Module 6 (Late Effects of Radiation) Flashcards
What are late effects of radiation?
Late effects of radiation are health effects that appear months or years after exposure, often as non-distinct diseases such as cancer or genetic mutations.
Why are late effects of radiation difficult to identify?
They occur long after exposure and are influenced by genetic, lifestyle, and environmental factors, making it hard to attribute them solely to radiation.
What is the main concern regarding late effects of radiation?
Carcinogenesis (cancer development).
How do researchers study the late effects of low-dose radiation exposure?
By comparing populations exposed to radiation (e.g., nuclear event survivors) with those who were not exposed.
What is the challenge in defining the effect of low-dose exposures?
Low-dose radiation does not cause immediate tissue damage, making it difficult to determine long-term effects, which could be due to other factors.
What are late tissue reactions?
Late tissue reactions are deterministic effects that appear years after exposure, such as cataracts, fibrosis, and organ atrophy.
Give examples of late stochastic effects.
Leukemia and other cancers.
Give examples of late tissue reactions.
Cataractogenesis, fibrosis, impaired fertility, and sterility.
What are the two categories of late effects from whole-body radiation exposure?
Somatic effects and genetic (hereditary) effects.
What is the Linear Non-Threshold (LNT) Dose-Response Model?
A conservative model that assumes no dose of radiation is completely safe and that risk increases proportionally with dose.
Why is the LNT model widely used in radiation protection?
It assumes any exposure carries some level of risk, promoting cautious exposure management.
What is the Linear Threshold Dose-Response Model?
A model suggesting there is a threshold dose below which no harmful effects occur.
What is the Hormesis Dose-Response Model?
A controversial theory that low-dose radiation may have beneficial effects by stimulating cellular repair mechanisms.
What is the most radiosensitive tissue reaction in the human body?
The lens of the eye (cataracts can form at 0.5 Gy of radiation).
What is the effect of radiation exposure on pediatric and fetal populations?
Increased radiosensitivity, with possible effects including inhibited growth, intellectual disability, microcephaly, and increased leukemia risk.
What is ALARA?
“As Low As Reasonably Achievable” – a principle for minimizing radiation exposure while achieving necessary diagnostic results.
Why is cumulative low-dose exposure a concern?
While individual low-dose exposures are negligible, increased use of medical imaging raises public health concerns over long-term cumulative effects.
What is the significance of atomic bomb survivor studies in radiation research?
They provide key data on the long-term effects of radiation exposure, influencing dose-risk models.
Have genetic effects from radiation been observed in humans?
No, studies (including atomic bomb survivors) have not shown evidence of genetic mutations passed to offspring.
What is the key risk management strategy for medical imaging professionals?
Justifying and optimizing radiation use through ALARA principles and risk-benefit analysis.
