Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
141 Cards in this Set
- Front
- Back
process of emitting radiant energy in the form of waves or particles
|
radiation
|
|
energy that is transmitted
|
radiation
|
|
found certain electronic tubes could emit radiant enery
|
1895, Roentgen
|
|
x stands for
|
unknown quantity
|
|
discovered certain natural thing emmitted radiation and discovered 3 types of radiation
|
1896, Becquerel
|
|
later named the 3 types of radiation alpha, beta, and gamma
|
Ernest Rutherford
|
|
electrically neutral
(same number of electrons as protons) |
atom
|
|
3 types of particles
|
electron
proton neutron |
|
very light particles that revolve around the nucleus in orbits
charge of -1 |
electron
|
|
particles with a mass about 2000 times that of the electron
charge of +1 |
proton
|
|
The number of protons in the nucleus is
|
Z number or the atomic number
|
|
particles with about the same mass of a proton electrically neutral
|
neutron
|
|
protons and neutrons are found in the
|
nucleus
|
|
protons and neutrons are made of particles called
(building blocks of an atom's nucleus) |
quarks
|
|
list the 6 types of quarks
|
up
down strange charm truth beauty |
|
electrons are not made up of smaller particles
an electron is a type of particle called |
lepton
|
|
same number of protons
different number of neutrons the additional neutrons to the nucleus may make it radioactive 1) particulate 2) electronmagnetic |
isotopes
|
|
mass of 4 amu (atomic mass unit)
CHARGE OF +2 doubly ionied helium atom in air, 1 cm/MeV of energy travel 4-8 cm low penetration |
Alpha
|
|
more penetrating than alpha particles
travel approximatley 12 feet/MeV of energy in air travel several millimeters in tissue mass of 0.00055 amu charge of -1 or +1 |
Beta
|
|
uses of beta rays
|
radioactive phosphorus helps reduce fluid accumilation
Iodine-131 helps to treat thyroid CA (beta and gamma) |
|
negative electron
produced by radioactive decay |
Negatron
|
|
positive electron
radioactive decay or pair production |
Positron
|
|
ionizing radiation and electromagnetic waves
|
x and gamma radiation
|
|
all electromagnetic waves have the same
|
velocity
|
|
Characteristic frequency (highest)
wavelengths (shortest) amplitudes travel in empty space |
x and gamma radiation
|
|
originate from within the nucleus
|
gamma rays
|
|
originate from outside the nucleus
|
x-rays
|
|
a measure of the amount of ionization produced by x-radiation or gamma radiation in air (below 3 MeV)
|
roentgen
|
|
unit of measurement used for calibrating x-ray equipment
|
coulombs per kilogram
|
|
radiation absorbed dose
|
rad
|
|
100 rads =
|
1 gray
|
|
dependent on the penetrating ability of the radiation and the composition of the absorbing matter
|
f factor
|
|
radiation equivalent man
quantity of any ionizing |
rems
|
|
100 rem =
|
1 Sv
|
|
measures radioactive decay of material (half-life)
|
curie
|
|
based on 50% original actvity
|
becquerel
|
|
milli
|
1/1000 th of the unit
|
|
larger unit to milli #
|
multiple the larger unit x 1000
|
|
smaller unit to larger unit
|
divide by 1000
|
|
amount, rate, & distribution of radiation emitted
|
dosimetry
|
|
detects and measures exposure to radiation
|
dosimeter
|
|
person who plans dosage and pattern in radiation therapy
|
dosimetrist
|
|
amount of radiation by collecting ions in a chamber filled with helium or argon gas
|
ionization chamber
|
|
determine exposure rate measurements in millroentgens per hour
|
ionization chamber
|
|
monitor staff/visitors in pt's room that has a radioactive implant
|
ionization chamber
|
|
great for x, gamma, and high-energy beta rays
|
ionization chamber
|
|
detects radiation sources and low level radioactive contamination (rate meter)
|
Geiger-Mueller counter
|
|
uses a sodium iodine crystal that produces flashes of light (scintillation)
similar to an AEC system |
pocket ionization chambers
|
|
most sensitive detector of x and gamma radiation
|
pocket ionization chambers
|
|
Basic Rules of Using Field Survey Instruments
|
1. read the instructions
2. chech batteries before use 3. handle carefully 4. keep calibrated 5. store securely, access quickly |
|
sensitive to doses as low as 10 mrem (0.1 Sv)
most sensitive to an energy of 50 keV |
film badges
|
|
advantages of film badges
|
in use since 1940's (most popular)
inexpensive easy to handle/easy to process |
|
disadvantages of film badges
|
wait for reading
accurate only at 10 mrem and higher fogs due to humidity, temp, light leaks |
|
film badge reports for x =, gamma radiation (penetrating x rays)
|
deep
|
|
film badge reports for beta, low -energy x and gamma radiation
|
shallow
|
|
basic features of personnel monitoring
|
portable
rugged sensitive reliable low cost |
|
true or false
a seperate badge must be worn at each job |
true
|
|
where should your badge be worn?
