Name: positron emission tomography imaging of cell trafficking: a method of cell radiolabeling
Uploaded: 2023-10-27T14:20:00
Description: Watch this Scientific Journal Video about Positron Emission Tomography Imaging of Cell Trafficking: A Method of Cell Radiolabeling at JoVE.com

This work was supported by NIH 5R21HL127389-02, NIH 4T32HL007111-39, NIH R01HL134664, and DOE DE-SC0008947 grants, International Atomic Energy Agency, Vienna, Mayo Clinic Division of Nuclear Medicine, Department of Radiology, and Mayo Clinic Center for Regenerative Medicine, Rochester, MN. All figures were created using BioRender.com.

Dendritic cells and melanoma cells were obtained commercially18. Hepatocytes were isolated from the liver of pigs following laparoscopic partial hepatectomy22,24. Stem cells were isolated from bone marrow aspirates18,19,26. The adipose tissue-derived stem cells were obtained from the Human Cellular Therapy Laboratory, Mayo Clinic Rochester<sup cla...

<ol>
	<li>Bhawnani, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+stem+cell+therapies+in+improving+clinical+outcomes+in+patients+with+heart+failure.">Effectiveness of stem cell therapies in improving clinical outcomes in patients with heart failure.</a> Cureus. 13 (8), e17236 (2021).</li><li>Zakrzewski, W., Dobrzynski, M., Szymonowicz, M., Rybak, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stem+cells:+past,+present,+and+future.">Stem cells: past, present, and future.</a> Stem Cell Research &amp; Therapy. 10 (1), 68 (2019).</li><li>Bukhari, A. B., Dutta, S., De, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+guidance+in+stem+cell+therapeutics:+unfolding+the+blindfold.">Image guidance in stem cell therapeutics: unfolding the blindfold.</a> Current Drug Targets. 16 (6), 658-671 (2015).</li><li>Momeni, A., Neelamegham, S., Parashurama, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current+challenges+for+the+targeted+delivery+and+molecular+imaging+of+stem+cells+in+animal+models.">Current challenges for the targeted delivery and molecular imaging of stem cells in animal models.</a> Bioengineered. 8 (4), 316-324 (2017).</li><li>Gnecchi, M., Zhang, Z., Ni, A., Dzau, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paracrine+mechanisms+in+adult+stem+cell+signaling+and+therapy.">Paracrine mechanisms in adult stem cell signaling and therapy.</a> Circulation Research. 103 (11), 1204-1219 (2008).</li><li>D'Aloia, M. M., Zizzari, I. G., Sacchetti, B., Pierelli, L., Alimandi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CAR-T+cells:+the+long+and+winding+road+to+solid+tumors.">CAR-T cells: the long and winding road to solid tumors.</a> Cell Death &amp; Disease. 9 (3), 282 (2018).</li><li>Zhang, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CAR-T+cell+therapy+in+cancer:+tribulations+and+road+ahead.">CAR-T cell therapy in cancer: tribulations and road ahead.</a> Journal of Immunology Research. 2020, 1924379 (2020).</li><li>Sterner, R. C., Sterner, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CAR-T+cell+therapy:+current+limitations+and+potential+strategies.">CAR-T cell therapy: current limitations and potential strategies.</a> Blood Cancer Journal. 11 (4), 69 (2021).</li><li>Shao, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radionuclide-based+molecular+imaging+allows+CAR-T+cellular+visualization+and+therapeutic+monitoring.">Radionuclide-based molecular imaging allows CAR-T cellular visualization and therapeutic monitoring.</a> Theranostics. 11 (14), 6800-6817 (2021).</li><li>Sakemura, R., Can, I., Siegler, E. L., Kenderian, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+CART+cell+imaging:+Paving+the+way+for+success+in+CART+cell+therapy.">In vivo CART cell imaging: Paving the way for success in CART cell therapy.</a> Molecular Therapy Oncolytics. 20, 625-633 (2021).</li><li>Wang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+cell+biology+and+its+role+in+tumor+immunotherapy.">Dendritic cell biology and its role in tumor immunotherapy.</a> Journal of Hematology &amp; Oncology. 13 (1), 107 (2020).</li><li>Bulte, J. W. M., Shakeri-Zadeh, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+MRI+tracking+of+tumor+vaccination+and+antigen+presentation+by+dendritic+cells.">In vivo MRI tracking of tumor vaccination and antigen presentation by dendritic cells.</a> Molecular Imaging and Biology. 24 (2), 198-207 (2022).</li><li>Holland, J. P., Sheh, Y., Lewis, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardized+methods+for+the+production+of+high+specific-activity+zirconium-89.">Standardized methods for the production of high specific-activity zirconium-89.</a> Nuclear Medicine and Biology. 36 (7), 729-739 (2009).