radiation physics

radiation

is energy in the form of electromagnetic waves or particulate matter traveling through space or air

matter

anything that occupies space and has mass

energy

when matter is altered, — may be released

atom

fundamental unit of matter

atom

smallest particle of an element

protons, neutrons, electrons

components of an atom

protons

components of an atom

• + charge

neutrons

components of an atom

• neutral

electrons

components of an atom

• - charge

nucleus

positively charged center

nucleus

contains protons and neutrons

electron cloud

orbiting electron with negative charge

electron cloud

located in shells around nucleus

atomic number

number of protons in the nucleus

atomic number

equals the number of electrons in a neutral atom

mass number

number of protons + neutrons

neutral atom

number of positive charges equals number of negative charges

7

electron shells has maximum of — shells

k,l,m,n,o,p,q

electron shells has maximum of 7 shells designated as —

valence electrons

electrons in the outermost shell

valence electrons

determine chemicaL properties of atoms

binding energy

attraction between positive nucleus and negative electrons

binding energy

energy required to remove an electron from a shell

incoming

important principle: to remove an electron, the — energy must exceed the electron’s binding energy

electron volt

is the kinetic energy gained by an electron accelerated through a potential difference of one volt

molecule

two or more atoms joined by chemical bonds

molecule

Smallest amount of a substance that retains its properties

ion

An atom that gains or loses electrons and becomes electrically unbalanced

ionization

Process of converting atoms into ions by removing or adding electrons.

tissues

X-rays produce ionization when interacting with —. This is the basis of both image formation and biologic effects

radioactivity

Spontaneous disintegration of unstable atoms to achieve stability.

unstable atoms

Possess excess energy, mass, or both.

• Emit radiation to become stable

ionizing radiation

Ionizing vs Non-Ionizing Radiation

• high energy

ionizing radiation

Ionizing vs Non-Ionizing Radiation

• removes electrons

ionizing radiation

Ionizing vs Non-Ionizing Radiation

• produces ions

ionizing radiation

Ionizing vs Non-Ionizing Radiation

• more biologically damaging

non-ionizing radiation

Ionizing vs Non-Ionizing Radiation

• lower energy

non-ionizing radiation

Ionizing vs Non-Ionizing Radiation

• cannot remove electrons

non-ionizing radiation

Ionizing vs Non-Ionizing Radiation

• excites electrons only

non-ionizing radiation

Ionizing vs Non-Ionizing Radiation

• less damaging

particulate radiation

Consists of particles with mass.

alpha particles

types of ionizing radiation

• 2 protons + 2 neutrons

alpha particles

types of ionizing radiation

• heavy

alpha particles

types of ionizing radiation

• poor penetration

alpha particles

types of ionizing radiation

• travels only about 5 cm in air

beta particles

types of ionizing radiation

• fAsT moving electrons

beta particles

types of ionizing radiation

• more penetrating than alpha particles

beta particles

types of ionizing radiation

• penetrate 10-100 cm in air and 1-2 cm in tissue

neutrons

types of ionizing radiation

• neutral charge

neutrons

types of ionizing radiation

• high peNetrating ability

protons

types of ionizing radiation

• positive charge

protons

types of ionizing radiation

• about 2000 times heavier than electrons

protons

types of ionizing radiation

• lose energy rapidly in matter

no mass, no electrical charge, travel at speed of light, exhibit wave and particle properties

characteristics of electromagnetic radiation

radio waves, visible light, infrared, ultraviolet, x-rays, gamma rays

examples of electromagnetic radiation

x-rays

x-rays vs. gamma rays

• produce outside nucleus

x-rays

x-rays vs. gamma rays

• originate from electron orbital interactions

x-rays

x-rays vs. gamma rays

• usually measured in keV

x-rays

x-rays vs. gamma rays

• used in dental radiology

gamma rays

x-rays vs. gamma rays

• produced within nucleus

gamma rays

x-rays vs. gamma rays

• originate from radioactive decay

gamma rays

x-rays vs. gamma rays

• usually measured in MeV

gamma rays

x-rays vs. gamma rays

• used mainly in nuclear medicine

wave concept

Describes radiation as waves.

velocity

Speed of the wave.

wavelength

Distance between successive crests.

frequency

Number of wavelengths passing a point per unit time.

inversely

Frequency and wavelength are — related.

higher frequency

Shorter wavelength =

greater energy and penetration

Higher frequency =

photons

Electromagnetic radiation can also be described as packets of energy called:

photons

Discrete bundles of energy

photons

Explain interaction of radiation with matter

produced by conversion of electrical energy into radiation, invisible, travel in straight line, penetrate opaque tissues, affect photographic film/sensors, can damage living tissues, cause ionization

properties of x-rays