|
at the level of the sternum
lab jacket collar |
|
should the film badge be worn outside or inside a lead apron
|
outside
|
|
common mistakes made while wearing a film badge
|
washing and drying film badge
LEAVING IT on a lead apron leaving it on the dash of car not always wearing it not inserting it correctly into the holder not being responsible |
|
uses lithium fluoride crystals that absorb energy
can be worn up to 3 months sensitive as low as 5 mrem (0.05 mSv) |
Thermoluminescent Dosimeters
|
|
Advantages of Thermoluminescent Dosimeters
|
are tissue equivalent
wear up to 3 months can be reused are highly accurate do not fog |
|
Disadvantages of Thermoluminescent Dosimeters
|
are expensive
do not provide a permanent record break |
|
looks like a pocket flashlight, electrode is positively charged
|
pocket dosimeters
|
|
advantages of pocket dosimeters
|
can be used for periods
can give immediate readings |
|
disadvantages of pocket dosimeters
|
charge can leak = false reading
trauma can change reading most sensitive / subject to false readings no permanent record |
|
particle spectrum
mass of 4 amu charge of +2 doubly ionized travel 4-8 cm lowest penetration most ionizing |
alpha
|
|
particulate
more penetrating 12 ft/MeV of enery air travel several millimeters in tissue mass of 0.0005 amu charge of -1 or +1 Uses |
beta
|
|
radiation equialent man
|
REM
|
|
occupational exposure
|
Quaintity received by workers
|
|
Rems effects on organs
|
amount of biological effects (effectiveness)
difference in anysis of film badges some types of radiation produce more damge than x-rays Amounts of effects is based on the effective dose (how it is used and how it relates to the absorbed dose) |
|
1 sievert = __ rem
|
100 rem
|
|
Radiation absorbed dose
|
rad
|
|
Dose to biological material
evergy deposited in tissue |
rad
|
|
Fraction of RAD depends on the energy (penetrating ability of the radiation and the composition of the absorbing material)
|
rad
f factor |
|
any type of ionizing radiation to expose the matter (can come from difference sources)
amount of radiation transferred to an object (dose to patient) amount of energy absorbed by an object |
rad
|
|
Rad =
|
Gray
|
|
1 gray= __ RAD
|
100 RAD
|
|
the number of photons that are absorbed in the patient
|
absorption
|
|
reduction in number of photons as they pass through matter
(due to absorption or deflection of the beam) |
attenuation
|
|
Monoenergetic radiation
emitted with a single energy therefore, attenuation is an exponential process |
gamma radiation
|
|
beam is consistent/amount of absorber will reduce the intensity to HVL
|
half value layer
|
|
____ can interact with the entire atom, nucleus or an orbital electron (influenced by the photon's energy)
|
photons
|
|
Middle energies
|
orbital electrons
|
|
hight energies
|
(MeV therapy) interact with the nucleus
|
|
closest to positive charged nucleus
greatest force of attraction to nucleus (binding energy) |
k shell electron
|
|
the farther an electron is form the nucleus, the _____
binding energy and the ____ the energy level |
lower
higher |
|
four factors affect attenuation
|
transmission
number of photons density atomic number |
|
interaction with matter in which a photon strikes an inner shell electron, causing its ejection from orbit with the complete absorption of the photon's energy
|
photoelectric effect
|
|
more likely to occur in bone, as opposed to soft tissue
|
photoelectric effect
|
|
atomic number of bone
|
13.8
|
|
in photoelectric absorption, the incident photon is ____ absorbed
|
completely
|
|
interaction are more likely to occur if the x-ray photons' energy is greater than, but close to, the binding energy of the electron
photoelectron interactions have a greater likelihood of occurrence when the electron is more tightly bound to its orbit (basis for lead aprons) |
photoelectric effect
|
|
The loss of an electron causes the atom to be positively charged or a/an
|
ionized Ion pair: atom and electron
|
|
number of ion pairs produced per unit of distance traveled
|
specific ionization
|
|
if LET is increased/si is
|
increased
|
|
alpha and beta
|
increased LET/increased si
less penetrating but causes more damage |
|
x and gamma LET
|
Decreased LET/ decreased si
more penetrating but don't give up energy quickly |
|
electrons move closer to the nucleus shell by shell
|
characteristic cascade
|
|
interaction with matter in which a low-energy photon (below 10MeV) is absorbed and released with its same energy, frequency and wavelength but with change of direction
|
coherent scattering
classic Thomson |
|
refers to as "unmodified scattering" occurs when a very low energy x-ray photon interacts with a relatively bound orbital electron and sets it into vibration. Unmodified scattering occurs in energy levels below the range useful in clinical radiology.
