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What is the responsibility of the radiographer when producing a diagnostic image while being consistent with the requirements of the examination?
to make sure each patient recieves the minimal dose of radiation
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what is ionizing radiation capable of doing when interacting with matter
it is capable of creating charged particles when interacting with matter
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what sources can ionizing radiation come from
natural sources and man made
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Can ionizing radiation affect tissues and various organs of the body
yes
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why can exposure to radiation be bad for you
the energy posessed by ionizing radiation is capable of displacing atomic electron bonds that hold molecules of matter together resulting in chemical changes, which can lead to harmful effects
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what are the two properties of ionizing electromagnetic radiation
excitation and ionization
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what biologic damages are related to ionizing electromagnetic radiation (2)
and explain them
- direct interaction - damage to DNA due to ionization
- indirect interactions - decomposition of water in the cell
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what two categories is radiation grouped in
ionization radiation is grouped as either particulate (particle) or electromagnetic
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are x-rays electromagnetic
yes
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what energy particles are included in partciulate radiation
what do they produce
- high energy electrons, neutrons and protons
- they produce ionizations in matter by direct atomic collisions
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what two principal types that are associated with radioactive decay (particulate radiation)
alpha and beta particles
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where does uranium come from
the ground
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what does a gamma ray behave as
an x-ray photon penetrates through the skin
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what radiation particle is the least penetrating and easily stopped in tissue
alpha particle
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how many protons and neutrons are in an alpha particle
2p 2n
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what particle does more damage in a small area of tissue, and has the ability to change the dna
alpha particle
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what particle has moderate penetration and is much smaller
what is its charge
- beta particles
- negative (electron)
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what ray or particle is the most penetrating and is made up of pure energy
gamma rays which also penetrate as photons
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which particle has no mass allowing it to penetrate more
gamma
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what particle has the most mass and is the least penetrating
alpha particles
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List the four characteristics of alpha particles
- 2protons 2 neutrons
- decaying radioactive material
- large amount of mass and charge
- can travel 5 cm in the air
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list the characterisitics of the beta particle
- its electrons are from decaying radioactive material
- little mass and charge
- can tracel 10-100 cm in the air
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what photon rays are the same but differ in origin
xrays come from a machine and gamma rays come from a nucleus
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what is the process in which electromagnetic radiation occurs
photolelectric absorption and compton scattering
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what the non ionizing types of photons
visible light infrared microwaves and radio
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waves of high frequency have what wavelengths
short wavelength
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waves of low frequency have what wavelength
long wavelengths
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the effects from ionizing radiation are classified into what 2 categories
genetic (changes DNA) or somatic (effects on skin and tissue)
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what are the biological effects influenced by
- dose recieved
- rate dose was recieved
- type of radiation
- the age at exposure - the younger you are the worse b/c the cells are still fresh and developing
- sensitivity of cells
- body part irridaiated
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what are the genetic effects on reproductive cells
defects in offspring
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what are some of the somatic effects and skin conditions
- skin erythema
- cataracts
- radiation induced malignancies
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what are the different modes of exposure
external exposure (outside of body) and internal exposure (inhaling, ingesting, beta, alpha and gamma rays)
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List some sources of natural ionizing radiation exposure
- cosmic radiation (space)
- terrestrial radiation (ground)
- radionuclides naturally present (both internal and external)
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list some sources of ionizing radiation exposure
- x-rays
- radiopharmeceuticals
- consumer products
- air travel
- nuclear fuel production
- fallouts (bombs and explosions)
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what quantities and units are elevant to radiation protection
- exposure
- absorbed dose
- equivalent dose
- effective dose
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what is radiolysis
when there is decomposition of a water cell
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what particle is most penetrating
least penetrating
most ionizing
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what are sensitive cells
they are cells that are more likely to divide and undergo mitosis
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what cells are radiosensitive
- wbcs, rbcs, thyroid cells, spermegonia, oogenia cells, skin cells
- because they are constantly dividing to give us more and more
- we give blood away, our body undergoes mitosis to create more blood
