Utilizing High-Energy γ-Photons for High-Resolution 213Bi SPECT in Mice.

Unlabelled: The combined α-, γ-, and x-ray emitter (213)Bi (half-life, 46 min) is promising for radionuclide therapy. SPECT imaging of (213)Bi is challenging, because most emitted photons have a much higher energy (440 keV) than common in SPECT. We assessed (213)Bi imaging capabilities of the Versatile Emission Computed Tomograph (VECTor) dedicated to (simultaneous) preclinical imaging of both SPECT and PET isotopes over a wide photon energy range of 25-600 keV.

Localization of Radiolabeled Somatostatin Analogs in the Spleen.

Radiolabeled somatostatin (SST) analogs, used to visualize and treat SST receptor (SSTR)-expressing neuroendocrine tumors, also accumulate in the spleen. There is a high interpatient variation and no significant radiation-induced splenic toxicity; however, an absorbed dose-related reduction in spleen size was detected. However, the exact localization of radioactivity and the role of SST receptors in splenic retention are unknown.

Dynamic and static small-animal SPECT in rats for monitoring renal function after 177Lu-labeled Tyr3-octreotate radionuclide therapy.

Unlabelled: High kidney radiation doses during clinical peptide receptor radionuclide therapy (PRRT) with β-particle-emitting radiolabeled somatostatin analogs will lead to renal failure several months after treatment, urging the coinfusion of the cationic amino acids lysine and arginine to reduce the renal radiation dose. In rat PRRT studies, renal protection by the coadministration of lysine was confirmed by histologic examination of kidney specimens indicating nephrotoxicity. In the current study, we investigated dedicated small-animal SPECT/CT renal imaging in rats to monitor renal function in vivo during follow-up of PRRT, with and without lysine.

Dose-response effect of Gelofusine on renal uptake and retention of radiolabelled octreotate in rats with CA20948 tumours.

Purpose: Peptide receptor radionuclide therapy using β-emitting radiolabelled somatostatin analogues like DOTA,Tyr3-octreotate shows beneficial results in patients suffering from somatostatin receptor overexpressing tumours. However, after high-dose therapy partial renal reabsorption of radiopeptides may lead to nephrotoxicity. Co-infusion of lysine/arginine lowers renal retention of these radiopeptides without affecting tumour uptake.