LINAC

Question 1

It is a device that uses high frequency electromagnetic waves to accelerate charged particle such as electrons to high energies through a linear metallic tube

Answer 1

Linear Accelerator

Question 2

Contains components that distribute and monitor primary electrical power and high voltage pulses to the magnetron or klystron

Answer 2

Modulator Cabinet

Question 3

Components of Modulator Cabinet

Answer 3

Fan Control, Auxillary Power, Primary Power

Question 4

Automatically turns the fan off and on as the need arises for cooling the power distribution

Answer 4

The fan control

Question 5

Contains the emergency off button that shuts off the power to the treatment unit.

Answer 5

Auxillary Power or Distribution System

Question 6

Primary Power - ___________

Answer 6

Distribution Power

Question 7

Provides a central location for monitoring and controlling the LINAC.
Take the form of a digital display, push button panel or video display terminal (VDT)

Answer 7

CONTROL CONSOLE

Question 8

• A stand containing the apparatus that drives the LINAC. Stand is anchored firmly to the floor.
• Open on both sides with swinging doors for easy access to gauges, valves, tanks, and buttons.

Answer 8

GANTRY STAND / DRIVE STAND / SUPPORT

Question 9

Components of GANTRY STAND / DRIVE STAND / SUPPORT

Answer 9

• Klystron/Magnetron
• Waveguide
• Circulator
• Water Cooling System

Question 10

Two types of waveguides

Answer 10

RF power transmission waveguide and Accelerating Waveguide

Question 11

Power source used to generate electromagnetic waves for the accelerator guides

Answer 11

Klystron/Magnetron

Question 12

Power source used to generate electromagnetic waves for the accelerator guides

Answer 12

Klystron/Magnetron

Question 13

electron tube that provides microwaves to accelerate electrons and is preferred for lower electron energies (4Mev-6Mev)

Answer 13

Magnetron

Question 14

Used for high energy LINACS (>6MeV)

Answer 14

Klystron

Question 15

Hollow tube-like structure that guide the electromagnetic waves from the klystron to the accelerating guide where electrons are accelerated.

Answer 15

Waveguide

Question 16

Transmits the RF power from power source to the accelerating waveguide

Answer 16

RF power transmission waveguide

Question 17

Accelerates the electrons in the gantry by means of energy transfer from high power RF fields

Answer 17

Accelerating waveguide

Question 18

Responsible for directing the photon (x-ray) energy or electron beam to the patient. It rotates 360 degrees around a line/point called the Isocenter.

Answer 18

GANTRY

Question 19

Components of a gantry

Answer 19

Electron Gun
Accelerator Structure
Treatment Head

Question 20

Produces electrons and injects them into the accelerator structure

Answer 20

Electron gun

Question 21

Two types of electron gun:

Answer 21

Diode and Triode.

Question 22

Two types of electron gun:

Answer 22

Diode and Triode.

Question 23

Both electron gun types contain a heated filament ______ and perforated _____________; in addition, the triode type also incorporates a _____.

Answer 23

Both electron gun types contain a heated filament CATHODE and perforated GROUNDED ANODE; in addition, the triode type also incorporates a GRID.

Question 24

A special type of waveguide in which electrons are accelerated.

Answer 24

ACCELERATOR STRUCTURE

Question 25

After the flowing electrons leave the accelerator structure, they are directed towards the ___________ or __________ located in the treatment head.

Answer 25

After the flowing electrons leave the accelerator structure, they are directed towards the target (for photon production) or scattering foil (for electron production) located in the treatment head.

Question 26

Designed to shape and monitor the treatment

Answer 26

TREATMENT HEAD

Question 27

Directs the electrons vertically towards the patient. Bends the pulsed electrons towards the target for x-ray production or the scattering foil for electron treatments. Produces different beam paths for different energies. Needed for energies >6MeV.

Answer 27

BENDING MAGNET

Question 28

Used for the production of x-ray photons by bombarding the electrons through it. It is located at the focus of Bending Magnet.

Answer 28

X-RAY TARGET

Question 29

Usually made up of lead, steel, copper etc., Modifies the narrow, non-uniform photon beam at the isocenter into clinically useful beam and scatter into periphery of the beam. It must be carefully positioned in the beam or the beam hitting the patient will be non-uniform, resulting in hot and cold spots.

Answer 29

BEAM FLATTENING FILTER

Question 30

Are thin metal sheets that lets the electrons to scatter, expanding the useful size of the beam.
Typically consist of dual lead foils to minimize the production of bremsstrahlung x-rays. Narrow beam is usually spread by two scattering foils and converts the pencil beam into usable wide beam.

Answer 30

SCATTERING FOIL

Question 31

Used for dose monitoring for the safety of the patients. There are two separate ion chambers and they are positioned between the flattening filter or scattering foil and secondary collimators.

Answer 31

ION CHAMBER

Question 32

Controls the field size by adjusting the upper and lower collimator jaws. Usually, made-up of materials with high atomic (Z) number like Tungsten or Lead. It can define a rectangular shaped beam up to 40cm-by-40cm x-ray beams.

Answer 32

COLLIMATORS

Question 33

Are heavy metal field-shaping devices with independent moving mechanisms used to create a custom like block to spare normal tissues and direct the radiation dose to the treatment target.

Answer 33

MULTI-LEAF COLLIMATORS (MLCs)

Question 34

Mounted on a rotational axis around the isocenter.
Moves mechanically in a horizontal and lengthwise direction - must be smooth and accurate allowing for precise and exact positioning of the isocenter during treatment

Answer 34

TREATMENT COUCH (PATIENT SUPPORT ASSEMBLY):