Name: Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of 68Ga-Labelled Nano Molecules (Video) | JoVE Journal
Uploaded: 2024-10-04T14:15:00.000+00:00
Duration: 9 min 55 s
Description: Learn radiosynthesis and quality control of 68Ga-labeled nanobody NM-02 for small animal PET/CT imaging in cancer research. This method enables theranostic applications for improved diagnosis and therapy.

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5 minutes

The authors are grateful to Susanne Allekotte for her technical support.

Radiosynthesis and PET/CT Imaging of 68Ga-Labelled Nanobody in Xenograft Models

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<li>Korde, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Practical+considerations+for+navigating+the+regulatory+landscape+of+non-clinical+studies+for+clinical+translation+of+radiopharmaceuticals%5BTitle%5D)+AND+%22EJNMMI+Radiopharm+Chem%22%5BJournal%5D)">Practical considerations for navigating the regulatory landscape of non-clinical studies for clinical translation of radiopharmaceuticals.</a> EJNMMI Radiopharm Chem. 7 (1), 18(2022).</li>
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<li>Velikyan, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((68ga-based+radiopharmaceuticals%3A+Production+and+application+relationship%5BTitle%5D)+AND+%22Molecules%22%5BJournal%5D)">68ga-based radiopharmaceuticals: Production and application relationship.</a> Molecules. 20 (7), 12913-12943 (2015).</li>
<li>Percie Du Sert, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Reporting+animal+research%3A+Explanation+and+elaboration+for+the+arrive+guidelines+2.0%5BTitle%5D)+AND+%22PLoS+Biol%22%5BJournal%5D)">Reporting animal research: Explanation and elaboration for the arrive guidelines 2.0.</a> PLoS Biol. 18 (7), e3000411(2020).</li>
<li>Smith, A. J., Clutton, R. E., Lilley, E., Hansen, K. E. A., Brattelid, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Prepare%3A+Guidelines+for+planning+animal+research+and+testing%5BTitle%5D)+AND+%22Lab+Anim%22%5BJournal%5D)">Prepare: Guidelines for planning animal research and testing.</a> Lab Anim. 52 (2), 135-141 (2018).</li>
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FMM is a medical advisor for NanoMab Technology Ltd. and Advanced Accelerator Applications (AAA) GmbH. He has recently received institutional grants from NanoMab Technology Ltd., Siemens, and GE Precision Healthcare LLC. Furthermore, he has an interventional research contract with CURIUM.

