113 Flashcards by Aubrey Mac

Building block of RT undertanding abt matter &ionizing rad

Atom

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Indivisible

Atomos

Greek 500bc

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Cant b broken down ny further & us seprsted from each othr by an empty space

Atom

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Smallest particle tha has poperties of an element

Atom

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Much smaller than atom

Subatomic particles

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“Evrythin is made up of atom

Democritus

Greek

500bc

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All matter are composed of 4 subs &modifid by 4 essence

Aritotle

Earth water fire air

Wet dry hot cold

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Diff ypes of spheres kight make up the diff elements

Atoms as solid spheres

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Composed of identical atoms & could be classifid accdg to integral values of mass

Elments

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Wherein particular size & # of eyes re diff for ech elemt

Eye and hook affair

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Elements- identical atomz similar in looks, construction & rxn

But differ from atoms of other elements

Compound

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Eye and hook affair

John dalton

1808

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1st perodic table

Dmitri mendeleev

1869

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Arranged in icrease atomic mss -soed then-known elements in 8 grps

Perioic table

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Det by the placement of electrons in each atom same grpings (similar physica prop & chem rxn)

Elmntal grpins

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Diff grps in periodic table

GROUP I :ALKALI METALS =soft metals w/ oxygen; violently reax h20

GROUP VII: HALOGENS= EASIly VPORZED w metal =water soluble salts

GROUP VIII: NOBLE GASES =H. resistant to rx w oher elem

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Sir Willim crookes

1870

Cthode ray tube & tv

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Xray developed

1896

William roentgen

Certain elem glowed when exposed to catjode rays

Rays no deflected by magnetc field from crt

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Electrons

concluded that e were an integral part of an atom while investigating prop of cathode rays (electrons)

1897 JOSEPH JOHN (JJ) THOMPSON

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prop of PLUM PUDDING MODEL

explain

plum = - charge
pudding = mass of + charge

neutral = e- = p+

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EARLY QUANTUM THEORY DEVELOPED

1900
MAX PLANCK

EM ENERGY = EMIT AS QUANTIZED FORM

(QUANTA =) PHOTON)

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NATURE OF LIGHT

1905
ALBERT EINSTEIN

special and general theories of relativity
hypothesizes about the particle nature of light.

= basis of nuclear energy.

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Robert Millikan
(1908-1917)

measured Charge of a single electron ( elementary charge ==fundamental physical
constants.)

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Structure of an atom developed: NUCLEAR MODEL

ERNEST RUTHERFORD
1911

NUCLEUS = MUO PROTONS
CLOUS OF E = AROUND NUCLEUS

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OTHER TERM FOR NUCLEAR MODEL

PLANETARY MODEL

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FATHER OF NUCLEAR P6

ERNEST RUTHERFORD

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Bohr atomic model

Niels Bohr, a Danish scientist,
1913

electrons traveling in orbits around the nucleus

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He also integrated the Planck
quantum theory,

Niels Bohr,
1913

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EXPLAIN
Planck quantum theory

when electrons change orbits, they
emit a quantum of discrete energy.

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OTHER TERM FOR Bohr atomic model

Miniature Solar
System.

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WHAT PREVENTS E- FROM COLLAPSING

ORBITS

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Math describes electron changes

Erwin Shrodinger
1926

Schrodinger equation = described how electrons move in waveform / how the
quantum state of a system changes with time.

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neutron discovered

1932
James Chadwick

the neutron component of the atomic
nucleus

explaining the nuclear fission of uranium 235

= possible to produce elements heavier than uranium in the lab.

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Nuclear fission developed

1938
Otto Hahn

the father of nuclear chemistry,

discovers nuclear fission W Lise Meitner.

