Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Radthera > Endterm > Flashcards

Endterm Flashcards

1
Q

A type of external beam radiation therapy (EBRT), stereo means 3-dimentional and tactic means probe, allows radiation beam to be given to a very specific are usually the brain, best for very small tumors, it can be completed in one-five days rather than over several weeks

A

Stereotatic radiotherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Delivers a single high dose of radiation to the tumor (called single fraction), this treatment doesn’t envolve surgery. An incision (cut) is not made and tissue is not surgically remove. __ is delivered by a team involving radiation oncologist and neurosurgeon.

Used to treat conditions involving the brain or spine including: CA that starts in the brain (gliomas, and other primary brain tumor, brain metastases, benign tumors arising from membranes covering the brain (meningiomas), abnormal blood vessels in the brain (arteriovenous malformations)

A

Stereotatic radiosurgery (SRS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Gives smaller dose of radiation over a number of treatment sessions (called multiple fraction), until the desired total dose given, it also refers to one or several stereotatic radiation treatment in the body excluding brain or spine.

Small lung CA, lung metastases, liver metastases

A

Stereotatic radiotherapy (SRT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When __ is used the head frame is attached to the skull. A neurosurgeon injects a local anesthesia just under the scalp to numb the area. Then the neurosurgeon places special screws or pins into the skull. These screws or pins fix the head frame to the skull. The skull screws and head frame are removed after the treatment is finished

A

Stereotatic radiosurgery (SRS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When __ is used, a removable head frame or a special mask keeps the head in position

A

Stereotatic radiotherapy (SRT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 delivery systems

A

Gamma knife, linear accelerator, cyberknife

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

A type of conformal radiotheraphy. Conformal radiotherapy shapes the radiation beams to closely fit the area of the CA. It is an advanced mode of high-precision radiotherapy. Uses a computer controlled LINAC to deliver precise radiation dose to malignant tumor. Allows radiation dose to coform more precisely to 3-dimensional shape of tumor. Allows higher radiation doses to be focused on the regions within the tumor while minimizing the dose to surrounding normal critical structures

A

Intensity modulated radiotherapy (IMRT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Currently, __ is being used most extensively to treat CA of the prostate, head and neck and CNS. Since __ uses a standard radiotherapy machine such as LINAC, it is excellent to use multi-leaf collimator

A

Intensity modulated radiotherapy (IMRT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Persons involved in the procedure in IMRT

A

Radiation oncologist, medical physicist, dosimetrist, radiation therapist, radiation therapy nurse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What the px feels during and after the procedure

A

No pain during the actual treatment with IMRT
machine can be stopped if you experience discomfort due to treatment position or positioning devices
As treatment progress some px may experience treatment-related side effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

IMRT treatment sessions usually takes between?

A

10-30 mins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Early side effects
Depending on the area being treated, other early side effects may include

A

Hair loss in the treatment area
Mouth problems and difficulty in swallowing
Eating and digestion problems
Diarrhea
Nausea and vomiting
Soreness and swelling in the treatment area
Urinary and bladder changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Late side effects
Which are rare, occurs months or years following treatment and are often permanent. They include

A

Infertility
Brain changes
Spinal cord changes
Lymphedema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Brachytherapy comes in to 2 treatment procedures:

A

High dose rate (HDR) brachytherapy and low dose rate (LDR) brachytherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A type of internal radiation therapy, delivers high dose of radiation from implants placed closed to or inside the tumor.

A

High dose rate brachytherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

3 types of HDR brachytherapy

A

Intracavitary implant
Intraluminal implant
Interstitial implant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

An applicator is inserted into a body cavity to reach the tumor. These are performed in clinic or out patient basis. Local anesthesia and/or conscious sedation is required

A

Intracavitary implant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

The catheters are inserted into a tube structure such as bronchus, esophagus, or bile duct. These are treated the same as intracavitary implants

A

Intraluminal implants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Implants are done in operating room with the px under local, general or spinal anesthesia, interstitial catheters are inserted through the body tissue to encompass tumor. In case of prostate and gynecological cases, a rubber template is sutured to the outside skin to hold the treatment catheters in position, in breast and head and neck cases, the treatment catheters are held in position on the skin by plastic buttons where the catheters enter and exit the skin, it is by means of needles or catheters

