Risk Estimates

Risk

Often expressed as the probability or likelihood that an event will occur

(BEIR) VII

Biological effects of Ionizing Radiations International Commission on Radiological Protection (ICRP) 103

Committee reports such as ____ and ____ state risk from radiation exposure as either absolute risk or relative risk.

Risk

Often expressed as the probability or likelihood that an event will occur

(BEIR) VII

Biological effects of Ionizing Radiations International Commission on Radiological Protection (ICRP) 103

Committee reports such as ____ and ____ state risk from radiation exposure as either absolute risk or relative risk.

probability or likelihood

Risk Often expressed as the ____ or ____ that an event will occur

relative risk

absolute risk

There are two models used to assess the risk of stochastic effects from radiation exposure: ____ and _____

Relative Risk

multiplicative risk model

Relative Risk

Computed by comparing the number of persons in the exposed population showing a given stochastic effect with the number in an unexposed population who show the same stochastic effect.

1 to 10

Relative risk rates range from

Relative Risk

rates range from 1 to 10, with 1 representing no risk at all

1

Relative Risk rates range from 1 to 10, with ___ representing no risk at all

expressing risk

The relative and absolute risk models are most often used for

relative & absolute risk

The ___ and ____ models are most often used for expressing risk

BEIR Committee

which is associated with the National Academy of Sciences, used the relative risk model

Committee on the Biological Effects of Ionizing Radiation

BEIR Committee

relative risk model

The BEIR Committee (Committee on the Biological Effects of Ionizing Radiation), which is associated with the National Academy of Sciences, used the

Incidence

Exposure

Latent Period

Excess Incidence

Spontaneous Incidence

Age

Relative Risk Model

this model predicts that the number of excess cancers will increase as the natural incidence of cancer increases with advancing age in a population

2.5

Relative Risk

A study of radiation-induced leukemia (cancer of blood-forming cells in bone marrow) was performed after diagnostic levels of radiation. Four hundred cases were observed in 150, 000 people irradiated. The normal incidence of leukemia is 120 cases per 100,000. What is the relative risk of radiation-induced leukemia?

5.08

Relative Risk

In Hiroshima, 61 leukemia deaths were observed as compared with the expected incidence of 12

2.85

Relative Risk

In Nagasaki, 20 leukemia deaths were observed as compared with the expected incidence of 7.

Excess Relative Risk

Equal to the relative risk minus 1

relative risk minus 1

Excess Relative Risk Equal to the ____

Excess Relative Risk

Determined by subtracting one from the relative risk calculated, e.g., if the relative risk is 1.5, the ____ would be 0.5

0.015 or 1.5%

Excess Relative Risk

Consider a population with a natural absolute risk for incidence of a disease of 20,000 cases. After this population is exposed to ionizing radiation, there are 20,300 disease cases observed.

Absolute Risk

additive risk model

Absolute Risk

predicts that a of specific number of excess cancers will occur as a result exposure.

Absolute Risk

states risk in terms of number of cases/10⁶ persons/rad/year

number of cases/10⁶ persons/rad/year

Absolute Risk states risk in terms of ___

Absolute Risk

assumes a linear dose-response relationship.

linear dose-response relationship

Absolute Risk assumes a

0.9

Absolute Risk

Absolute risk for radiation-induced breast cancer is presumed to be 6 cases/106 persons/rad/year at a 15-year at risk period. If 10, 000 women receive 1 rad during mammography, what would be the total number of cancers expected to be produced?

3.6

Absolute Risk

Absolute risk for radiation-induced breast cancer is presumed to be 12 cases/106 persons/rad/year at a 30-year at risk period. If 10, 000 women receive 1 rad during mammography, what would be the total number of cancers expected to be produced?

Excess risk

observed cases - expected cases

5 cases

EXCESS RISK

If 52 cases of a disease are observed in a population exposed to 200 rad and 47 were expected, the excess is?

~12.9

EXCESS RISK

Problem: In a population of 2,000 radiologists, 13 cases of skin cancer were detected. The incidence for the general population is 0.5/100,000. How many excess skin cancers were produced in the radiologist population?

EXCESS ABSOLUTE RISK (EAR)

or excess attributable risk

EXCESS ABSOLUTE RISK (EAR)

Equal to the rate of disease in exposed population minus the rate of disease in unexposed population

excess attributable risk

EXCESS ABSOLUTE RISK (EAR) or ____

EAR per unit dose

Difference between two absolute risk and is commonly used in radiation epidemiology expressed as the ____

radiation epidemiology

Difference between two absolute risk and is commonly used in ____ expressed as the EAR per unit dose.

two absolute risk

Difference between ____ and is commonly used in radiation epidemiology expressed as the EAR per unit dose.

300/100,000 or 300 in 100,000

EXCESS ABSOLUTE RISK (EAR) Problem: Consider a population with a natural absolute risk for incidence of a disease of 20,000 cases in every 100,000 individuals. After this population is exposed to ionizing radiation, there are 20,300 disease cases observed

Absolute Risk Model

This model predicts that a specific number of excess cancers will occur as a result of exposure