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RADIOBIOLOGY: PART TWO

RADIOBIOLOGY: PART TWO. CELLULAR EFFECTS OF IRRADIATION . Instant death Reproductive death Apoptosis, programmed cell death(interphase death) Mitotic or genetic death Mitotic Delay Interference of Function Chromosome Breakage. Survival curves for Mammalian Cells .

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RADIOBIOLOGY: PART TWO

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  1. RADIOBIOLOGY: PART TWO

  2. CELLULAR EFFECTS OF IRRADIATION Instant death Reproductive death Apoptosis, programmed cell death(interphase death) Mitotic or genetic death Mitotic Delay Interference of Function Chromosome Breakage

  3. Survival curves for Mammalian Cells • Shoulder indicates an area of cellular repair with Low LET exposures

  4. Blood cells Epithelial tissue Muscle Tissue Nervous Tissue Reproductive cells Blood Cells ??? Find the dose for Whole body hematologic depression What are stem or precursor cells? What dose moderately to severely deplete bone marrow cells? What are the most sensitive stems cells of human tissue? Cell radiosensisitivy and Law of Bergonie and Tribondeau

  5. Is death caused from high doses to red blood cells or white blood cells or platelets?Why? What is the lethal dose for humans? What dose level can impact lymphocytes and why is it so low? Why are radiation patients monitored Blood Cells -MORE QUESTIONS

  6. Epithelial tissue Muscle Tissue Nervous Tissue Radiosensitive Insenstive When are nerve cells most sensitive?

  7. Mature spermatogonia-sensitive or insensitive? Why? What dose can cause temporary sterility in male? In female? What dose can cause permanent sterility in male? In female? Mature ova sensitive or insensitive? What dose may suppress male sperm population? When are a woman’s ovaries most sensitive? Reproductive cells

  8. STOCHASTIC • Random • “all or nothing” • linear,nonthreshold • playing the lottery

  9. Deterministic Effect • AKA nonstochastic or certainty effect • Nonlinear threshold curve • threshold assumed • increases with severity of dose

  10. Dose Linear Curves (PG 112 in Sherer, Pg.498-499 Bushong) • Linear, non-threshold • Linear threshold • Nonlinear (Curvilinear, Sigmoid) Threshold curve • Non-linear, non threshold curve • Linear Quadratic Non threshold

  11. AGE • The age of the biological structure determines sensitivity • Bergonie and Tribondeau • Embryo-fetus-newborn-young child • Decreases in late teens • Stabilizes until old age • increases in old age

  12. GENDER • Females tolerate 5-15% more

  13. RECOVERY • Cell can recover if sufficient time is given between irradiation • some cells have greater capacity for repair • Sufficient radiation causes atrophy

  14. REVIEWPRINCIPLES OFRADIOBIOLOGY ARE BUILT ON THE FOLLOWING:1)RANDOM NATURE2)RADIATION INTERACTS AT CELLULAR LEVEL3)FACTORS THAT ALTER THESE INTERACTIONS

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