Exam 1

• Radiation is the transfer of energy from one location to another
• Radiant energy is emitted from the x-ray tube in the form of waves or particles
• The modern goal of radiation protection is to protect persons from both short and long term effects
• Radiation protection is effective measures employed by radiation workers to safeguard patients, personnel, and to the general public from unnecessary exposure to ionizing radiation
• Exposure is measured in coulomb per kilogram (C/kg) or milliroentgen (mR)
• Exposure is the amount of ionization produced in air when ionizing radiation is present
• Ionization chambers can measure the quantity of radiation directly and are used to measure the amount of radiation produced by x-ray equipment
• Absorbed dose is 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 Gray (Gy)
• Effective dose provides a quantity that is a measure of general harm in humans; best overall measure of the biologic effects of ionizing radiation
• Effective dose is measured in millisievert (mSv), a subunit of the sievert (Sv)
• Harm caused to animals and humans caused by exposure to ionizing radiation is referred to biological effects
• Diagnostic efficacy is the degree to which the diagnostic study accurately reveals the the presence or absence of disease in the patient, while adhering to radiation safety guidelines
• Optimization for radiation protection (ORP) is synonymous with ALARA
• In a hospital, the radiation safety officer (RSO) is expressly charged by the hospital administration with being directly responsible for the execution, enforcement, and maintenance of the ALARA program
• Risk is the possibility of inducing adverse biological effects, such as injury to the skin or induction of cancer or genetic defect after irradiation
• The background equivalent radiation time (BERT) method relates natural radiation to radiation from medical sources.
• For children, the radiation risk is three times greater than adults
• The Alliance for Radiation Safety in Pediatric Imaging is a partnership of medical societies whose overall common purpose is to reduce the radiation dose for pediatric patients
• The Image Gently Campaign gives information about CT exams on children and overall radiation safety when working with pediatrics
• The Image Wisely campaign addresses concerns with adult radiation safety
• The FDA mandates that measures of dose in CT be available as part of the record of each exam
• The Joint Commission requires monitoring of CT and IR exams
• Reference values of patient dose are based upon large scale surveys of actual measurements of x-ray machines in hospitals
• Alert levels occurs when a patient is predicted to or has exceeded normal dose level
• Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation defines what?

  Radiation protection
• What is a method that can be used to answer patients' questions about the amount of radiation received from a radiographic procedure?


  BERT
• The term optimization for radiation protection (ORP) is synonymous with what?

  ALARA
• The amount of ionization produced in the air when ionizing radiation is present is known as what?

  exposure
• The degree to which the diagnostic study accurately reveals the presence or absence of the disease in the patient while adhering to radiation safety guidelines defines what term?

  diagnostic efficacy
• The millisievert (mSV) is equal to?

  1/1000 of a sievert
• Consequences of ionization in human cells include:

  1. creation of unstable atoms
  2. production of free electrons
  3. production of low energy photons
  4. creation of highly reactive free molecules (free radicals) capable of producing substances poisonous to the cell
  5. creation of new biological molecules detrimental to the living cell
  6. injury to the cell that may manifest itself as abnormal function or loss of function
• Properties of x-ray:

  1. invisible
  2. vary degree of penetration
  3. cannot be deflected, electrically neutral
  4. cannot be focused by a lens
  5. travel in straight lines at the speed of light
  6. produce charged particles and can cause fluorescence
  7. will darken film
  8. have a wide range of energies
• The three main types of radiation quantities are:

  1. amount of exposure
  2. amount of absorbed dose
  3. overall effective dose
• When measuring absorbed dose, the more molecules that are disrupted, the more energy that is deposited
• The effective dose is an attempt to provide the quantity of radiation that causes harm to humans; must include

  1. amount of absorbed dose
  2. type of radiation received
  3. specific organ or organ system irradiated
• The US population background exposure is about 3 mSv per year
• A chest x-ray is equal to 10 days of background radiation
• An abdomen/pelvis x-ray is equal to 4 months of background radiation
• A lumbar spine x-ray is equal to 1 year of background radiation