</li><li>Larenkov, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+of+zirconium-89+solutions+for+radiopharmaceutical+purposes:+interrelation+between+formulation,+radiochemical+purity,+stability+and+biodistribution.">Preparation of zirconium-89 solutions for radiopharmaceutical purposes: interrelation between formulation, radiochemical purity, stability and biodistribution.</a> Molecules. 24 (8), 1534 (2019).</li><li>Pandey, M. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+solid+target+design+for+the+production+of+89Zr+and+radiosynthesis+of+high+molar+activity+[89Zr]Zr-DBN.">A new solid target design for the production of 89Zr and radiosynthesis of high molar activity [89Zr]Zr-DBN.</a> American Journal of Nuclear Medicine and Molecular Imaging. 12 (1), 15-24 (2022).</li><li>Pandey, M. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+production+and+processing+of+89Zr+using+a+solution+target.">Improved production and processing of 89Zr using a solution target.</a> Nuclear Medicine and Biology. 43 (1), 97-100 (2016).</li><li>Pandey, M. K., Engelbrecht, H. P., Byrne, J. P., Packard, A. B., DeGrado, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+89Zr+via+the+89Y(p,n)89Zr+reaction+in+aqueous+solution:+effect+of+solution+composition+on+in-target+chemistry.">Production of 89Zr via the 89Y(p,n)89Zr reaction in aqueous solution: effect of solution composition on in-target chemistry.</a> Nuclear Medicine and Biology. 41 (4), 309-316 (2014).</li><li>Bansal, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+89Zr+cell+labeling+approach+for+PET-based+cell+trafficking+studies.">Novel 89Zr cell labeling approach for PET-based cell trafficking studies.</a> EJNMMI Research. 5, 19 (2015).</li><li>Bansal, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=89Zr]Zr-DBN+labeled+cardiopoietic+stem+cells+proficient+for+heart+failure.">89Zr]Zr-DBN labeled cardiopoietic stem cells proficient for heart failure.</a> Nuclear Medicine and Biology. 90-91, 23-30 (2020).</li><li>Friberger, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimisation+of+the+synthesis+and+cell+labelling+conditions+for+[89Zr]Zr-oxine+and+[89Zr]Zr-DFO-NCS:+a+direct+in+vitro+comparison+in+cell+types+with+distinct+therapeutic+applications.">Optimisation of the synthesis and cell labelling conditions for [89Zr]Zr-oxine and [89Zr]Zr-DFO-NCS: a direct in vitro comparison in cell types with distinct therapeutic applications.</a> Molecular Imaging and Biology. 23 (6), 952-962 (2021).</li><li>Lee, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Feasibility+of+real-time+in+vivo+89Zr-DFO-labeled+CAR+T-cell+trafficking+using+PET+imaging.">Feasibility of real-time in vivo 89Zr-DFO-labeled CAR T-cell trafficking using PET imaging.</a> PLoS One. 15 (1), e0223814 (2020).</li><li>Nicolas, C. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hepatocyte+spheroids+as+an+alternative+to+single+cells+for+transplantation+after+ex+vivo+gene+therapy+in+mice+and+pig+models.">Hepatocyte spheroids as an alternative to single cells for transplantation after ex vivo gene therapy in mice and pig models.</a> Surgery. 164 (3), 473-481 (2018).</li><li>Yang, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracking+and+therapeutic+value+of+human+adipose+tissue-derived+mesenchymal+stem+cell+transplantation+in+reducing+venous+neointimal+hyperplasia+associated+with+arteriovenous+fistula.">Tracking and therapeutic value of human adipose tissue-derived mesenchymal stem cell transplantation in reducing venous neointimal hyperplasia associated with arteriovenous fistula.</a> Radiology. 279 (2), 513-522 (2016).</li><li>Nicolas, C. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+cell+therapy+by+ectopic+hepatocyte+transplantation+treats+the+porcine+tyrosinemia+model+of+acute+liver+failure.">Ex vivo cell therapy by ectopic hepatocyte transplantation treats the porcine tyrosinemia model of acute liver failure.</a> Molecular Therapy. Methods &amp; Clinical Development. 18, 738-750 (2020).</li><li>Bansal, A., Sharma, S., Klasen, B., Rosch, F., Pandey, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+different+89Zr-labeled+synthons+for+direct+labeling+and+tracking+of+white+blood+cells+and+stem+cells+in+healthy+athymic+mice.">Evaluation of different 89Zr-labeled synthons for direct labeling and tracking of white blood cells and stem cells in healthy athymic mice.</a> Scientific Reports. 12 (1), 15646 (2022).</li><li>Behfar, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guided+cardiopoiesis+enhances+therapeutic+benefit+of+bone+marrow+human+mesenchymal+stem+cells+in+chronic+myocardial+infarction.">Guided cardiopoiesis enhances therapeutic benefit of bone marrow human mesenchymal stem cells in chronic myocardial infarction.