Radiation carcinogen Flashcards
What’s LET? What’s the difference between high and low LET? Give examples
It is the average amount of deposition of energy when the molecule is travelling linearly.
High LET-Deposits high energy but’s difficult to pass through a barrier-alpha, neutron
Low LET- Deposits low energy but passes through barriers easily. Photon,x-ray, beta
What are two ways to administer inonizing radiation?
Stochastic- No threshold dosage, low doses, used for radiation diagnostics, single cell effect
Deterministic- Intermediate to high dosage, organ effect, used for radiotherapy
What is the age of expression? Which ones has the shortest?
When the cancer progresses and is manifested. Leukaemia
Explaon Xerdoma pigmentosum
Defects of NER leads to development of many different types of cancer. UV radiation often causes dimer formation that need to be repaired by the NER, people with this autosomal recessive disease can’t repair thymine dimers and this leads to an accumulation of mutations and eventually cancer
How many complementation groups are there in xerdoma pigmentosum?
8
T/F
UV radiation doesn’t induce malignant and non malignant melanoma
F
Dosage isn’t positively correlated with cancer rates
F
What’s inverse dose effect
Fragmented low doses of radiation results in a more effective biological response
All types of radiations are carcinogens
true
UV radiation is a complete carcinogen
True
What kind of cancer is associated with radon exposure
Osteosarcomas
Age of expression of induced and spontaneous cancer of the same type is the same
True
What are some problems with radiation carcinogen studies?
Little information on:
confounding factors between different populations and same cancer type incidence
High LET/ high doses externally
Low dose low LET
Influence of cancer background on cancer incident
Need large samples to detect small changes in cancer rates
Why is the transformationof rodent cells the best method in studying carcinogens?
Becuase it’s quantitative, can see the relationship between dose and cancer
Why was the radon refuted to be treated as a dangerous carcinogen?
Becuase there were mixed results. There is a complex relationship between LET dosage, stage of cell cycle and dose protraction.
2Different particles were studied
retrospective dosimetry
With high LET there is the highest transformation at the G1, while the low LET had the highest transformation at the G2/M different dosing intervals had different results
