Radbio Flashcards
What is TEDE?
Total effective dose equivalent - dose weighted by how damaging the type of radiation is (dose equivalent) AND by how sensitive the tissue is (effective dose), and summed for both internal and external exposures
What tissues have the highest tissue weighting factors?
gonads (0.2), red bone marrow, colon, lung, and stomach (0.12)
Where do treatment protocols/normal tissue constraints for lung treatments come from?
RTOG 0813
What is the increase in cancer risk for whole body exposures?
~5%/Sv (ICRP 60)
What is the dose range/typical symptoms of hematopoietic syndrome?
1-6 Gy,
- drop in blood cell count
- infections (due to low blood cell count)
- poor wound healing
- fever
- headache
- alopecia (after 3 Gy)
What is the dose range/typical symptoms of gastrointestinal syndrome?
6-30 Gy
- Hematopoietic syndrome
- nausea
- vomiting
- loss of appetite
- abdominal pain
- death common
What is the survival rate of hematopoietic syndrome?
50-95%
What is the survival rate of gastrointestinal syndrome?
0-50%
What is the dose range/typical symptoms of neurovascular syndrome?
> 30 Gy
- gastrointestinal syndrome +
- dizziness
- headache
- seizures
- tremor
- ataxia (loss of coordination)
- loss of consciousness
What are radiation weighting factors?
meant to normalize how damaging a particular radiation type is - specifically for stochastic effects of low levels of ionizing radiation
What are some common radiation weighting factors?
- photons, electrons = 1
- protons = 2
- Neutrons = 5-20 (depends on energy)
- Alphas = 20
What’s the difference between a radiation weighting factor and RBE?
radiation weighting factors are for stochastic effects from low levels of ionizing radiation, RBE is specifically for the endpoint of tumor control at therapeutic exposures
Where do radiation weighting factors come from?
ICRP
Where do tissue weighting factors come from?
ICRP
What is a typical alpha/beta ratio for tumors?
10 Gy
