Safety Flashcards
_______-Used to define radiation exposure or radiation delivered to a specific point
-Measured in ______ or _______
so 1_____ = 1 ______
- Described as:
Air kerma
gray (Gy) — Gya (a indicates air)
1 Gy = 1 joule/kilogram (J/kg)—
described as energy absorption per kilogram of tissue irradiated
_______(____)—absorbed dose
_______(____)—air kerma
_______(___)—absorbed dose in tissue
________(___)—unit of effective and equivalent dose
_________(___)—unit of radioactivity
Gray (Gy)
Gray (Gya)
Gray (Gyt)
Sievert (Sv)
Becquerel (Bq)
Results of ionization in human cells:
a.
b.
c.
d.
e.
a. Unstable atoms
b. Free electrons
c. Production of low-energy x-rays
d. Formation of new molecules harmful to the cell
e. Cell damage may be exhibited as abnormal function or loss of function
Types of radiation damage: __________ & ____________
1._________ - Damage to the exposed individual
2. ________ - Damage to the genetic code of the germ cell contained in the DNA; may be passed to the next
generation
Somatic
Genetic
Greatest source of natural background exposure to humans is __________
_______ accounts for the largest increase in total dose and medical dose to the population
_______ - Remove electron from atom
Radon
CT
Ionization
_________-Radiation exiting the x-ray tube
_________-(image-producing radiation): X-rays that emerge from the patient and strike the image receptor; composed of ________ & _______ photons
_________- Absorption and scatter (loss of intensity) of the x-ray beam as it passes through the patient
_________- X-ray beam that contains photons of many different energies
Primary Radiation
Exiting Radiation
primary & scatter photons
Attenuation
Heterogeneous Beam
-Most common photon–tissue interactions in diagnostic radiography are _______ & _______
-Photoelectric Absorption & Compton Scatter
What Interaction is shown?
Explain process of it
Photoelectric Absorption
b. Incoming x-ray photon strikes a K-shell electron
c. Energy of x-ray photon is transferred to electron
d. Electron is ejected from the K-shell and is now called a photoelectron
e. X-ray photon has deposited all of its energy and ceases to exist
f. Photon has been completely absorbed
h. Hole in K-shell is filled by electrons from outer shells, releasing energy that creates low-energy characteristic photons that are locally absorbed
What interaction is shown?
Explain Process
Compton scattering
b. Incoming x-ray photon strikes a loosely bound, outer-shell electron
c. Photon transfers part of its energy to the electron
d. Electron is removed from orbit as a scattered electron, referred to as a recoil electron
f. Photon scatters in another direction with less energy than before
g. Scattered photons emerging from the patient travel in divergent paths in random directions
What interaction is shown?
Explain Process
Coherent scatter
a. Produced by low-energy x-ray photons
b. Atomic electrons are not removed but vibrate because of the deposition of energy from the photon
c. As the electrons vibrate, they emit energy equal to that of the original photon
d. This energy travels in a path slightly different from the path of the original photon
e. Ionization has not occurred, although the photon has scattered
Which interactions do NOT occur in xray: _______ & ________.
What is coherent scatter? what is incoherent scatter?
Which intersection produces contrast on an image?
Photodisintegration & Pair Production
- Coherent = Classical
- Incoherent = Compton
-Photoelectric Absorption
What interaction is shown
explain process
Interaction with Tungsten Atom
Bremsstrahlune Radiation “Braking Radiation”
- Incoming electrons interact with the electronic field of the atom’s nucleus [
2.Incoming e-slows (brakes) and changes direction some energy is lost as a Brem’s x-ray photon
(closer to nucleus = more energv lost) - The incoming electron now leaves with the remaining energy in a different direction
The energy of the x-ray photon depends on ____________________
Formula for Brem’s x-ray photon energy:
The maximum energy of the Brem’s x-ray is __________________
how close it gets to the nucleus and how much energy is lost during bremstaug interaction
Incoming electron energy - outgoing electron energy = ray energy
the same as the tube potential
i.e.: 100 kVp (tube potential) = 100 keV (max Brem’s energy)
_____________ - Conducts research and provides recommendations
on radiation protection to the worldwide community based on fundamental scientific principles
___________- Formulates and publishes scientifically researched recommendations on radiation protection and measurements in the United States
What are the dose response relationships?
- International Commission on Radiological Protection (ICRP)
-National Council on Radiation Protection and Measurements (NCRP)
-Linear & Nonliear
- Threshold & nonthreshold
- stochastic & deterministic
What response curve is this?
Is there a safe level of radiation?
when do responses occur?
Is it proportional or nonproportional?
