Approaches to Dose Reduction in Molecular Imaging
In molecular imaging the effective dose is proportional to the administered activity of the radiopharmaceutical, which indicates the amount of the isotope. Activity is measured in Becquerel (Bq), where 1 Bq equals 1 decay per second, and Curies (Ci), where 1 Ci equals 3.7 x 1010 decays per second.
Additional physical parameters are physical half-life, and type and properties of the emitted radiation. Isotopes with a physical half-life in the range of the total examination duration should be applied. Thus, unnecessary radiation is prevented that would result from using isotopes with longer half-lives. Pure gamma emitters such as 99mTc or pure positron emitters such as 18F are preferred. Additional radiation components do not contribute to the diagnostic image, but contribute to the overall effective dose.