RT206: M5 - INDIVIDUAL RADIATION EFFECTS

Growth retardation

________ means that the mental capacity is reduced than normal.

• Stochastic or probabilistic effect

• Deterministic or non-stochastic effect.

Biological effects of irradiation are classified as either:

stochastic effect

A _________ is one where the probability of occurrence of effects increases with dose. It is also assumed that stochastic effects do not exhibit a threshold dose.

stochastic effect

Stochastic effect is the probability of acquiring or the probability of the occurrence of effects increases with dose.

Meaning that for stochastic effects, the higher the

dose, the higher the probability of occurrence to

radiation effects. And these effects are regarded as

the main health risk from low-dose radiation

exposures in the diagnostic radiology

department.

• Hereditary Effects

• Carcinogenesis

Example of Stochastic Effects:

Deterministic Effect

_______ are thought to have a threshold dose.

Deterministic Effects

Doses below the threshold have no observable effects and the severability of effects increases with dose.

• Cataract induction

• Skin erythema

• Fibrosis

• Hematologic deficiencies

• Impairment to fertility

Examples of Deterministic Effect

mutation frequency

The classic study of the effect of radiation on _________ was done in 1927 by Herman J. Müller in a comprehensive study of fruit flies.

1927

The classic study of the effect of radiation on mutation frequency was done in _____ by Herman J. Müller in a comprehensive study of fruit flies.

Herman J. Müller

The classic study of the effect of radiation on mutation frequency was done in 1927 by ______ in a comprehensive study of fruit flies.

fruit flies

The classic study of the effect of radiation on mutation frequency was done in 1927 by Herman J. Müller in a comprehensive study of ______.

Mutation Frequency

Radiation did not produce any new or unique mutations, but simply increased the number of mutations that spontaneously arise in each generation. And all mutations, however, did not show the same susceptibility to induction by radiation.

mutation frequency

what the ________ implies is that radiation does not produce new mutations, but rather, it multiplies or reproduce the existing mutations.

embryo

Radiation has long been known to have profoundly damaging effects on the developing ________.

1. Embryonic

2. Fetal or Neonatal Death

3. Malformations

4. Growth Retardation

5. Congenital Defects

6. Cancer Induction

The principal effects of radiation on an embryo or fetus are:

Preimplantation

(conception to 10 days following conception)

Organogenesis

(Organ formation, 6th week)

Fetal or growth stage

(after the 6th week)

earliest

In the ______ stage of development, radiation exposure may destroy enough of the cells to terminate the pregnancy.

radiation

That is why, in the early days, _____ was used as a way of abortion.

middle

In the ______ stages of the fetal development, where the parts are not yet fully formed, radiation exposure may cause damage to a part or stunned its development.

Late effects

_________ of radiation are the most common in later stages in the fetal growth or the fetal development when the fetus is growing rather than developing.

20 weeks

Radiosensitivity begins to decrease at _______ post-conception, but the fetus then becomes more susceptible to late effects and central nervous systems.

12 hours, 30 hours and 60 hours

The most critical times of exposure are at_______ post-conception and at ______ post- conception, which is when the first two divisions take place.

major organogenesis

The incidence of congenital abnormalities is more frequent during the period of ___________ .

organogenesis stage

And congenital abnormalities such as microcephaly or hydrocephaly can result from radiation exposure in the _________.

leukemia

And in the fetal stage, few abnormalities are noted with radiation exposure. So instead, late effects of radiation such as _______, or more likely to be observed.