Linear-nonthreshold relationship:
a. Indicates that no level of radiation can be considered completely safe
b. A response occurs at every dose
c. The degree of response to exposure is directly proportional to the amount of radiation received
What response curve is this?
Is there a safe level of radiation?
when do responses occur?
Is it proportional or nonproportional?
example?
- Linear-threshold relationship
a. Indicates that at lower doses of radiation exposure no response is expected
b. When the threshold dose is exceeded, the response is directly proportional to the dose received
c. As an example, cataractogenesis does not occur at low levels of radiation exposure; there is a threshold dose below which cataractogenesis does not occur
What response curve is this?
Is there a safe level of radiation?
when do responses occur?
Is it proportional or nonproportional?
example?
- Nonlinear-threshold relationship
a. Indicates that at lower doses of radiation no response is expected
b. When threshold dose exceeded, the response is not directly proportional to the dose received and is increasingly effective per unit dose
What response curve is this?
Is there a safe level of radiation?
when do responses occur?
Is it proportional or nonproportional?
example?
- Nonlinear-nonthreshold
a. Indicates that no level of radiation can be considered completely safe
b. A response occurs at every dose
c. The degree of the response is not directly proportional to the dose received
d. The effect is large even with a small increase in dose
____________- Randomly occurring effects of radiation
- probability of such effects is
____________
___________-Effects that become more severe high levels of radiation exposure and do not occur below a certain threshold dose
What is NRCP #116?
- Stochastic effects
-proportional to the dose (increased dose equals increased probability, not severity, of effects) - Deterministic effects
-Annual dose limits published
Occupational exposure annual limit:
a. Lens of the eye—
b. Localized areas of skin, hands, feet-
Cumulative effective dose limit =
Students (older than age 18)—annual dose limit =
General public—annual effective dose limit for frequent exposure is:
- annual effective dose limit for infrequent exposure is:
- effective dose limit is 50 mSv
a. 150 mSv
b. 500 mSv - Age (in years) × 10 mSv
- effective dose limit is 50 mSv
-Frequent: 1 mSv.
-Infrequent: 5 mSv
Embryo-fetus—total equivalent dose for gestation is
Embryo-fetus—equivalent dose limit per month is:
Level of negligible risk is:
5 mSv total
.5 mSv per month
.01 mSv
_________ -is the upper boundary dose that can be absorbed, either in a single exposure or annually, with a negligible risk of somatic or genetic damage to the individual
Three main parts of the cell:
Effective dose limit
- Cell membrane
- Cytoplasm
- Nucleus
Cell membrane functions:
________, ________, & __________
Cytoplasm
Contains:________ & Functions: _______
- Protects cell
- Holds in water and nucleus
- Allows water, nutrients, and waste products to pass into and out of the cell (it is semipermeable)
- Composed primarily of water
- Conducts all cellular metabolism
- Contains organelles
a.______: Participate in cell division
b.______: Synthesize protein
c.______: Contain enzymes for intracellular digestive processes
d.______: Produce energy
e.______: Combines proteins with carbohydrates
f._______: Acts as a transportation
system to move food and molecules within the cell
a. Centrosomes
b. Ribosomes
c. Lysosomes
d. Mitochondria
e. Golgi apparatus
f. Endoplasmic reticulum
Nucleus Contains_________ and ________
2. DNA controls _______ & _______
Mitosis occurs in what cells?
deoxyribonucleic acid (DNA) & ribonucleic acid [RNA])
cell division & cellular functions
somatic cells
Mitosis:
Occurs in: _____ cells
Step 1 is ________, What occurs in this phase?
Step 2 is ________, What occurs?
Step 3 is ________, What occurs?
Step 4 is ________, What occurs?
Step 5 is ________, What occurs?
Mitosis results in:
Somatic
1. Interphase
Cell growth before mitosis
DNA synthesis
2. Prophase—nucleus enlarges
3. Metaphase—nucleus elongates
4. Anaphase—two complete sets of chromosomes
5. Telophase—separates the two sets of genetic material; division complete
46 chromosomes in EACH somatic cells
Meiosis:
Occurs in: _____ cells
Step 1 is ________, What occurs in this phase?
Step 2 is ________, What occurs?
Step 3 is ________, What occurs?
Meiosis results in:
Cell division of sperm or ovum (germ cells)
- Replication division
- Reduction division
- Sperm and ovum unite to return the number of chromosomes in each cell of the new individual to 46
Results in halving # chromosomes in each cell
As LET of radiation increases, biological damage _________
B. _________- Ability to produce
biological damage; varies with LET
E. Somatic cell exposure may result in __________
F. Reproductive (germ) cell exposure may result in __________
increases
B. Relative biologic effectiveness (RBE)
E. a disruption in the ability of the organism to function
F. changes, called mutations, being passed on to the next generation