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Nuclear medicine and I-131

1951
Glenn Seaborg,

discoveries of the transuranium elements = advances in nuclear medicine == devt of I-131 for thyroid disease

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Elementary particles smaller than the atom Murray Gell

1964
Mann + George Zweig

quark model = elementary particles have no
substructure == can’t be split

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Modern Atomic Theory

20th Century

Schrodinger, Heisenberg, Einstein, and many other scientists

electrons do not orbit the nucleus

move at high speeds in an electron cloud around the nucleus. = not random patterns;

E- LOC DEP ON ITS ENERGY

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UNCERTAINTY PRINCIPLE

IMPOSSIBLE TO PINPOINT LOC+ SPEED

== QUANTUM MECHANICAL MODEL OF AN ATOM

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FUNDAMENTAL PARTICLES

ELECTRON
PROTON
NUCLEUS

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Unit of measure used to identify the size of an atomic particle that is so small.

Atomic mass units (amu)

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1 AMU =

one-twelfth of the mass of a carbon-12 atom.

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A system of whole number that is used when precision is not necessary.

Atomic mass numbers

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FORMULA Atomic mass numbers

“A,= “protons+neturons.”

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particles contained in the nucleus of an atom,

Nucleons (protons and neutrons.)

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T/F
“The atom is essentially empty space.”

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ELECTRON

CHARGE
MASS
ATOMIC MASS #
AMU
LOC

9.109 X 10-31 KG
0
0.000549
SHELL

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PROTON

CHARGE
MASS
ATOMIC MASS #
AMU
LOC

+
1
1.673 X10-27 KG
1
1.00728

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NEUTRON

CHARGE
MASS
ATOMIC MASS #
AMU
LOC

0
1.675 X 10-27
1
1.00678 AMU

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circles where the
electrons orbit is

energy levels or shells.

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WHICH ORBIT HAS THE HIGHEST ENERGY LEVEL

E- in the outermost circles have higher
energy

= more effort to pull the E a greater
distance from the nucleus.

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The value of n

principal
quantum number

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REMOVAL / ADDITION OF E-

IONIZATION

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RELN OF ENERGY LEVEL AND # OF E-

DIRECT

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final location where electrons
reside.

Orbitals

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ENERGY NEEDED FOR IONIZATION

34 eV

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-det the chemical element and the behavior of
an atom

of protons

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center-seeking force.

Centripetal force

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The force that
keeps an electron in orbit.

Centripetal force

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flying-out-from-the-center force.

Centrifugal Force

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The force that causes an electron to travel
straight and leave the atom.

Centrifugal Force

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The strength of the attachment of an electron to the nucleus.

Electron Binding Energy

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alphabetic abbreviations of an element

Chemical Symbols

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det the chemical properties of an element

& Arrangement of Electrons

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-Number of Protons
-Symbol: Z

Atomic number

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protons + neutrons
-Symbol: A

Atomic Mass Number

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-Upper Left:

atomic mass (A)

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-Lower Left:

atomic number (Z)

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-Upper Right:

valence state (+/-)

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-Lower Right:

of atoms/molecules

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T/F

“The atomic number & the precise mass of an atom are equal!”

NOT EQUAL

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smallest unit of a
compound.

Molecules

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Any quantity of one type of molecule.

Chemical Compound

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chemical union between atoms
formed by sharing one or more pairs of
electrons.

Covalent Bond

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> The bonding that occurs because of
an electrostatic force between ions

Ionic Bond

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-The primary constituents of the x-ray tube target

Tungsten (W-74) & Molybdenum (Mo-42)

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-Radiographic & fluoroscopic contrast agents

Barium (Ba-56) & Iodine (I-53)

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-The important component of human tissue

Carbon (C-6)

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-The amount of energy (34 keV) necessary to ionize tissue atoms

Ionization Potential

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T/F

“The smallest particle of an element is an atom; the smallest particle of a compound is a
molecule!”

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the force that holds all the objects onto the Earth.

