Endosonography in head and neck imaging and surgery.

This CME article explores the evolving role of endosonography in otorhinolaryngology and head and neck surgery. Endosonography offers significant potential to improve imaging inside the upper respiratory tract, particularly with advancements in probe technology and imaging resolution. The article will describe the sonoanatomy of the oral cavity, pharynx, and larynx and the selection of probes and scanning techniques used for the various anatomical sites.

Amide-to-Triazole Switch in Somatostatin-14-Based Radioligands: Impact on Receptor Affinity and In Vivo Stability.

The use of metabolically stabilized, radiolabeled somatostatin (SST) analogs ([Ga]Ga/[Lu]Lu-DOTA-TATE/TOC/NOC) is well established in nuclear medicine. Despite the pivotal role of these radioligands in the diagnosis and therapy of neuroendocrine tumors (NETs), their inability to interact with all five somatostatin receptors (SSTR) limits their clinical potential. [In]In-AT2S is a radiolabeled DOTA-conjugate derived from the parent peptide SST-14 that exhibits high binding affinity to all SSTR subtypes, but its poor metabolic stability represents a serious disadvantage for clinical use.

Quality Assurance Investigations and Impurity Characterization during Upscaling of [Lu]Lu-PSMA.

[Lu]Lu-PSMA is widely used for the radioligand therapy of metastatic castration-resistant prostate cancer (mCRPC). Since this kind of therapy has gained a large momentum in recent years, an upscaled production process yielding multiple patient doses in one batch has been developed. During upscaling, the established production method as well as the HPLC quality control were challenged.

Synthesis and Preclinical Evaluation of Radiolabeled [Ru]BOLD-100.

The first-in-class ruthenium-based chemotherapeutic agent BOLD-100 (formerly IT-139, NKP-1339, KP1339) is currently the subject of clinical evaluation for the treatment of gastric, pancreatic, colorectal and bile duct cancer. A radiolabeled version of the compound could present a helpful diagnostic tool. Thus, this study investigated the pharmacokinetics of BOLD-100 in more detail to facilitate the stratification of patients for the therapy.

Experimental studies and mathematical modeling of the viscoelastic rheology of tracheobronchial mucus from respiratory healthy patients.

Background: Tracheobronchial mucus plays a crucial role in pulmonary function by providing protection against inhaled pathogens. Due to its composition of water, mucins, and other biomolecules, it has a complex viscoelastic rheological behavior. This interplay of both viscous and elastic properties has not been fully described yet.

Unexpected transformation of n.c.a. [In]InCl in stock solutions into an unreactive [In]In-species.

While performing multiple indium-111 labeling of DOTA-modified peptides from a single batch of [In]InCl, inconsistent radiochemical yields were observed. We found that the formation of a radioactive impurity in the [In]InCl stock solution hampered the reactivity of the indium-111 during radiolabeling reactions. The formation of this unknown In-species could be successfully suppressed by increasing the concentration of chloride ions in the stock solution and [In]InCl was "recovered".

The Race for Hydroxamate-Based Zirconium-89 Chelators.

Metallic radionuclides conjugated to biological vectors via an appropriate chelator are employed in nuclear medicine for the diagnosis (imaging) and radiotherapy of diseases. For the application of radiolabeled antibodies using positron emission tomography (immunoPET), zirconium-89 has gained increasing interest over the last decades as its physical properties (t = 78.4 h, 22.

Radiolabelling of the octadentate chelators DFO* and oxoDFO* with zirconium-89 and gallium-68.

In recent years, clinical imaging with zirconium-89 (Zr)-labelled monoclonal antibodies (Ab) by positron emission tomography (immunoPET) has been gaining significant importance in nuclear medicine for the diagnosis of different types of cancer. For complexation of the radiometal Zr and its attachment to the Ab, chelating agents are required. To date, only the hexadentate chelator desferrioxamine (DFO) is applied in the clinic for this purpose.