A

Interstitial implant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Type of internal radiation therapy that delivers low doses of radiation from implants placed closed to or inside the tumor in the body, implants are the same as in the HDR. Sources used are: Ra-226, Cs-137, Ir-192, I-125 and Pa-103. Source handling and loading into the applicator or tissue can be performed manually or remotely by the afterloader with source loading performed by a computerized unit

A

Low dose rate brachytherapy (LDR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

In __, tiny radioactive particles the size of rice are implanted directly into the size of the tumor these particles are known as seeds

A

LDR brachytherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Measurement of the absorbed dose delivered by ionizing radiation calculation and assessment of radiation dose received by the human body used extensively for radiation protection and is routinely applied to occupational radiation workers

A

Dosimetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

dose absorbed unit in time. indicates the amount of radioactive dose received by the person within a certain period of time. Expressed in rems or sievert (Sv) per hour.

A

Dose rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Ordinarily measured on the central axis at a standard source surface distance (SSD) at the depth of Dmax in phantom

A

Dose rate in tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Displays relative doses across the treatment plan consisting of multiple beams

A

Dose profile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

4 radiation quantities and qualities
Quantity, (old), name (new), other units

A

Activity (A), curie(Ci), becquerel (Bq), Ci= 3.7x10^1, Bq 1Bq= dis/s

Absorbed dose (D), rad, gray(Gy) Gy= 100 rad j/kg, ms2/s2, 1 Gy= 1j/kg

Equivalent dose (H), rem, sievert (Sv) Sv=100 rem

Exposure (E), roentgen, coulomb/kg, R=2.58x10-4 c/kg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Used for all kinds of radiation for any material. Energy transferred by ionizing radiation to the interacting medium per unit mass. Unit dose that refers to dose received by the patients

A

Absorbed dose (D)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

D=
E=
M=

A

Absorbed dose
Energy
Mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Amount of radiation exposure received by the radiation workers, Unit used that refers to the dose received by the radiation workers

Formula H=DQN

A

Equivalent dose (H)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

H=
D=
Q=
N=

A

Equivalent dose
Absorbed dose
Quality factor
20 for alpha radiation
10 for both proton and neutron
1 for both x-ray and gamma ray
Modifiying factor always equal to 1 (no unit)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Device that measure dose distribution within such phantoms The constancy of the machine must have been routinely checked otherwise irreversible harm may be caused either by overdosing – which lead to tissue damage or underdosing – which result in failure to cure. It is advisable to measure the dose actually delivered to the patient by means of __ placed in body cavities or in catheters or needles inserted in the tissues.

A

dosimeters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

at a point is an absorber such as tissue in the energy deposited in small fixed weight of material

A

Dose or absorbed dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

When radiation beam reaches the patient, the dose delivered to a point within the patient depends on the following.

A

Dose measurements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

depth of calculation point below the surface

A

a. Depth

35
Q

penetration power of the beam

A

b. Energy

36
Q

type of tissue (muscle, bone, fat) that the beam must penetrate

A

Density

37
Q

distance from the radiation source to the skin surface

A

SSD

38
Q

size of the field on the skin surface An essential step in treatment planning is to establish measured data tables for each treatment machine that will be used.

A

Field size

39
Q

tissue equivalent material or dummy patients The __ material used is often water, which is like soft tissue as far as radiation absorption is concerned.

A

Phantoms

40
Q

3 devices most commonly used for dose determination

A
  1. Ionization chamber
  2. Thermoluminiscent dosimeters (TLD’s)
  3. Photographic film
41
Q

a comparison between measurements comparison between the standard unit and the unit under test

A

Calibration

42
Q

calibrates the safety machine and checks all the safety system so that the characteristics of the machine and dose delivered are known to a highly degree accuracy

A

Medical Physicist

43
Q

allows certain judgements to be made relative to the adequacy of the therapy

A

Accurate calibration

44
Q

constructed to shield critical organs in the treatment portal commonly used for the treatment of thyroid, kidneys, liver, lens of the eyes and lungs. the blocks are placed in a tray attached to the head near the collimator of the machine

A

Special blocks

45
Q

often slopes away from the normal cross-sectional areas of the beam. This creates an air gap.