GRAVITATIONAL FORCE

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force of attraction between all masses in the Universe,

ADDING MOTION TO UNIVEFRSE
CREATNG ENERGY

GRAVITATIONAL FORCE

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gravitational acceleration on Earth

9.8m/s^2

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gravitational acceleration on MOON

1.6m/s^2.

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PROPERTIES OF GRAV FORCE

long-range

strength of only about 10^(−38) times

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APPEARS IN β-
decay of a nucleus.

Weak Nuclear Force

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β-decay,

nucleus emits an e- & uncharged particle called the neutrino.

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PROPERTIES OF NUCLEAR FORCE

WEAKER < NF & EMF

RANGE: 10-16 M

ALLOW FUSION OF P+N == DEUTERIUM === SUN

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FX OF NUCLEAR FORCE

CONVERT P TO N = RELEASING RADN

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the force that causes the interaction
between electrically charged particles.

force b/n charged particles.

can be attractive or repulsive.

Electromagnetic Force

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FORCE GIVEN WHEN CHARGE @ REST

Coulomb’s law: ATTRACTION AND REPULSION

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PROP / FX OF EMF

LONG RANGE

BIND ATOMS / MOL TO FORM= MATTER

GEN LIGHT

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strong, attractive force between nucleons in the atomic nucleus that holds
the nucleus together.

binds protons and neutrons in a nucleus.

strongest of all fundamental force

responsible for the stability of nuclei.

Strong Nuclear Force

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PROP & FX OF STRONG NF

charge-independent.
short-range force.
dependent on the spin of the nuclei.

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emission of particles & energy to become stable

Radioactivity

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Radioactive DecaY

nucleus spontaneously emits particles & energy &transforms itself into another atom to reach stability

nucleus contains too few or too many neutrons.

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OTHER TERM FOR Radioactive Decay

Radioactive Disintegration

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Radioactive atoms that have the same number of protons

Radioisotopes

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Two primary sources of naturally occurring radioisotopes

Uranium (U-92) & Carbon-14

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TYPES OF IONIZING RADIATION

Particulate and Electromagnetic

: Mass, Energy, Velocity, Charge & Origin

Particulate Radiation

;alpha & beta Particles

Electromagnetic Radiation

; x-rays & gamma

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Alpha Particle

2 protons & 2 neutrons
o Symbol: α
o Mass: 4 amu
o Charge: +2
o Origin: nucleus of heavy radioactive nuclei
o Energy: 4-7 MeV
o Range: 1-10 cm (air); <0.1 mm (soft tissue)
o Ionization Rate: 40,000 atoms/cm

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Beta Particle

Light particles
▪ Symbol: β- or β+
▪ Mass: 0 amu
▪ Charge: -1 or +1
▪ Origin: nucleus of radioactive nuclei
▪ Energy: 0-7 MeV
▪ Range: 10-100 cm (air); 1-2 cm (soft tissue)
▪ Ionization Rate: several hundred of atoms/cm

same with electrons, they only differ in origin

Negative Beta Particles

The same mass with electrons
o Positrons
o Antimatter

Positive Beta Particles

often called photons
▪ It has unlimited range in matter

EMR

Photons

No mass & no charge
o Travel at the speed of light (c)
o c: 3 x 108 m/s or 1.86 x 105 mi/s

“X-rays and gamma rays are the only forms of ionizing electromagnetic radiation of radiologic interest!”

X-rays

Symbol: X
o Mass: 0
o Charge: 0
Origin: electron cloud
o Energy: 0-25 MeV
o Range: 0-100 m (air); 0-30 cm (soft tissue)
o Ionization Rate: 100 ip/cm (equal to beta particles)

Gamma Rays

Symbol: γ
o Mass: 0
o Charge: 0
o Origin: nucleus/radioactive nuclei
o Energy: 0-5 MeV
o Range: 0-100 m (air); 0-30 cm (soft tissue)
o Ionization Rate: 100 ip/cm (equal to beta particles)

