RAD 208 Radiation Detection and Measurements

Anything that occupies space & has mass

Described by energy equivalence (mass)

Matter

Basic quantities

Mass

Time

Length

unit for matter

kilogram (kg)

Force exerted on a body under the influence of gravity

weight W=mg

The ability to do work

Energy

unit of energy

joules (J)

unit of energy for radiology

electron volt (eV)

x-rays are dual nature because they behave both like

waves and particles

Atoms and molecules are the fundamental building blocks of

matter

Every measurement has 2 parts

magnitude and unit

Motion of an object

velocity

formula for velocity

v=d/t

rate of change of velocity with time

acceleration

what is another name for velocity

speed

inertia is

resistance to a change on motion

Equation for Force

F=ma

How many fundamental laws of motion did Newton formulate?

3

formula for Work

W=Fd

A form of energy that is the result of electric and magnetic disturbances in space. This type of energy travels through space as a combination of electric and magnetic fields and is produced by the acceleration of a charge

electromagnetic energy

what are the properties of electromagnetic energy

frequency

wavelength

velocity

amplitude

smallest quantity of any type of electromagnetic energy

photon

small, discrete bundle of energy

photon or quantum

Properties of a photon

Travel speed of light

No mass

Sinusoidal field

an individual photon is measured in

eV

Planck’s Quantum Equation

E=hf

represents distance between to successive crest or troughs

wavelength

Why can x-rays be described as waves?

because they move in waves that have wavelength and frequency

Represents the number of waves passing a given point per unit of time

Frequency

Measured from midpoint to crest

Amplitude

The rate of rise and fall of a sine wave is called its

Frequency

The energy of a photon is directly proportional to its

Frequency

The energy of a photon is inversely proportional to its

Wavelength

wavelength formula

λ = c/f (velocity/frequency)

The regions most important to us for electromagnetic radiation

visible light

x-ray and gamma rays

radio frequency

photons differ in

frequency and wavelength

types of particulate ionizing radiation

alpha

beta

neutrons

protons

fast moving electrons

types of electromagnetic ionizing radiation

gamma rays

x-rays

properties of an Alpha particle

come from radioactive decay

each contain 2 protons and 2 neutrons

have large mass and large positive charge

what results from Alpha particles having large mass and large positive charge

are less penetrating and lose energy fast which makes them not travel long distance

when can alpha particles be damaging

As an internal source of radiation so when inside the body unlike when it’s an external source it causes minimal harm

properties of beta particles

come from decaying radioactive material

have small mass and charge

can travel long distances and highly penetrating

How much lighter are beta particles than alpha particle

8,000x lighter

beta particles are identical to high-speed electrons except in

origin (high-speed electrons are man-made)

which has higher penetrating capabilities alpha or beta

beta

How far do alpha particles travel

5cm in air

How far do beta particles travel

10-100cm in air

high-speed electrons are produced in a radiation oncology treatment machine called

linear accelerator

Number of protons in the nucleus of an atom

atomic number or Z

If two atoms have the same number of protons but a different number of neutrons in their nuclei

Isotopes

Total amount of ionization (charge) an x-ray beam produces in a known mass of air must be obtained by using a

standard or free-air ionization chamber

unit of exposure in air or also defined as the quantity of x-rays or gamma rays required to produce a given amount of ionization in a unit mass of air

Exposure (is a unit of radiation exposure or intesity)

what units are used for Exposure

Roentgen (R), Air kerma (GYa), coulomb per kilogram (C/kg)

What unit is used for x-ray equipment calibration, calibrations of survey instrument

Roentgen (R)

Kinetic energy transferred from photons to electrons during ionization and excitation replacing traditional quantity of Exposure

Air kerma (GYa)

Quantity that reflects dose and volume of tissue irradiated

DAP (Dose Area Product)

Describes total amount of energy imparted to matter

Product of dose and mass over which the energy is imparted (dose x volume)

Intergral Dose

The amount of energy per unit mass absorbed by the irradiated object

Absorbed Dose

What is the unit used for Absorbed Dose

Gray (GYt) or Rad

Equal absorbed dose of different types of radiation produce different amounts of biologic damage in the body (quality factor)

Equivalent Dose (EqD)

what’s the formula for Equivalent Dose (EqD)

EqD=D x Wr

what units are used for Equivalent Dose (EqD)

sieverts (Sv) or rems

Measure of the overall risk of exposure to ionizing radiation

Sum of the weighted equivalent doses for all irradiated tissues or organ

Effective Dose (EfD)

what’s the formula for Effective Dose (EfD)

EfD= D x Wr x Wt

what’s the unit used for Effective Dose (EfD)

sieverts or rems

Describes exposure of a population or group from low doses of different sources of ionizing radiation

Collective Effective Dose (ColEfD)

What’s the formula for ColEfD

ColEfD= pop x EfD

What’s the unit used for Collective Effective Dose (ColEfD)

person-sievert

Radioactive atoms spontaneously decay by transforming or disintegrating into different atoms

Radioactivity Activity

Amount of radioactivity atoms present is measured by their …

activity or the # of disintegrations per seconds (dps)

What’s the unit used for Radioactivity

Becquerel (Bq) or Curie (Ci)

quality factors for x-ray, beta particle and gamma photon is what

1

quality factor for alpha particle and fast neutron is what

20