“…The use of this method is difficult in any laboratory because such a radioisotope (RI)-based method requires special facilities and handling procedures. Several authors have conducted investigations into the development of alternative non-RI methods for performing LLNA (Takeyoshi et al, 2001(Takeyoshi et al, , 2005(Takeyoshi et al, , 2006Lee et al, 2002;Suda et al, 2002;Ehling et al, 2005a, b;Idehara et al, 2008).…”