Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
118 Cards in this Set
- Front
- Back
|
What does the term linear mean?
|
The dose and response are dependent on each other: the relationship is directly proportional.
|
|
|
What does the term threshold mean?
|
There is a safe dose until a certain point.
|
|
|
What are the four basic types of dose response relationships?
|
Linear threshold, linear non-threshold, nonlinear threshold and nonlinear non-threshold
|
|
|
What is linear threshold
|
The particular threshold will be proportional at one point
|
|
|
What is linear non-threshold
|
There is no safe dose. Response increases proportionately to dose.
|
|
|
What is nonlinear threshold
|
There is a safe dose. Response and dose do not increase proportionately
|
|
|
What is nonlinear non-threshold
|
There is no safe dose and no relationship between response and dose.
|
|
|
What dose response to relationships does diagnostic radiology follow
|
Linear non-threshold
|
|
|
What are the early and late biological effects of radiation
|
Genetic and somatic, indirect and direct, stochastic and non-stochastic
|
|
|
What is somatic?
|
happens to the body
|
|
|
what is genetic
|
effects the offspring
|
|
|
what is direct
|
only effects the part exposed
|
|
|
what is indirect
|
goes through a medium
|
|
|
What is stochastic?
|
The probability of the effect occurring depends on the amount of radiation dose
|
|
|
What is non-stochastic?
|
Those effects for which the severity of the effect in the exposed individual increases as the radiation dose increases, *also called deterministic effects.
|
|
|
What is the indirect effect of radiation on the body
|
Radiolysis of water
|
|
|
What is the equation for radiolysis of water?
|
H2O + proton = HOH+ + e-
|
|
|
What are the two possible results of the radiolysis of water?
|
Water disassociates - either returns as water molecule (no damage) OR water molecule does not rejoin & becomes the water molecule with a positive charge (HOH+) & an electron (e-) which will now be able to join with another water molecule to become HOH-. Positive water molecule (HOH+) & the negative water molecule (HOH-) will break apart into smaller molecules. (HOH+) becomes a hydrogen ion (H+) and a hydroxyl radical (OH*) and (HOH-) becomes a hydroxyl ion (OH-) and a hydrogen radical (H*).
|
|
|
What is a free radical?
|
A solitary atom or most often a combination of atoms that behave as an extremely reactive single entity as a result of the presence of an unpaired electron. A configuration of one or more atoms having an unpaired electron but no net electrical charge. This object is highly reactive b/c the unpaired electron will pair up with another electron even if it has to break a chemical bond to do so.
|
|
|
What are the five radiation responses to DNA?
|
Single-break strand (main chain scission with only one side rail severed), double strand break (main chain scission with both side rails severed), rung breakage (whole chromosome breaks and causes separation of bases), a change or loss of base, and main-chain scission and subsequent cross linking (exchange of information may occur)
|
|
|
What is a karyotype?
|
Instrument to compare chromosomes.
|
|
|
What are the seven biological effects radiation has on chromosomes?
|
Single strand break in a chromosome, single strand break in a chromatid, single strand break in separate chromosomes, a strand break in separate chromatids, more than one break in the same chromosome, more than one break in the same chromatid, chromosome stickiness or clumping together
|
|
|
What is the target theory?
|
There are sensitive critical molecules that are essential to cell survival and that radiation to these cells will result in cell death, supports idea that DNA and chromosomes interchange material
|
|
|
What is reciprocal translocation?
|
An alteration of chromosomes where two chromosomes interchange material.
|
|
|
What are the seven cellular effects of radiation?
|
Instant death, reproductive death, interphases death (apoptosis), mitotic death, mitotic delay, interference of function and chromosome breakage.
|
|
|
What does the term linear mean?
|
The dose and response are dependent on each other: the relationship is directly proportional.
|
|
|
What does the term threshold mean?
|
There is a safe dose until a certain point.
|
|
|
What are the four basic types of dose response relationships?
|
Linear threshold, linear non-threshold, nonlinear threshold and nonlinear non-threshold
|
|
|
What is linear threshold
|
The particular threshold will be proportional at one point
|
|
|
What is linear non-threshold
|
There is no safe dose. Response increases proportionately to dose.
|
|
|
What are the seven early effects of radiation?
|
Erythema, epilation, acute radiation syndrome, chromosome aberration, gonadal dysfunction, hematologic depression and death.
|
|
|
When do the early effects occur?
|
within a month
|
|
|
What is erythema and what is the dose response to relationships
|
reddening of the skin; linear threshold
|
|
|
What is epilation and what is the dose response to relationships?
