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Dose equivalent or Equivalent dose, effective dose is measured in what unit
which takes into affect the quality factor of the radiation
- REM or Sv or Eqd
- dose equivalent or REM
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who has to wear a personnel dosimeter
for employees that regularly exposed
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what is purpose of personnel dosimeters
- indicate working habits and conditions
- measure quantity of radiation exposure over time
- records exposure to the are it is worn
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describe placement of the the dosimeters
w/o lead apron at collar level
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TLD badges need what to excite the lithium fluoride crystals to read the amount of radiation
the crystals need to be heated
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what level of radiation can tld badges read
5-10mrem
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what are pros and cons to tld badges
- pros: more accurate than film badge can be worn for 3 months crystals can be reused
- cons: can only read once, calibrated dosimeters must be used
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dosimeters at the collar level serve what purpose
provide an approx. dose equivalent to the thyroid and lens of the eye
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what is the lead equivalency of a lead apron
.5mmpb/eq
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List the main advantages and disadvantages of film badges
advantages: cheap reliable can distinguish between types of radiation and energies
disadvantages: only lasts a month, and are extremely sensitive to extreme temperature and humidity
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what is the function of a control badge
it is a badge that is from the monitoring company that comes with other film badges it serves as basis for radiation while in transit, to ensure that false readings are not recorded the control badge is reported to the health care facility
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what is a personnel monitoring report
a report that lists the deep eye and shallow occupational exposure of each covered person on a monthly, quarterly, year to dateĀ and lifetime equivalent basis
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tld osl and film badges use sensing material to radiation
- tld uses lithium fluoride
- osl = aluminum dioxide
- film badges = film
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what dosimeters are measured in mRem
osl tld's film badges
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describe osl pro and cons
- lightweight durable easy to carry can be worn up to 1 year
- can measure readings as low as 1mrem
- cons:
- only records radiation near the part it is worn and exposure can read on day of occurrence not efficient if not worn every day
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list the main pros and cons to using a pocket dosimeter
- pro: immediate readings, good for high exposure areas like when workers go back to nuclear fallout areas
- cons: extremely expensive, doesnt provide a permanent record and must be read daily
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what are radiation survey instruments
they monitor radiation and indicate the presence or absence of radiation
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identify diff types of radiation survey instruments of area monitoring
geiger mueller - primary radiation survey instrument for area monitoring in the nuc med field used to locate a last radioactive source or detect low level radioactive contamination
cutie pie an ionization chamber instrument that measures rate meter and cumulative exposure to radiation 1mR-several thousand and can detect exposure over a wide range of are within a few seconds
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what three detectors measure radiation in mR
cutie pie geiger mueller instruments pocket dosimeters all measure radiation in air
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what are densitometers
devices that measure radiation exposure in film badges of workers that reads the density of the film in the badge
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cell division:
what are the types
- multiplication process where one cell divides to form two or more cells.
- mitosis and meiosis
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differentiate between mitosis and meiosis
mitosis a parent cell divides to form two daughter cells identical to the parent cell
meiosis is a special type of cell division that reduces the number of chromosomes in each daughter cell to half the number of chromosomes in the parent cell
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describe the four phases of cellular life
- M (mitosis phase)
- G1 (pre-DNA synthesis phase)
- S(synthesis phase)
- G2 (post DNA synthesis phase)
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what phase is most radiosensitive
radioresistant
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during what phase can chromosomal damage from radiation be evaluated
during metaphase of mitosis
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describe the four sub phases of mitosis
prophase - first phase of cell division nucleus enlarges the dna complex coils tightly and chromatids become more visible
metaphase - fibers between mitotic spindle form between the centrioles
anaphase - duplicate centromeres migrate in opposite directions along the mitotic spindle and carry the chromatids to opposite sides of cell
telophase - chromatids undergo changes in appearance by uncoiling and becoming long, loosely spiraled threads
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define let
linear energy transfer is the average energy (ionizations) of deposited per unit length of track
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define RBE
relative biologic effectiveness describes the relative capabilities of radiation with differing LET's to produce a biologic reaction
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define OER
oxygen enhancement ratio is numerical value of the ratio of radiation dose required to cause a particular biologic response of cells or organisms in an oxygen deprived environment to the radiation dose required to cause an identical response under normal oxygenated conditions
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radiolysis
when xray photons can interact with and ionize water molecules contained within human body, thereby separating them into other molecular components
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how does high LET radiation increase the risk of DNA damage
with high let multiple strand breaks are possible are possible reapir enzymes are not effective at undoing damage cell death will occur
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differentiate between direct and indirect interaction
direct interaction = biologic damage occurs as a result of ionization of atoms on essential molecules that may potentially cause these molecules to become inactive or functionality altered.
indirect interaction - refers to effects produced by free radicals that are created by the interaction radiation with water they are highly reactive and result in cell death
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how does radiolysis produce cell damaging substances
a hydroxyl radical (OH) can bond with another hydroxyl radical and form hydrogen peroxide (H202) a substance that is very posionous to the cell
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differentiate single strand break and double strand break
single strand has what damage
what fx has most damage in chromsoome
single strand break - occurs commonly with low LET radiation enzymes are often capable of reversing this damage
double strand break occurs with high LET and are often associated with the loss or gain of one or more nitrogenous bases
base fx
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define mutation
is the loss or change in a nitrogenous base in the DNA chain
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define covalent cross links
are chemical unions create between atoms by the single sharing of one or more pair of electrons
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what are the possible effects of ionizing radiation on chromosomes
- restitution - breaks rejoin with no visible damage
- deletion - part of chromosome is lost at the next division
- broken end arrangement - misshape chromsome produced
- broken end rearrangement - geneticm aterial is rearranged damage not visible results in mutation
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describe the target theory
states that when cel lDNA is directly or indirectly inactivated by exposure to radiation that cell will die
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what is pmat
- prophase
- metaphase
- anaphas
- telophase
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proportional counter
serves no useful purpose in diagnostic imaging it is generally used in a laboratory setting to detect alpha and beta radiation
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what is caused by the low let radiation
radiolysis
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what type of interaction btw radiation and matter is most likely to occur between xradiation and human tissue
indirect actions
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