203Pb and 212Pb have emerged as promising theranostic isotopes for image-guided α-particle radionuclide therapy for cancers. Here, we report a cyclen-based Pb specific chelator (PSC) that is conjugated to tyr3-octreotide via a PEG2 linker (PSC-PEG-T) targeting somatostatin receptor subtype 2 (SSTR2). PSC-PEG-T could be labeled efficiently to purified 212Pb at 25 °C and also to 212Bi at 80 °C. Efficient radiolabeling of mixed 212Pb and 212Bi in PSC-PEG-T was also observed at 80 °C. Post radiolabeling, stable Pb(II) and Bi(III) radiometal complexes in saline were observed after incubating [203Pb]Pb-PSC-PEG-T for 72 h and [212Bi]Bi-PSC-PEG-T for 5 h. Stable [212Pb]Pb-PSC-PEG-T and progeny [212Bi]Bi-PSC-PEG-T were identified after storage in saline for 24 h. In serum, stable radiometal/radiopeptide were observed after incubating [203Pb]Pb-PSC-PEG-T for 55 h and [212Pb]Pb-PSC-PEG-T for 24 h. In vivo biodistribution of [212Pb]Pb-PSC-PEG-T in tumor-free CD-1 Elite mice and athymic mice bearing AR42J xenografts revealed rapid tumor accumulation, excellent tumor retention and fast renal clearance of both 212Pb and 212Bi, with no in vivo redistribution of progeny 212Bi. Single-photon emission computed tomography (SPECT) imaging of [203Pb]Pb-PSC-PEG-T and [212Pb]Pb-PSC-PEG-T in mice also demonstrated comparable accumulation in AR42J xenografts and renal clearance, confirming the theranostic potential of the elementally identical 203Pb/212Pb radionuclide pair.

In this paper, we present the numerical results of conduction in a disordered quasi-one-dimensional wire in the possible presence of magnetic impurities. Our analysis leads us to the study of universal properties in different conduction regimes, such as the localized and metallic ones. In particular, we analyze the crossover between universality classes occurring when the strength of magnetic disorder is increased. For this purpose, we use a numerical Landauer approach, and derive the scattering matrix of the wire from the electron's Green's function. t i j is the hopping term from site i to j. In the following, t i j will take two different values: t i j = t // in the longitudinal x-direction and t i j = t ⊥ in the transverse y-direction. The scalar disorder potential V = {v i } i is diagonal in electron-spin space. We choose the v i to be random scalars uniformly distributed in the interval [−W/2, W/2]. In this work, we have chosen without loss of generality to fix t // = 1 so that all energy scales are relative to the bandwidth t // = 1, and the amplitude of disorder W = 0.6. In equation (1), s, s label the SU(2) spin of electrons and the S i account for spins of the frozen magnetic impurities. A realistic choice for these frozen New Journal of Physics 14 (2012) 023026 (http://www.njp.org/) 〈 g 2 〉 c J = 0.025 J = 0.05 J = 0.075 J = 0.1 J = 0.15 J = 0.2 J = 0.3 J = 0.4 Analytical fits Quasi 1d UCF L y = 40