A

Skin surfaces

46
Q

devices to compensate for the air-gap

A

Bolus and compensating filter

47
Q

made up from tissue equivalent materials whose properties simulate those of soft-tissue and may be filled with rice or water.

A

Bolus bag

48
Q

perform essentially the same functions as bolus bags but are individually designed by the physicist according to the patient contours.
§Tissue compensating filter generally preserve the skin-sparing properties of the radiation.

A

Tissue compensating filter

49
Q

Probably have the most contact with the patient. Must have a cheerful and sympathetic attitude. Assist the oncologist and the physicist during the first treatment in placing the patient in treatment position. The position of the patient and the size of the treatment will be checked by dimming the lights in the room and making use of field lights located in the head of machine.

A

Radiologic technologist

50
Q

lights on the sides of the room which are used to check the height of the treatment table

A

Sidelights

51
Q

illuminates an area that coincides with the radiation treatment field on the patient’s skin

A

Field lights

52
Q

3 MOST IMPORTANT TISSUE ABSORPTION FACTORS

A

a. TMR
b. TAR
c. PDD

53
Q

Include both primary dose and the dose due to scatter in the irradiation volume.Dependence on the field size increase with a increased FS(field size) Varies inversely with the square of the distance from the source

A

Dose rates in phantom

54
Q

TISSUE ABSORPTION FACTORS
a. PDD -
b. TAR –
c. BSF –
d. TPR –
e. TMR –

A

percentage depth dose
Tissue Air Ratio
Back scatter Factor; TAR in Dmax
Tissue Phantom Ratio
Tissue Maximum Ration

55
Q

depth dose ratio express in percent absorb dose at a given depth expressed as a percentage of the absorb at reference depth on the central axis of the field. the reference depth on the central axis of the field. affected by energy, field size, SSD and by composition of the irradiated medium PDD also change with depth. dmax – reference depth.

A

PDD (PERCENTAGE DEPTH DOSE)

56
Q

as the FS is increased, the absorb dose in a medium is greater due to the increased scatter, thus the PDD is increased.

A

Dependence on FS and Shape

57
Q

Higher energy beams have greater penetrating power and thus the PDD at a given depth and SSD is increased

A

Dependence on energy and depth

58
Q

absolute dose rate decreases with increased distance from source PDD increase with increased distance

A

Dependence on distance

59
Q

ratio of the absorb dose at a given depth in phantom to the absorb at the same point in free space or in air TAR is independent of SSD Is the ratio of the dose at a given point in a medium to the dose at the same point in free
space For given energy, the TAR depends on depth and FS but independent of the distance.

A

Tissue air ratio (TAR)

60
Q

first introduced by Karzmark in an effort to overcome the limitations of the TAR the ratio of dose at a specified point in tissue or in a phantom to the dose at the same distance in the beam at reference depth, usually 5cm. sometimes used instead of TAR in dosimetry of high energy beams Retains the properties of TAR but eliminates the difficult and unreliable measurements in air.

A

TISSUE PHANTOM RATIO (TPR)

61
Q

a special case of TPR where the reference depth is chosen to be at Dmax.

A

TISSUE MAXIMUM RATIO

62
Q

ratio of dose rate with a scattering medium (water or phantom) to the dose at the same point without a scattering medium (air) at the level of maximum equilibrium. TAR at the level of Dmax independent of SSD but depends on the energy and the FS

A

BACK SCATTER FACTOR (BSF)

63
Q

is the gross palpable visible and/or tissue demonstrable extent and location of malignant growth The volume of known disease

A

GROSS TUMOR VOLUME (GTV)

64
Q

is a tissue volume containing the GTV and or subclinical microscopic malignant disease The volume that must always be enclosed by the treatment isodose Untreated portions of the CTV could lead to a local failure of therapy.

A

CLINICAL TARGET VOLUME (CTV)

65
Q

also known as standard ionization chamber. instrument used in the measurement of roentgen used for the calibration of secondary instruments designed for the field use. Too delicate and bulky for the routine use.

