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EARLY NONSTOCHASTIC EFFECTS/LATE STOCHASTIC EFFECTS

EARLY NONSTOCHASTIC EFFECTS/LATE STOCHASTIC EFFECTS. Sherer Chapter 7 and 8 Reference: Bushong , Chapter 36 and 37 . Review of Dose response curves. Threshold Non threshold Linear quadratic non threshold curve Non linear (s-shaped or sigmoid) . Early, Nonstochastic Effects:.

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EARLY NONSTOCHASTIC EFFECTS/LATE STOCHASTIC EFFECTS

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  1. EARLY NONSTOCHASTIC EFFECTS/LATE STOCHASTIC EFFECTS Sherer Chapter 7 and 8 Reference: Bushong, Chapter 36 and 37

  2. Review of Dose response curves • Threshold • Non threshold • Linear quadratic non threshold curve • Non linear (s-shaped or sigmoid)

  3. Early, Nonstochastic Effects: • Soon after Rad. Exposure • minutes • hours • days • weeks • “x-ray burns”

  4. ACUTE RADIATION SYNDROMES • Total body exposure • acute exposure in a matter of minutes • 100’s or 1000’s of rads

  5. RADIATION AND MAMMALS • 200-1000 rads • 1000-10,000 rads • 10,000 + • Survive a few weeks • 3-4 days • few minutes

  6. FOUR STAGESTOTAL BODY IRRADIATION 1) PRODROMAL (NVD SYNDROME) 2)LATENT 3) MANIFEST ILLNESS 4) RECOVERY OR DEATH

  7. 1)Prodromal • Initial • can occur as low as 100 rads • within minutes with exposure to 1000 rads • nausea, vomiting, diarrhea (NVD)

  8. 2) Latent period • Weeks in low dose • Hours in high dose • pt appears symptom free • lethal effects or recovery is beginning

  9. 3) Manifest Illness A) Hematologic • Gastrointestinal • Cardiovascular • Cerebrovascular/ CNS • Bone Marrow

  10. A) HEMATOLOGIC • AKA: bone marrow or hemotopoietic syndrome • Rad exposure-low • Stages: • Prodromal (NVD) • Latent Mitotic stem cells are sterilized pancytopenia-diminished supply of blood cells Death due to dehydration, electrolyte imbalance infection

  11. B) GI syndrome • 600 rads(6 gy)-1000 rads (10 gy) • prodromal - one day • latent 3-5 days-deterioration of the lining of the GI tract has begun • manifest of illness • death ( dehydration, anorexia ) 3-4 days • cannot prevent progression of syndrome

  12. CARDIOVASCULAR • Not a syndrome • Decreased BP • Increased pulse rate • Acute myocardial insufficiency

  13. C) Cerebrovascular/CNS • 5000 RADS • Prodromal (nausea and vomiting) • latent period 6-12 hours • Death occurs within hours- to several days • GI and Hemopoietic syndrome occurring simultaneously

  14. L/D • LD 50/30 (Sherer), LD 50/60 (Bushong) • used in animals • humans tend to survive longer (Chernobyl) • see curve (figure 36-1) on page 519 of Bushong or LD curve on page 120 Sherer

  15. REPAIR? • Can occur with sublethal doses but dependent on cell or organ’s potential for recovery. • 10% of radiation induced damage - irreparable

  16. LOCAL TISSUE DAMAGE • High doses • atrophy of organ • Skin-many x-ray pioneers suffered x-ray burns to skin

  17. Skin layers • Subcutaneous • middle layer • outer layer (epidermis) • accessory structures • sensory • hair • sebaceous • sweat

  18. Erythema • 200 rad – within 24-48 hours • Desquamation at a higher dose • Hair loss –epilation-moderate dose • High level fluoroscopy studies-10-2Rmin

  19. A karyotype is • A) study of the genetics of cells • B) a new type of karaoke machine • C) a chromosome map • D) a chromosome aberration • Cytogenetic • Not!!! • Correct answer. Used for cytogenetic analysis • Structural damage

  20. Late Radiation effectsChapter 7 Months or years after whole or partial ARS OR Low doses sustained over a couple of years

  21. DOSE RESPONSE CURVES • LINEAR NON-THRESHOLD • NON LINEAR NON-THRESHOLD • LINEAR THRESHOLD • NONLINEAR THRESHOLD

  22. DOSE RESPONSE CURVES

  23. WHAT ARE THE THREE MAJOR TYPES OF LATE SOMATIC EFFECTS?

  24. RISK ESTIMATES • Low doses (below 10 rem) effect must be estimated • Risk still exists –controversial concept • Absolute risk –specific # of excess cancers will result due to exposure • Relative risk - # of excess cancers will increase as the natural incidence of cancer increases in the population with age

  25. Carcinogenesis • Distinguishing radiation induced cancer from low doses difficult. Why? • Epidemiologic studies from high doses are used. Examples include: • Radium watch dial painters • Uranium miners • Early Radiation workers • Infants treated with radiation for enlarged thymus • Children of Marshall Island • Japanese atomic bomb survivors • Evacuees from Chernobyl

  26. Match the pathology (can use more than once) • Radium dial workers • Uranium miners • Early Medical radiation workers • Infants treated for enlarged thymus • Children of Marshall Islands • Japanese atomic bomb survivors • Chernobyl • Thyroid • Leukemia • Breast cancer • Bone cancer • Skin cancer • Lung cancer

  27. EXTREMITIES • Amputations • radiodermatitis • shoe fluoroscopy • nuc med. techs

  28. LIFE SPAN SHORTENING • CATARCTOGENESIS • GENETIC EFFECTS

  29. American RT’s • Ongoing study of 146,000 RT’s • Higher risk of dying? • Higher risk of dying from leukemia? • Higher risk of dying from breast cancer? • When did these risks become less?

  30. GONADS • Highly sensitive • can pass on effects to future generations • animal studies/radiotherapy patients, radiation accident victims, convicts • oogonia • spermatogonia

  31. TESTES • 10 rad effect? • 200-250 rads effect? • 500-600 rads effect?

  32. OVARIES • 10 rad effect? • more sensitive in fetus /small children why? • 200 rad effect? • 500-625 rads compare this range with males why the difference?

  33. To Be continued • See power point entitled Chapter 8

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