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