Radiosynthesis 
The radiosynthesis described here is typical for a new 68Ga-labeled compound - short synthesis time, with emphasis on suitable pH and avoiding metals whenever possible. For this, it is important to strictly follow the order in which the components are added. In any case, the pH value of the 68Ga solution must first be adjusted to pH 4 with 3 M NH4OAc; otherwise, the nanobody may degrade if the pH is too acidic. The general concepts of 68Ga-synthesis have been described earlier16, so we will not go into details here. The automated synthesis module requires further optimization regarding a reduction of the radiation dose. This requires a significant effort that is beyond the scope of exploratory research in a typical preclinical experiment, as described here. Moreover, an automated synthesis is unlikely to yield the small volumes we can produce with the current method (&#60; 1 mL), allowing higher concentrations of 68Ga and higher specific activity.
Quality control should still be performed and registered in great detail. One exception to this detail is the pH: while pH measurements for clinical syntheses are frequently performed very accurately using pH meters, here it is sufficient to measure the pH with a simple pH strip as the requirements for intravenous injections do allow this (any pH between 6 and 8 is permissible14). This simple technique reduces the cost and the chance of contaminating equipment with radioactive material.
Formulations for animal models 
The final formulation of the tracer is a crucial aspect of the tracer, an aspect that is often described only poorly in preclinical research. While there is clear legislation for the formulation of pharmaceuticals for human trials, including radiopharmaceuticals, preclinically, there are only guidelines17,18 that do not specifically discuss solvents or formulations. These guidelines are often used when drafting or evaluating legally required protocols for approval by (animal) ethical committees (in Germany: LANUV19), but these documents insufficiently emphasize the importance of formulation. It is likely that poor formulations can lead to false (negative) results, but such a claim is hard to verify considering the persistent publication bias that still exists, also in the field of oncology20.
In addition to the ARRIVE guidelines, we opted to follow the legislation designed for human applications as much as possible, assuming that formulations suitable for humans are generally also suitable for rodents. The major difference is the size of the subject and, therefore, the amount of volume that can safely be injected. For this purpose, we opted to purify the compound whenever possible using molecular weight cut-off (MWCO) filters, as these have been proven to be effective for purifying large compounds21. They allow a typical 68Ga-labelled tracer to finally be dissolved in a solution of choice and in a small volume suitable for mice (typical maximum intravenous injection 100 - 150 &#181;L).
In Germany, the GV-SOLAS (Gesellschaft f&#252;r Versuchstierkunde, English: Association for laboratory animals) serves as an intermediator between animal protection and research, benefiting both humans and animals. Therefore, this association has set up recommendations for multiple aspects of animal research, especially in the fields of oncology and anesthesia, to standardize animal care at a national level14. Henceforth, most competent authorities and national ethical committees enforce the adherence of animal protocols to those recommendations. GV-SOLAS has recommendations for maximum volumes of most application routes. For intravenous injection, a maximum of 5 mL/kg of body weight is recommended; for a 25 g mouse, this equals 150 &#181;L. For this reason, all radioactive tracer productions are set for a maximum injection volume of 150 &#181;L per animal. Exceeding this threshold when injecting intravenously increases the risk of acute heart insufficiency caused by hypervolemia. Repeated intravenous injections exceeding this threshold leads to an increased risk of pulmonary fibrosis, as each injection, depending on the flow speed, causes minor pulmonary edema. A human equivalent of the mouse IV presented in this paper would be to inject intravenously in bolus (within 10 s) a total volume of 375 mL for a 75 kg human. In standard clinical care, 500 mL of 0.9% NaCl solution is administered over 1 h; this means that 375 mL would be administered over 45 min in order to avoid any complications.
GV-SOLAS recommends that the tumor burden not reach more than 5%; in case the animal is under treatment, the burden may be extended up to 10%22.&#160;This difference between treated and untreated groups has the potential to create a research bias, especially in the case of survival, as treated tumor mice may achieve a higher tumor burden than the afferent control group. To avoid such cases, either the 5% tumor burden should also be fixed for treatment animals; however, this may lead to ethical dilemmas for killing research animals prior to reaching a so-called humane endpoint, or (preferably) argue that the increase to 10% in the case of the afferent control groups is ethically grounded in order to avoid bias.
As the tumor burden needs to be calculated every day in a non-invasive manner, we apply a correction factor (i.e., 0.82) to convert the daily calculated tumor volume to a tumor weight. We calculated this factor by measuring tumor diameters using a digital caliper before the animals were killed according to the protocol and later the actual tumor weight using a scale. This correction factor is different from the density of the tumor tissue, as the measured tumor volume also includes the skin. Therefore, this factor is probably &#60; 1.0, as the measured tumor volume is larger than the real tumor volume. As the tumors we weighed were relatively large, because the assessment was done on the last day of the experiment, this factor indeed overestimates the weight of small tumors. It should only be used in the assessment of tumor load.
Another aspect of GV-SOLAS recommendations is that for mice, a fixed tumor diameter of 15 mm is set as a humane endpoint17. Frequently, the tumor has a tendency to grow fast along the needle canal made by the subcutaneous injection if no air or plug is injected after the solution containing tumor cells. Therefore, the 15 mm are reached faster to certain routes of application. Since, experience-wise, some tumors grow in an elliptical shape, we adapted and used the above-mentioned tumor volume formula to make unbiased comparisons between different routes of application.
The animal models we use are designed following the ARRIVE17 and PREPARE18 guidelines, allowing an easy experimental reproduction. The model is subject to a certain degree of variation as the tumor growth rate&#160;varies between different mice, making standardization and interpretation more difficult to handle. However, these variations reflect the intra- and intertumoral heterogeneity being present in the cancer patients23.
This protocol is not without its limitations. Animals must be sedated during the injection, especially during the PET/CT scan. Sedation, particularly with isoflurane, affects blood flow, and animals may become hypothermic, requiring the use of a heating mat and monitoring the depth&#160;of the sedation. This issue can be avoided by scanning awake animals; however, this requires specialized in-house software and expertise, which are often not available.
Another limitation is the radiation dose. Although the dose received by the animals is negligible for a single scan, performing multiple scans (i.e., especially if more than 10) can result in a significant cumulative dose, potentially impacting tumor growth. When tumor growth is a read-out parameter, it is essential that all animals receive the same number of scans and doses to ensure comparable groups, adding to the workload of the entire project. Using a PET/MRI system instead of a PET/CT system could reduce radiation exposure. However, this approach involves longer scan times, additional costs, and a different method of obtaining anatomical information.
By adhering to recommendations from welfare organizations such as GV-SOLAS in Germany and following established guidelines such as ARRIVE and PREPARE, we strive to standardize animal models and minimize variability in experimental protocols. These efforts are crucial for ensuring the reliability and reproducibility of preclinical studies, ultimately facilitating the translation of promising radiopharmaceuticals from bench to bedside.