</a> Journal of the American College of Cardiology. 56 (9), 721-734 (2010).</li><li>Charoenphun, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=89Zr]oxinate4+for+long-term+in+vivo+cell+tracking+by+positron+emission+tomography.">89Zr]oxinate4 for long-term in vivo cell tracking by positron emission tomography.</a> European Journal of Nuclear Medicine and Molecular Imaging. 42 (2), 278-287 (2015).</li><li>Sato, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+tracking+of+adoptively+transferred+natural+killer+cells+in+rhesus+macaques+using+89zirconium-oxine+cell+labeling+and+PET+imaging.">In vivo tracking of adoptively transferred natural killer cells in rhesus macaques using 89zirconium-oxine cell labeling and PET imaging.</a> Clinical Cancer Research. 26 (11), 2573-2581 (2020).</li><li>Volpe, A., Pillarsetty, N. V. K., Lewis, J. S., Ponomarev, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+of+nuclear-based+imaging+in+gene+and+cell+therapy:+probe+considerations.">Applications of nuclear-based imaging in gene and cell therapy: probe considerations.</a> Molecular Therapy Oncolytics. 20, 447-458 (2021).</li><li>Fogli, L. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Challenges+and+next+steps+in+the+advancement+of+immunotherapy:+summary+of+the+2018+and+2020+National+Cancer+Institute+workshops+on+cell-based+immunotherapy+for+solid+tumors.">Challenges and next steps in the advancement of immunotherapy: summary of the 2018 and 2020 National Cancer Institute workshops on cell-based immunotherapy for solid tumors.</a> Journal for Immunotherapy of Cancer. 9 (7), e003048 (2021).</li><li>Li, X., Hacker, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+imaging+in+stem+cell-based+therapies+of+cardiac+diseases.">Molecular imaging in stem cell-based therapies of cardiac diseases.</a> Advanced Drug Delivery Reviews. 120, 71-88 (2017).</li><li>Puges, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrospective+study+comparing+WBC+scan+and+18F-FDG+PET/CT+in+patients+with+suspected+prosthetic+vascular+graft+infection.">Retrospective study comparing WBC scan and 18F-FDG PET/CT in patients with suspected prosthetic vascular graft infection.</a> European Journal of Vascular and Endovascular Surgery. 57 (6), 876-884 (2019).</li><li>Butterfield, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+cells+in+cancer+immunotherapy+clinical+trials:+are+we+making+progress.">Dendritic cells in cancer immunotherapy clinical trials: are we making progress.</a> Frontiers in Immunology. 4, 454 (2013).</li><li>de Vries, I. J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+resonance+tracking+of+dendritic+cells+in+melanoma+patients+for+monitoring+of+cellular+therapy.">Magnetic resonance tracking of dendritic cells in melanoma patients for monitoring of cellular therapy.</a> Nature Biotechnology. 23 (11), 1407-1413 (2005).</li><li>Gosmann, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Promise+and+challenges+of+clinical+non-invasive+T-cell+tracking+in+the+era+of+cancer+immunotherapy.">Promise and challenges of clinical non-invasive T-cell tracking in the era of cancer immunotherapy.</a> EJNMMI Research. 12 (1), 5 (2022).</li></ol>

Following are critical steps in the protocol that need optimization for effective cell radiolabeling. In protocol steps 1.2 and 1.3, depending on the volume of [89Zr]Zr(HPO4)2 or [89Zr]ZrCl4 employed, an appropriate volume (microliters) of base must be used; 1.0 M K2CO3 solution must be used for the neutralization of [89Zr]Zr(HPO4)2 and 1.0 M Na2CO3 solution for the neutralization of [8...

Stem cell and chimeric antigen receptor (CAR) T-cell therapies are gaining popularity and are under active investigation for the treatment of various diseases, such as myocardial failure1,2, retinal degeneration2, macular degeneration2, diabetes2, myocardial infarction3,4,5, and cancers6,7,8,9,10. Among the two plausible approaches of stem cell therapies, stem cells can either be directly engrafted on the disease site to cause a therapeutic response, or cause changes in the microenvironment of the disease site without adhering to the disease site to initiate an indirect therapeutic response. An indirect therapeutic response could cause changes in the microenvironment of the disease site by releasing factors that would repair or treat the disease5. These approaches of stem cell therapies could be evaluated by noninvasive imaging of radiolabeled stem cells. Noninvasive imaging could correlate the uptake of the radiolabeled cells on the disease site with a therapeutic response to decipher the direct versus indirect therapeutic response.
