The development of radioligands targeting prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) has shown promising results for the imaging and therapy of prostate cancer. However, studies have shown that tumors and metastases can express such targets heterogeneously. To overcome this issue and to improve protein binding, radioligands with the ability to bind both PSMA and GRPR have been developed. Herein, we present the preclinical characterization of [68Ga]Ga-BQ7812; a PSMA/GRPR-targeting radioligand for the diagnostic PET imaging of prostate cancer. This study aimed to evaluate [68Ga]Ga-BQ7812 to promote the translation of such imaging probes into the clinic. [68Ga]Ga-BQ7812 demonstrated rapid and specific binding to both targets in a PSMA/GRPR-expressing PC3-pip cell line. Results from the biodistribution study in PC3-pip xenografted mice showed specific binding to both targets, with the highest activity uptake at 1 h pi in tumor (PSMA+/GRPR+, 10.4 ± 1.0% IA/g), kidneys (PSMA+, 45 ± 16% IA/g), and pancreas (GRPR+, 5.6 ± 0.7% IA/g). At 3h pi, increased tumour-to-organ ratios could be seen due to higher retention in the tumor compared with other PSMA or GRPR-expressing organs. These results, together with low toxicity and an acceptable estimated dosimetry profile (total effective dose = 0.0083 mSv/MBq), support the clinical translation of [68Ga]Ga-BQ7812 and represent a step towards its first clinical trial.

Several candidates for antihelium events have been found in the AMS-02 experiment. They cannot be created by natural astrophysical sources and, if confirmed, imply the existence of antimatter stars in our galaxy. This immediately reduces the class of inflationary models with baryosynthesis to those that can provide the creation of an antimatter domain of surviving size together with the general baryon asymmetry of the Universe. To confront the future results of experimental searches for cosmic antihelium with predictions of this hypothesis, we develop numerical studies of the creation and propagation of antihelium flux from antimatter globular clusters in the Galaxy. This article presents the results of such a simulation: a function of the magnetic cut-off for the penetration of antihelium nuclei into the Galaxy disk and an estimate of the energy range in which the search and detection of antihelium is most optimal.