Number of neutrons exceeds the protons
* Have both odd Z and N

Stable Nuclides

Modes of Decay

ALPHA DECAY : nuclei too large to be stable. (-4 -2)

BETA MINUS DECAY: nuclides too large for stability (+1 -0) = positron and antineutrino

BETA PLUS DECAY: nuclides too small for stability. (-1, 0 ) = positron and neutrino

ELECTRON CAPTURE: E- +P = neutron and neutrino === EMIT NEUTRINO AND XRAY

GAMMA RAY EMISSION: EXCITED NUCLEI - DECAY - 10 KEV - 5 MEV GAMMA RAY

FX OF GRAVITATIONAL FORCE

-Adding motion to the Universe
Creating energy

FX OF WEAK NUCLEAR FORCE

Converting protons into neutrons
Releasing Radiation

FX OF ELECTROMAGNETIC FORCE

Forming atoms and molecules
Generating light

FX OF STRONG NUCLEAR FORCE

Binding protons in atomic nuclei
Breaking the bond

disintegrate into a stable isotope of different elements at a decreasing rate so that
the quantity of radioactive material never quite reaches zero.

radioisotopes

radioactive material IN BQ

1 Bq =
disintegration of 1 atom each second.

FORMULA OF DECAY CONSTANT

Formula: λ =
ln (2) / T1/2
or
0.693 / T1/2

rate of decay of
radionuclides

Decay Constant

Types of Half-life

Radioactive/Physical Half-Life :

time req for a quantity of Radioactivity to be reduced to one-half its original value

Biological Half-life (Tb):

The time required for the body to eliminate one-half of the administered dose by biological processes (perspiration, urine, feces, exhalation)

Effective Half-Life (Te):

time req for a radioactive elim in the body to be diminished by 50% as a result of the combined action of radioactive decay and biological
elimination.

are manifestations of a single underlying electromagnetic
force.

Electricity and Magnetism

X-ray Imaging System-

primary function:

convert electric energy into
electromagnetic energy

study of stationary electric
charges

Electrostatics

study of the distribution of
fixed charges

Electrostatics

TYPES OF ELECTROSTATIC CHARGE

ELECTRIC POTENTIAL (V)

is potential energy per unit charge

1 V = 1 J/C

ELECTRIC CURRENT (I)

is one Coulomb of electric charge
flowing per second

1 A = 1 C/s

Positive or negative

Electric charge

Fundamental Unit (S.I.) of Electric charge

Coulomb (C)

1 C: 6 x 1018 electron charges

Transfer or movement of an electron from one object to another object.

Electrification

HOW IS Electrification CREATED

FRICTION: rubbed against another

CONTACT: touch, electrons move from one to the other

INDUCTION: the process of electrical fields acting on another without contact

Most important method
(used in the operation of electronic devices)

INDUCTION:

If object has too few or too many electrons

Electrified Object

The object that behaves as a reservoir for stray electric charges

Electric Ground

The electrostatic force is directly proportional to the product of the electrostatic
charges & inversely proportional to the square of the distance between them

Coulomb’s Law

F =

= electrostatic force (N)

k =

constant of proportionality (9x109 coulomb-meter)

The lines of force that causes charged particles to move from one pole to another

Electric Field

POINTS OUTWARD
POINTS INWARD IN Electric Field

Positive charge:
Negative charge:

Unlike charges attract; Like charges
repel

REPULSION-ATTRACTION

do not have an electric field

Uncharged particles

Charges uniformly distributed at the surface

Distribution

Sharpest curvature of a surface

Law of Concentration

The force of attraction between unlike charges or repulsion between like
charges.

