Chapter 8: Early Tissue Reactions and Their Effects on Organ Systems Flashcards
Biologic effects of radiation that occur relatively soon after humans receive high doses of ionizing radiation (alpha, beta)
Early Effects
Not common in diagnostic imaging
Early Effects
Substantial evidence of the consequences of such effects comes from numerous laboratory animal studies and data from observation of some irradiated human populations
Early Effects
Produced by a substantial dose of ionizing radiation
Early Effects
Biologic effects of radiation that occur relatively soon after humans receive high doses of ionizing radiation
Substantial evidence of the consequences of such effects comes from numerous laboratory animal studies and data from observation of some irradiated human populations
Not common in diagnostic imaging
Produced by a substantial dose of ionizing radiation
Early Effects
The term somatic originates from the Greek term “soma” meaning
body
are effects upon the body that was irradiated
somatic effects
are effects upon future generations
Genetic effects
are effects upon future generations because of irradiation of germ cells in previous generations
Genetic effects
Biologic damage sustained by living organisms (such as humans) as a consequence of exposure to ionizing radiation
Somatic Effects
Depending upon the length of time from the moment of irradiation to the first appearance of symptoms of radiation damage, the effects are classified as either:
Early somatic effects
Late somatic effects
Vary depending on the duration of time after exposure to ionizing radiation
Early Tissue Reactions
a point at which they begin to appear and below which they are absent
These results have a threshold,
As the radiation dose increase
the severity of these effects also increase
The amount of biologic damage depends on the
actual absorbed dose of ionizing radiation
Vary depending on the duration of time after exposure to ionizing radiation
As the radiation dose increases, the severity of these effects also increases.
These results have a threshold, a point at which they begin to appear and below which they are absent.
The amount of biologic damage depends on the actual absorbed dose of ionizing radiation.
Early Tissue Reactions
If the consequences include cell killing and are directly related to the dose received, they are
somatic tissue reactions
Appear within minutes, hours, days, or weeks of the time of radiation exposure
Early tissue reactions
Requires a substantial dose of ionizing radiation to produce these biologic changes soon after irradiation
Early Tissue Reactions
With the exception of certain lengthy high-dose-rate procedures, diagnostic imaging examinations do not usually impose radiation doses sufficient to cause early tissue reactions
True or False
True
Early Tissue Reactions
Early tissue reactions are caused by
cell death
High-dose effects include:
- Nausea
- Fatigue
- Erythema (diffuse redness over an area of skin after irradiation)
- Epilation (loss of hair)
- Blood disorders
- Intestinal disorders
- Fever
- Dry and moist desquamation (shedding of the outer layer of skin)
- Depressed sperm count in the male
- Temporary or permanent sterility in the male and female
- Injury to the central nervous system (at extremely high radiation doses)
diffuse redness over an area of skin after irradiation
Erythema
loss of hair
Epilation
shedding of the outer layer of skin
Dry and moist desquamation
at extremely high radiation doses
Injury to the central nervous system
Whole-body dose of 6 Gyt can result in
many of these manifestations or organic damage occurring in succession (acute radiation syndrome).
The various types of organic damage may be related to
the cellular effects
intestinal disorders are caused by damage to the sensitive epithelial tissue
lining the intestines
- High-dose effects include nausea, fatigue, erythema, epilation, blood disorders, intestinal disorders, fever, dry and moist desquamation, depressed sperm count in the male, temporary or permanent sterility in the male and female, and injury to the central nervous system (at extremely high radiation doses)
.Whole-body dose of 6 Gyt can result in many of these manifestations or organic damage occurring in succession (acute radiation syndrome)
Early Tissue Reactions
Radiation sickness
Acute radiation syndrome (ARS)
Occurs in humans after whole-body reception of large doses of ionizing radiation delivered over a short period of time (from several hours to a few days).
Acute radiation syndrome (ARS)
Data from epidemiologic studies of human populations exposed to doses of ionizing radiation sufficient to cause ARS have been obtained from:
- Atomic bomb survivors of Hiroshima and Nagasaki
- Marshall Islanders who were inadvertently subjected to high levels of fallout during an atomic bomb test in 1954
- Nuclear radiation accident victims, such as those injured in the 1986 Chernobyl disaster
- Patients who have undergone radiation therapy
is the medical term that defines a collection of symptoms
Syndrome
is a collection of symptoms associated with high-level radiation exposure
Acute radiation syndrome (ARS)
Three separate dose-related syndromes occur as part of the total-body syndrome
Acute radiation syndrome (ARS)
Three separate dose-related syndromes or conditions occur as part of the acute radiation syndrome:
- Hematopoietic syndrome
- Gastrointestinal syndrome
- Cerebrovascular syndrome
known as “bone marrow syndrome,”
- most radiation sensitive out of the 3
Hematopoietic syndrome
occurs when people receive whole-body doses of ionizing radiation ranging from 1 to 10 Gyt
Hematopoietic syndrome
manufactures the corpuscular elements of the blood and is the most radiosensitive vital organ system in humans
The hematopoietic system
Radiation exposure causes the number of red blood cells, white blood cells, and platelets in the circulating blood to decrease
Hematopoietic syndrome
Dose levels that produce this syndrome may also damage cells in other organ systems and cause the affected organ or organ system to fail
Hematopoietic syndrome
For persons with hematopoietic syndrome, survival time shortens as the
radiation dose increases
Because bone marrow cells are being destroyed, the body becomes more susceptible to infection (mostly from its intestinal bacteria) and more prone to hemorrhage
hematopoietic syndrome
because of excessive bone marrow destruction causing anemia and little or no resistance to severe infection.
death occurs
Death may occur 6 to 8 weeks after irradiation in some susceptible human subjects who receive a whole-body dose just exceeding
2 Gyt
as the whole-body dose increases from 2 to 10 Gyt, all irradiated individuals will die and in a
shorter period
If the radiation exposure is, however, in the range of 1 to 2 Gyt, bone marrow cells will eventually
repopulate to a level adequate to support life in most individuals. Many of these people recover from 3 weeks to 6 months after irradiation.
Survival probability of patients with hematopoietic syndrome is enhanced by
intense supportive care and special hematologic procedures
benefited from bone marrow transplants is not an absolute cure for patients with because many individuals undergoing bone marrow transplant die of burns or other radiation-induced damage they sustained before the transplanted stem cells have had a chance to support recovery.
hematopoietic syndrome
*From 1 to 10 Gyt
*Damage to the body
*Outcome
- once you get to 5 and 10 GYt with no medical attention you have death
- bone marrow transplant are not always a cure but does help
Hematopoietic syndrome (bone marrow syndrome)
The irradiated person’s general state of health at the time of irradiation strongly influences the possibility of
recovery
appears at a threshold dose of approximately 6 Gyt and peaks after a dose of 10 Gyt.
Gastrointestinal syndrome.
Without medical support to sustain life, exposed persons receiving doses of 6 to 10 Gyt may die if not medically treated within how many days
3 to 10 days after being exposed.
Even if medical assistance is provided, the exposed person will live only a few days longer. Survival time does not change with dose in this syndrome.
Gastrointestinal syndrome
minutes, hours, days and couple weeks
Early Tissue reactions
considered days, week, and minutes what kind of somatic effect
early somatic effects
considered months, years what kind of somatic effects?
late somatic effects
- no tolerance to radiation
- going to have biological damage
Threshold or Non threshold
Non threshold
Up to a certain point radiation is okay until it reaches a certain number / point then you are going to start seeing biological damage
Threshold or Non threshold
Threshold
repeated radiation injuries is considered a
cumulative dose
is the medical term that defines a collection of symptoms
Syndrome