UNIT 1: Intro To Protection Flashcards
Radiation
the transfer of energy from one location to another
Ionizing Radiation
radiation that produces positively and negatively charged particles (ions) when passing through matter, may cause damage to cells
Free Electrons
come from the thermionic emission, electrons travel from cathode to the anode
Free Radical
Highly reactive free moleules capable of producing substances poisinous to the cell
Radiation Protection
Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation. Both human and environmental physical determinants
-Technical elements
-Procedural factors
Risk
the possibility of inducing adverse biologic effects, such as injury to the skin or induction of cancer or a genetic defect after irradiation
How does radiation cause injury to normal biologic tissue?
Destructive radiation interaction at the atomic level results in molecular change, and this, in turn, can cause cellular damage, leading to abnormal cell function or even complete loss of cell function.
• Mutations
• Cataracts
• Leukemia
What are the consequences of Ionizing radiation in human cells?
Ionizing radiation damages living systems by removing electrons from (ionizing) the atoms comprising the molecular structures of these systems
What is the goal of Radiation Protection?
To protect persons from both short-term and long-term effects of radiation. Some of these effects occur in just specific organs and organ systems.
What effects can occur as a result of radiation exposure?
• Creation of unstable atoms
• Production of free electrons
• Production of low-energy x-ray photons
• Creation of highly reactive free molecules (called free radicals) capable of producing substances poisonous to the cell
• Creation of new biologic molecules detrimental to the living cell
• Injury to the cell that may manifest itself as abnormal function or loss of function
How many rad equals a Gray?
*100 rad = 1 Gy
* 1/100 Gy=1 Rad
How many rem equal a millisievert?
*0.1 rem= 1 mSv
*1 rem= 10 mSv
Define exposure and its units of measure
the amount of ionization produced in air when ionizing radiation is present. Exposure is measured in coulomb per kilogram (C/kg) in the metric International System of Units (SI), or historically and still quite commonly in milliroentgens (mR)
Define absorbed dose and its units of measure
The amount of energy that is deposited in a material per unit mass of the material. Absorbed dose is measured in milligray (mGy), a subunit of the gray (Gy) in the SI. The milligray is equal to 1/1000 of a gray
Define effective dose and its units of measure.
an attempt to provide a quantity that is a measure of general harm in humans. It takes into account the amount of absorbed dose that is received by a human, the exact type of radiation (the effects of alpha particles, beta particles, protons, and neutrons are all somewhat different at the same absorbed dose levels), and the specific organs or organ systems irradiated. The effective dose is the best
overall measure of the biologic effects of ionizing radiation. In SI units, effective dose is measured in millisievert (mSv), a subunit of the sievert (Sv). The millisievert is equal to 1/1000 of a sievert.
Define diagnostic efficacy and what is its significance with radiation protection?
The degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient, while adhering to radiation safety guidelines. It is maximized when essential images are produced with the least radiation exposure to the patient. Thus this concept of efficacy is a vital part of radiation protection in the healing arts, providing the basis for deciding whether an imaging procedure or practice is justified.
What is ALARA?
As low as reasonably achievable
What is another term related to ALARA?
Optimization for radiation protection
How can the 3 Cardinal Principles be applied in diagnostic imaging?
• Time: Reduce the amount of the x-ray “beam-on” time
• Distance: Use as much distance as warranted between the x-ray tube and the patient for the examination
• Shielding: Specific area shielding devices may be required under some circumstances
What is BERT and how is it used in diagnostic imaging?
-Background Equivalent Radiation Time
-Besides a normal explanation of a medical imaging procedure, another way that radiographers can improve understanding and reduce fear and anxiety for the patient is to use the background equivalent radiation time (BERT) method which compares the amount of radiation acquired during a particular procedure to the amount of background radiation acquired during a given amount of time
What are the advantages of incorporating BERT into clinical practice?
The intent of this dialog with the patient is not to provide high scientific accuracy but to relieve anxiety about radiation by giving an understandable and reasonably correct answer. The BERT method compares the amount of radiation received, for example, from a patient’s chest x-ray examination or from radiography of any other part of the anatomy, with natural background radiation received over a specified period such as days, weeks, months, or years
What is the purpose/ significance of the Image Gently Campaign?
