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131 Cards in this Set
- Front
- Back
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Energy of radiation is associated with what type of energy?
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Kinetic energy
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E = ½ mV2
4 – 8 MeV ^What kind of particle is being described |
alpha particles
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travels near speed of light, requires relativistic correction
E = 0.511 MeV |
beta particles
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Pure electromagnetic radiation
E = hν * What two types of radiation are being described above? |
x and y radiation
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This type of particle is Monoenergetic
-Heavy, charged particle(s): 2+ Charge -7300 times mass of β particles |
Alpha
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Range (air) = 0.325 E3/2
For 226Ra, Range (air) = 3.4 cm Range (tissue) ~ 1/1000 of range (air) For 226Ra, Range (tissue) = 34 μm * what type of particle is being described above? |
Alpha
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What is the percentage of 4.8 Mev Alpha Particle
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94.5%
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What is the percentage of 4.6 Mev Alpha Particle
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5.5%
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What is the half life of 222Rn
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3.8 Days.
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In Linear Energy Transfer of alpha particles, how much energy (in percent) is lost traveling through 10 cm of tissue?
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10-20%
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What is the half life of 226Ra
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1600 years
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Which particle has a greater chance to interact with matter, so energy loss per unit distance is greater?
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alpha
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What leads to ionization and dissociation in tissue?
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High energy transfer of alpha particle to tissue
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At what MeV do alpha particles damage DNA?
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.6 or 5.0 MeV
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These types of particles can damage DNA and can even cause a cause a double-strand break
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alpha particles
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What are the two mechanisms of damage in the linear energy transfer of alpha particles?
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by direct production of ions or by the ejection of electrons which may have enough energy to produce further ionization
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Why can't beta particles' energy loss in matter be descried as for alpha particles?
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-Relativistic effects must be considered
-Electrons interact with particles of same mass -Radiative or bremsstrahlung energy loss occurs when electrons slowing in matter |
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this type of particle are low in Linear Energy Transfer radiations
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Beta particles
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What is the half life of 210 Pb?
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22.3 years
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What is the half life of 210Bi?
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5.0 Days
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What is the percentage of .015 MeV Beta?
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81%
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What is the percentage of .061 MeV Beta?
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19%
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What is the fundamental unit in Electromagnetic phenomena?
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the photon
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Phton is radiation emitted by which three possibilites?
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-THErmally excited matter
-NUclear processes (fission, fusion) -BOMBardment with other radiation |
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Photons are known to have a dual nature. What two forms can photons take?
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- particle like, subatomic
- wave-like, sine wave pattern |
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Dual Nature
*Particle-like, subatomic *Wave-like, sine wave pattern -Massless -Quanta of energy -Move at speed of light 300,000 km s-1 186,000 mi s-1 669.6 million mi h-1 |
The characteristics of the photon
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this is the distance between two adjacent peaks on a wave
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wavelength
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the number of peaks of a wave that pass by a reference point in one second
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frequency
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How many hertz is one cycle per second?
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1
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What is the formula for calculating energy?
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E=hv
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What is the wavelength of red wavelength?
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700 nanometers
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What is the frequency of the "red wave"?
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428.570 THz
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The longer the wave length the ______ the energy, and the ______ the frequency
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low. low
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1 micrometer is how many meters?
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= 10^-6
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How many meters is in 1 nanometer?
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=10^-9
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How much is 1 angstrom
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=10^10
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______ have no mass or charge
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photons
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interaction with orbital electron--> full energy of photon
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photoelectric effect
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Part of photon energy is transferred to an electron, and the photon scatters with less energy
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Compton effect
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Photon energy converted to an electron-positron pair.
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pair production
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This type of particle can be stopped by a sheet of paper
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alpha particles
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This type of particle can be stopped by a layer of clothing or by a few millimeters of a substance such as aluminum
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beta particles
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This type of particle is stopped by several feet of concrete or a few inches of lead
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gamma rays
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What type of radiation does Roentgen(R) refer to?
