Radiation Biology and Safety Flashcards
All radiation is harmful and produced __ changes in living tissue
biological
An x-ray photon interacts with an atoms’ orbital electron causing the electron to vibrate-guitar string
Energy produced can be emitted as:
Light or heat (harmless)
Break molecular bond and disrupt molecule
Excitation
electron is ejected from its shell creating an ion pair. Atom is no longer electrically neutral and becomes chemically reactive as it attempts to find an electron to replace the missing one.- Chemical reaction-biological change
Ionization
Effects of radiation on atoms causes ___ of molecules
breaking- broken molecules no longer work the same
- loss of cell function
- Cell death
When a xray photon interacts with human tissue there will be either ____ or _____ which lead to chemical changes which is biological change
Excitation or ionization
- Ionizing radiation with a molecule of water is called
- Ionized water molecules form ___
- ___ ___ molecules containing upaired electrons and are extremely chemically reactive
- radiolysis
- Free radicals
- Free radicals
Is there a higher likelihood of a xray pohton interacting with H2o or a “chemical of life”
H20
Human cells contain __ % water and __ % other kinds of molecules “chemical of life”
80 percent
20 percent
DNA RNA ADP ATP examples of
chemcials of life
The physical process leading to damage to the “chemicals of life” are divided into 2 categories
Direct Effects
Indirect Effects
Which occurs more frequently the direct effect of radiation or indirect effect
Indirect effect
Ionizing radiation deposited in water instead of chemicals of life- absorbed
Free radicals formed by radiolysis of water cause damage to chemicals of life in the cell
Result
Death of molecule
Molecule doesn’t function properly
Occurs more frequently
Indirect Effect
Cell damage occurs when ionizing radiation directly hits the chemicals of life within a cell DNA, RNA, ATP, etc. Result Death of molecule Molecule doesn’t function properly Occurs infrequently
Direct Effect
Time between radiation exposure and observable biologic damage called
latent period
When there is a high dose of radiation is there more or less capability to repair damage
less
Quantity of radiation received, or amount of radiation energy absorbed
total dose
when xray penetrates deeper parts of the body is this a high energy kVp or lower kVp
high kVp
Which produces more adverse effects:
a. total body radiation
b. small localized areas
total body
__ damage takes place with a high dose rate because rapid delivery doesnt allow for cells to repair
more
Are dental x-rays examples of chronic exposures or acute exposures
chronic
Tissues are NOT inherited from generation to generation
Somatic or Genetic effects of radiation
somatic
Tissues ARE inherited from generation to generation
Genetic
Animals exposed to radiation to somatic tissues don’t produce visible changes in tissue until a certain ___ ____.- when change is seen
Threshold Dose
Mutations follow a __ ____ or ___ dose response
non-threshold
linear type
curve-indicates that below a certain level (threshold), no response is seen.
Threshold curve
curve: indicates that the response is proportion to the dose.
Linear
Threshold is
somatic tissues
Linear is
genetic tissues
Lens of eye reproductive cells fetus bone marrow thyroid gland skin
Critical organs
concept that allows comparison of the biologic effect of different types of ionizing radiation
Dose Equivalent
Equal doses of different types of radiation produce ___ levels of biologic damage
different
Are Gray and Sievert larger or smaller units than old system( R, rad and rem
Larger
Gray an Sievert are
New system
Roentgen, rad, rem
Old system
___mSv: average over five years for radiological personnel (employees in nuclear industry or hospital workers)
__ mSv/year: typical background radiation from natural sources in North America
20mSv
3
ALARA
as low as reasonably allowable
Radiation protection
minimum __ kvp
most moderan xray machines operate at a ___ kVp or higher
60kVp
70kVp
Maximum _ cm diamater with Round Cone
7cm
Reduces patient radiation risk by __ % using rectangular
50 %
operator should be __ feet away from primary beam and ___ - ___ from direction of beam
6 feet away
90-135 degrees
MPD for radiation workers a year to whole body
50mSv
MPD for general public
5 mSv to whole body
pregnant operator falls under this category
