Chapter 1 - Intro to Radiation Protection Flashcards
A form of ionizing radiation
X-rays
Is radiation that produces positively and negatively charges particles (ions) when passing through matter
Ionizing Radiation
The production of these ions is the event that may cause injury in normal biologic tissue
ionizing radiation
List some consequences of ionization in human cells
- 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.
Goals of Radiation Protection
-protect persons from both short term and long term effects of radiation
-Use of knowledge of radiation-induced hazards that have been gained over many years
-employ effective methods to eliminate those hazards
-control radiation produced from an x-ray tube and ensure safety during all medical radiation procedures
-limiting the energy deposited in loving tissue by radiation can reduce the potential for adverse effects
Control of “radiant Energy”
Any radiation exposure that does not enhance the quality of the study
Unnecessary Radiation
Any radiation exposure that does not benefit a person in terms of diagnostic information obtained for the clinical management of medical needs.
Unnecessary Radiation
Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation
Radiation Protection
-Ongoing responsibility of diagnostic imaging professionals to ensure radiation safety during all medical radiation procedures
-obligation is fulfilled by adhering to an established radiation protection program
Concept of radiation protection
Measured in coulomb per kilogram [C/kg], or milliroentgen [mR]
Exposure Dose
The amount of energy that is deposited in a material per unit mass of the material. measured in milligray [mGy]
Absorbed Dose
Amount of radiation produced in air when ionizing radiation is present. Measured in coulomb per kilogram [C/kg], or milliroentgen [mR]
Exposure Dose
A quantity that is a measure of general harm in humans. Measured in millisievert [mSv]
Effective Dose
protects against leakage radiation and electric shock
Tube housing
Vacuum environment
Tube or glass envelope
-negative electrode
-contains the filament and focusing cup
Cathode
-made of thoriated tungsten
-high melting point
-responsible for producing thermionic emission
-source of electrons for xray production
-determines the size of the focal spot
-may have 2- dual focus tube
Filament
-made of nickel /molybdenum
-keeps the electron cloud/ space charge
Focusing cup
-made of tungsten or tungsten rhenium alloys
-serves as a target for projectile electrons and primary thermal conductor of the tube
-rotating anodes : allow for greater heat capacity
Rotating Anodes
examples of short term
hair loss
redness of skin
long term
cancer
somatic
yourself
genetic
for the future
measured in millisievert [mSv]
Effective dose
Which dose is the overall better measurement
Effective Dose
What dose reflects what type of radiation how much of a dose and what organ or tissue it is hitting
Effective Dose
Which dose is type of radiation and dose received
Equivalent dose
What is equivalent dose measured in
millisievert or sievert
ALARA
As low as reasonably achievable
synonymous with the term optimization for radiation protection
ALARA
Intention behind these concepts of radiologic practice is to keep radiation exposure and consequent dose to the lowest possible level
ALARA
The degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient
Diagnostic Efficacy
Maximized when essential images are produced under recommended radiation protection guidelines
Diagnostic Efficacy
Provides the basis for determining whether an imaging procedure or practice is justified
Diagnostic Efficacy
Benefit versus risk
Patient can elect to assume the relatively small risk of exposure to ionizing radiation.
To obtain essential diagnostic medical information when illness or injury occurs.
When a specific imaging procedure for health screening purposes is prudent.
Example: When women elect to undergo screening mammography to detect breast cancer in its early stages.
The three basic principles of radiation protection
Time
Distance
Shielding
The three basic principles of radiation protection can be applied to the
patient and radiographer
Educating patients about imaging procedures helps to ensure the highest quality of service.
Use appropriate and effective communication.
Answer questions about the potential risk of radiation exposure honestly
Inform patients of what needs to be done, if anything, as a follow-up to their examination
Patient Protection and Patient Education
- Be aware of rules governing the workplace.
- Perform duties consistent with ALARA
Radiation Workers’ Responsibilities
- Implement and maintain an effective radiation safety program in which to execute ALARA by providing the following:
- Necessary resources
- Appropriate environment for ALARA program
- Make a written policy statement describing the ALARA program and identifying the commitment of management to keep all radiation exposure ALARA available to all employees in the workplace.
- Perform periodic exposure audits to determine how to lower radiation exposure in the workplace.
Employers Responsibilities
The probability of injury, ailment, or death resulting from an activity
Risk in general terms
with reference to the radiation sciences
The possibility of inducing a radiogenic cancer or genetic defect after irradiation
Risk in medical industry
Perception that the potential benefit to be obtained is greater than the risk involved.
Willingness to accept risk
A method that can be used to improve understanding and reduce fear and anxiety for the patient.
BERT( Background Equivalent Radiation Time)
Compares the amount of radiation received with natural background radiation received over a given period of time (see Table 1-1 in textbook)
Based on an annual U.S. population exposure of approximately 3 mSv per year
BERT
does not imply radiation risk; it is simply a means for comparison.
emphasizes that radiation is an innate part of our environment.
is easy for the patient to comprehend.
BERT
Who is significantly more radiation sensitive
Children
Started by the alliance
Dissemination of information on pediatric CT dose reduction among the various medical specialties that refer patients for CT examinations
Image Gently Campaign
Partnership of medical societies whose overall common purpose is to reduce the radiation dose for pediatric patients.
Goal: Raise awareness among nonradiology users.
Alliance for Radiation Safety in Pediatric Imaging
Created to address concerns about the increase of public exposure to ionizing radiation from medical imaging.
Image Wisely Campaign
project in place to provide data on the measurement of radiation of x-ray machines.
Reference values set at some fraction, for example, 75% of the maximum of the distribution of dose values measured.
Levels may be used to allow individual institutions to determine where they stand with regard to standard practices at the majority of institutions.
NEXT Program and Reference Values
When patient dose is predicted to or has substantially exceeded present dose levels, the staff radiologist is notified.
A medical physicist may be called upon to estimate patient doses such as effective dose, peak skin dose, or fetal dose.
Protocols for Dose Alerts