Electrostatic force

IN Electrostatic force

▪ Directly proportional to the

▪ Inversely proportional to the

product of their charges

square of the distance between them

Movement INElectrostatic Laws

Only (-) charges = move along the solid conductors

Protons = tightly bound inside the nucleus

The study of electric charges in motion

Electrodynamics

Work with electric current

Electrical Engineer

Concerned with electron flow

Physicist

Movement electrons along the wire

Electric Current

Two Types of Current

Direct Current
Alternating Current

Direct Current

E- flow only one direction
o Waveform: straight line

Alternating Current

E- flow alternately in the opposite direction
o Waveform: sinusoidal

Four States of Matter

CONDUCTOR : electrons flow easily

INSULATOR : not allow electron flow

SEMICONDUCTOR : insulator & as a conductor

SUPERCONDUCTOR : e- to flow W/O resistance

Characteristics: CONDUCTOR

Variable resistance
▪ Obeys Ohm’s law
▪ Requires voltage

▪ Exs: copper (Z=29), aluminum (Z=13) & water

Characteristics: INSULATOR

▪ Does not permit electron flow
▪ Extremely high resistance
▪ Necessary with high voltage

▪ Ex: glass, rubber & clay

Characteristics: SEMICONDUCTOR

Can be conductive
▪ Can be resistive
▪ Basis for computers
▪ Ex: silicon (Si-14) & germanium (Ge-32)

Characteristics: SUPERCONDUCTOR

No resistance to electron flow
▪ No electric potential required
▪ Must be very cold
▪ Ex: niobium (Nb-41) & titanium (Ti-22)

demonstrated semiconduction

William Shockley (1946)

The property of some matter to exhibit no resistance below a critical
temperature

Superconductivity (1911)

A pathway that permits electrons to move in a complete circle from their source
through the various components & back again

Electric Circuits

The flow of electrons through a conductor

Electric Current/Electricity

Direction: always opposite the electron flow

Electric Current/Electricity

1 A: 1 C/s

measured in ohms (Ω)

Electric Resistance

More complex → the greater the resistance → decrease the electric current

Ohm’s Law

V = IR

2 Basic Types of Electric Circuit

SERIES CIRCUIT :

All circuit elements are connected in a line along the same conductor

PARALLEL CIRCUIT:

Elements connected at their ends rather than lying in a line along a conductor

Magnetite

o Oxide of iron (Fe3O4)
o Lodestone or leading stone

A fundamental property of forms of matter

It has no smallest unit

Magnetism

“Any charged particle in motion creates a electric field!”

MAGNETIC FIELD

-A property created when electrons behave as if they rotate on its axis

Electron Spin

-It is neutralized in electron pairs

Electron Spin

-It creates a magnetic field

Electron Spin

“The lines of a magnetic field are always open loop!”

F
CLOSED LOOP

-A nuclear magnetic dipole created when a magnetic field is created by
spinning electric charge

Magnetic Moment

-The basis of MRI

Magnetic Moment

▪ Any material that produces a magnetic field
▪ Has north and south pole

MAGNETS

Magnets that have two poles

BIPOLAR/DIPOLAR

The small magnet created by the electron orbit

Magnetic Dipole

An accumulation of many atomic magnets with their dipoles aligned

Magnetic Domain

The ability of a material to attract the lines of magnetic field intensity

MAGNETIC PERMEABILITY

has a high magnetic permeability

Iron

has a low magnetic permeability

Wood

The degree to which a material can be magnetized

MAGNETIC SUSCEPTIBILITY

has a high magnetic susceptibility

Iron

has a low magnetic susceptibility

Wood

TYPES OF MAGNETS

NATURAL MAGNET: from the Earth
▪ e.g., Lodestone

ARTIFICIAL-PERMANENT MAGNET:
artificially-produced

▪ A bar or horseshoe-shaped magnet
▪ e.g., compass

ELECTROMAGNETS
▪ A coil of wire wrapped around an iron core that
intensifies the magnetic field

“All matters can be classified into how it interacts with the ____________________ !”

external magnetic field

FOUR MAGNETIC STATES OF MATTER

NONMAGNETIC – unaffected by MF
▪ Wood & glass

DIAMAGNETIC – weakly repelled from both poles of MF
▪ Copper, water & plastic

PARAMAGNETIC – Weakly attracted to both poles of MF
▪ Gadolinium (Gd-64): contrast agent in M.R.I.

