Hall 13 - Radiation Cataractogenesis Flashcards
1
Q
What are the three cataract types?
A
Cortical = outer layers of lens
Nuclear = central region of lens
Posterior subcapsular = posterior lens pole
2
Q
What kind of cataract does radiation induce?
A
Posterior subcapsular cataracts (posterior lens pole)
Aberrant lens fiber cells migrate to posterior pole and accumulate, interfering with transparency
3
Q
What kind of effect is radiation cataractogenesis?
A
Deterministic effect (tissue reaction - threshold-sigmoid curve)
4
Q
What is the threshold dose for radiation cataractogenesis?
A
0.5 Gy (previously thought to be 2 Gy single dose or 5-8 Gy fractionated)
Latent period decreases with increasing dose
5
Q
What is the NRCP lens exposure limit?
A
50 mSv per year
