radiation biology part 2 Flashcards
acute radiation syndrome
somatic short term deterministic effects
genetic effects short term deterministic effects
sterility
stochastic effects
still being determined
collection of signs and symptoms following acute whole-body radiation exposure
-info from animal experiments, patient therapeutic radiation exposures, atomic bombing and radiation accidents
acute radiation syndrome
sub lethal exposure of acute radiation syndrome
<2 G7 (200 Rads)
lethal exposure of acute radiation syndrome
~2-8 Gys (~200 to 800 Rads)
supralethal exposures of acute radiation
> 8 Gys (800 Rads)
higher dose, shorter latent period and
rapid onset of severe symptoms
acute radiation syndrome
1. prodromal period:
2. hematopoietic syndrome:
3. gastrointestinal syndrome:
4. central nervous system and cardiovascular syndrome (CNS/CNS syndrome):
- prodromal period: <200 R; <2 Gy
- hematopoietic syndrome: 200-1,000R; 2-10 Gy
- gastrointestinal syndrome:
1,000-10,000R; 10-100 Gy - central nervous system and cardiovascular syndrome (CNS/CNS syndrome):
>10,000R; >100 Gy
this is <2Gy (<200 Rads) and is a sub-lethal exposure
prodormal syndrome
shortly after exposure to whole-body radiation, an individual may develop
nausea
vomiting
diarrhea
anorexia
causes general malaise, fatigue, drowsiness and listlessness
prodormal syndrome
acute radiation syndrome lethal exposure range
~2-8 Gys
(~200 to 800 Rads)
acute radiation syndrome supralethal exposure
-short latent period and rapid onset on severe symptoms
> 8 Gys (>800 Rads)
irreversible injury to the proliferative capacity of the spleen and bone marrow with loss of circulating peripheral blood cells
hemopoietic syndrome
-infection from the lymphopenia and granulocytopenia
-hemorrhage from thrombocytopenia
-anemia from the erythrocytopenia
-death within 10-30 days
hemopoietic syndrome
-extensive damage to the GI system (in addition to the hemopoietic system)
-There is extensive injury to the rapidly proliferating basal epithelial cells of the intestinal villi which leads to atrophy and
ulceration.
gastrointestinal syndrome
-loss of plasma and electrolytes
-hemorrhage and ulceration
-diarrhea, dehydration, weight loss
-Infection
-Death in 3 - 5 days
gastrointestinal syndrome
-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.
cardiovascular and central nervous system syndrome
Combined surgical, radiation and chemotherapy
often provides the optimum treatment
radiation treatment to the oral cavity
Oral tissues are subjected to ____ doses of radiation during the treatment of malignant
tumors of the soft palate, tonsils, floor of the mouth, nasopharynx, and hypopharynx
(radiation treatments to the oral cavity)
high
Total radiation doses to treat malignant tumors ranges from= ______Rads or ____Gy
6,000-8,000 Rads or 60-80 Gy
dose for solid tumors=
60-80 Gy
dose for lymphomas
20-40 Gy
dose for intraoral cancer
50 Gy
1Gy= ____uSv
1 million
single intraoral: ___uSv
FMX (20 images: ___uSv
panoramic radiograph: ___uSv
1.3
35
9
which provides greater tumor destruction?
1. fractionation of the total dose into multiple small doses
or
2. single large dose
- fractionation of the total dose into multiple small doses
this increases cellular repair of the normal tissues
fractionation
radiation effects on the oral cavity
mucosa
taste buds
salivary glands
teeth
bone
muscle
mucosa:
- mucositis
- 20 infections
taste buds:
-loss of taste
salivary glands:
-xerostomia
teeth:
-radiation caries
bone:
-osteoradionecrosis
muscle:
-fibrosis
recovery of taste
sensitivity will occur in
_______following
treatment
2-4 months
Epithelial atrophy,
xerostomia and
mucositis all result in
loss of taste
(hypoguesia) by the
taste buds
hypoguesia
by 2nd-3rd week of treatment
salivary glands:
There is marked and
progressive loss of
salivary secretion
____ are very resistant to the direct effects of radiation exposure
adult teeth
radiation does not increase the solubility of teeth
There is no discernible effect on the crystalline
structure of enamel, dentin, or cementum
T/F
true
When teeth are irradiated during the
developmental stage, their growth may be:
If the radiation precedes calcification, the
tooth bud may:
Irradiation after initiation of calcification,
teeth may demonstrate ______ and
arresting general growth
severely retarded
may be destroyed
malformations
Generally, if some portion of the salivary gland
has been spared, the dryness of the mouth
subsides in
However, xerostomia may persist without any
significant return of salivation
6 months to year
______ are often exposed
unavoidably to radiation during treatment
for carcinoma of the oral cavity or
oropharynx
Major salivary glands
_____________(especially of the parotid
glands) are very sensitive to X-rays and are
replaced by fibrosis and adiposis with
parenchymal degeneration and loss of fine
vasculature
parenchymal cells
The ________ makes the mouth dry
(xerostomia) and tender. Swallowing is difficult
and painful
scanty saliva
The residual saliva has a ___pH which is _____ enough to inititate decalcification of enamel
lowered pH
(from 6.5 to 5.5)
acidic enough
buffering capacity of saliva is reduced from
40-45%
Children may show defects in the permanent
dentition, such as retarded root development,
dwarfed teeth, or failure to form one or more
teeth.
dose as low as _____at the age of 5 months has been reported to cause hypoplasia of enamel
200R
Although irradiation may retard or abort tooth
formation, the eruptive mechanism is much
more _______
* Irradiated teeth with altered root formation
will ______
radiation resistant
still erupt
A rampant form of decay that may affect
individuals who received a course of
radiation therapy that include exposure of
the salivary glands
radiation caries
The primary damage to bone is from irradiation to
– fine vasculature
– marrow – affecting vascular and hemopoietic elements.
bone Osteoradionecrosis
in bone osteoradionecrosis, primary damage to bone is from irradiation to
- fine vasculature
- marrow – affecting vascular and hemopoietic
elements
inflammation and fibrosis – results in contracture and
trismus in the muscles
musculature
radiation effects in oral tissues
