Trigger 4, Radiation Protection: Basic Radiation Concepts

Ma'am Abi's Hand-Outs

absorbed dose

absorbed dose

• Refers to the fundamental quantity for describing the effects of radiation in a tissue or organ

• It is the energy deposited in a small volume of matter (tissue) by the radiation beam passing through the matter divided by the mass of the matter. D=E/m

• Gray tissue (Gy_t)

• Radiation absorbed dose (rad)

• Joules per kilogram (J/kg)

absorbed dose is meassure in:

100 rad

1 Gy_t is equivalent to, what?

effective dose

refers to an estimate of the uniform, whole-body equivalent dose that would produce the same level of risk for adverse effects that results from the non-uniform partial body irradiation.

• Sievert (Sv)

• Radiation equivalent man (rem)

• Joules per kilogram (J/kg)

effective dose is meassure in:

100 rem

1 Sv is equivalent to, what?

radioactivitiy

refers to the act of emitting radiation spontaneously

• curie (Ci)

• becqueral (Bq)

• disintegrations per second (dps)

radioactivity is measured in:

1 Bq

1 dps is equivalent to, what?

3.7 × 10¹⁰ Bq

1 Ci is equivalent to, what?

exposure

• refers to the total electrical charge per unit mass that x-ray and gamma ray photons with energies generate in air.

• the amount of ionizing radiation that may strike an object, such as the human body, when in the vicinity of a radiation source.

• gray air (Gy_a)

• roentgen (R)

• coulombs per kilogram (C/kg)

exposure is measured in:

2.08 × 10⁸

1 R is equivalent to, what? (in ip/cm³)

2.58 × 10^-4

1 R is equivalent to, what? (in C/kg)

somatic effects

are those which occurs in the exposed individual

sunburn-like injuries to the skin with accompanying hair loss

according to Jefferson Laboratory, a short-term does of 200 to 300 rad can result in, what?

upset (nausea, electrolyte imbalance)

At doses over 1,000 rads, the gastrointestinal system suffers, what?

• shock, leading to:

  • confusion

  • loss of coordination or coma due to internal bleeding and pressure in the brain

In excess of 5,000 rads, the nervous system undergoes, what?

• tumor

• cancer

• cataracts

delayed, longer-term somatic effects include the possible development of, what?

genetic effects

• are those that occur in the descendants of a parent whose DNA molecules are modified due to exposure to ionizing radiation.

• these are impossible to distinguish from mutations due to other causes.

stochastic effects

• occur a long time after exposure.

• can result from high-dose, short-term exposure, but the concern in diagnostic imaging involves low-dose exposures over time.

deterministic effect

• immediate response of radiation exposure

• after exposure to a high radiation dose, humans can experience a response within a few days to a few weeks

50 mSv (5000 mrem)

• what is the annual effective dose in occupational exposure?

• what is the equivalent dose for tissues and organs for the skin, hands, and feet in annual public exposures?

• what is the equivalent dose for tissues and organs for the skin, hands, and feet in annual education and training exposures?

10 mSv x age (1000 mrem x age)

what is the cumulative effective dose in occupational exposure?

150 mSv (15 rem)

what is the equivalent annual dose for tissues and organs for the lens of the eyes in occupational exposure?

500 mSv (50 rem)

what is the equivalent annual dose for tissues and organs for the thyroid, skin, hands, and feet in occupational exposure?

1 mSv (100 mrem)

• what is the effective dose, frequent exposure in annual public exposure?

• what is the effective dose in annual education and training exposures?

15 mSv (1500 mrem)

• what is the equivalent dose for tissues and organs for the lens of eye in annual public exposures?

• what is the equivalent dose for tissues and organs for the lens of eye in annual education and training exposures?

5 mSv (500 mrem)

what is the total equivalent dose for embryo-fetus exposure?

0.5 mSv (50 mrem)

what is the equivalent dose in 1 month for embryo-fetus exposure?

0.01 mSv (10 mrem)

the annual dose limit for negligible individuals, is what?

small incidence of latent harmful effects.

current studies suggest that even the low doses of x-radiation used in routine diagnostic procedures may result in, what?

human fetuses

they are sensitive to x-radiation in early pregnancy

as low as reasonably achievable

ALARA

• shielding

• time

• distance

what are the cardinal principles of radiation protection?

shielding

cardinal principle of radiation protection

• wear protective apparel

time

cardinal principle of radiation protection

• minimize the time of radiation exposure

distance

cardinal principle of radiation protection

• maximize the distance from the source