|
Hair loss, linear threshold
|
|
|
What is the dose response to relationships for acute radiation syndrome
|
Non-linear nonthreshold
|
|
|
What is prodromal syndrome
|
Immediate response
|
|
|
What is the dose for hematologic syndrome
|
100-1000 rads
|
|
|
What is the prodromal syndrome for the hematologic syndrome
|
Happens in a few hours
|
|
|
What is the latent period for the hematologic syndrome?
|
4 weeks
|
|
|
What is the manifest illness stage for hematologic syndrome
|
Vomiting, mild diarrhea, lethargy, and fever
|
|
|
What is the recovery for hematologic syndrome
|
2-4 weeks or as long as 6 months
|
|
|
What is the dose for gastrointestinal syndrome?
|
600-1000 rads
|
|
|
What is the prodromal syndrome for gastrointestinal syndrome?
|
Vomiting and diarrhea within hours as long as 24 hours
|
|
|
What is the latent period for gastrointestinal syndrome
|
3-5 days
|
|
|
What is the manifest illness stage for gastrointestinal syndrome
|
Second wave of nausea and vomiting, loss of appetite and lethargic.
|
|
|
What is the recovery for gastrointestinal syndrome
|
3-10 days in which death will occur
|
|
|
What is the dose of the cerebrovascular (CNS and cardiovascular system) syndrome
|
5000 rads or more
|
|
|
What is the prodromal syndrome for the cerebrovascular syndrome
|
Hours to 3 days. Vomiting, diarrhea, nervousness and confusion
|
|
|
What is the latent period of the cerebrovascular syndrome
|
12 hours
|
|
|
What is the manifest illness stage for the cerebrovascular syndrome
|
Symptoms of prodromal return but more severe possibility of convulsion and seizures
|
|
|
What is the recovery of the cerebrovascular syndrome?
|
No recovery time, death occurs
|
|
|
What is the dose response to relationships for chromosome aberration?
|
Nonlinear non-threshold
|
|
|
What are the six late effects of radiation?
|
Chromosome aberration; change in skin; cataracts; life span shortening; radiation induced malignancies and infertility
|
|
|
When do the late effects occur?
|
Beyond a month to years
|
|
|
What can a change in skin also be
|
erythema
|
|
|
What do cataracts effect
|
eyes
|
|
|
What is the dose response to relationships for cataracts
|
nonlinear threshold
|
|
|
What is the dose response to relationships for life span shortening
|
Linear non threshold
|
|
|
What are the expected days of life lost as a radiation worker
|
12 days
|
|
|
What are the six radiation induced malignancies
|
Leukemia, skin cancer, thyroid cancer, breast cancer, lung cancer, and bone cancer
|
|
|
What is the dose response to relationships for leukemia?
|
Linear non-threshold
|
|
|
What is the dose response to relationships for skin cancer
|
Linear threshold
|
|
|
What is the dose response to relationships for thyroid cancer
|
Linear non-threshold
|
|
|
What is the dose response to relationships for breast cancer
|
Linear threshold
|
|
|
What is the dose response to relationships for lung cancer
|
Linear threshold
|
|
|
What is the dose response to relationships for bone cancer
|
Linear quadratic
|
|
|
What is the dose response to relationships for infertility
|
Linear non-threshold
|
|
|
what diseases to dose response are linear threshold?
|
lung cancer, breast cancer, skin cancer,
|
|
|
what diseases are dose response linear nonthreshold?
|
infertility, thyroid cancer, leukemia
|
|
|
What is doubling dose
|
The dose of radiation expected to double the number of genetic mutations in a generation
|
|
|
What are the laws proposed to determine radiosensitivity?
|
Law of Bergonie and Tribondeau
|
|
|
What are the four laws of Bergonie and Tribondeau?
|
1. Stem cells (immature cells) are radiosensitive than mature cells;2. younger tissue and organs are more radiosensitive than older tissue and organs; 3. the higher the metabolic activity in a cell the more radiosensitive it is; 4. the greater the proliferation rate the greater the radiosensitivity.
