Dose Optimization

  • One of the most efficient ways to ensure that a patient is receiving an acceptable radiation dose is to optimize a scanning protocol to each patient.
    • Adjustments to technical parameters and scanning range of a protocol are made based upon the patient’s size, age, and clinical areas of interest.
      • mA has a proportional relationship to radiation dose. If mA is halved, the radiation dose is halved.
      • kV has a direct effect on patient dose. As the kV is increased, the patient’s radiation dose is also increased.
        • mA and kV should be kept to the lowest possible levels to acquire optimal images to keep the patient’s radiation dose to a minimum.
    • The collimation that is utilized during a CT exam can have an indirect impact on the dose a patient receives.
      • The collimation of the x-ray beam impacts the dose profile of a patient.
        • The dose profile is the area of the patient that is exposed to radiation.
      • Wide collimation means that the patient’s dose will be increased in the z-axis (thick slices) and narrow collimation means the patient dose will be decreased in the z-axis (thin slices).
        • However, thin slices can produce images with increased noise which may require an increase in mA.