A

FREE AIR IONIZATION CHAMBER

66
Q

Shaped liked a sewing thimble Has a wall-thickness of 1mm or less with closed fitting caps made up of Plexigals §Most commonly used wall materials are graphite, bakelite or a combination of both

A

Thimble Chambers

67
Q

Provide a stable and reliable secondary standard for x and gamma rays for all energies in the therapeutic range

A

Farmer Chamber

68
Q

Basic method of determining absorbed dose in a medium Used a thermistor to measure in small rise temperature. Thermistors are semi-conductors that shows a large change in electrical resistance with a small change in electrical resistance with a small change temperature about 5% or 1 degree Celcius.

A

Calorimetry

69
Q

The energy absorbed from ionizing radiation may produced a chemical change and this can be determined to measure the absorbed dose

A

Chemical dosimetry

70
Q

also known as the Fricke Dosimeter Consist of ferrous sulfate or ferrous ammonium sulfate and sulfuric acid

A

Ferrous sulfate

71
Q

Radiation chemical yield may be expressed in terms of the number of molecules produced per 100 eV of energy absorbed.

A

G value

72
Q

Lithium fluoride is the most extensively studied and most frequently used for clinical dosimetry Has an effective atomic number of 8.2

A

Thermoluminescene Dosimetry

73
Q

a geometric volume the dimension believed to always contain the CTV. Includes margin around CTV It allows for target motion and uncertainty in positioning.

A

Planning target volume

74
Q

Two types of technique

A

Sad technique
Ssd technique

75
Q

involves the measurement of radiation based on the change in the thermal energy per unit mass of the medium. It is based on the fact that almost all the energy deposited in the medium by the radiation beam eventually appears as heat within the medium. For water, 1 Gy produces a temperature rise of 2.4x 10-4 Calories/gram which can be measured using a sensitive device called thermistors.

A

CALORIMETRY

76
Q

based on chemical changes caused by radiation. The chemical radiation dosimeter most commonly used is Ferrous Sulfate in which it is oxidized by radiation into ferric sulfate. Ferric Ion concentration is measured by absorption spectrometry at 224 nm and 304

A

FRICKED DOSIMETRY

77
Q

When x-ray film is exposed to ionizing radiation. the exposed siver bromide crystaIs form a latent image. The degree of blackening of the film is proportional to the energy absorbed and is measured by determining the optical density with a densitometer.

A

FILM DOSIMETRY

78
Q

measurement of radiation energy based on ion pairs produced in a given mass of medium.

A

IONIZATION METHOD

79
Q
  • used for photon beam
  • used for photon
  • used for electron beam
A

Thimble Chamber
Farmer Chamber
beam Markus Chamber

80
Q

when a crystal is irradiated, a very minute fraction of the absorbed energy is stored in the crystal lattice. Some of this energy can be recovered later as visible light if the material is heated. This phenomenon of the released of visible photon by thermal means is known as Thermoluminescence

A

THERMOLUMINESCENCE DOSIMETRY

81
Q

Treatment through one single field arrangement is the simplest treatment and the dose distribution in tissue is essentially as represented on an isodose chart for the particular energy and the field used.
With this field arrangement, Electron is usually the type of radiation used to treat shallow tumors where a rapid drop in dose beyond the 57 depth of the tumor.

A

Single field

82
Q

-Is a pair of fields directed along the same axis from opposite sides of the treatment volume. are relatively easy to set-up and to reproduced from day to day.cThe 100% isodose line is with in the entire treatment volume.
Advantages- Simplicity and reproducibility of set-up Homogenous dose to the tumor Less chances of geometrical miss
Disadvantage- Excessive dose to normal tissues critical organs above and below tumors

A

Parallel opposed fields

83
Q

The use of multi-fields directed at the target volume requires that the beam entrance and exit of each field be aimed at different angles/segments, thereby reducing the dose to adjacent tissues.
The most popular multi-field arrangement is the “box Technique”, which is often used in the treatment of pelvic malignancies. The technique consists of opposed anterior and posterior fields and opposed right lateral and left lateral field.

A

Mult-field arrangement

Radthera (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions