11/9 Scott

Radiation with sufficient energy to seperate an electron from its atom

What are the 2 major groups of radiation sources?

Which source of radiation use gamma rays, x-rays, and sometimes electrons

What source od radiation use gamma rays & x-rays from sources such as cesium-137, iridium-192, and iodine-125.

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Consist of 2 protons and 2 neutrons and therefore are simply helium neclei

They are emitted from unstable heavy nuclei such as radium or radon during the decay process

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Can only travel short distances.
--most can be stopped by a sheet of paper, but they produce intense ionization and are therefore high linear energy transfer (LET) radiation

They are extremely hazardous if ingested or inhaled but are less dangerous if the exposure is external

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Electrons emitted by nucleus

They may be either negatively or positively charged

Negatively charged beta particles are called

positively charged beta particles are called

_______ are not stable and may exist for only very short periods of time

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Whenever beta particles are emitted, they are accompanied by a small, massless, chargeless particles known as the

metals may be used for shielding, but ____ radiation may result

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The probability of bremsstrahlung x-ray production is ___
___ to the square of the atomic number of the absorber and ___ ___ to the square of the mass of the incident particle

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Bremsstrahlung radiation is much more likely to occur with ____ particles than with ____ particles

____ & ____ are both forms of electromagnetic radiation (photons)

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____ have no mass and no charge

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____ are photons emitted froma nucleus

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_____ are extranuclear and result from rearrangements
within the electron shells or from bremsstrahlung radiation

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Except for their origin, there is no difference between ___ and ____.

NOTE:
xrays, gamma rays, and electrons are the most common types of ionizing radiations

It is estimated that ___% of the radiation exposure of the United States population comes from natural background sources

What are the amounts of radiation exposure for

natural _____%

man made ____%

What are the 3 sources of natural background radiation?

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The primary cosmic rays interact with molecules in the atmosphere to create reactive agents known as _____.

Whhat natural radiation originates from nuclear reations in spce or from our own sun

Exposure is _____ at the polar regions than at the equator

Latitude, solar cycels, and other factors may account for a variation of ___% in exposure.

The intensity varies even more with increasing elevation

What natural source is made up of small amounts of long lived isotopes of uranium, thorium, and radium among others

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The ___ ___ ___ estimates that radon exposure is the 2nd leading cause of lung cancer in the U.S. (following smoking)

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___ ___ results from the radioactive material that are normally in our bodies

What are examples of man-made sources?

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___ is defined as the amount of ionization produced by photons in AIR per unit mass of air

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___ ___ is defined as the energy absorbed per unit mass of any material

___ Gy = ___ cGy = ___ rad

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___ ___ takes into account the fact that different types of radiation produce different amounts of biologic damage

Alpha particle & neutrons are __ ___ LET radiation and therefore have a greater biologic efect than x-rays

NOTE:
To account for differences in biologic response, each type of radiation is assigned a quality factor

What is the traditional unit of:
Exposure:
Absorced Dose:
Dose Equivelent:
Activity

The QF of
xrays & gamma rays=
fast nuetrons=

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___ ____ ___ takes into account the effect of irradation of only part of the body or the effect of non uniform irradation of the body

NOTE:
The units for the effective dose equivelent are also the Sievert & the REM

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___ is the rate at which a radiaoactive isotope undergoes nuclear decay

NOTE:
The traditional unt of activity is the curie (CI)

This SI unit is the becquerrel

What are the 2 kinds of gas-filled detectors that may be found in a RT dept.

** When ionization chambers re properly calibrated their accuracy approaches ___% which makes them suitable for measurement of the radiaiton output of therapy equipment

What form of ionization chamber is used for personal monitoring

Note:
becuase ionization chambers are not very sensitive, they are not suitable for the detection of very low levels of radiation or radiation contamination

** NOTE
Because of their sensitivity, G-M detectors are best for finding contamination and other low levels of radiation

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Because of their small size, ___ ___ are widely used to measure radiation in a number of applications

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Thermoluminscent materials give offlight when heated

The atomic number of LIF is close to that of tissue

With proper care, doses can be measured with an accuracy of approximately ___ %

**After development, x-ray film exposed to radiation turns black.
This amount of blackness is called the ___ ___

NOTE:
The optical denisty is the amount of radiation received by the film

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The primary task of ___ ___ is to analyze the existing data related to radiation exposure and to access the radiobiologic risk associated with those exposures

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It is the role of the ___ ___ to license users of radioactive materials & radiaiton-producing equipment, inspect such users, and enforce the laws
 

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many states have entered into agreements concerning licensing, inspection and enforcement with the NRC have become ___ states

effects have no threshold and for which the probability of occurance is a function of dose

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___ effects are those for which a threshold exist and for which the severity of the effect increases with dose

What are the significant long term effects related to exposure to radaition?

WHat does the LD 50/30 means?

we have a far greater knowledge of the effects of high doses than those of low doses.

In sufficiency high quanitites, radiation can be lethal.  A single whole body dose of 4.5 ___ is lethal for ___5 of the exposed population with in ___ days of the event

what agency oversees the use of isotopes produced in nuclear reactors.
These isotopes are currently used in nuclear med dept, labs as sources for teletherapy & brachytherapy

NOTE:
TLD's are also used for mail intercomparision of therapy units calibration, in ring badges used for personal monitoring, and for measurements of enviromental levels of radiation.

A typical ___ ___ has a slot in which the film may be placed and several thin, metal, filters that surround portions of the film.