One topic that is of utmost relevance is research in the breast cancer field. Breast cancer remains a frequently occurring cancer, accounting for roughly 1/3rd of all cancers in women. The treatment is tailored to the biological and histological characteristics of the tumor and to the stage of the disease. The chance of survival is generally good unless the tumor has already metastasized, in which case the 5-year survival is only about 30%1. Other gynecologic cancers suffer from a similar fate, with, for example, ovarian cancer showing &#62; 95% 5-year survival for stage 1 tumors but only 15% for metastasized stage 4 tumors2,3.
Non-invasive imaging, particularly positron emission tomography (PET), has been transforming cancer research as it offers unparalleled insights into tumor molecular aspects, such as metabolism, receptor expression, and therapeutic response4,5,6. It allows both visualization and quantification of specific metabolic areas - allowing not only to accurately diagnose, but also to monitor the effect of (new) therapies at very short time points. Indeed, PET allows evaluation of response versus non-response after 1-3 therapy cycles and does this better and faster compared to morphological changes as seen by classical computed tomography (CT) imaging7. The non-invasive nature of PET also enables longitudinal studies.
Any animal model requires maximal standardization in order to thoroughly assess the therapeutic capacity of new (radioactive) pharmaceuticals, so the emphasis has to be put on this - both in the generation of the tumor model and in the small animal PET imaging/data analysis. One could debate about the best tumor model in animals (subcutaneous inoculation or orthotopic implantation, mice, human, or syngeneic tumors, accompanied or not accompanied by routine clinical care), but that would be beyond the goal of this publication. Several models are used by us for cancer studies, and the one described here is a relatively simple subcutaneous model.
Quality control in radiochemistry is paramount for animal safety and treatment efficacy. This does not only affect the radiopharmaceutical itself but also the product formulation. There is extensive legislation on the production of radiopharmaceuticals for clinical applications8,9 (see&#160;10 for an extensive overview of current legislation and guidelines), and several guidelines on the properties of radiopharmaceuticals for preclinical research (see 11 for an extensive overview). We produce radiopharmaceuticals both for clinical and preclinical applications, simplifying the translation from high-end quality control as found in syntheses for clinical applications into those for preclinical applications.
Our research focus is on directed theranostics, especially on human epidermal growth factor receptor 2 (HER2)-positive cancers. Hence, we develop new radiopharmaceuticals to diagnose and monitor cancer during treatment. Successful diagnostic radiopharmaceuticals are also evaluated as therapeutic compounds using different radioisotopes. The evaluation of these radiopharmaceuticals is performed at first in animal models, striving for clinical translation after promising preclinical results. In this article, we will present the protocols used, exemplified with one radiopharmaceutical, to ensure quality control and assurance, as well as standard practice for mouse intravenous injection and PET/CT scan, in order to improve the accuracy and reliability of preclinical investigations in molecular imaging. The protocol is divided into three different sections: radiochemistry (tracer synthesis and quality control), animal model generation (subcutaneous tumor model), and imaging.

