Radiation 2 Flashcards
define radiation dose
when ionizing radiation penetrates the human body or an object, it deposits energy
Define dose
the energy absorbed from exposure to radiation
what are the three ways radiation dose quantities are described?
Absorbed dose
Equivalent dose
Effective dose
What is the tradition and SI units of radiation quantity exposure?
traditional= R SI = Coulombs per kilogram (C/Kg)
What is the tradition and SI units of radiation quantity absorbed dose?
traditional = Rad SI = Gray (Gy)
What is the traditional and SI unit of the radiation quantity equivalent dose?
traditional = Rem SI = Sievert (Sv)
What is the traditional and SI units of the radiation quantity effective dose?
Traditional = Rem SI = Sievert (Sv)
define exposure
is a radiation quantity that expresses the concentration of radiation delivered to a specific area, such as the surface of the human body
define air kerma
a quantity used to express how energy is transferred from a beam of radiation to a material, such as the patients skin
Used to describe x-ray tube outputs and inputs to image receptors
What are the units for air kerma?
metric units if joule per kilogram (j/kg) or may be stated in Gy
define dose area product (DAP)?
is the sum total of air kerma over the exposed area of the patients surface
What are the units for Dose area product?
mGy-cm2
define absorbed dose and what is it measured in?
the amount of energy per unit mass absorbed by an irradiated object
measured in gray (Gy)
Define equivalent dose
the product of the average absorbed dose in a tissue or organ in the human body and its associated radiation weighting factor
what does equivalent dose take into account?
the potential variation in biological harm that is produced by different kinds of radiation
What are the units of equivalent dose?
Sieverts (Sv)
define effective dose
provides a measure of the overall risk of exposure to ionizing radiation
what does effective does take account in?
for the risk of the entire organism brought on by irradiation of individual tissues and organs
What are the units for effective dose?
Sieverts (sV)
What must be used when determining equivalent dose (EqD)?
Wr
What must be used in determining EfD (effective dose)?
tissue weighting factor (Wt)
what is the difference between equivalent dose and effective dose?
- equicalent uses Wr and effective uses Wt
- equivalent is absorbed dose and effective is equivalent dose
- equivalent is different capacities for producing biologic harm by various types of energies of ionizing radiation. Effective is both the type of radiation and the part of the body
Define collective effective dose (ColEfD) and what is it expressed in?
Represents an attempt to describe the radiation exposure of a population or group from low doses of different sources of ionizing radiation
expressed in person-sievert
What is the total effective dose equivalent (TEDE)?
is designed to take into account all possible sources of radiation exposure and is used for dose monitoring for occupationally exposed personnel who are likely to receive possibly significant radiation exposure during the course of the year
What are the three ways of specifying the amount of radiation received by a patient?
- Entrance skin exposure (ESE)
- Gonadal dose (GSD)
- Bone marrow dose
where is the maximum exposure received by in a patient?
NOT at the area of interest but at the skin surface
Why is Gonadal Dose of particular concern in DI?
because genetic effects may result from exposure to ionizing radiation
What is genetically significant dose (GSD)?
is used to assess the impact of gonadal dose. It represents an estimate of the genetic significance of gonad radiation doses
define bone marrow dose
the average radiation dose to the entire active bone marrow. It is measured as an estimate from ESE.
(Can also be referred to as mean marrow dose (MMD)
define personnel monitoring
is the monitoring of equivalent dose to any person occupationally exposed on a regular basis to ionizing radiation.
It ensures that occupational radiation exposure levels are kept well below annual effective dose (EfD) limits.
Where should the dosimeter be worn?
under the apron, more can be worn at extremities are needed
where should the dosimeter be placed for a pregnant women?
- primary dosimeter worn at collar level
- Second monitoring device is worn at abdominal level
what type of detector is in the optically stimulated luminescent (OSL)?
aluminum oxide
What is the most common dosimeter?
OSL
Which dosimeter is read out by a laser light at selected frequencies?
OSL