P3: PPT - LATE EFFECTS OF RADIATION (IRRADIATION IN UTERO)

First Trimester

Irradiation in Utero

• All observations point to the ___ during pregnancy as the most radiosensitive period.

Utero

The effects of radiation in ___ are time related and radiation dose related.

Irradiation in Utero

They include prenatal death, neonatal death, congenital abnormalities, malignancy induction, general impairment of growth, genetic effects, and mental retardation

2 Weeks

Irradiation in Utero

Within ___ of fertilization, the most pronounced effect of a high radiation dose is prenatal death, which manifests as a spontaneous abortion.

Spontaneous Abortion (Miscarriage)

Irradiation in Utero

Within 2 weeks of fertilization, the most pronounced effect of a high radiation dose is prenatal death, which manifests as a ____.

High

Irradiation in Utero

• Within 2 weeks of fertilization, the most pronounced effect of a high radiation dose is prenatal death, which manifests as a spontaneous abortion.

• Observations in radiation therapy patients have confirmed this effect, but only after very ___ doses.

Major Organogenesis

Irradiation in Utero

• During the period of ____, from the 2nd through the 12th weeks, two effects may occur.

• Early in this period, skeletal and organ abnormalities can be induced.

• As major organogenesis continues, congenital abnormalities of the central nervous system may be observed if the pregnancy is carried to term.

Skeletal and Organ

Irradiation in Utero

• During the period of major organogenesis, from the 2nd through the 12th weeks, two effects may occur.

• Early in this period, ___ abnormalities can be induced.

Congenital Abnormalities

Irradiation in Utero

• During the period of major organogenesis, from the 2nd through the 12th weeks, two effects may occur.

• As major organogenesis continues, ____ of the central nervous system may be observed if the pregnancy is carried to term.

100

Summary of Effects After ___ mGyt in Utero

Type of Response
1. Spontaneous Abortion
- Time of Exposure: 0-2 wk
- Natural Occurrence: 25%
- Radiation Response: 0.1%

2. Congenital Abnormalities
- Time of Exposure: 2-10 wk
- Natural Occurrence: 5%
- Radiation Response: 1%

3. Intellectual Disability
- Time of Exposure: 2-15 wk
- Natural Occurrence: 6%
- Radiation Response: 0.5%

4. Malignant Disease
- Time of Exposure: 0-9 mo
- Natural Occurrence: 8/10,000
- Radiation Response: 12/10,000

5. Impaired growth and development
- Time of Exposure: 0-9 mo
- Natural Occurrence: 1%
- Radiation Response: Nil (nothing i zero)

6. Genetic Mutation
- Time of Exposure: 0-9 mo
- Natural Occurrence: 10%
- Radiation Response: Nil (nothing i zero)

Childhood Malignancy

Irradiation in Utero

• Irradiation in utero at the human level has been associated with ____ by a number of investigators.

• Although the Oxford Survey has reviewed all malignancies, it is the findings of radiation-induced leukemia that have been of particular importance.

Leukemia

Irradiation in Utero

• Irradiation in utero at the human level has been associated with childhood malignancy by a number of investigators.

• Although the Oxford Survey has reviewed all malignancies, it is the findings of radiation-induced ___ that have been of particular importance.

Relative

_____ Risk of Childhood Leukemia After Irradiation in Utero by Trimester

Time of X-ray Examination
1. 1st Trimester: 8.3 (Relative Risk)
2. 2nd Trimester: 1.5 (Relative Risk)
3. Third Trimester: 1.4 (Relative Risk)

Total: 1.5 (Relative Risk)