<table><tbody><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Activity meter ISOMED 2010</td><td>Nuviatech Healthcare&amp;nbsp;</td><td>-</td><td></td></tr><tr><td>Centrifuge MIKRO 185</td><td>Andreas Hettich GmbH &amp;amp; Co. KG</td><td>1203</td><td></td></tr><tr><td>Endotoxin testing Endosafe nexgen-PTS</td><td>Charles River</td><td>-</td><td></td></tr><tr><td>Heating block NANOCOLOR VARIO C2</td><td>Macherey-Nagel</td><td>919350</td><td></td></tr><tr><td>HPLC system, including radio detector</td><td>Knauer &amp;amp; Raytest</td><td>-</td><td></td></tr><tr><td>Image analysis software Pmod 4.4&amp;nbsp;</td><td>PMOD Technologies LLC</td><td>-</td><td></td></tr><tr><td>Small animal PET/CT system &amp;beta;-CUBE and X-CUBE</td><td>Molecubes NV</td><td>-</td><td></td></tr><tr><td>TLC MiniGITA*</td><td>Elysia-Raytest</td><td>-</td><td></td></tr><tr><td>&lt;strong&gt;Materials&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>0.3 mm diameter PE10 tube</td><td>fisher scientific</td><td>22-204008</td><td></td></tr><tr><td>30G needle</td><td>B|Braun</td><td>4656300</td><td></td></tr><tr><td>Centrifugal filter; 10 kDa MWCO, 0.5 mL</td><td>Millipore</td><td>UFC501008</td><td></td></tr><tr><td>Chromatography paper strip iTLC-SG</td><td>Agilent Technologies</td><td>SGI0001</td><td></td></tr><tr><td>Endotoxin Cartridge, 0.05 EU/ml sensitivity&amp;nbsp;</td><td>Charles River</td><td>PTS-2005</td><td></td></tr><tr><td>HPLC Column Biosep SEC-s2000</td><td>Phenomenex</td><td>-</td><td></td></tr><tr><td>Microcentrifuge tube (1.5 mL)</td><td>Eppendorf</td><td>0030125150</td><td></td></tr><tr><td>pH strip 0.0 - 6.0</td><td>Merck KGaA</td><td>109531</td><td></td></tr><tr><td>pH strip 0-14</td><td>Merck KGaA</td><td>109535</td><td></td></tr><tr><td>PS-H&lt;sup&gt;+&lt;/sup&gt; SPE cartridge</td><td>Macherey Nagel GmbH &amp;amp; Co. KG</td><td>731861</td><td></td></tr><tr><td>Sterile vial 10 mL</td><td>ALK Life Science Solutions</td><td>SEV100</td><td></td></tr><tr><td>&lt;strong&gt;Reagents&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>&lt;sup&gt;68&lt;/sup&gt;Ge/&lt;sup&gt;68&lt;/sup&gt;Ga-Generator</td><td>NRF-iThembaLABS</td><td>-</td><td></td></tr><tr><td>Ammoniumacetate</td><td>Merck KGaA</td><td>101116</td><td></td></tr><tr><td>Citric acid</td><td>Merck KGaA</td><td>100241</td><td></td></tr><tr><td>Hydrochloric acid</td><td>Merck KGaA</td><td>320331</td><td></td></tr><tr><td>NaCl</td><td>Merck KGaA</td><td>S9888</td><td></td></tr><tr><td>Nanobody NM-02</td><td>Radiopharm Theranostics</td><td>-</td><td></td></tr><tr><td>P-SCN-Bz-DOTA-GA</td><td>CheMatech</td><td>C115</td><td></td></tr><tr><td>Trifluoracetic acid</td><td>Merck KGaA</td><td>T6508</td><td></td></tr><tr><td>Ultrapure water</td><td>Merck KGaA</td><td>101262</td><td></td></tr></tbody></table>

radiosynthesis, quality control, and small animal positron emission tomography imaging of 68ga-labelled nano molecules

Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of 68Ga-Labelled Nano Molecules

Small animal Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging techniques are crucial in preclinical cancer research, necessitating meticulous attention to radiotracer synthesis, quality assurance, and in vivo injection protocols. This study presents a comprehensive workflow tailored to enhance the robustness and reproducibility of small animal PET experiments. The synthesis process in the radiochemistry laboratory using 68Ga is detailed, highlighting stringent quality control and assurance protocols for each radiotracer production. Parameters such as concentration, molar activity, pH, and purity are rigorously monitored, aligning with standards applicable to human studies. This methodology introduces streamlined syringe preparation and a custom-designed 30G cannula for precise intravenous injections into mice. Monitoring of animal health during scanning, including temperature and heart rate, ensures their well-being throughout the procedure. Dosages for PET and SPECT scans are predetermined to balance data acquisition with minimizing radiation exposure to animals and researchers. Similarly, CT scans employ pre-programmed settings to limit radiation exposure, especially pertinent in long-term studies assessing treatment effects. By optimizing these steps, the workflow aims to standardize procedures, reduce variability, and enhance the quality of small animal PET/SPECT/CT imaging. This resource provides valuable insights for researchers seeking to improve the accuracy and reliability of preclinical investigations in molecular imaging, ultimately advancing the field.

One of the most important aspects of quality control of a radiopharmaceutical is by means of HPLC, as this shows not only the chemical and radiochemical purity (98.2% in this case) but also allows to prove the identity of the radiopharmaceutical by comparing the elution time and peak shape to that of a non-radioactive reference compound. This reference compound is, in this case, an unlabeled nanobody, proven to be the correct compound by classical techniques such as mass spectrometry or nuclear magnetic resonance. These techniques cannot be applied directly to the radioactive compound (there is not enough mass to generate a signal), but by comparing the radioactive compound with its reference, sufficient evidence is gathered that the correct compound was indeed labeled and not altered during synthesis. Note the minor difference in retention time between the radioactive product and the reference in Figure 1, corresponding to the serial measurement of the HPLC flow (UV is measured first; the flow then needs roughly 0.2 min to reach the radioactivity detector in a typical setup).
<img alt="Chromatography results diagram; peptide separation via HPLC; UV detection at 280 nm; CPS data." class="xfigimg" src="/files/ftp_upload/67048/67048fig01.jpg" data-altupdatedat="1788304762000" data-alt="Figure 1"> 
Figure 1: Typical analytical HPLC chromatogram for quality control of 68Ga-labeled nanobody NM-02 (GLNM-02). The cold compound's UV absorbance (i.e., upper panel) is measured at 280 nm and shows a peak at 4.18 min, with a shift of 0.22 min. The peak of the 68Ga-labeled product can be seen in the gamma detector (i.e., lower panel). The radiochemical yield is 98.2%. mAU = milli Absorbance Units, NM-02 = our product, UV = ultraviolet light channel, nm = nanometer, min = minute, CPS = counts per second, GLMN-02 = 68Ga-labeled nanobody NM-02, 68Ga-DOTA-GA = [68Ga]Ga-DOTA-GA, γ ChA = gamma channel. <a href="https://www.jove.com/files/ftp_upload/67048/67048fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In the absence of HPLC or in addition to it, TLC can be used to determine the labeling yield and purity of the final product (but not the identity, and not as detailed as HPLC). Due to its low complexity, TLC is ideal when the radiosynthesis pathway is still being optimized. Figure 2 shows the TLC chromatogram of 68Ga-labeled nanobody NM-02 (apparent radiochemical purity 99.9%).
<img alt="Chromatography graph, TLC result, concentration vs. distance, peak analysis, solvent front visualization." class="xfigimg" src="/files/ftp_upload/67048/67048fig02.jpg" data-altupdatedat="1788304762000" data-alt="Figure 2"> 
