Deterministic Effects and Threshold Doses of Radiation Exposure by Gestational Age
| Deterministic effect | Gestational age (weeks) | Threshold dose (mGy) |
|---|---|---|
| Embryo death | 3–4 | 100–200 |
| Major malformations | 4–8 | 250–500 |
| Growth retardation | 4–15 | 200–500 |
| Severe mental disability | 8–15 | 60–500 |
| >16 | >1,500 | |
| Microcephaly | 8–15 | >20,000 |
| Reduced intelligence | >16 | >100 |