Clinical Radiation Generators Flashcards

1
Q

Two Major types of radiation generators

A

Kilovoltage Theraphy Units

Megavoltage Theraphy Units

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2
Q

machines that can generate xray voltages up to 300kVp

A

Kilovoltage Theraphy Units

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3
Q

Used up to about 1950

A

Kilovoltage Theraphy Units

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4
Q

Kilovoltage Theraphy Units is useful in the treatment of skin cancer extending no more than

A

1 cm below the surface

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5
Q

types of Kilovoltage Theraphy Units

A

Grenz Ray
Contact Therapy
Superficial Therapy
Deep Therapy Unit

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6
Q

German word which means border

A

Grenz

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7
Q

Characteristic of Grenz Ray

A

very soft xrays
operates below 20kV
very low depth penetration

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8
Q

Clinical Application of Grenz Ray

A

Dermatological use

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9
Q

derived by the way the treatment unit actually came in contact with the patient

A

Contact Therapy

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10
Q

Characteristic of contact therapy

potential

A

40-50kV

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11
Q

Characteristic of contact therapy

tube current

A

2mA

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12
Q

Characteristic of contact therapy

SSD

A

2cm or less

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13
Q

Characteristic of contact therapy

filter

A

0.5 to 1mm thick aluminum

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14
Q

Clinical application of contact therapy

A

tumors not deeper than 1mm

primarily used to treat superficial skin lesions

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15
Q

Characteristic of Superficial therapy

potential

A

50-150kV

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16
Q

Characteristic of Superficial therapy

tube current

A

5-8 mA

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17
Q

Characteristic of Superficial therapy

SSD

A

15 to 20 cm

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18
Q

Characteristic of Superficial therapy

filtration

A

1-6mm aluminum

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19
Q

Clinical Application of Superficial therapy

A

5mm depth

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20
Q

also called Orthovoltage

A

Deep Therapy Units

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21
Q

Characteristic of Deep Therapy Units

potential

A

150-500 kV

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22
Q

Characteristic of Deep Therapy Units

tube current

A

10-20 mA

23
Q

Characteristic of Deep Therapy Units

SSD

A

50cm

24
Q

Clinical Application of Deep Therapy Units

A

tumors within 2cm depth

25
Q

Disadvantages of kV units

A

large skin dose
poor depth dose distribution
increased absorbed dose in bone
increased scattering

26
Q

radiotherapy equipments that deliver beams with high dose rate in the multimillion volt range

A

Megavoltage Therapy Units

27
Q

Telecurie therapy units use

A

Radium 226
Cobalt 60
Cesium 137

28
Q

are emitted from these sources as they undergo radioactive disintegration

A

Gamma (y) rays

29
Q

placed in contact with patient’s skin for treatment of underlying skin lesions

A

brachytherapy

30
Q

larger amount of radium placed at some distance from the skin with subsequent improvement in depth dose

A

teletherapy

31
Q

replace radium as the active source in telecurie units

A

Cobalt 60

32
Q

advantages of cobalt 60

A

higher specific activity
greater radiation output per curie
higher average photon energy

33
Q

relatively long half-life which promised to a desirable source

A

cesium 137

34
Q

disadvantages of cesium 137

A

limited specific activity limits its application to head and neck

35
Q

Clinical Application of cesium 137

A

Used in head and neck

36
Q

electrostatic accelerator designed to acceleate electrons to produce high energy xrays typically at 2MV, but can generate beam energy of 10MV

A

Van de Graaf Generator

37
Q

Machine capable of accelerating electrons to 2.3 MeV

A

Betatron

38
Q

Operates on the principle that an electron on a changing magnetic field experiences acceleration in a circular orbit

A

Betatron

39
Q

Can provide xray and electron therapy beams from less than 6 to more than 40 MeV

A

Betatron

40
Q

uses high frequency electromagnetic waves to accelerate charged particles such as electrons to high energies through linear tube

A

Linear Accelerator

41
Q

Used to treat superficial tumors or it can be made to strike a target to produce x-rays to treat deep seated tumors

A

Linear Accelerator

42
Q

first linear accelerator was installed in

A

Hammersmith Hospital in London, had an 8 MeV xray beam and limited gantry rotation

43
Q

An electron accelerator which combines the principles of both the linear accelerator and the cyclotron

A

Microtron

44
Q

Capable of producing both x-rays and electron beams

A

Microtron

45
Q

Source of high energy proton for proton beam therapy

A

Cyclotron

46
Q

Other uses of Cyclotron

A

generation of neutron beam

production of certain radionuclide

47
Q

cyclotron consists of short metallic cylinders divided into 2 sections

A

Dees (Ds)

48
Q

Used to generate higher energy charged particles such as deuterons, protons and alpha particles

A

Synchocyclotron

49
Q

Deuterons

A

200 MeV

50
Q

Protons

A

680 MeV

51
Q

Alpha particle

A

400 MeV

52
Q

Machines designed to accelerate electrons and protons by means of radiofrequency-modulated magnetic field to compensate for the relativistic increase in particle mass

A

Neutron Beam Generator

53
Q

Electron energies of 10 to 100 MeV results to energy in Giga or billion of electron volts

A

Electron synchrotron

54
Q

Largest proton synchotron in Fermi Nat. Accelerator Lab can generate as much as

A

400 GeV energy