Rad Physics Final

Sievert

Occupational dose

Coulomb

Radiation in the air

Gray

Absorbed dose

Becquerel

Radioactivity

Beam Quantity

# of photons in an x-ray beam (amount of radiation)

What is the primary controller of beam quantity?

MaS

Beam Quality

Penetrating power of the beam

What is the primary controller of beam quality?

KVp

Who discovered x-rays

Wilhem Roentgen

When did dr. Roentgen discover x-rays

November 8th, 1895

Inverse Square Law

I^1 / I² = (D²)² / (D^1)²

Why is the inverse square law important to know?

Controls radiation exposure with distance

Atomic Number

# of photons in the nucleus

Atomic Mass number

Protons and neutrons in the nucleus

Binding energy

Energy that holds protons & neutrons in nucleus also measure of how much energy needed to split an atom (remove an electron)

Which shell has the strongest binding energy

The K-shell

What is the equation used to determine how many electrons are in each orbital shell?

2n²

Period

Row of the periodic table

Elements in the same period have….

The same # of electron shells

Groups

Columns of the periodic table

Each group in the periodic table has the same…

number of electrons in the outermost shell (valence electrons)

Covalent bonding

Two atoms sharing electrons that orbit both nuclei

Ionic bonding

One atom giving up an electron and another atom taking that electron

Electromagnetic spectrum in order

(Lowest - highest) RAdio waves, Microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays

What two areas of the electromagnetic spectrum have more particulate characteristics?

X-rays and gamma rays

How do x-rays and gamma rays differ?

The origin; x-rays come from electron interaction while gamma rays come from nucleus

What are three characteristics of particulate radiation?

Has mass, has charge, and travels slower than light

Three products of radioactive decay

Alpha particles, Beta particle, and Gamma rays

Alpha particle

Heavy and positive charge

Beta particle

Electron and negative charge

Gamma rays

Electromagnetic energy

Where do the three products of radioactive decay originate from?

The nucleus

Increasing kVp by 15% does what….

Doubles the exposure to the IR

Decreasing by 15% does what…

Halves the exposure to the IR

Anode

Positive side of the x-ray tube

Cathode

Negative side of the x-ray tube

Where is the filament located?

In the cathode

Where is the focusing cup located

In the cathode

Where is the rotor located?

In anode

Where are the stators located?

Outside tube

Where is the anode located

Positive side (to the left of radiographer)

Why is a rotating anode preferred in diagnostic medial imaging

It distributes heat preventing damage

What is the purpose of the glass envelope

Maintains vacuum

What part of the tom is manipulated for x-ray production?

The electron

What two interactions occur in the x-ray tube

Characteristic and bremsstrahlung

What percent of the x-ray production process results in heat

99%

Characteristic interaction

Electron knocks out inner shell - outer electron fills - and emits x-ray

Bremms interaction

Electron slows near nucleus and energy released as x-ray

What energy is required of a filament electron to remove a tungsten target K-shell electron from orbit

69.5 KeV

What does a characteristic interaction occur between

Filament electron and target electron

Brems interaction occurs between what?

Filament electron and targets nucleus

What must occur for a high-energy brems photon to be produced?

Close interaction with the nucleus

Inherent filtration makes up how much of the tube?

0.5 - 1 mm AL eq

Added filtration makes up how much of the tube?

1.5 mm. AL eq

What is the NCRP requirement for total filtration for diagnostic radiology equipment producing 70 kVp or higher

2.5 mm AL eq

What is us3d to measure beam quality

HVL - half value layer

Primary beam

Beam leaving the collimate before entering the patient

Remnant beam

Beam that remains after exiting the patient

Continuous emission spectrum

Represents brems

Discrete emission spectrum

Represents characteristic interactions

Transmission

Passes through the tissue/patient and appears dark

Absorption

Stops in the tissue and appears white