[en] A composition useful in the preparation of technetium-99m-based imaging agents is described comprising: (a) a metal selected from the groups consisting of tin and tin-containing alloys, the metal being employed in an amount effective to reduce the technetium to be added to form an imaging agent; and (b) a stabilizing amount of stabilizer selected from the group consisting of gentisate, ascorbate, and reductate compounds, and mixtures thereof. A composition useful in the preparation of technetium-99m-based imaging agents is described comprising: (a) a stabilizer selected from the group consisting of gentisate, ascorbate and reductate compounds, and mixtures thereof; dissolved in (b) an oxidized pertechnetate solution; and (c) a metal selected from the group consisting of tin and tin-containing alloys

[en] A process for making a lyophilized composition useful for skeletal imaging whereby an aqueous solution containing an ascorbate, gentisate, or reductate stabilizer is contacted with tin metal or an alloy containing tin and, thereafter, lyophilized. Preferably, such compositions also comprise a tissue-specific carrier and a stannous compound. It is particularly preferred to incorporate stannous oxide as a coating on the tin metal

[en] Radioactively labeled peptides are powerful tools for an individualized, patient based treatment of oncological diseases. The excellent targeting concomittant with the easy radiolabeling enable such fully synthetic molecules for patient selection (diagnosis) and internal irradiation (therapy). Peptides labeled with radiohalogenes as well as radiometals were used successfully for the diagnosis and therapy of numerous malignancies. The use of ⁹⁰Y-DOTATOC and ¹⁷⁷Lu-DOTATATE for the treatment of patients with neuroendocrine tumors, refrectory to chemotherapy, underline the potential of radiopeptides. ^99mTc-NeoTect registered, another somatostatin targeting peptide-radiometal conjugate, detects lung lesions with 97% sensitivity and > 70% specificity employing SPECT. Pre-clinical results of ¹⁸⁸Re-NeoTide registered, the radiotherapeutic counterpart of ^99mTc-NeoTect registered, indicate significant tumor regression in lung tumor models. The α_vβ₃-targeted detection of neoangiogenesis proves radiopeptides to be valuable tools for the diagnostic imaging of multiple tumor entities, since α_vβ₃-receptors are overexpressed in a variety of tumors undergoing new blood-vessel formation. The application of (¹⁸F)-Galacto-RGD, a high-affinity binder for α_vβ₃-receptors, pinpoints the potential of peptides for tumor detection (Fig. 5) and staging. The successful use of ^99mTc-Demogastrin registered for detection of medullary thyroid carcinoma and its multiple metastases opens a new field in diagnosis and therapy of solid tumors. (orig.)

[en] In the present study, we have designed novel, unsulfated CCK octapeptide analogs linked to the metal chelating DTPA and DOTA, and have tested them for their binding affinity to CCK-B receptor-positive tissue from human tumors: The most potent compounds assayed were DTPA-[Nle^28,31]-CCK(26-33) (MP2286) and DTPA-[d-Asp²⁶,Nle^28,31]-CCK(26-33) (MP2288) with an IC₅₀ of 1.5 nM. For comparison, analogs with C-terminal DTPA, such as [Nle^28,31,Aphe³³(p-NH-DTPA)]-CCK(26-33) and CCK-(26-33)-NH(CH₂)₂ NH-DTPA, had an IC₅₀ of >100 nM. DOTA-[d-Asp²⁶,Nle^28,31]-CCK(26-33) had an IC₅₀ of 3.9 nM. The compounds were selective for CCK-B receptors as they did not bind with high affinity to CCK-A receptors expressed in human tumors (meningiomas or gastroenteropancreatic tumors). In vivo rat biodistribution studies with indium-111 labeled MP2286 and MP2288 showed that the primary mode of clearance was renal, and the primary sites of uptake (% ID/g 24 h p.i.) were kidneys (0.270 and 0.262, respectively) and the gastrointestinal tract. The CCK-B receptor-expressing gastric mucosa showed specific in vivo accumulation of ¹¹¹In-labeled MP2288 which could be blocked in the presence of excess unlabeled MP2288. ¹¹¹In-labeled MP2286 and MP2288 were also found to be stable in human plasma whereas both compounds were degraded in urine (>40% after 3 h at 37 C). The affinity, specificity, biodistribution, and stability of these two DTPA-CCK analogs indicate that these compounds have substantial promise for use in the in vivo visualization of CCK-B receptor-expressing tumors. (orig./MG) (orig.)