|
coherent scattering
|
|
Causes excitation rather than ionization
|
coherent scattering
|
|
coherent scattering results in a
|
change of direction of the incident photon
|
|
interaction with matter in which a higher-energy photon strikes a loosely bound outer electron, removing it from its shell, and the remaining energy is released as a scattered photon
|
compton scattering
|
|
occurs when the x-ray photons interact with a loosely bound OUTER shell electron
|
compton scattering
|
|
can pose a danger for radiology personnell especially during fluroscopy
|
compton scattering
|
|
acquires a certain amount of kinetic energy which must be subtracted from the energy of the entering photon
|
compton electron
|
|
As Z number increases the probability of Compton scatter
|
decreases
|
|
the energy of the incident photon is ___ absorbed
|
partially
|
|
incoming x-ray photon from the primary beam
|
incidetn photon
|
|
less energy than the incident photon
longer wavelength lower frequency |
compton photon
|
|
0-180 degrees
|
scatter
|
|
interaction between matter and a photon possesing a minimum of 1.02 MeV of energy, producing two opposite charged particles
|
pair production
|
|
occurs when a megavoltage with energy of at least 1.02 MeV splits into a positron and negatron
|
pair production
|
|
conversion of mass into energy
|
Annihilation
|
|
does nto occur in diagnostic radiology (nuclear industry only) x-ray photons with a minimum of 10 MeV of energy that can interact directly with the nucleus of the atom. Causes a state of excitement within the nucleus, followed by the emission of a nuclear fragment.
|
photodisintregration
|
|
no charge in the total energy of the interacting particles
|
elastic
|
|
total kinetic energy is changed
|
inelastic
|
|
rate at which energy is deposited in the form of a charged particle as it travels through matter
|
Linear Energy Transfer (LET)
|
|
amount of radiation absorbed by the patient
|
dose
|
|
5 methods of dose
|
1. skin
2. ESE 3. depth dose 4. organ dose 5. intergral dose |
|
radiation received by a portion of the patient's skin max. dose any tissue will receive during this exposure most often used easiest to measure
|
skin dose
|
|
used to regulate diagnostic exposures based on technical factors
|
Entrance skin dose
|
|
measures percentage of skin dose at certain depths
|
depth dose
|
|
conversion of mass into energy
|
Annihilation
|
|
does nto occur in diagnostic radiology (nuclear industry only) x-ray photons with a minimum of 10 MeV of energy that can interact directly with the nucleus of the atom. Causes a state of excitement within the nucleus, followed by the emission of a nuclear fragment.
|
photodisintregration
|
|
no charge in the total energy of the interacting particles
|
elastic
|
|
total kinetic energy is changed
|
inelastic
|
|
rate at which energy is deposited in the form of a charged particle as it travels through matter
|
Linear Energy Transfer (LET)
|
|
amount of radiation absorbed by the patient
|
dose
|
|
5 methods of dose
|
1. skin
2. ESE 3. depth dose 4. organ dose 5. intergral dose |
|
radiation received by a portion of the patient's skin max. dose any tissue will receive during this exposure most often used easiest to measure
|
skin dose
|
|
used to regulate diagnostic exposures based on technical factors
|
Entrance skin dose
|
|
measures percentage of skin dose at certain depths
|
depth dose
|
|
amoutn received by a specific organ
|
organ dose
|
|
total amount of energy absorbed by a specific mass of tissue
|
integral dose
|
|
output intensity varies directly with
|
mAs and the square of the kVp
|
|
inverse relation ship with the square of the distance from the focal spot K is constant
|
inverse relation ship with the square of the distance from the focal spot K is constant
|
|
Output intensity
|
K (mAs) KVP2
over d2 |
|
Exposure from Radionuclides
|
1. the amount of the radionuclide in curies
2. the physical half-life of the radionuclide 3. the mixture of radiation emitted 4. the biodistribution 5. the biologic half-life of the material |
|
x and gamma pass through matter by
|
absorption
attenuation transmission |