Biological Effects of Radiation

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Biological Effects of Radiation

• Tim Marshel, R.T. CNMT

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The Cell

• Cell Membrane
• Cytoplasm
• Mitochondria
• Lysosome
• Nucleus
• DNA
• Chromosomes

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The Cell
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Basic Cell Structure Cell Membrane

• Regulates
• Transports

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Basic Cell Structure Cell Membrane
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Basic Cell Structure Cytoplasm

• The term cytoplasm refers to everything between
  the cell membrane and the nuclear envelope. It
  consists of primarily of water. It also contains
  various organelles as well as salts, dissolved
  gasses and nutrients.

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Basic Cell Structure Mitochondria

• The mitochondria is the powerhouse of the cell.
  It is the site of respiration.

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Basic Cell Structure Lysosomes

• Lysosomes are called suicide sacks. They are
  produced by the golgi body. They consist of a
  single membrane surrounding powerful digestive
  enzymes.

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Basic Cell Structure Nucleus

• The nucleus is the headquarters of the cell. It
  regulates all cell activity. It consists of a
  nuclear envelope, (the outer membrane) and
  nucleoplasm. In the nucleoplasm you can see
  chromatin and the nucleolus.

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DNA

• Contains genes
• Master blueprint of the cell

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Radiation Effects on the Cell

• 3,000-5000 rads (30-50 gray) will rupture the
  cell membrane
• Less than 3,000 rads increases permeability of
  the cell membrane and some leakage occurs
• 500-1,000 rads (5-10 gray) the lysosome ruptures
• The nucleus is the most radiosensitive

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Radiation Effects on the Cell

• Mitochondria
• It takes a few thousand Rad to disrupt function
• Disruption occurs with the food supply
• ATP

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Radiation Effects on the Cell

• Lysosomes
• Rupture at 500-1,000 rad
• Enzyme releasedigestion of cell (suicide)
• Over 1,000 enzymes are of no value

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Radiation Effects on the Cell

• Nucleus

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Radiation Effects on the Cell
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Mitosis
Prophase
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Mitosis
Metaphase
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Mitosis
Anaphase
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Mitosis
Telophase
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Law of Bergonie and Tribondeau

• A high metabolic rate increases the
  radiosensitivity of cells.
• With increased cell maturity, cells are more
  resistant to radiation (radioresistant). Mature
  cells have lower metabolic rates generally.
• Younger cells and tissues are more
  radiosensitive.
• An increased mitotic rate for cells and an
  increased growth rate for tissues increase the
  radiosensitivity of cells.
• Stem cells are radiosensitive. Stem cells are the
  precursors of specialized cells such as muscle or
  neuro cells and these cells have very high
  mitotic rates and are not yet specialized.

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The Radiosensitivity of Cells

• Cells that have a high division rate
• Cells that have a high metabolic rate
• Cells that are of a non-specialized type
• Cells that are well nourished

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Radiosensitive

• Germinal cells
• Hematopoietic tissues
• Basal cells
• Epithelium of the GI tract

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Radioresistant

• Bone
• Liver
• Kidney
• Cartilage
• Muscle
• Nervous tissue

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Effects

• Primary
• Secondary

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Effects

• H2OH0OH0

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Effects
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Stochastic Health Effects

• Stochastic effects
• Effects that occur by chance, generally occurring
  without a threshold level of dose, whose
  probability is proportional to the dose and whose
  severity is independent of the dose. In the
  context of radiation protection, the main
  stochastic effects are cancer and genetic
  effects.
• U.S. Nuclear Regulatory Commission

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Non-Stochastic Health Effects

• Non-stochastic effect
• The health effects of radiation, the severity of
  which vary with the dose and for which a
  threshold is believed to exist. Radiation-induced
  cataract formation is an example of a
  non-stochastic effect (also called a
  deterministic effect) (see 10 CFR 20.1003).
• U.S. Nuclear Regulatory Commission

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Lethal Dose

• LD 50/30
• 50 in 30 days
• 450 rad

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Somatic Effects of Chronic Exposure

• Cancer
• Cataracts
• Life Span

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Acute Effects

• Radiation Syndrome
• Exposure Levels
• Symptoms
• Prodromal Stage
• Latent Phase
• Illness
• Recovery or Death

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Hematopoietic Syndrome

• Bone Marrow
• Lymph Nodes
• Spleen
• Thymus

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Hematopoietic Syndrome

• Effects on Blood Cells
• Lymphocytes
• Granulocytes
• Platelets
• Erythrocytes

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Hematopoietic Syndrome

• Progress of Hematopoietic Syndrome
• Prodromal Stage
• Latent Phase
• Illness
• Death

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Gastrointestinal Tract Syndrome

• Gastrointestinal Tract Lining

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Gastrointestinal Tract Syndrome

• Effects of Radiation

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Gastrointestinal Tract Syndrome

• Progress of Gastrointestinal Tract Syndrome
• Prodromal Stage
• Latent Phase
• Illness
• Death

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Central Nervous System Syndrome
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Embryological Effects

• Law of Bergonie and Tribondeau
• Children/Adults
• Fetuses/Children
• Embryos/Fetuses

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Embryological Effects

• Response to Irradiation
• Total dose
• Rate of dose
• Quality of radiation
• Stage of development

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Heritable Effects

• 46 Chromosomes
• 2 sets
• 23 Chromosomes each
• Genes
• Determine physical and psychological
  characteristics
• Occur in Pairs
• Dominant
• Recessive

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Genes
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Somatic Cells

• Body cells are called somatic cells
• Chromosome aberrations that are caused by
  radiation can take place in both genetic and
  somatic cells
• Effects of radiation seen in person exposed

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Germ Cells

• Heritable
• Future generations see effects

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Mutations
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Thank You