TABLE 2

Decay Data for the Positron Emitters Studied (22,23)

Element	Radionuclide	Decay mode	Half-life	Positron yield	p/e	Total p/e	Mean electron energy (keV/decay)	Mean positron energy (keV/decay]
Cerium/lanthanum	¹³⁴Ce/¹³⁴La	EC/EC, β⁺	3.16 d/6.45 min	0.63	4.4/0.95	0.98	6/2	−/756
Neodymium/ praseodymium	¹⁴⁰Nd/¹⁴⁰Pr	EC/EC, β⁺	3.37 d/3.39 min	0.51	4.78/1.00	1.04	6/4	−/544
Neodymium	¹⁴¹Nd	EC, β⁺	2.49 h	0.025	5.05	5.05	6	9

p/e value is total photon energy emitted per decay divided by total electron energy emitted per decay. Total p/e ratio is total photon energy emitted per decay divided by sum of total energy emitted by electrons and positrons per decay. Annihilation photons are included in total photon energy emitted per decay. Mean electron energy is mean energy of Auger and conversion electrons emitted per decay.