Figure 2: Typical analytical TLC chromatogram for quality control of 68Ga-labeled nanobody NM-02 (GLNM-02). Area counts are plotted against the distance traveled by the solvent (citrate) on the TLC plate. The Rf is 0.2, and the radiochemical purity is 99.9%. C = Counts, mm = millimeter, GLNM-02 = 68Ga-labeled nanobody NM-02, TLC = thin layer chromatography. <a href="https://www.jove.com/files/ftp_upload/67048/67048fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In the process of preparing imaging data for publication, it is standard practice to show at least one standalone CT and PET image. This approach enables a comprehensive evaluation of tracer biodistribution. Standard CT scaling is between -1000 HU and 1000 HU, which allows for the visualization of all soft tissues within a single window. As shown in Figure 3A, this method enables clear demarcation of mouse kidneys while simultaneously allowing for bone assessment.
For the PET scale, set the lower threshold at an SUV of 0.0 while maintaining a minimum upper threshold of 1.0 (Figure 3B), preferably using body weight normalization during the SUV calculation (i.e., SUVbw). Additionally, for quantification, SUVmean is preferred compared to SUVmax; should the SUVmax be used, then use the average of the hottest 10 voxels instead of the value of the hottest single voxel in the SUVbw calculation. Prepare feature fusions of PET/CT images by merging the CT and PET slices (Figure 3C).
To further enable readers to independently assess the full-body tracer biodistribution, the maximum intensity projection of the same PET scan can be presented using the same scale as the PET slice (Figure 3D).
<img alt="CT, PET, PET/CT imaging comparison diagram; reveals anatomical and functional data in study." class="xfigimg" src="/files/ftp_upload/67048/67048fig03.jpg" data-altupdatedat="1788304762000" data-alt="Figure 3"> 
Figure 3: In vivo PET/CT images of a subcutaneous SKOV-3 tumor-bearing mouse. The image was acquired 3 h after intravenous injection of 5 MBq 68Ga-labeled nanobody NM-02 (GLNM-02). (A) The CT image is scaled between -1000 HU and 1000 HU, while (B) the PET image is between an SUV of 0.0 and 5.0. (C) The PET/CT fusion uses the same scale. (D) The maximum intensity projection (MIP) PET image is also scaled using an SUV of 0.0 and 5.0. All PET images show a good tumor uptake of GLNM-02, and the renal clearance is clearly visible. CT = computed tomography, PET = positron emission tomography, MIP = maximum intensity projection, HU = Hounsfield unit, SUV = standardized uptake value. <a href="https://www.jove.com/files/ftp_upload/67048/67048fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
In the specific case of the 68Ga-labeled nanobody NM-02, notable tumor uptake can be observed in the left flank of the mouse. Additionally, the renal clearance of the tracer is also evident. By presenting the PET maximum intensity projection, the urinary bladder activity also becomes visible, reinforcing the renal clearance of the tracer. In this specific case, it is worth mentioning that the kidney, tumor, and bladder cannot be shown in the same 2D slice. By including the maximum intensity projection in publications, the entire biodistribution of the tracer is presented in the same image.

This paper describes the radiosynthesis, formulation, quality control of a new radiolabeled probe (i.e., 68Ga-labeled nanobody NM-02), and its use for small animal PET/CT imaging in a xenograft model.

Small animal Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging techniques are crucial in preclinical ...

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Research

JoVE Journal

Cancer Research

We demonstrate the semi-automated radiochemical synthesis of [18F]3F4AP and quality control procedures.

Automated Radiochemical Synthesis of [18F]3F4AP: A Novel PET Tracer for Imaging Demyelinating Diseases

We describe a protocol for preclinical in vivo tracking of cancer metastasis. It is based on a radionuclide-fluorescence reporter combining the sodium iodide symporter, detected by non-invasive [18F]tetrafluoroborate-PET, and a fluorescent protein for streamlined ex vivo confirmation. The method is applicable for preclinical in vivo cell tracking beyond tumor biology.