FERROMAGNETIC – can be strongly magnetized

▪ AlNiCoFe (Al-12, Ni-28, Co-27) & iron (Fe-26)

An excellent temporary magnet

Soft Iron

MAGNETIC LAWS

Like = repel
Unlike = attract

Imaginary lines of MF

enter = south pole
leave = north pole

force of attraction between unlike poles or
repulsion between like poles

Magnetic Force

DP = product of the magnetic pole strengths
IP = square of the distance between them

Magnetic Field Strength

SI Unit: tesla (T)

Older unit: gauss (G)

1 T: 10,000 G

He observed that a dissected frog leg twitched when touched by two different
metals

Luigi Galvani (1700’s)

HE Contributed to the development of battery

Alessandro Volta

precursor of modern battery

Voltaic Pile:

A copper-zinc plate like a Dagwood sandwich

Voltaic Pile:

Modern Battery:

carbon rod (+) & zinc cylindrical can (-)

Any device that converts some form of energy directly into electric energy

Source of Electromotive Force

He demonstrated that electricity could be used to generate magnetic fields

HANS OERSTED (1820)

It determines the direction of the magnetic field

Right-Hand Rule

A coil of wire

Solenoid

A current-carrying coil of wire wrapped around an iron core

It intensifies the induced magnetic field

Electromagnet

ADVAN OF Electromagnet

MF can be adjusted or
turned on & off

An electric current is induced in a circuit if some
part of that circuit is in a changing magnetic
field

ELECTROMAGNETIC INDUCTION

Faraday and Oersted Experiment

He observed the current in a changing magnetic field

He described the first law of electromagnetic induction

MICHAEL FARADAY

MICHAEL FARADAY’S EXPERIMENT

Changing magnetic field induces current

o The magnetic field generates electricity

o Ammeter: measures current

HANS OERSTED EXPERIMENT

Moving or spinning charges induces a MF

Electricity generates a MF

ELECTROMAGNETIC DEVICES

ELECTRIC MOTOR :

electric current produces mechanical motion

ELECTRIC GENERATOR:

Mechanical motion produces an electric
current

TRANSFORMER

It changes the intensity of alternating voltage
& current

INDUCTION MOTOR

A type of motor used with x-rays tubes

Applicable only on AC
▪ Turns ratio greater than 1

TRANSFORMER

A type of motor used with x-rays tubes

▪ It powers the rotating anode of an x-ray tube

ROTOR

-Stationary coil windings
(electromagnet)

-Situated in the protective housing but
outside the glass envelope

STATOR

TRANSFORMER LAW

Voltage and number of turns
are directly proportional

TYPES OF TRANSFORMER

CLOSED-CORE TRANSFORMER
SHELL-TYPE TRANSFORMER

square core of ferromagnetic materials built up of laminated layers of iron

Reduced energy losses caused by eddy
current

CLOSED-CORE TRANSFORMER

Has two-closed core

▪ Confines more of the magnet field lines

▪ More efficient than closed-core

SHELL-TYPE TRANSFORMER

▪ Consists of one winding and one core

▪ Step up transformer

▪ Located in the operating console

▪ controls the kVp

AUTOTRANSFORMER

consist of both electric and magnetic field waves.

waves oscillate in perpendicular planes with respect to each other and are in phase.

