Ch. 8 Flashcards
Somatic and Genetic (Hereditary) Damage Factors:
The 1 of ionizing radiation to which subject is exposed.
Ability of ionizing radiation to cause ionization of 2.
Amount of body 3 exposed.
Specific __4__ exposed.
1) Quantity
2) Human Tissue
3) Area
4) Parts
Ionizing radiation produces greatest amount of biologic damage when a large dose of densely ionizing (__) radiation is delivered to a large or radiosensitive area of the body.
High LET (Linear Energy Transfer)
1 effects occur when living organisms (ex: humans) experience biologic damage from exposure to radiation. Either classified as 2 or 3.
1) Somatic Effects
2) Early Somatic
3) Late Somatic
Somatic Effects: If the consequences include cell killing and are 1 related to dose received, they are called 2 SOMATIC EFFECTS (formerly called 3)
1) DIRECTLY
2) Deterministic
3) Nonstochastic Somatic Effects
Somatic Effects: As radiation dose increases, severity of early deterministic effects ___.
1) Increase
Somatic Effects: These results have a __, which is a point at which they begin to appear and below which they are absent. Amount of damage depends on actual dose.
Threshold
Early Deterministic Somatic Effects: These effects depend on the __ of exposure and appear within minutes, hours, days, or weeks.
Time
Early Deterministic Somatic Effects: The higher the dose, the __ the appearance of effects.
Earlier
Early Deterministic Somatic Effects: With the exception of certain lengthy high-dose-rate fluoro procedures (HLCF=20 R/min. tabletop), diagnostic imaging does _ usually impose doses sufficient to cause early deterministic effects, so they are of little consequences to us.
NOT
Possible high dose consequences: nausea, fatigue, 1 (skin reddening), 2 (hair loss), blood disorders, dry and moist desquamation, depressed sperm count, temporary or permanent 3.
1) Erythema
2) Epilation
3) Sterility
1= whole body dose. Data from Atomic Bomb survivors in Hiroshima and Nafasaki, Japan; Marshall Islanders;Chernobyl victims; radiation therapy pts.
Acute Radiation Syndrome (ARS
Divisions of ARS (the higher the dose, the __ the Latent Period)
SHORTER
1-10 Gy (100-1000 Rads)= 1 Syndrome. May die within 6-8 wks due to decreased # of RBC, WBC, and Platelets causing destruction of 2 system.
1) Hematopoietic -Sydrome
2) Immune System
10-50 Gy (1000-5000 Rads)= 1 Syndrome. May die within 3-10 days due to catastrophic damage to epithelial cells that line the 2 tract.
1) Gastrointestinal Syndrome
2) Intestinal Tract
50 Gy+ (5000 Rads +)= 1 Syndrome. May die within a few hours to 2-3 days due to failure of CNS and CV systems from excessive 2 resulting in increased cranial pressure.
1) Cerebrovascular (CNS)
Response Stages of ARS:
1 or initial stage= occurs within hours after whole body exposure of 1 Gy (100 Rads). Includes nausea, vomiting, diarrhea, fatigue, leukopenia. Severity of symptoms is dose related.
2 Period= occurs app 1 wk after Prodromal Stage when NO symptoms are visible.
3 Illness= when signs and symptoms become visible.
4 or Recovery= Recovery may occue in app 3 mths, but pt may experience long term effects of radiation.
1) Prodromal
2) Latent
3) Manifest
4) Death
ARS from 1 and from 2 both provide data for radiobiologists to study.
1) Chernobyl Nuclear Power Plant Accident on 4/26/86
2) Hiroshima and Nagasaki Japan bombings in 1945
Lethal Dose 50/30 (1)= this is whole body dose of radiation that can be lethal to 2 of the exposed population within 3 days. Range of 3-4 Gy (300-400 Rads) The LD 50/0 is the same range.
1) LD 50/30
2) 50 %
3) 30 days
____- occurs when cells are exposed to SUBLETHAL doses radiation. App 1 of radiation induced damage is irreparable, whereas 2 is able to be repaired, even though some permanent damage may occur.
Repair and Recovery
1) 10%
2) 90%
____- significant cell death may lead to the shrinkage of organs or tissue, which is known as 1, which can affect their function. Exposure response depends on A, B, C.
Local Tissue Damage 1) Atrophy A) Radiosensitivity B) Reproductive Characteristics C) Growth Rate
Exs of tissues that suffer immediate consequences after high doses include the 1, 2, 3.
1) Skin
2) Male and Female Reproductive Organs
3) Bone Marrow
Skin Damage= Radiodermatitis (1) suffered by early dentists and radiologists; 2 or shedding of the outer layer of skin (moist or dry); 3 or “hair loss” (AKA apolecia). Some diseases were treated with 4 Rays of 10-20 kVp such as ringworm and it often lead to diffuse radness of the skin or 5. The use of 6 for extended periods of time can result in skin injury. NCRP says tabletop dose for routine fluoro can’t exceed 10 R/min, and 20 R/min for HLCF.
1) Significant Reddening of the skin
2) Desquamation
3) Epilation
4) B. Grenz Rays
5) Erythema
6) HIGH LEVEL CONTROL FLUOROSCOPY (HLCF)
Repro System Damage= doses as low as 0.1 Gy (10 Rad) can depress the sperm count and delay or suppress menstruation. TEMPORARY STERILITY (for up to 12mths) may occur from a dose of 1 to the testes or ovaries, with PERMANENT STERILITY occurring at 2.
1) 2 Gy (200 Rads)
2) 5-6 Gy (500-600 Rads)
Hematologic Effects- a whole body dose as low as 1 may cause measurable hematologic depression and depress the immune system and causing Anemia. Personnel monitoring in the 2 consisted of periodic blood testing.
1) 0.25 Gy (25 Rads)
2) 1920s and 1930s
___- the study of cell genetics with an emphasis on cell chromosomes.
Cytogentics
___- a chromosome “map” that is a photomicrograph taken of the cell nucleus during METAPHASE to demonstrate each chromosome.
Karotype
Cells are most sensitive to radiation damage during ___- can cause chromosome and chromatid aberrations.
METAPHASE
1 of damage is from the INDIRECT and 2 from DIRECT.
1) 95 %
2) 5 %
