What is radiation with suffiecient enough energy to seperate an electron from an atom?
Alpha particles consist of ___ and ____ and are therfore _____
What consists of 2 protons and 2 neutrons and are therefore thought to be helium nuclei
What are emitted from unstable heavy nuclei such as radium or radon during the decay process
Alpha particles are emitted from ___ such as ____ or_____ during the decay process
unstable heavy nuclei
Why can alpha particles only travel a short distance?
Because of their charge and heavy mass
(most can be stopped by a piece of paper)
Alpha particles produce intense ionization and are therefore
high linear energy transfer (LET) radiation
Because of their charge and heavy mass ___ can travel only short distances, but they produce intense ionization and are high linear energy transfer (LET) radiations
What are extremely hazardous if ingested or inhaled bu are less danagerous if externally exposed
Where are the below found?
In the nucleus
only the xrays are found on the electron shells
Where are xrays found?
What are electrons emitted by the nucleus
What is a negatively charged beta particle
What is a positron
postively charged beta particle
Which beta particle is not stable and only exists for very short periods
Whenever beta particles are emitted, they are accompanied bu a small massless chargeless particle known as
Both types, positive and negative beta particles have the same rest mass as an electron and are usually emitted from the nucleus with high
If metals are used for shielding what can result?
The probability of bremsstrahlung xray production is ____ to the square of the atomic number of the absorber and ____ to the square of the mass of the incident particle.
The probability of bremsstrahlung xray production is directly proportional to the square of the ______of the absorber and inversely proportional to the square of the _____of the incident particle.
What is the bremsstrahlung radaition much more likely to occur with?
rather than alpha
xrays and gamma rays are both forms of
electromagnetic radiation (photons)
Photons have ___mass and ____ charge
What are extranuclear and result from rearrangements within the electron shells or from bremsstrahlung radiation
What is the only difference between xrays and gamma rays
What are the most common types of ionizing radiation used in radation therapy
What % of radiation exposure of the US comes from natural background sources
Where does most of our radiation exposure come from
what % of radiation exposure is man made
Natural background radation comes from what 3 sources?
internal deposits of radionuclides
Although the earth's atmosphere acts as a shield from cosmic rays, the primary cosmic rays interact with molecules in the atmosphere to create other reactive agents known as
Where is cosmic ray radiation exposure higher?
at the polar regions rather than the equator
Latitude, solar cycles and other factors may account for a variation of 10% exposure. The intensity varies even more with ____
Between the Rockys in CO and the swamps of Gainsville, FL, who gets the most cosmic ray radiation?
Rockys due to higher elevation
Presence of small amts of long lived isotopes of uranium, thorium, and radium is
source of terrestrial radiation
Who estimated that radon exposure is the 2nd leading cause of lung ca in the US?
enviromental protection agency
The EPA estimates that ____ exposure is the 2nd leading cause of lung cancer in the US
Which exposure results from the radioactive materials that are normally present in our bodies
What is defined as the amt of ionization prodced by photons in air per unit mass of air
The traditional unit of exposure is
What is defined as the energy absorbed per unit mass of any material
The SI unit is the ____, which is defined as 1 joule of energy absorbed per kg of absorbing material
What takes into acct the fact that different types of radiation produce different amts of biologic damage
Alpha particles and neutrons are high LET and therefore have a greater ____ than xrays
What is the traditional unit of exposure
What is the traditional unit for absorbed dose
What is the traditional unit for dose equivalent
What is the traditional unit for activity
What takes into acct the effect of irradiation of only part of the body or the effect of non uniform irradiation of the body
Effective dose equivalent
What is the rate at which a radioactive isotope undergoes nuclear decay
The Si unit of activity is the
What are 2 kinds of gas-filled detectors used to detect when radaition is present?
ionization chamber and geiger-Muller detector
The ____, consists of 2 electrodes within a gas filled chamber, an applied voltage across the electrodes and electronics and a meter to amplify and measure the electrical signal.
When ionization chambers are properly calibrated, their accuracy approaches ____ which makes them suitable for measurement of the radiation ouput of therapy equipement
What is the form of ionization chamber that is used for personnel monitoring?
Are ionization chambers sesitive? What are they suitable or not suitable for?
They are not sensitive, so they are are not suitable for the detection of very low levels of radiation or radiation contamination
Because of their sensitivity ____ are best for finding contamination and other low levels of radiation
Because of their small size, ____ are widely used to measure radiation. These materials give off light when heated.
thermoluminescent dosimeters TLD
The atomic # of LiF (lithium fluoride) is close to that of ____, and since it does, it is therefore useful as a patient or phantom dosimeter.
If proper care if taken, doses of radiation can be measured with an accuracy of approx ____
After development, xray film exposed to radiation turns ____
The amt of blackness from xray that was exposed to radiation is called ____ and this is related to the amt of radiation received by the film
A typical ____ has a slot in which the film may be placed and several thin metal filters that surround portions of the film.
The filters from a film badge allow discrimination between different types of radiation. ____ will not penetrate any of the filters but can reach the film in the area where no filters are
low energy radiation
the primary task of ____ is to analyze the existing data related to radiation exposure and to assess the radiobiologic risks with those exposures
advisory agency (set the laws)
which agency can develop dose recommendations for dose limits
The recommendations of this agency may be acted on by Congress or state govt and made into a law
Name some of the advisory agencies?
NCRP-National Council on Radiation Protection and Measurement
ICRP- International Commission on Radiation Protection
UNSCEAR- United Nations Scientific Committee on the Effects of Atomic Radiation
NAS-BEIR- National Academy of Sciences Advisory Committee on the Biological Effects of Ionizing Radiation
The role of this agency is to license users of radioactive materials and radiation-producing equipment, inspect users, and enforce the appropriate laws
What is one of the leading federal regulatory agency that oversees the use of isotopes produced in nuclear reactors
Nuclear Regulatory Commission
The isotopes are commonly used in nuclear medicine depts and as sources for teletherapy (external beam radiation) and brachytherapy. many states have entered into licensing, inspection, and enforcement agreements and are called the agreement states with the
Nuclear Regulatory Commission
Give an example of a Regulatory Agency
Nuclear Regulatory Commission
Transportation of radioactive material is primarily the concern of
DOT- Department of Transportation
The use of machines that produce ionizing radiation, such as xray units and linear accelerators fall under the jurisdiction of
FDA-Food and Drug Administration
A single whole body dose of _____ is lethal for 50% of the exposed population within 30 days
4.5 GY (450 rads)
Even at levels below the lethal dose, there are significant long-term effects related to exposure to radiation, which 2 categories do these fall in
_____are those for which a threshold exists and for which the severity of the effect increases with dose.
What are examples of a nonstochastic effect
______-are those that have no threshold and for which the probability of occurrence is a function of dose