Radiation Biology Flashcards
How many rads is 1 Gy?
1 Gy = 100 rads
How does absorbed does get converted mathematically into equivalent dose?
radiation weighting factor
How does equivalent does get converted mathematically into effective dose?
tissue weightig factor
If all dose is absorbed, how many gray is 1 Sievert?
if all absorbed, 1 gray = 1 sievert
Are tissue doses generally a little bit higher or a little bit lower than KERMA?
little bit higher
What does KERMA stand for?
kinetic energy released per unit mass
What dose parameter is totally independent of distance?
KAP
What is the equation for Relative Biological Effectiveness (RBE)?
dose of 250 kV Xrays/test dose
What does Direct Ionizing Radiation act on?
direct = DNA
What does Indirect Ionizing Radiation act on?
water
Xray or gamma ray of what dose will kill a large number of cells in a few seconds?
1,000 gray
In what cell cycle phase are cells MOST susceptible to radiation?
M
In what cell cycle phase are cells LEAST susceptible to radiation?
S
Surviving Cell Synchonization
yes
What is the most radiosensitive part of the GI tract?
small bowel
Greater than what dose is needed to effect bone marrow?
> 2 Gy
Greater than what dose is needed to effect the GI tract?
> 8Gy
Greater than what dose is needed to effect the CNS?
> 20
What is LD 50/30?
radiation dose that will kill 50% of people in 30 days
What is the typical LD 50/30?
3-4 Gy (whole body) WITHOUT treatment
What weeks of gestation are most susceptible to radiation?
weeks 8-15
The fetal thyroid does not take up iodine prior to what week of gestation?
week 8
What is the annual dose limit for cataract exposure?
150 mSv
What is the onset of epilation?
21 days
