Clinical Radiation Generators

Question 1

Two Major types of radiation generators

Answer 1

Kilovoltage Theraphy Units

Megavoltage Theraphy Units

Question 2

machines that can generate xray voltages up to 300kVp

Answer 2

Kilovoltage Theraphy Units

Question 3

Used up to about 1950

Answer 3

Kilovoltage Theraphy Units

Question 4

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

Answer 4

1 cm below the surface

Question 5

types of Kilovoltage Theraphy Units

Answer 5

Grenz Ray
Contact Therapy
Superficial Therapy
Deep Therapy Unit

Question 6

German word which means border

Answer 6

Grenz

Question 7

Characteristic of Grenz Ray

Answer 7

very soft xrays
operates below 20kV
very low depth penetration

Question 8

Clinical Application of Grenz Ray

Answer 8

Dermatological use

Question 9

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

Answer 9

Contact Therapy

Question 10

Characteristic of contact therapy

potential

Answer 10

40-50kV

Question 11

Characteristic of contact therapy

tube current

Answer 11

2mA

Question 12

Characteristic of contact therapy

SSD

Answer 12

2cm or less

Question 13

Characteristic of contact therapy

filter

Answer 13

0.5 to 1mm thick aluminum

Question 14

Clinical application of contact therapy

Answer 14

tumors not deeper than 1mm

primarily used to treat superficial skin lesions

Question 15

Characteristic of Superficial therapy

potential

Answer 15

50-150kV

Question 16

Characteristic of Superficial therapy

tube current

Answer 16

5-8 mA

Question 17

Characteristic of Superficial therapy

SSD

Answer 17

15 to 20 cm

Question 18

Characteristic of Superficial therapy

filtration

Answer 18

1-6mm aluminum

Question 19

Clinical Application of Superficial therapy

Answer 19

5mm depth

Question 20

also called Orthovoltage

Answer 20

Deep Therapy Units

Question 21

Characteristic of Deep Therapy Units

potential

Answer 21

150-500 kV

Question 22

Characteristic of Deep Therapy Units

tube current

Answer 22

10-20 mA

Question 23

Characteristic of Deep Therapy Units

SSD

Answer 23

50cm

Question 24

Clinical Application of Deep Therapy Units

Answer 24

tumors within 2cm depth

Question 25

Disadvantages of kV units

Answer 25

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

Question 26

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

Answer 26

Megavoltage Therapy Units

Question 27

Telecurie therapy units use

Answer 27

Radium 226 Cobalt 60 Cesium 137

Question 28

are emitted from these sources as they undergo radioactive disintegration

Answer 28

Gamma (y) rays

Question 29

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

Answer 29

brachytherapy

Question 30

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

Answer 30

teletherapy

Question 31

replace radium as the active source in telecurie units

Answer 31

Cobalt 60

Question 32

advantages of cobalt 60

Answer 32

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

Question 33

relatively long half-life which promised to a desirable source

Answer 33

cesium 137

Question 34

disadvantages of cesium 137

Answer 34

limited specific activity limits its application to head and neck

Question 35

Clinical Application of cesium 137

Answer 35

Used in head and neck

Question 36

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

Answer 36

Van de Graaf Generator

Question 37

Machine capable of accelerating electrons to 2.3 MeV

Answer 37

Betatron

Question 38

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

Answer 38

Betatron

Question 39

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

Answer 39

Betatron

Question 40

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

Answer 40

Linear Accelerator

Question 41

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

Answer 41

Linear Accelerator

Question 42

first linear accelerator was installed in

Answer 42

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

Question 43

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

Answer 43

Microtron

Question 44

Capable of producing both x-rays and electron beams

Answer 44

Microtron

Question 45

Source of high energy proton for proton beam therapy

Answer 45

Cyclotron

Question 46

Other uses of Cyclotron

Answer 46

generation of neutron beam | production of certain radionuclide

Question 47

cyclotron consists of short metallic cylinders divided into 2 sections

Answer 47

Dees (Ds)

Question 48

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

Answer 48

Synchocyclotron

Question 49

Deuterons

Answer 49

200 MeV

Question 50

Protons

Answer 50

680 MeV

Question 51

Alpha particle

Answer 51

400 MeV

Question 52

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

Answer 52

Neutron Beam Generator

Question 53

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

Answer 53

Electron synchrotron

Question 54

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

Answer 54

400 GeV energy