Effects of long-term Exposure to Radiation Ch. 5
Neuroblasts
Embryonic nerve cells
Parenchymal
Essential life-sustaining cells
Absolute risk model
Estimates a continual increase in risk, independent of the age-specific cancer risk at time of exposure
Zygote
Fertilized egg
Which of the following is considered the most radiosensitive?
Fetus
Cavity
Follicular
Decrease the intensity of the primary beam by 50%
Half-value Layer (HVL) is defined as the thickness of a designated absorber required to
2.5 mm Al
How much total filtration is required when using over 70 kVp?
Carcinoma
A growth or tumor
Fibrosis
Abnormal formation of fibrous tissue
0.11
Absolute risk for radiation induced osteosarcoma is ___________ cases/one million persons/rad/year
Number of cases/one million persons/rad/year
Absolute risk states risk in terms of
Genetically significant dose (GSD)
An average calculated from the gonadal dose received by the entire population and used to determine the genetic influence of low dose to whole population
Accurate and effective positioning
An effective way of reducing patient dose is through
Total dose and rate of dose, quality of radiation, and/or stage of development
An embryo's response to irradiation depends upon following:
Turner's Syndrome
An endocrine disorder caused by the failure of the ovaries to respond to pituitary hormone stimulation
4-7 years
Approximate latent period for radiation induced leukemia?
Osteosarcoma
Bone cancer
Epidemiology
Branch of medical science that deals with incidence, distribution and control of a disease
Leukemia
Cancer of blood-forming cells in bone marrow
Carcinogenic
Cancer-causing
BEIR
Committee on the Biological Effects of Ionizing Radiation
Which of the following is most likely to follow irradiation in utero if the radiation is received during the organogenesis stage?
Congenital abnormalities
Nonstochastic
Deterministic
Doubling dose
Dose of radiation required per generation to double the spontaneous mutation rate:
Congenital abnormalities
If radiated during organogenesis, which is most likely to occur?
ankylosing spondylitis
Immobility of the vertebrae
Use an immobilization device
In order to reduce the possibility of voluntary patient motion, the radiographer should:
The type of dose-response relationship demonstrated by human lethality is:
Linear, nonthreshold
Hypoxic
Low levels of oxygen
Lymphoid
Lymph tissue
Myeloid
Marrow
Relative or multiplicative risk model
Model explains how age at the time of radiation exposure may influence cancer risk estimate
What is the minimum radiation level below which no genetic or somatic damage would occur?
No minimum level exists
Benign
Nonprogressive
Stochastic
Occurring randomly in nature
Progeny
Offspring
Elective scheduling
One way to ensure against irradiating a woman in the early stages of pregnancy is to institute
Linear Quadratic
Osteosarcoma follows which dose response relationship?
Nipple-like protrusion
Papillary
High speed film is used with high speed screens
Patient dose decreases when
High-speed radiographic film is used in combination with high-speed intensifying screens
Patient dose decreases when:
Epidemiology is defined as the study of:
Populations
Atomic Bomb survivors, medically exposed patients, and/or occupationally exposed personnel
Populations that are used as sources of data on the incidence of radiation induced cancer
malignant
Progressive, threatening
Linear, nonthreshold
Radiation induced leukemia is judged to be:
Linear, nonthreshold
Radiation induced lung cancer follows which dose response relationship
Leukemia, Skin cancer, thyroid cancer, breast cancer, osteosarcoma, and/or lung cancer
Radiation induced malignancies include the following:
Linear, nonthreshold
Radiation induced thyroid cancer is judged to be:
Radiocarcinogenesis
Radiation-producing cancer
Radon
Radiogenic gas
Radium
Radiogenic substance
Acute
Rapid, severe
A double exposure of radiation to the patient
Repeat radiographs result in:
Which of the following types of radiation-induced cancers demonstrates a threshold dose-response relationship?
Skin
Chronic
Slow, progressive, also good weed
Loci
Spot, place of origin
What is the term that describes radiation damage that increases the probability of causing a late effect, but will not increase the severity of the effect?
Stochastic
6
The absolute risk for radiation induced breast cancer is _________ cases/million persons/rad/year
Doubling dose
The dose of radiation required per generation to double the spontaneous mutation rate
Observed cases - expected cases
The formula for excess risk:
observed cases/expected cases
The formula for relative risk is:
Long wavelength radiation
The function of a filter is to remove which of the following from the x-ray beam?
Increase beam hardness, thus reducing patient skin dose
The function of filtration in diagnostic radiology is to:
Longer, smaller
The greatest beam limitation is accomplished when the cone is ____________, and the diameter is ___________.
Excess risk
The number of excess cases of cancer observed compared with expected spontaneous occurence
Relative risk model
The ratio of cancer incidence in an exposed population to that of an unexposed population
1.5 (50%)
The relative risk for development of radiation induced leukemia is approximately:
15 inches (38 cm), 12 inches (30 cm)
The source-tabletop distance must not be less than ________ for fixed fluoroscope and not less than _______________ for mobile fluoroscopes
Neoplasm
Tumor
Grids
What is placed between the patient and the image receptor to absorb scatter radiation?
5-10 years
What is the approximate latent period for radiation induced skin carcinoma?
First trimester
When does the greatest radiation hazard to a fetus exist?
Collimator
Which is the most versatile type of x-ray beam limitation device?
Skin
Which of the following cancers demonstrates a threshold dose response relationship?
Higher kVp, lower mAs, increased filtration
Which of the following combinations would reduce patient dose during an x-ray exam?
Higher kVp, lower mAs, increased filtration
Which of the following combinations would reduce patient radiation dose during an X-ray examination?
Stochastic
Which of the following describes radiation damage that increases probability of a late effect?
Filter
Which of the following is not a type of beam limitation device?
Collimator
Which of the following is the most versatile type of X-ray beam limitation device?
American radiographers
Which of the following populations has NOT shown an increase in radiation induced leukemia?
Use rare earth screens
Which of the following will best reduce radiation exposure to the patient?
50 mAs, 90 kVp
Which of the following will provide least radiation exposure to the patient
2%
Within what % of the SID must the collimator light and actual irradiated area be accurate?
genetically significant dose (GSD)
_________ is an average calculated from the gonadal dose received by the entire population
