Rad Protection

radiation contained in the unpolluted environment

also called man-made radiation

radiation exiting the x-ray tube

x-rays that emerge from the patient and strike the image receptor

absorption and scatter (loss of intensity) of hte x-ray beam as it passed through the patient

x-ray beam that contains photons of many different energies

absorption of x-ray photons in the atoms of the body

scatter of x-ray photons from the atoms of the body

traditional unit of in-air exposure

SI unit of in-air exposure

traditional unit of absorbed dose

SI unit of absorbed dose

traditional unit of eequivalent dose and effective dose

SI unit of equivalent dose and effective dose

traditional unit of activity

SI unit of activity

Study biologic effects of ionizing radiation protection guidelines

Publishes internation radiation protection guidelines

Published radiation protection guidelines for the United States

Enforces radiation protection standards at the federal level related to use of radioactive material

Makes recommendations on equipment design and protection regarding lead shielding and fluoroscopic and mobile exposure rates

Makes recommendations pertaining to risk-benefit analysis of radiation exposure; states that somatic and genetic effects should be kept to a minimum when radiation is used for diagnostic imaging; defines annual exposure limits

The upper boundary dose that can be absorbed, either in a single exposure or annually, with a negligible risk of somatic or genetic damage to the individual; effective dose implies whole body radiation exposure

limit lifetime occupational exposure must not exceed the radiographer's age multiplied by 1 rem

equal to the absorbed dose multiplied by the radiation weighting factor; formerly known as dose equivalent

Upper boundary dose that can be absorbed, either in a singler exposure or annually, with a negligible risk of a deterministic levels

A concept of radiologic practice that encourages radiation users to adopt measures that keep the dose to the patient and themselves at minimal levels

graphs taht illustrate the relationship between radiation dose and the response of hte organisim to exposure; may be linear or nonlinear, threshold or nonthreshold

radomly occurring effects of radiation; the probabitlity of such effects id proportional to the dose (increased dose equal increased probability, not severity, of effects)

Effects of radiation that become more severe at high levels of radiation exposure and do not occur below a certain threshold dose

Average annual gonadal dose of radiation to the individuals of childbearing age; addresses the relationship of gonadal doses to individuals versus and entire population and overall effects

amount of energy deposited by radiation per unit length of tissue

Ability t oproduce biolgoic damage; varies with the LET

occurs when raidaiton directly strikes DNA in the cellular nucleus

Occurs when radiaiton strikes the water molecules in the cytoplasm of the cell

Occurs as radiation energy is deposited in the wate rof the cell; the result of radiolysis is an ion pair in the cell: a positively charged water molecule (HOH+) and a free electron

Erroneous information passed to subsequent generation via cell division

Cells are most sensitive to radiation when they are immature, undifferentiated, and rapidly dividing

hemopoetic syndrome, gastrointestional syndrome; central nervous system syndrome

Carcinogenesis, cataractogenesis, embryologic effects, thyroid dysfunction, life span shortening

• Distance
• Time
• Shielding

Best protection against radiation exposure

• Optically stimulated luminescence (OSL) badge
• Film Badge
• Thermoluminescent dosimeter (TLD)

average dose of radiation to the bone marrow

unstable atoms, free elctrons , or formation of new molecules harmful to the cell

• Somatic
• and
• Genetic

Radon

Natural Background Radiation

• Incoming x-ray photon strikes a K-shell electron
• Energy of x-ray photon is transferred to electron
• Electron is ejected from the K-shell and is now called a photoelectron
• X-ray photon has depsoited all of its energy and ceases to exist
• Photon has been completely absorbed
• Photoelectron may ionize or excite other atoms until it has deposited all of its energy
• Characteristic cascade happens to fill hole in K-shell
• Produces contrast in image because of differential absorption of incoming x-ray photons

• Incoming x-ray photon stikes a loosely, bound outer-shell electron
• Photon transfers part of it's energy to the electron
• Electron is removed from orbit as a scattered electron, referred to as a recoil electron
• Ejected electrons may ionize other atoms or recombine with an ion needing an electron
• Scattered photon may interact with other electrons, causing more ioniziation, addition scattering events, or photoeletric absorption, or it may exit the patient
• Scattered photons emerging from the patient travel in very divergent paths in random directions
• Scattered photons may also be present in the room and expose the radiographer or radiologist

• Produced by low energy photons
• Electrons are not removed but vibrate from deposition of energy from photon
• As electrons vibrate they emit energy equal to original photon
• Does not affect image under 70 kVp

• does not occur in radiography
• produced a photon energies above 1.02 mEv
• involves interacton between incoming photon and atomic nucleus

does not occur in radiography