Electromagnetic waves

The type of energy in x-rays, radio waves, microwaves & visible light

Electromagnetic Energy

The smallest quantity of any kind of
electromagnetic energy

o It may be pictured as quantum

Photon

o Waveform: sinusoidal fashion

o Quantum: a small bundle of energy

Photon

Frequency

No. of cycles per second
✓ Equal to the number of crests or valleys that
pass the point of an observer per unit time.
✓ Inversely proportional to the wavelength.
✓ Symbol: f
✓ S.I. Unit: hertz (Hz)

▪ 1 Hz: 1 cycle/second

Wavelength

Distance from one crest to another
✓ Distance from one valley to another
✓ Distance from one point on the sine wave to the next
corresponding point
✓ Unit: Lambda (λ)

o Inversely proportional to the frequency

c: speed of light
✓ Constant SI Unit: 3 x 10^8 m/s
✓ Constant British Unit: 186,000 mi/s

The width of a waveform
✓ It is not related to wavelength or frequency

Amplitude

He showed that visible light has both electric & magnetic properties

James Clerk Maxwell (Late 19th Century)

Three Wave Parameters

Velocity, Frequency & Wavelength

used for both sound & electromagnetic energy

Electromagnetic Wave Equation

He synthesized our understanding of electromagnetic radiation

Max Planck

1918: He received the Nobel Prize

Planck’s Quantum Theory

XRS created with the speed of light (c)

XRS exist with velocity, or they
do not exist at all

PLANCK’S CONSTANT

4.15 x 10-15 Ev-s

6.63 x 10-34 J-s

They behave more like waves

Visible Light Photons

They act more like particles

X-ray Photons

Wave Particle duality

both wave & particle concepts must be
retained, because wave-like properties are exhibited in some
experiments & particle-like properties are manifested in others

“Photons interact with matter most easily when the matter is approximately the same size
as the ______________________________!”

photon wavelength

The reduction in intensity that results from
scattering & absorption

Electromagnetic Energy Attenuation

Interaction Between Light & Absorbing Material

✓ Transparency: not at all (transmission)

o e.g., window glass

✓ Translucency: partially (attenuation)

o e.g., frosted glass

✓ Opacity: completely (absorption)

o e.g., black glass

The structures that absorb x-rays

Radiopaque

The structures that transmit x-rays

Radiolucent

A continuum of
electromagnetic energy

Electromagnetic Spectrum

Energy: 10−12 − 1010eV

o Frequency: 102 -1024 Hz

o Wavelength: 10 7-10−16 m

Radiofrequency

Range: 0.3 kHz-300 GHz

Range in M.R.I.: 1-100 mHz

Low energy & long wavelength

Microwaves

Very-short wavelength R.F.

 Higher than broadcast R.F.

 Lower than infrared

 It is measured in cm

interacts with hotdogs & hamburgers

Infrared

Longer λ than visible light \

 Shorter λ than microwaves

 It heats any substance on which it shines (radiant heat)

Visible Light

occupies the smallest segment of the electromagnetic spectrum

It is measured in nanometer
o It interacts with rods & cones of the eye
o Range: 400 nm (violet) to 700 nm (red)

Visible Light

The wave of moving molecules

o It requires matter
o It cannot exist in a vacuum

Lies between visible light &
ionizing radiation

o It interacts with molecules

Ultraviolet

produced by the decay from
high energy states of atomic nuclei.

o It comes from inside the nucleus of
a radioactive atom

o It is emitted spontaneously from
radioactive material

Gamma

are used in medical imaging, radiation therapy, airport security scanners, and material characterization.

o It is emitted from the electron cloud
o It is produced in diagnostic imaging
systems
o It interacts with electrons

Xrays

Sources of gamma

gamma decay from naturally occurring radioisotopes

secondary radiation from atmosphere interactions with cosmic ray particles;

lightning strikes

gamma-ray flashes

3 Regions Important to Radiologic Science

Visible Light Region : viewing = dx
X-Ray Region: get hq img
Radiofrequency Region: MRI

Others
▪ U.V. light, infrared light, & microwave radiation

difference between x-rays &
gamma rays

their origin!”

DIFFERENCE B/N
VISIBLE LIGHT
RF
XR

“Visible light is identified by wavelength,

R.F. is identified by frequency,

x-rays are identified by energy!”

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