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x and y
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how many ion pairs/cm^3 is 1 Roentgen
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2 billion
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This unit of radiation measures dose in water or tissue
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Rad
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how many ergs/gram must be absorbed to = 1 Rad?
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100
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This unit of Radiation produces the same biological effect as 1 Roentgen (R)
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Rem
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in 1 rad X radiation weighting factor how many rem is there?
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1 Rem
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in one Gray how many rad is there?
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100
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in one Sievert (Sv) how many rems are there?
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100
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in one Becquerel how many many Ci?
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2.7 x10^-11
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How many disintegrations per minute from picoCurie (pCi)
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2.22
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Definition: mean energy imparted, e, imparted by ionizing radiation to matter of mass m
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Absorbed dose
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what is the formula for absorbed dose?
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D= e/m
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how many Joules per kilogram is 1 gray or 100 rad?
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1
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Definition: is the charge of ions of one sign when all electrons liberated by photons are completely stopped in air of mass m (ionization in air)
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Exposure
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The RWF, or biological effectiveness factor depends on?
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Radiation type
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what is the Wr for x radiation?
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1.0
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What is the Wr for y radiation?
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1.0
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What is the Wr for beta radiation
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1.0
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What is the RFW, or biological effectivenesss factor, of alpha radiation
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20
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What is the RWF of a radiation from neutron?
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5-20 depending on its energy
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What SI unit is used to measure equivalent dose?
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sievert (Sv)
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what is the formula for Equivalent dose?
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H= D wr
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What is the effective dose equivalent formula (it's older units)
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rem=rad x RWF
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-weighted for radiation type
-weighted for tissue at risk |
Doubly weighted dose
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What is the risk of fatal cancer for adult workers?
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.04 per sievert
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What is the risk of fatal cancer for whole adult population?
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.05 per sievert
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Radiation tracks deposit energy directly in DNA
35% - exclusively direct Small contributor to base pair damage |
Direct effect ionization
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Radiation tracks may ionize other molecules closely associated with DNA (hydrogen, oxygen) free radicals damage DNA
Effect occurs over very short distances (few nm) 65% indirect Hydroxyl radicals – major contributors to base damage |
indirect effect
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What is the treatment for ankylosing spondylitis
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224 Radium
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What medicine was given for over a 150 illnesses?
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radithor
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What is the half life of 224Ra
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3.62 days
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What type of radioactive material was in Little Boy?
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238Ur
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What type of radioactive material was in Fat man?
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239Pu
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Little boy was dropped in which city in japan?
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Hiroshima
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Fat man was dropped in which city in Japan?
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Nagasaki
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How many deaths were within 1 km of explosion due to blast and thermal effects.
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64,000
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What kind of radiation do photoelectric effect, compton effect, and pair production have to do with?
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x and y radiation
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In absorbed dose, D= e/m, what does e and m represent?
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e= energy deposited
m= mass |
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In exposure how many Coulombs are there per kilogram of air?
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2.58 x 10^-4 Coulombs
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How many rads in aborbed energy of air
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0.87 rad
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1 C/kg = ______ Gy
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33.85
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In the equivalent dose formula H= D wr.. What does H, D, and wr represent?
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H=Equivalent dose in sievert
D=dose (gray) wr= radiation weighting factor |
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What is the occupational guideline for He
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20mSv per yr.
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100 mSv in 5 years with limit of 50 mSv in any single year
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1990 Occupational guidelines
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What is the lifetime limit risk of fatal cancer formula?
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age x 10 mSv
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What is the average annual limit of exposure?
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20 mSv
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What is the maximum annual limit of exposure?
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50 mSv
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What are the mechanism of DNA Damage?
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-Damage may affect any of its components
- Loss of base sequence has genetic consequences |
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In an 8 micrometer diameter nucleus how many ionizations come from gamma radiation?