Radionuclide-fluorescence Reporter Gene Imaging to Track Tumor Progression in Rodent Tumor Models

Here, we present a protocol to obtain 68Ga core-doped iron oxide nanoparticles via fast microwave-driven synthesis. The methodology renders PET/(T1)MRI nanoparticles with radiolabeling efficiencies higher than 90% and radiochemical purity of 99% in a 20-min synthesis.

Synthesis of 68Ga Core-doped Iron Oxide Nanoparticles for Dual Positron Emission Tomography /(T1)Magnetic Resonance Imaging

Positron-emission tomography (PET) imaging sites that are involved in multiple early clinical research trials need robust and versatile radiotracer manufacturing capabilities. Using the radiotracer [18F]Clofarabine as an example, we illustrate how to automate the synthesis of a radiotracer using a flexible, cassette-based radiosynthesizer and validate the synthesis for clinical use.

Automation of a Positron-emission Tomography (PET) Radiotracer Synthesis Protocol for Clinical Production

Here, we represent a protocol for the fully automated radiolabelling of [11C]SNAP-7941 and the analysis of the real-time kinetics of this PET-tracer on P-gp expressing and non-expressing cells.

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

This method estimates the absorbed dose of different structures for peptide-receptor-radionuclide-therapy (PRRT) with the possibility of avoiding organ overlap on 2D-projections. Serial whole-body planar images permit estimation of mean absorbed doses along the whole body, while the hybrid approach, combining planar images and 3D-SPECT/CT image, overcomes the limitations of structure overlapping.

A Whole Body Dosimetry Protocol for Peptide-Receptor Radionuclide Therapy (PRRT): 2D Planar Image and Hybrid 2D+3D SPECT/CT Image Methods

The synthesis of fluorine-18 (18F) labeled radiopharmaceuticals for positron emission tomography typically requires months of experience. When incorporated into a radiotracer, the silicon-fluoride acceptor (SiFA) motif enables a simple 18F-labeling protocol that is independent of costly equipment and preparatory training, while reducing precursor quantity needed and utilizing milder reaction conditions.

18F-Labeling of Radiotracers Functionalized with a Silicon Fluoride Acceptor (SiFA) for Positron Emission Tomography

This study developed a noninvasive and real-time method to evaluate the distribution of programmed death-ligand 1 in the whole body, based on positron emission tomographic imaging of [68Ga] D-dodecapeptide antagonist. This technique has advantages over conventional immunohistochemistry and improves the efficiency of identifying appropriate patients who will benefit from immune checkpoint blockade therapy.

Development of a 68Gallium-Labeled D-Peptide PET Tracer for Imaging Programmed Death-Ligand 1 Expression

This work describes the automated production of up to 1.7 GBq of [68Ga]Ga-FAPI-46 on the iPHASE MultiSyn synthesizer for PET imaging of fibroblast activation protein.

An Automated Radiosynthesis of [68Ga]Ga-FAPI-46 for Routine Clinical Use

This protocol presents a detailed procedure to prepare four carbon-11 radiotracers by way of the “loop method” [11C]methylation. We describe the procedure to synthesize [11C]ER-176,  with data for three additional radiotracers: [11C]MRB, [11C]mHED, and [11C]PiB. The loop method provides an efficient synthesis with increased radiochemical yields against traditional reaction vessel [11C]methylation.

Enhancing Efficiency and Radiolabeling Yields of Carbon-11 Radioligands for Clinical Research Using the Loop Method

This research describes the automated process for [68Ga]Ga-3BP-3940 production with the GAIA V2 synthesizer, for PET imaging of fibroblast activation protein. The results of quality control tests performed on three test batches are also presented.

Automated Preparation of [68Ga]Ga-3BP-3940 on a Synthesis Module for PET Imaging of the Tumor Microenvironment

Learn radiosynthesis and quality control of 68Ga-labeled nanobody NM-02 for small animal PET/CT imaging in cancer research. This method enables theranostic applications for improved diagnosis and therapy.

Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of ⁶⁸Ga-Labelled Nano Molecules

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