UNIT 3: Early Tissue Reactions Flashcards
List the events/populations that provide evidence of early effects: Whole body doses
-Atomic Bomb Survivors
-Marshall islanders who were inadvertently subjected to high level of fallout during an Atomic bomb test in 1974
-Nuclear radiation accident victims, such as those injured in the 1986 chernobyl disaster
-Patients who have undergone radiation therapy
List the events/populations that provide evidence of early effects: Local tissue damage
An enourmous amount of radiation from high level fluoro cases and multiphase CT will cause those early effects
Genetic effects
effects upon future generations due to the irradiation of germ cells in previous generations
Somatic effects
divided into early and late effects
Threshold dose
● effect is only seen after dose is received to the tissues or whole body
● most early effects follow this mode
● local tissue effects such as skin, hair follicles, cataracts
● ARS
Non-Threshold Dose
any dose may cause the effect seen with some late effects
What is the dose/response graph?
A generalized graph for all early tissue effects
Label the dose/response graph (curve) of early tissue reactions: A, B, C
A. Severity of biological effect
B. Absorbed dose of ionizing radiation
C. Response to increasing absorbed dose
What are the 3 syndromes of ARS?
Hematopoietic, Gastrointestinal, Cerebrovascular
Hematopoietic Symptoms and Threshold
-Nausea; vomiting; diarrhea; decrease in number of red blood cells, white blood cells, and platelets in the circulating blood; hemorrhage; infection
- 1–10 Gy
Gastrointestinal Symptoms and Threshold
-Severe nausea, vomiting, diarrhea, fever, fatigue, loss of appetite, lethargy, anemia, leukopenia, hemorrhage, infection, electrolytic imbalance, and emaciation
- 6–10 Gy
Cerebrovascular Symptoms and Threshold
-Same as hematopoietic and gastrointestinal, plus excessive nervousness, confusion, lack of coordination, loss of vision, burning sensation of the skin, loss of consciousness, disorientation, shock, periods of agitation alternating with stupor, edema, loss of equilibrium, meningitis, prostration, respiratory distress, vasculitis, coma
- 50 Gy and above
List and define the 4 stages of ARS:
- Prodromal- initial signs and symptoms: Nausea, vomiting and diarrhea
- Latent period- symptoms fade
- Manifest illness – symptoms return with more intensity
- Recovery or death- exposed recovers or dies
Define LD’s
the % of deaths in a irradiated population/days
What does LD 50/30 mean?
Often used to express the lethality of radiation doses on experimental animals. 50% of animals will die in 30 days.
What does LD 50/60 mean?
Often used to express the lethality of radiation doses on humans. 50% of humans will die in 60 days.
List the LD 50/30 for adults without medical support
LD 50/30 for adult humans is estimated to be 3.0 to 4.0 Gyt without medical support
3 layers of the skin
-Epidermis, or outer, layer
-Dermis, or middle, layer composed of connective tissue
-Hypodermis, a subcutaneous layer of fat and connective tissue
What are the local skin effects?
Erythema, Moist and Dry Desquamations, Epilation (hair loss)
Erythema and its threshold dose
Redening of skin. A single absorbed dose of 2 Gyt can cause radiation-induced skin erythema within 24 to 48 hours after irradiation
Moist and dry Desquamation and its threshold dose
Shedding of the outer layer of skin, occurs at higher radiation doses. Desquamation generally manifests first as moist skin peeling, and then a dry skin flaking may develop. 18 Gy.
Epilation Symptoms and Threshold dose
Hair loss (also called alopecia), can be caused by exposure to radiation since hair follicles are growing tissue. Moderate doses of radiation generally produce temporary hair loss, whereas large radiation doses can result in permanent hair loss.
Temporary: 3Gyt
Permanent: 7 Gyt
Who is at risk for local skin effects during high dose fluoroscopy?
- Larger patients: Less possible SOD, Automatic Brightness Stabilization
- Drugs: Actinomycin D & Adriamycin
- Patients with Ataxia, Telangiectasia, Diabetes or Collagen vascular disease
- Previous fluoroscopic guided procedures
Early effects on reproductive systems and doses: Male and Female
-Males: Doses as low as 0.1 Gy can depress the male sperm population, and this same dose has the potential to cause genetic mutations in future generations
-Females: a gonadal dose of 0.1 Gy may delay or suppress menstruation
The hematopoietic system consists of:
Bone marrow, Circulating blood, Lymphoid organs (lymph nodes, spleen, and thymus gland)
Hematologic Effects
a whole-body radiation dose of 0.25 Gy would be required to produce a measurable hematologic depression. Such a dose could cause enough of a decrease in the number of lymphocyte in the blood to render the body vulnerable to infection by foreign invaders.
Cytogenetic effects
May be defined as the study of cell genetics with an emphasis on cell chromosomes. Metaphase is the phase of cell division in which chromosome damage caused by radiation exposure can be evaluated. Chromosome aberrations (deviation from normal development or growth of structures that contain genetic material) and chromatid aberrations have been observed at metaphase. Difficult to see at <100mGy. Multi-hit aberrations are more concerning for late effects. No known threshold.
List the possible effects after bone marrow and circulating blood receives a significant (cell killing) dose: Lymphocytes
The lymphocytes and the spermatogonia are the most radiosensitive cells in the body. Lymphocytes are reduced in number within minutes or hours after exposure, and they are very slow to recover.