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Radiation Dose         Share on Facebook

The Informed Patient

  • “ However, estimation of the risk of cancer from radiation doses associated with standard CT examinations requires certain assumptions (e.g. linear no threshold model) that may not be correct. To date, there is no scientific evidence showing a causitive relationship between CT radiation dose and cancer risk.”
    Body CT: Technical Advances for Improving Safety
    Marin D et al.
    AJR 2011; 197:33-41
  • “ Although CT is a powerful tool that has transformed the practice of medicine, the benefits are accompanied by important risks. Radiologists must understand these risks and the strategies available to minimize them as well as the risks associated with contrast medium delivery in abdominal CT.”
    Body CT: Technical Advances for Improving Safety
    Marin D et al.
    AJR 2011; 197:33-41
  • Sample Visual Aid Chart for Use When Discussing Radiation Imaging Procedures

    Imaging Examples

    Effective Dose Range (msv)

    Background Equivalent radiation Time

    Radiation Risk Descriptor

    Probability of Cancer from Imaging (%)

    Probability of No Cancer From Imaging (5)

    CT scan

    1-10

    years

    minor

    0.05

    99.95

    Abdominal Radiograph

    0.1-1.0

    months

    minimal

    0.005

    99.995

    Chest X-ray or Mammogram

    <0.1-0.1

    Days to weeks

    negligible

    0.0005

    99.9995


    AJR 2011;196:756-761 (modified)

  • Typical Comparison Approaches for Communicating Medical Radiation Risk

    Comparison

    Chest radiographs (0.1 mSv)

    CT of the Abdomen (<10 mSv)

    Equivalent to how many CXRs

    1100

    Background equivalent radiation time US

    12d

    3.3y

    Background equivalent radiation time Colorado

    9d

    2.5y

    Number of flights NYC to Seattle

    3.6

    360

    Fraction of occupational dose limit (50 mSv/y)

    0.002

    0.2


    AJR 2011;196:756-761

  • "The risk associated with a radiologic examination appears to be rather low compared with the natural risk. However, any added risk, no matter how small, is unacceptable if it does not benefit the patient."

    Radiation Risk: What You Should Know to Tell your Patient
    Verdun FR et al.
    RadioGraphics 2008:28:1807-1816
  • "A small proportion (1.9%) of emergency department patients undergoing CT of the neck, chest, abdomen, or pelvis have high cumlative rates of multiple or repeat imaging. Collectively, this patient subgroup may have a heightened risk of developing cancer from cumulative radiation exposure."


    Cumulative  Radiation Exposure and Cancer Risk Estimates in Emergency Department Patients Undergoing Repeat ot Multiple CT
    Griffey RT, Sodickson A
    AJR 2009; 192:887-892