X-Ray Physics Review part 1 Flashcards
What is the SI unit equivalent for REM (Radiation Equivalent Man)?
Seivert
What units of measure account for differences in biologic tissue?
REM or Seivert
What is the SI unit for Roentgen (R)?
c/Kg or coulombs per kilogram
What unit is used to measure exposure in air?
the Roentgen (R) or coulombs per kilogram (c/Kg)
What does LET stand for?
Linear Energy Transfer
What does LET measure?
The amount of energy transferred to tissue per unit path length traveled in that tissue.
What does RBE stand for?
Relative Biological Effectiveness
As LET increases RBE _____
increases
As RBE increases biological damage _____
increases
What is the purpose of “Quality Factor (QF)” ratings of different types of radiation?
To be able to compare different types of radiations ability to produce biologic damage. Ie. alpha particles have a very high let and so have a high QF of 20. Xrays have a low LET and so have a low QF of 1.
Where is Equivalent Dose used and in what units is it expressed?
It is used to report doses on radiation safety reports (in REM or Seiverts) and attempt to take in to account radiation damage from multiple sources
What (biological thing) does Effective Dose Equivalent take into account?
The sensitivity of the different organs to determine the overall harm done
How many rad to a Gray?
there are 100 rads in a Gray. rad/100 = Gray
How many rem to a Seivert?
There are 100 rem in a Seivert. rem/100 = Seivert
The unit of does equivalent is the ____
REM (Radiation Equivalent Man)
What uses organ weighting factors to determine the risk of radiation induced cancer?
Effective dose equivalent
What units are used to report occupational dose?
REM or Seiverts
What does ALARA stand for?
As Low As Reasonably Acheivable
No does is a ____ dose
safe
What is the occupational worker effective does limit (annual)?
50 mSv or 5 rem
What is the public exposure limit (annual)?
1 mSv or 0.1 rem
Are stochastic effects guaranteed to happen?
No, there is only a probablility that they might occur. Also, not a direct relationship - ie. cancer or genetic effects
What is the relationship between Non-stochastic effects and absorbed dose?
Non-stochastic effects (ie. erythema, cataracts, desquamation) increase in severity with absorbed dose.
Is Direct effect or Indirect effect responsible for the production of free radicals?
Indirect Effect
What is a molecular product produced via the radiolysis of water that is toxic to the cell?
Hydrogen peroxide
Between Interphase and mitosis, which is the most radiosensitive?
Mitosis
What are the cardinal rules of radiation protection
Time, Distance, Shielding
How does collimation improve radiographic contrast?
by reducing scatter
