Radiobiology > Deterministic Effects > Cataracts - Skin - & Sterility
Deterministic Effects: Cataracts, Skin, & Sterility
Cataracts
Cataracts are progressive lens opacity, developing after disruption of the progenitor lens epithelium or lens fibers, or accumulation of oxidative damage.
- A single dose of direct irradiation of 2 to 6 Gy leads to eventual cataract formation.
- Fractionated doses of 6 Gy are also likely to result in cataract.
Skin
- Transient erythema, peaking in 1-2 weeks post-exposure, is expected at doses 2 to 6 Gy.
- Desquamation occurs at doses in excess of 10 Gy.
- Temporary epilation (hair loss) occurs at doses from 3 to 7 Gy. Above 7 Gy, hair loss is permanent.
Sterility
Testes are more susceptible to temporary, radiation-induced sterility than are ovaries. Stem cells (type A spermatagonia) play an important role in continued male potency. As might be expected, type A spermatagonia are more radiosensitive than differentiated sperm. In contrast to the male, a female of reproductive age has no further capacity for oogenesis - she is born with her entire compliment of oocytes.
- In males, temporary sterility occurs with gonadal doses of 15 rad (0.15 Gy). No effect is seen on libido (Leydig cells are relatively radioresistant). Because of the sequential development of sperm, a latent period is observed for temporary sterility. Permanent sterility is seen in doses greater than 6 Gy.
- A female may be rendered immediately infertile after ovarian doses of 4 to 6 Gy (with some risk noted above 2.5 Gy). The patient will undergo hormonal changes identical to those associated with ovarian failure at menopause, including decreased libido.
