1. Which of the following statements is false?

a. Radiation can cause the following effects in the unborn child: cancer, lethality, organ malformations or growth disturbances.

b. The effect of radiation on the unborn child is influenced by the total dose, the stage of gestation and the dose rate.

c. The estimation of radiation-induced damage in utero has to be done against the naturally occuring level of inborn defects.

d. The incidence of spontaneously malformed infants at birth is about 1%.

2. The most sensitive stage for the lethal effects of radiation is:

a. Preimplantation.

b. Early organogenesis.

c. Late organogenesis.

d. The fetal period.

3. Which of the following statements is false?

a. During preimplantation, radiation damage can only result in death of the embryo. If the embryo survives, it grows normally.

b. During organogenesis, the main effects of radiation is the production of anomalies in the structure of the embryo and growth retardation.

c. The damage caused by radiation on the fetus include effects on the hematopoietic system, liver and kidneys. Growth retardation and lethality have also been documented.

d. Higher doses of radiation are required in order to cause lethality in the early stages of embryonic development than in the fetal period.

4. Which of the following statements is not part of the observations made about children exposed in utero at Hiroshima and Nagasaki?

a. Increased fetal loss or infant mortality rate.

b. No birth defects for irradiation that took place in the first 15 days of gestation.

c. Growth retardation in irradiated embryos.

d. Catch-up growth in the cases mentioned in answer c.

5. The main effects on children irradiated in utero in Hiroshima and Nagasaki are:

a. fetal loss and mental retardation.

b. infant mortality and microcephaly.

c. microcephaly and mental retardation.

d. growth retardation and teratogenesis.

6. Find which of the following statements does not belong to the conclusions drawn about mental retardation caused by irradiation in utero of children in Hiroshima and Nagasaki.

a. Severe mental retardation was not observed if the irradiation took place before 8 weeks or after 25 weeks after conception.

b. The most sensitive period was between 8 to 15 weeks after conception.

c. The incidence of mental retardation in the sensitive period (mentioned in answer b) is a linear function of the dose with a probability of 40% at a dose of 1 Gy.

d. There was no dose threshold observed in the dose-response curve for mental retardation.

7. Which of the following statements regarding exposure in utero to medical radiation is true?

a. Large doses (2.5 Gy) delivered to the embryo before 2 to 3 weeks of gestation are not likely to cause lethality.

b. Irradiation between weeks 4 and 11 is not likely to cause organ abnormalities.

c. Irradiation between weeks 11 and 16 may produce eye, skeletal and genital organ abnormalities as well as microcephaly and mental retardation.

d. Irradiation between weeks 16 and 20 has not been observed to lead to microcephaly, mental retardation or stunting of growth.

e. Irradiation after week 30 is not expected to cause functional disabilities.

8. One difference between animal experiments and the observation of in utero irradiation results in children in Hiroshima and Nagasaki was that the wide range of congenital malformations found in animal data was not observed in the data of human origin, which, on the other hand, reported several cases of mental retardation and microcephaly. This is believed to be due to the fact that:

a. in the case of humans, the period of susceptibility to congenital malformations (10-32 days of gestation) is short in comparison to the 8 weeks (16 weeks) during which mental retardation (microcephaly) can be induced.

b. the physiology of mice and humans is very different in that respect.

c. the doses delivered in animal experiments were not high enough to cause microcephaly.

9. An obstetric x-ray examination increases the spontaneous risk of childhood cancer by:

a. 10%.

b. 20%.

c. 30%.

d. 40%.