Figure 3.

Plot of ratio of average radiance (p/s/cm²/sr)/activity concentration (μCi/μL) vs. radionuclide. Positron-emitting radionuclides are arranged in order of increasing average β⁺ kinetic energy (¹⁸F: E_β+=249.8 keV [I_β+=100%]; ⁶⁴Cu: E_β+=278.2 keV [I_β+=17.6%]; ⁸⁹Zr: E_β+=395.5 keV [I_β+=22.7%]; ¹²⁴I: E_β+=820 keV [I_β+=22.7%]). For ¹³¹I, E_β−=181.9 keV [I_β− 100%]. ²²⁵Ac decays by 100% α-particle emission with E_α in the range 5021–5830 keV (1). Ave. = average