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70
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In an 8 micrometer diameter nucleus how many ionizations come from 4- MeV alpha radiations?
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30,000
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-More uniformly distributed over cell population
-Readily repaired by cellular enzymes *High or Low radiation? |
Low LET radiation
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-Severe DNA structure damage
-Very large clusters of ionizations-->irreparable damage and unique cellular consequences |
High LET radiation
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Who had the highest exposures to 226 and 228 Ra and how many microcuries were ingested?
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radium dial painters and 10's to 1000's
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What was the late effect of Radium?
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Osteogenic sarcoma
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Why were there no excess of leukemia even after massive doses of Radium?
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-because target cells for leukemia in bone marrow are outside the short range of the radium alpha particles
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Where does radium go once it is ingested?
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It is incorporated on bone surfaces into the mineralized portion of bone
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Where are target cells for osteogenic sarcoma located?
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bone marrow on endosteal surfaces, 10 micrometer from bone surface
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Average skeletal dose – 30 Gy over 1 to 45 months
899 Juveniles and adults – no difference in response 60 patients developed bone sarcoma Other solid tumors: Breast CA, thyroid CA, Liver CA |
Spiess and Mays (1970), Mays (1988)
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What were the deaths in japan due to?
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blast, thermal radiation, y and neutron radiations
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How far did the radiation travel from the hypocenter?
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1-2 km
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In japan, at how many km, was there no increase in dose of radiation?
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2.5 km
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Which organization conducted the studies in 1950 of the atomic bomb survivors?
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Atomic Bomb Casualty Commission (ABCC)
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Who conducts the studies ongoing today of the atomic bomb survivor casualty commission?
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Radiation effects research foundation (RERF)
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In the 2003 report of Lifespan study how many deaths were of solid cancer deaths due to radiation?
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440 solid cancer deaths
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In the 2003 report of lifespan study how many deaths were of noncancer deaths due to radiation?
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250 noncancer deaths
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How many people were within 2000 meters of hypocenter (substantial exposure)
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16,207
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How many kiloton-yield was there in Nagasaki?
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21 kiloton
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How many kiloton-yield was there in Hiroshima?
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16 Kiloton
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18,500 persons with detailed shielding information complete
57,000 included by estimation of dose 16,207 of the 75,991 subcohort were within 2000 m of hypocenter (substantial exposure) |
Dose system of 1986
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Noncancer disease incidence associated with exposures > ____
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0.5 Sv
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What kind of cancers were statistically significant from Japan explosions
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-Heart Disease
-Stroke -Digestive -Respiratory |
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ERR decreases both with _____ subsequent to exposure and with attained _______
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time; age
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Energy deposited in living tissue
100 ergs of energy deposited per gram of tissue What Unit are they referring to above? |
RAD- Radiation Absorbed Dose
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At how many rad is there radiation sickness and severe burns
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100 rad
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At how many RAD is there death within a few weeks and digestive tract & blood vessel damage?
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400-3000 rad
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At how many rad is there death within a few hours and central nervous system damage?
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3000 rad
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What are the sensitive cells that rapidly divide?
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Fetal cells
sex cells thyroid cells |
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What are the sensitive cells that slowly divide?
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Nerve Cells
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How many Bq is a kilobecquerel?
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103 bq
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How many Bq is a megabecquerel?
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106 bq
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How many Bq is a gigabecquerel?
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109 bq
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How many Bq is a terabecquerel?
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1012 bq
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How many Bq is a petabecquerel?
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1015 bq
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How many bq is an exabecquerel?
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1018 bq
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At Chernobyl what was the initial exposure
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131 I and short lived radionuclides
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At Chernobyl what was the subsequent exposure?
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Radiocesium (134 Cs and 137 Cs)
- external exposure -consumption of contaminated food |
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In 2002 how many cases of thyroid cancer in children from 131 I exposure in milk?
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4000
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What is the most significant pathway for 131 I exposure?
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Ingestion
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