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what is the most radioresistant cell in the body
- cells of CNS b/c they do not regenerate if they are damaged they can repair but we cant make more nerve cells
- spinal cord
- muscle cells
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List examples of radiosensitive cells (anything that can regenerate itself)
- skin
- blood
- wbc
- thyroid cells
- sperm cells
- these cells are always dividing so they can regenerate which makes them sensitive to radiation
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what is skin erythema
skin reddening
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what are radiation induced malignancies
leukemia
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what are the 2 largest man made sources of radiation
Medical xray (cat scan) and nuclear medicine
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what has highest amt of radiation that is a from a natural source
radon
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what is the new total annual background per person
6.25 mSv
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what is the measurement of the number of ionizations in a given quantity in a chamber of air
roentgen (R)
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what measurement measures the amt of energy absorbed
- Traditional/Conventional - RAD(absorbed Dose)
- SI unit - Gray (Gy)
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what is the measurement that measures the type of radiation, weighing factor, the product of the aabsorbed dose and radiation weight
- T.U. - REM (equivalent dose)
- SI Unit - Sv
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how do we convert the following back and forth:
RAD - Gy
REM - Sv
- divide by 100 from RAD + REM to Gy & Sv
- multiply from vice versa
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what measurement determines how sensitive the sum of the equivalent doses of specific tissue
Effective Dose (E)
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what is a dosimeter
dose measuring device
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What are the two classification os detection and measurement of ionizing radiation
- field survey instruments
- personnel monitoring devices
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what are the natural sources of natural radiation
cosmic (space) and terrestrial (ground)
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what is BERT
background equivalent radiation time
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what is the BERT for taking a chest xray
it is compared to living on earth for ten days
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what field survey instrument detects spilled radioactivity
Geiger mueller survey instruments
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which field instrument has a gas filled detector betweentwo electrodes and has ionizing radiationion pairs in gas
GM survey instruments
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what particles are GM instruments not so good at picking up
- x-ray and gamma
- better at picking up alpha and beta
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what detection device emits a light when simulated by ionizing radiation in which the light is converted to an electri signal (commonly used CT scan)
scintillation detection devices
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what instrument meaures in roetngen and is used to evaluate equiment performence leakage radiation and patient exposure
ionization chamber instruments
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Peronnel monitoring devices are given to workers who accumulate how much radiation of the reccomended dose
1/10 = 5 rem
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where should monitoring devices be worn and wear if you only have one
- one out side the collar
- and under the shirt at waist level
- if you have one wear it outside the collar
- if you are weating a lead apron make sure both, one is under the apron at waist level and the other is collar level outside the apron
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what are the five different monitoring devices
- optically stimulated luminescence OSL
- thermoluminescent TLD
- Film badge dosimeter
- pocket dosimeter
- care of personnel monitoring devices
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what is the best dosimeter
OSL
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In an OSL monitor what detects the radiation
thin layer of aliminum dioxide
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in an OSL dosimeter the level of luminiscence is porportional to what? the
the amt of radiation recieved
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In an OSl dosimeter what is the purpose of the filters of copper and tin
it gives an idea of how strong the radiation you were exposed to
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which dosimeter is sensitive to 1mrem
OSL dosimeters
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what is the metal that detects the radiation in a TLD
what is the purpose of the crystals
- lithium fluoride crystals
- the crystals store energy when exposed to radiation
- but the stored energy is exposed to heat and emits a light poprptional to the amt of radiaition exposed to
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what monitoring device is least sensitive and how much
TLD and 10mrem
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the TLD is very sensitive to what other factors
- environmental factors
- heat, humifity temp pressure and prolonged exposure to light
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what dosimeters are sensitive to environmental factors and not as sensitive as the others
- TLD and film badge monitors
- 10 mrem
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how is the detector in a film badge detect radiation
- it has two pieces of film in light tight packet
- filters provide info on the energy
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which dosimeter has a small ionization chamber (measures ionization in air) and has a hairline fiber that moves on an exposure scale
pocket dosimeters
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which dosimeter can be used by anyone and is used for short period puproses i.e. visiting a certain radioactive spill somewhere)
pocket dosimter looks like a pen
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what is downfall of the pocket dosimeters
it doesnt keep cumulative record of the persons radiation exposure and is then calibrated back to back zero once done
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