dose, biological effects, and exposure models
DESCRIPTION
Dose, Biological Effects, and Exposure Models. David Weisz – Nuclear Forensics. …so what exactly is dose?. 1 Gy = 100 rad = 1 J/Kg 1 Sv = 100 rem (usually) = 1 Gy x weighting factor. Rem vs. Sv. Sv = dose ( Gy ) x w R. rem = dose ( rads ) x Q. Linear Energy Transfer. - PowerPoint PPT PresentationTRANSCRIPT
Acute Radiation Syndrome
What tissues are most sensitive to radiation damage???
Tissues with high cellular reproduction rate
• How much radiation energy absorption needed to kill a human?
4 Gy x 1 J/kg x 70 kg = 280 Joules
• How much heat energy absorbed from drinking a cup of hot coffee?
250ml x 23o = 5,750 calories
5,750 calories x 4.19 J/cal = 24,092 Joules (96 J/ml of coffee)
4 Gy = 3 ml hot coffee
Excess temp = 60o – 37o = 23oC
LD50/60 = 4 Gy
The Human Toll:• Hiroshima: 90,000-166,000 deaths within 2 months
• Nagasaki: 60,000-80,000 deaths within 2 months• (50% of deaths occurred on the first day)
What was the main cause of death/injury?
How do we determine risk?
Human Epidimiological Studies
Animal Studies
• Cohort Studies
• Case Control Studies
• Ecological Studies