Genetic Effects from Radiation Exposure

							Genetic Effects from
Radiation Exposure
The Basics of Genetic Effects
•Characteristics such
as eye, hair or skin
color that make each
person unique are
called genetic traits
•Changes in the genes
of DNA can arise
naturally, or as a
result of exposure to
radiation or to
chemical and physical
agents
•There are two types
of mutations: germ
line and somatic
How Radiation Can Harm a Cell
• When a radioactive particle or wave hits a
  cell in the body, one of four things can
  happen
• It may pass through the cell without doing
  damage.
• It may damage the cell, but the cell may be
  able to repair the damage before it produces
  new cells.
• It may damage the cell in such a way that the
  damage is passed on when new cells are
  formed.
• It may kill the cell.
How Radiation Exposure Occurs
•Radiation exposure
can be external or
internal
•External and internal
radiation exposure
comes from a variety
of sources
• Medical and dental
X-rays, and
radioactive substances
in the environment,
such as radon and
cosmic rays
Radiation Exposure of Either
 Parent before Pregnancy
              •Human reproductive cell
              are relatively
              radiosensitive
              •In males a radiation dose
              of 2 Gy may cause
              temporary sterility, and at
              5 to 6 Gy permanent
              sterility
              •In females the effects of
              radiation depend on the
              age of the individual
              •Temporary sterility results
              from a dose of 2 Gy and a
              dose of 5 Gy generally
              causes permanent sterility
Effects of Radiation Exposure
         before Birth
               •The first trimester of
               pregnancy is the most
               critical period for radiation
               exposure to the pregnant
               woman
               •Radiation induced
               abnormalities can occur
               between 10 days and 6
               weeks after conception
               •Radiation exposure in the
               second and third
               trimesters can cause
               congenital abnormalities,
               functional disorders, and a
               predisposition for
               childhood cancer
Radiation safety for everyone
•As with other health
effects from radiation, it is
assumed that any exposure
to radiation carries some
risk of genetic effects and
birth defects
•A child's exposure to
radiation before birth is
linked to problems such as
childhood leukemia,
mental retardation, small
head size and lower IQ
•There is no 100% safe
gonadal radiation dose