than ___mV

A
  • proton
  • photon
  • 10 mV
126
Q

proprotional counters typically used in ___ dosimetery

A

Photon

RTT Science Fall 24 (6 decks)

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