|
|
|
What are two terms that refer to being less likely damaged by radiation
|
Radiation resistance and radiation nonsensitivity
|
|
|
What are the three gestation stages and what occurs in each
|
1. Preimplantation (fertilized ovum divides and forms a ball like structure containing undifferentiated cells; 0-9 days), 2. organogenesis (undifferentiated cells differentiate into organs, abnormalities in the fetus cause neonatal death 10 days–6 weeks);3. and fetal (last stage 6 weeks to term
|
|
|
What is the most radiosensitive phase of gestation
|
Organogenesis
|
|
|
When is the first trimester of pregnancy
|
First three months
|
|
|
What is the most radiosensitive part of the cell cycle
|
Mitosis
|
|
|
define radiosensitive
|
sensitive to x-rays and other radiant energy
|
|
|
What is the most radiononsensitve part of the cell cycle
|
S phase of interphase
|
|
|
What are the most radiosensitive blood cells
|
White blood cells
|
|
|
What is the most radiosensitive white blood cell
|
Lymphocytes
|
|
|
What are the four physical factors effecting radiosensitivity
|
1. LET (linear electric transfer) 2. RBE (ratio biologic effect), 3. proteaction, 4. fractionation
|
|
|
What is LET
|
Linear electric transfer - measure at which energy is transferred from ionizing radiation to soft tissue
|
|
|
What is LET measured in
|
keV/micrometer
|
|
|
What does a high LET mean
|
high response
|
|
|
What is the LET of diagnostic radiology
|
3 keV/micrometer
|
|
|
What is RBE?
|
Relative biologic effectiveness; ratio of dose of standard radiation necessary to produce a given effect to the dose of test radiation needed for that same effect
|
|
|
What is the formula for RBE
|
Reference radiation ÷ test radiation = RBE
|
|
|
What is fractionation
|
Radiation dose given as the same dose in equal intervals
|
|
|
What is protraction
|
Administration of dose delivered continuously over a relatively long period at a relatively low dosage
|
|
|
What are the five biological factors affecting radiosensitivity
|
OER, age, recovery, chemical agents, and hormesis
|
|
|
What is OER
|
Oxygen enhancement ratio – ratio of radiation dose required causing a particular biological response of cells or organisms in an oxygen deprived environment to the radiation dose required to cause an identical response under normal oxygenated conditions.
|
|
|
What is the formula for OER
|
Without oxygen ÷ with oxygen = OER
|
|
|
How does age affect radiosensitivity
|
Radiosensitivity is higher when younger, stabilizes in adult years and in the later years (elderly) of life it increases again.
|
|
|
What do the radiosensitizers do
|
Increases sensitivity/ make more radiosensitive
|
|
|
What is hormesis
|
A theoretical phenomenon of dose-response relationships in which something (as a heavy metal or ionizing radiation) that produces harmful biological effects at moderate to high doses may produce beneficial effects at low doses./ a little radiation is okay
|
|
|
What is the formula for radiolysis of water?
|
H2O + proton = HOH+ + e-
|
|
|
What is LET
|
amount of energy deposited by radiation per length of tissue
|
|
|
What is RBE?
|
ability to produce biologic damage
|
|
|
Define threshold dose
|
the dose that is just below lethal dose
|
|
|
what dose-response relationship is used for diagnostic x-rays?
|
linear non-threshold
|
|
|
what are the major types of biologic effects?
|
early or late & stochastic or non-stochastic
|
|
|
define reciprocal translocation
|
a chromosome abberation where genes have been rearranged
|
|
|
what are the things that can happen to a cell when it is irradiated?
|
nothing, damage but damage is temporary, or cell death
|
|
|
what is an abberation?
|
deviation from normal development or growth/ a break or change in a chromosome
|
|
|
what are the differences b/t stochastic and non-stochastic
|
Stochastic deals with probability and non-stochastic deals with severity
|
|
|
what is acute radiation syndrome?
|
radiation sickness that occurs in humans after whole body reception of large doses of ionizing radiation (1Gy [100 rads] or more) are delivered over a short period of time
|
|
|
which type of blood cells (specific) are the most radiosensitive?
|
lymphocytes
|
|
|
which is NOT a form of acute radiation syndrome? 1. carcinogenic, 2.hematopietic, 3. gastrointestinal, 4. cerebrovascular
|
carcinogenic syndrome
|
|
|
the term ld 50/30 refers to?
|
50% of the population killed in 30 days
|
|
|
radiation induced cataracts in humans follow______ dose response relationship
|
nonlinear, threshold
|
|
|
the prodromal stage of acute radiation syndrome is also referred to as the ?
|
initial stage
|
|
|
a protracted dose of radiation is given
|
over a long period of time
|
|
|
humans are most radiosensitive during?
|
fetal stages
|
|
|
radiation induced genetic damage follows a ______ dose-response relationship
|
linear nonthreshold
|
|
|
skin effects from localized doses of radiation follow a ______dose-response relationship
|
linear threshold
|
|
|
the theory of radiation hormesis suggests that radiation doses below 10 rads are
|
beneficial
|
|
|
which action of ionizing radiation is most harmful to the human body?
|
direct action
|
