A. Different treatment types and procedures Flashcards by carlos cordova

_______ Radiation Therapy Conforms the radiation beam so that the target volume receives the prescribed dose and the surrounding healthy tissue receives a much lower dose

3-D Conformal

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Planning uses 3D imaging such as ______

computed tomograpy

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________ is a monoenergetic beam that is used to treat superficial tumors

Electron beam

mono energetic beam
treat superficial tumors <5 cm deep
6-20 Mev

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Electron beams Scatter easily in

air

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Electron beams r equires a cone to confine the beam closer to the

patient’s skin surface

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Electron beam field edges balloon out because of _____and aren’t definitive like photon beams

scatter

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For electron beams, there is a “rapid falloff” of dose, which means that

deeper organs and tissues will receive very little or no dose

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For electron beams there is _____________, which means more dose to the skin compared to photons

Less skin sparing

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_____ is a radiation beam that has varying intensities throughout the beam

IMRT

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IMRT has Many smaller beams or “beamlets”. Beamlets are commonly as small as

1 cm x 1 cm

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T/F for IMRT the dose is uniform

FALSE

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IMRT allows for higher doses to tumors while minimizing doses to

surrounding healthy tissues

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IMRT uses _____ treatment planning and dynamic MLCs

inverse

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______ treats small tumors within the cranium at a high dose

SRS

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SRS treats tumors with how many fractions?

One

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SRS tumors are normally less than ____Cm

3cm

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Treatment positioning must be +/- ___mm

1mm

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SRS of intracranial lesions may require

a frame attached to the patients head

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What are the common disease treated with SRS that are in the cranium?

AVMS, trigeminal neuralgia, acoustic neuromas, meningiomas, pituitary adenomas, metastatic and primary brain tumors, less common in spine

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What are some examples of machines that preform SRS treatment?

Gamma Knife and Cyber Knife

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______ treats small tumors outside of the cranium with a very high dose for about 3-5 fx

SBRT

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_____ is a type of radiation therapy that targets the whole body to prepare for bone marrow transplants and to treat other malignancies

TBI

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_____ is used prior to treatment to confirm patient position

Image Guided Radiation Therapy (IGRT)

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What are examples of IGRT

EPID, KV, MV cone beam, Ultrasound

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_____ = high energy charged particles such as protons, alpha particles, and carbon ions

Particle beam radiotherapy

______ is the dose curve of a proton beam. It starts off low at the beginning but then rapidly rises toward the end of the path. Then abruptly falls to zero.

Bragg peak

___________ Helps to position the patient for treatment

Patient positioning aids

Positioning aids do NOT....

limit the patient's movement

What are positioning devices than can be used for multiple patients

head holders, sponge pillows, foam cushions, neck rolls

________________ immobilization devices- Limit the patients movement and create a very reproducible setup

Complex

Complex immobilization devices are Customized for each patient. What are some examples?

alpha cradle, vac-lok, thermoplastic molds, bite blocks

_______immobilization devices Help to constrain patient

Simple

Simple immobilization devices are Used with positioning aids. They are Not as restricting as complex immobilization devices. What are some examples?

tape, rubber band, arm-to-foot straps

When is contrast used?

simulation

What does contrast do to help create the treatment plan?

It will highlight specific organs

What can contrast highlight?

Area to be treated and critical structures to be avoided

______ contrast agents appear radiopaque (white) on radiographic imaging due to high atomic numbers

positive

What are examples of positive contrast agents?

iodine, gadolinium, and barium

______ contrast agents appear radiolucent (black) on radiographic imaging due to low atomic numbers

negative

What are some examples of negative contrast agents?

air, oxygen, carbon dioxide, and nitrous oxide

_____ is the most common imaging modality used for RT treatment planning

computed tomography (CT)

CT simulators create ____ images

CT images are produced by

X-ray, detectors, and computer

the CT scanner follows A XYZ axis

Z axis = length of patient x axis = width y axis = height

CT images are acquired through

Spiral or helical scanning

_____ is the thickness of the section in the patient that contributes to echo signals on any one image

slice thickness

Slice thickness is Controlled by pre-patient collimation within the

CT gantry

Thinner image slices are a result from _________ collimation that narrows the x-ray beam

___________ slices reduce scatter and create better image quality

thinner

Typical CT simulation slice thickness is ___ to ___ mm

2-3 mm

One CT slice delivers __to___ cgy at the skin's surface

1 to 6 cGy

Spacing between CT slices should be less than ____

5 mm

__________ space between the slices leads to less information obtained by the scan and more interpolation performed by the computer algorithms

What are two key factors for generating high-quality DRRs?

slice thickness and space between slices

_____ Measures the beam quantity, or how many x-rays are produced

mA Increase leads to higher

patient dose

mA is a Technical factor used to create a

high-quality image

CT image displays use a matrix size of _______ x _______

512 X 512

CT images are a display of many small pixels with different shades of gray, depending on the

attenuation rate or Hounsfield units

the number of shades of gray displayed on an image or the contrast of the image.

window width (WW)

A _____ window width has more contrast

narrow

the median shade of gray or hounsfield unit within the window width

Window Level (WL)

Window level changes the image

brightness

An increase in window level creates a

darker image

A decrease in window level creates a

brighter image

_____ is a value that represents a shade of gray

CT number

CT number is also known as the

Hounsfield Unit (HU)

CT number represents the _____ of different tissues

density

For CT number the shade of gray is determined by

how the structure attenuates the x-ray beam

What is CT number for air

-1,000

What is CT number for water

What is CT number for bone

1000

____ is where the computer uses algorithms to create the CT image in different planes

Reconstruction

Where are reconstructed CT Images first acquired?

the axial plane

CT Images are reconstructed to be viewed in the _______ planes

coronal and sagittal

During a _______, raw data is acquired during a scan and it is then reconstructed into image data to be viewed

CT simulation

The computer assigns each pixel an HU to become _______ in reconstruction of image

image data

The amount of raw data used to create or display an image

display field of view (DFOV)

Area of interest to be scanned

Scan field of view (SFOV)

_______ is a 3-D image taken in the treatment position that provides data of the anatomy of the patient, such as the skin, tumor and other organs within the body

contour

Contours are necessary for creating accurate treatment plans and

calculating doses

In the _______ ( treatment planning system) the physician can identify the treatment borders and the isocenter location

Virtual simulator

What does DICOM stand for

Digital imaging and communication in medicine

DICOM is used to

Transfer of images and patient reports to planning computers

Used to store and share images

PACS

____ lasers are at a fixed distance from the internal scanner lasers usually 500mm (50cm)

External

___ lasers are mounted to the side of wall and project vertical and horizontal directions

Wall

_____ laser is a single laser located on the ceiling and is moveable. It moves in the left/ right position. Important since CT table cant move Lt/Rt.

Sagittal

___ lasers are internally mounted within the gantry bore

Scanner

Who created Sim order

Radiation oncologist

What should be included in Sim order?

Patient position, body part to be simmed, laterality of body part, contrast instructions, and immobilization technique

what is Non - volumetric arc therapy ?

used for small tumors - where gantry rotates but the mlc stay stationary - 3D plan

you can find the range depth in electron by doing

Mev/2

A. Different treatment types and procedures Flashcards

(93 cards)