Sorbitol as a Polar Pharmacological Modifier to Enhance the Hydrophilicity of Tc-Tricarbonyl-Based Radiopharmaceuticals.

The organometallic technetium-99m tricarbonyl core, [Tc][Tc(CO)(HO)], is a versatile precursor for the development of radiotracers for single photon emission computed tomography (SPECT). A drawback of the Tc-tricarbonyl core is its lipophilicity, which can influence the pharmacokinetic properties of the SPECT imaging probe. Addition of polar pharmacological modifiers to Tc-tricarbonyl conjugates holds the promise to counteract this effect and provide tumor-targeting radiopharmaceuticals with improved hydrophilicities, e.

Manganese in PET imaging: Opportunities and challenges.

Several radionuclides of the transition metal manganese are known and accessible. Three of them, Mn, Mn, and Mn, are positron emitters that are potentially interesting for positron emission tomography (PET) applications and, thus, have caught the interest of the radiochemical/radiopharmaceutical and nuclear medicine communities. This mini-review provides an overview of the production routes and physical properties of these radionuclides.

Mini-review: Targeted radiopharmaceuticals incorporating reversible, low molecular weight albumin binders.

The combination of low molecular weight, reversible human serum albumin (HSA) binders with targeted radiopharmaceuticals in dual-targeted radioconjugates holds great promise, in particular for endoradiotherapy. Attachment of HSA-binders to radiopharmaceuticals extends their blood circulation time and results in an enhanced tumour uptake as well as often in an improved pharmacokinetic profile. In this mini-review, an overview of currently pursued approaches of this novel strategy is provided.

Mn-Labelled CDTA-based trimeric complexes as novel bimodal PET/MR probes with high relaxivity.

trans-1,2-Diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA) labelled with a mixture of paramagnetic 55Mn(ii) and β+-emitting 52gMn(ii) offers access to bimodal Positron Emission Tomography/Magnetic Resonance (PET/MR) tracers. To enhance the number of NMR-active nuclei and simultaneously improve the longitudinal relaxivity r1, a complex composed of three CDTA units was designed. Accordingly, a functionalised tris-CDTA-1,3,5-tris-triazolobenzene was prepared and labelled with c.

An Overview of PET Radiochemistry, Part 2: Radiometals.

This continuing educational review provides an overview on radiometals used for PET. General aspects of radiometal-based radiotracers are covered, and the most frequently applied metallic PET radionuclides, Ga, Zr, and Cu, are highlighted with a discussion of their strengths and limitations.

Novel CDTA-based, Bifunctional Chelators for Stable and Inert Mn Complexation: Synthesis and Physicochemical Characterization.

In the search for Mn MR and PET/MR imaging agents with optimal balance between thermodynamic stability, kinetic inertness, and relaxivity, two novel bifunctional Mn chelators (BFMnCs) based on CDTA (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid) were synthesized. A six-step synthesis, involving the buildup of a functionalized trans-1,2-diaminocyclohexane core, provided CuAAC-reactive 6a and 6b bearing an alkyne or azide substituent on the cyclohexane ring, respectively (CuAAC = Cu-catalyzed azide-alkyne 1,3-dipolar cycloaddition). Thermodynamic, kinetic, and relaxometric studies were performed with 4-HET-CDTA (8a) as a "model chelator," synthesized in two steps from 6a.

Radiolabelling with isotopic mixtures of (52g/55)Mn(II) as a straight route to stable manganese complexes for bimodal PET/MR imaging.

Radiolabelling using isotopic mixtures of (52g/55)Mn(ii) offers fast and easy access to new small molecule PET/MR tracers, composed of chemically identical reporting units. trans-1,2-Diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA) was radiolabelled with carrier-added (52g)Mn(ii) in >99% radiochemical yield, producing the first manganese-based bimodal PET/MR probe. The Mn-CDTA chelate was shown to be very stable to air oxidation and sufficiently inert to decomplexation in blood serum.