radiation biology

Question 1

rad

Answer 1

radiation absorbed dose - measures dose to a specific tissue

rad = gray (gy): (1 rad = 0.1 Gy; 1 Gy = 100 rad)

Question 2

rem

Answer 2

radiation equivalent in man. xrays have a quality factor of 1
thus 1 R = 1 rad = 1 rem
rem = seivert (sv): (1 rem = 0.01 Sv; 1 Sv = 100 rem)

Question 3

95% of cell damage is repaired within

Answer 3

3 days if it will repair at all

Question 4

Laws of bergonie and tribondeau: cell sensitivity depends on several variables (4)

Answer 4

1. age: younger = more sensitive (fetus vs. adult)
2. differentiation: less = more sensitive (blast cells vs. mature osteocytes)
3. Mitotic rate: higher rate = more sensitive (epithelium vs. neurons in CNS)
4. Metabolic Rate: higher metabolic rate = gland tissue vs. bone tissue

Question 5

stochastic

Answer 5

probabilistic, random.
probability of experiencing effect is proportional to exposure volume, but severity of effect not really affected (?)(cancer, leukemia, mutagenesis (Genetic effects))
low dose exposure effects fall here.
Can be somatic/genetic

Question 6

Nonstochastic

Answer 6

deterministic, predictable.
severity of feffect = proprotional to exposure volume. threshold beneath which effects aren’t seen.
Short term = GI syndrome; hematopoietic syndrome; CNS syndrome

Question 7

radiation exposure in trimester 2

Answer 7

increases risk of organ system mutations = birth defects

Question 8

2006 man made radiation exposure

Answer 8

rose to half of annual radiation dose/capita (diagnostic imagine dose/capita hwich rose 6x from 80’s = this is mostly CT scanning)