Final Flashcards
1 Gray = ? Rads
100 rad = 1 Gray
What are rad and gray a measure of?
The dose (energy imparted) to a specific tissue
What does rem stand for?
Roentgen equivalent in man
QF x rad = ?
Rem
QF x Gy = ?
Sievert
1 Sievert = ? Rem
100 rem = 1 Sv
100 rem = ? Sv
1 Sv = 100 rem
What are rem and sievert used to measure?
Occupational dose and population dose
T/F Relative biological effectiveness (RBE) does not vary with different TYPES of radiation?
False
Which unit is useful when several types of radiation are involved?
Rem (it takes into account the QUALITY FACTOR for different types of ionizing radiations)
What is LET?
Linear Energy Transfer
How much energy an ionizing particle transfers to a material per unit distance
T/F LET depends only on the energy of the radiation and not on the material traversed
False
For x-ray energies in the diagnostic x-ray range: 1 R = ? Rad = ? Rem?
1 R = 1 rad = 1 rem
Organ dose
Probability of stochastic effects (mainly cancer creation) as the absorbed dose averaged over an organ
Absorbed dose
Energy absorbed per unit mass at a given point
Equivalent dose
Organ dose corrected by a radiation weighting factor that takes into account the relative biological effectiveness of the incident radiation in producing stochastic effects
Effective dose
Weighted sum of equivalent doses to all relevant tissues + organ w/the purpose “to indicate the combo of different doses to several different tissues in a way that’s likely to correlate well w/the total of the stochastic effects”
Where is patient dose usually calculated from?
The skin
Readings obtained from Focus to Skin Dose graph (F2S Dose Graph) are usually measured in what units?
Mrad ESE (Entrance Skin Exposure)
What are the direct effects radiation can have on cells?
- Point mutations in DNA
What are the indirect effects of radiation on cells?
- Ionization of water in the cell produces free radicals that may damage DNA directly or produce toxic substances that affect DNA
T/F: DNA repair is more successful when only a single strand is broke
True!
What are the 4 factors of cell sensitivity, according to the laws of Bergonie and Tribondeau
- Age (young cells)
- Differentiation (simple cells)
- Mitotic rate (rapidly dividing cells)
- Metabolic rate (energy-devouring cells)
A baby has mutations from mother being irradiated prior to pregnancy. Is this somatic or genetic radiation effects?
Genetic
What are non-stochastic radiation effects?
- Relatively high doses of radiation with severe effects that are proportional to the amount of radiation received – effects are predictable
- non-stochastic = “non-survivors”
What is stochastic radiation effect?
Likelihood of the effects is proportional to dose, but the severity is unrelated to the dose (X-rays are this kind!)
– effects are random and unpredictable!
What does rad stand for?
Radiation Absorbed Dose
