threshold point undifferentiated to begin at a threshold dose Gy neurogenesis conception radiosensitive
While a lack of statistical data, with just 30 individuals out of 1,800, prevents a definitive determination of a threshold point, the data collected suggests a threshold intrauterine or fetal dose for SMR, at the most radiosensitive period of cognitive development, when there is the largest number of undifferentiated neural cells (8 to 15 weeks post-conception) to begin at a threshold dose of approximately "0.09" to "0.15" Gy, with the risk then linearly increasing to a 43-percent rate of SMR when exposed to a fetal dose of 1 Gy at any point during these weeks of rapid neurogenesis.