Pediatric CT dose reduction among the various medical specialties that refer patients for CT examinations or even operate their own CT scanner. The latest campaign of the Image Gently Alliance was created to provide radiologic technologists a full understanding of the safe operation of fluoroscopic devices on pediatric patients
What is the purpose/ significance of the Image Wisely Campaign?
objectives of lowering the amount of radiation used in medically necessary imaging studies and eliminating unnecessary procedure
What are some characteristics of the frequencies on the electromagnetic spectrum?
Each frequency within the spectrum has a characteristic wavelength and energy. Some of the practical uses of these different frequency ranges are listed. Note that higher frequencies are associated with shorter wavelengths and higher energies; therefore, as the wavelength ranges from largest to smallest, frequencies and energy cover the corresponding smallest to largest ranges. Precise frequency intervals attributed to different parts of the electromagnetic spectrum may vary in different references, and there is substantial overlap of ranges
What types of radiation are classified as ionizing?
• X-rays
• Gamma rays
• Ultraviolet radiation with an energy greater than 10 eV
What types of radiation are classified as non-ionizing?
• Ultraviolet radiation with energy less than 10 eV
• Visible light
• Infrared rays
• Microwaves
• Radio waves
What is the difference between ionizing and non-ionizing radiation?
Ionizing radiation are capable transferring sufficient energy to remove orbital electrons from the atoms to which they were attached (eject electron), non-ionizing radiation does not do this
Particulate Radiation
-Subatomic particles that are ejected from the nucleus of atoms at very high speed
-Another category of ionizing radiation. This form of radiation includes the following:
• Alpha particles
• Beta particles
• Neutrons
• Protons
Alpha Particles
Alpha particles, also known as alpha rays, are emitted from nuclei of very heavy elements, such as uranium and plutonium, during their radioactive decay
Beta particles
Beta particles, also known as beta rays, are identical to high-speed electrons except for their origin. Electrons originate in atomic shells (Appendix F) outside of the nucleus, whereas beta particles, like alpha particles, are emitted from within the nuclei of radioactive atoms. Can penetrate matter deeper than alpha particles but with less damage to surrounding tissue.
Proton
positively charged components of an atom
Neutron
the electrically neutral components of an atom and have approximately the same mass as a proton
Absorbed dose
the amount of energy per unit mass that has been absorbed in a material due to its interaction with ionizing radiation. It is usually measured in units called milligray (mGy)
Effective dose (EfD) and its unit of measurement
The effective dose is intended to be the best estimate of overall harm that might be produced by a given absorbed dose of radiation in human tissue. It takes into account both the type of radiation and the part of the body irradiated. mSv.
Equivalent dose (EqD) and its unit of measurement
takes into account the type of ionizing radiation that was absorbed. The EqD provides an overall dose value that includes the different degrees of tissue interaction that could be caused by the different types of ionizing radiation.
mSv. 1 mSv = 1/1000th of a Sievert.
Describe how potential damage can result from ionizing radiation
While penetrating body tissue, ionizing radiation primarily causes biologic damage by ejecting electrons from the atoms, composing the tissue. Destructive radiation interaction at the atomic level results in molecular change, and this, in turn, can cause cellular damage, leading to abnormal cell function or even complete loss of cell function
-Biological damage
-Molecular change
-Cellular damage
-Abnormal or loss of cell function
What are the sources of radiation?
• Natural
• Human-made (artificial)
Natural sources of ionizing radiation
• Terrestrial radiation from radioactive materials in the crust of the Earth
• Cosmic radiation from the sun (solar) and beyond the solar system (galactic)
• Internal radiation from radioactive atoms, also known as radionuclides, which make up a small percentage of the body’s tissue
What is the average annual background radiation exposure people receive?
3.1 mSv
Identify and describe the sources of manmade radiation
-Ionizing radiation created by humans for various uses is classified as human-made, or artificial radiation
• Consumer products containing radioactive material
• Nuclear fuel for the generation of power
• Atmospheric fallout from nuclear weapons testing
• Nuclear power plant accidents
• Nuclear power plant accidents as a consequence of natural disasters
• Medical radiation
What is the average annual exposure people receive from medical imaging?
2.3 mSv
