Radiation Biology Part 2 Flashcards
what is acute radiation syndrome
- a collection of signs and symptoms following acute whole body radiation exposure
how is acute radiation syndrome recorded
- animal experiments
- patient therapeutic radiation exposures
- atomic bombings
- radiation accidents
what is sub lethal exposure considered
less than 2 Gy - 200 rads
what is lethal exposure considered
~2-8 Gys - 200-800 rads
what is supralethal exposure considered
more than 8 Gys- 800 rads
higher dose, ____ latent period and _____ onset of severe symptoms
shorter; rapid
what are the stages of acute radiation syndrome
- prodromal period
- hematopoietic syndrome
- gastrointestinal syndrome
- central nervous system and cardiovascular syndrome
describe the prodromal syndrome
- less than 2 Gy or less than 200 rads
- sub lethal exposure
- shortly after exposure to whole body radiation individual might develop nausea, vomiting, diarrhea, anorexia, malaise, fatigue, drowsiness and listlessness
- symptoms resolve after several weeks
describe hemopoietic syndrome
- 2-10 Gy or 200-1,000 rads
- irreversible injury to the proliferative capacity of the spleen and bone marrow with loss of circulating peripheral blood cells
- infection from the lymphopenia and granulocytopenia
- hemorrhage from thrombocytopenia
- anemia from the erythrocytopenia
- death within 10-30 days
describe gastrointestinal syndrome
- 100-100 Gy or 1,000-10,000 rads
- extensive damage to the GI system and hemopoietic system
- extensive injury to the rapidly proliferating basal epithelial cells of the intestinal villi which leads to atrophy and ulceration
- loss of plasma and electrolytes
- hemorrhage and ulceration
- diarrhea, dehydration and weight loss
- infection
- death in 3-5 days
describe cardiovascular and central nervous system syndrome
more than 100 Gy or 10,000 rads
- radiation induced damage to neurons and fine vasculature of brain
- intermittent stupor, incoordination, disorientation and convulsions from extensive CNS damage
- irreversible damage with death in a few minutes to 48 hours
when are radiation treatments to the oral cavity done
surgical, radiation and chemotherapy
oral tissues are subjected to high doses of radiation during treatment of malignant tumors of:
the soft palate, tonsils, floor of mouth, nasopharynx, and hypopharynx
what are the total radiation doses to treat malignant tumors
6,000- 8,000 rads
what is the dose for solid tumors, lymphomas and intraoral cancer
- solid tumor: 60-80 Gy
- lymphomas 20-40 Gy
- intraoral cancer: 50 Gy
1 Gy = ______ micro Sv
1 million
what is the dose for FMX
3.5 microSv
what is the dose for single intraoral radiograph
1.3 micro SV
what is the dose for panoramic radiograph
9 micro Sv
describe fractionation
- fractionation of the total dose into multiple small doses provides greater tumor destruction than a single large dose
- also increases cellular repair of the normal tissues
what are the effects of radiation on the. mucosa
- mucositis
- secondary infections
what are the effects of radiation on the taste buds
loss of taste
- epithelial atrophy by 2nd-3rd week of treatment
- recovery of taste will occur 2-4 months following treatment
what are the effects of radiation on the salivary glands
xerostomia
- if a portion of the salivary gland has been spared, dryness subsides in 6 months to 1 year
what are the effects of radiation on bone
osteoradionecrosis