Additionally, immune cell-based therapies are being developed to treat various cancers using CAR T-cell6,7,8,9,10and dendritic cell immunotherapy11,12. Mechanistically, in CAR T-cell immunotherapy6,7,8,9,10, T-cells are engineered to express an epitope that binds to a specific antigen on tumors that needs to be treated. These engineered CAR T-cells, upon administration, bind to the specific antigen present on the tumor cells through an epitope-antigen interaction. After binding, the bound CAR T-cells undergo activation and then proliferate and release cytokines, which signals the immune system of the host to attack the tumor expressing the specific antigen. In contrast, in the case of dendritic cell therapies11,12, dendritic cells are engineered to present a specific cancer antigen on their surface. These engineered dendritic cells, when administered, home to the lymph nodes and bind to the T-cells in the lymph nodes. The T-cells, upon binding to the specific cancer antigens on the administered dendritic cells, undergo activation/proliferation and initiate an immune response of the host against the tumor expressing that specific antigen. Hence, the assessment of trafficking of administered CAR T-cells to a tumor site9,10 and homing of dendritic cells to the lymph nodes11,12 is possible by imaging radiolabeled CAR T-cells and dendritic cells to determine the efficacy of immunotherapy. Furthermore, noninvasive cell trafficking can help to better understand the therapeutic potential, clarify the direct versus indirect therapeutic response, and predict and monitor the therapeutic response of both stem cell and immune cell-based therapies.
Different imaging modalities for cell trafficking have been explored3,4,9,10,12, including optical imaging, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and positron emission tomography (PET). Each of these techniques has its own advantages and disadvantages. Among these, PET is the most promising modality due to its quantitative nature and high sensitivity, which are essential for the reliable quantification of cells in imaging-based cell trafficking3,4,9,10.
The positron-emitting radioisotope 89Zr, with a half-life of 78.4 h, is suitable for cell labeling. It allows PET imaging of cell trafficking for over 1 week and is readily produced by widely available, low-energy medical cyclotrons13,14,15,16,17. Additionally, an appropriately functionalized, p-isothiocyanatobenzyl-desferrioxamine (DFO-Bn-NCS) chelator is commercially available for the synthesis of a 89Zr-labeled, ready-to-use, cell labeling synthon, [89Zr]Zr-p-isothiocyanatobenzyl-desferrioxamine, also known as [89Zr]Zr-DBN18,19,20,21,22,23,24,25.&#160;The principle of [89Zr]Zr-DBN-mediated cell labeling is based on a reaction between primary amines of cell membrane proteins and the isothiocyanate (NCS) moiety of [89Zr]Zr-DBN to produce a stable covalent thiourea bond.
[89Zr]Zr-DBN-based cell labeling and imaging have been published to track a variety of different cells, including stem cells18,23,25, dendritic cells18, cardiopoietic stem cells19, decidual stromal cells20,&#160;bone marrow-derived macrophages20, peripheral blood mononuclear cells20, Jurkat/CAR T-cells21, hepatocytes22,24, and white blood cells25. The following protocol provides step-by-step methods of preparation and cell radiolabeling with [89Zr]Zr-DBN and describes changes that may be required in the radiolabeling protocol for a specific cell type. For greater clarity, the method of cell radiolabeling presented here is divided into four sections. The first section deals with the preparation of [89Zr]Zr-DBN by chelating 89Zr&#160;with DFO-Bn-NCS. The second section describes the preparation of a biocompatible formulation of [89Zr]Zr-DBN that can be readily used for cell radiolabeling. The third section covers the steps needed for the preconditioning of cells for radiolabeling. The preconditioning of cells involves washing the cells with protein-free phosphate buffered saline (PBS) and HEPES buffered Hanks balanced salt solution (H-HBSS) to remove external proteins, which might interfere or compete with the reaction of [89Zr]Zr-DBN with primary amines present on the cell surface proteins during radiolabeling. The final section provides steps involved in the actual radiolabeling of the cells and quality control analysis.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetonitrile</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, MA, USA</td>
			<td>A996-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Alpha Minimum Essential Medium</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, MA, USA</td>
			<td>12571063</td>
			<td></td>
		</tr>
		<tr>
			<td>Anion exchange column</td>
			<td>Macherey-Nagel, Inc., D&#252;ren, Germany</td>
			<td>731876</td>
			<td>Chromafix 30-PS-HCO3&#160;SPE 45 mg cartridge</td>
		</tr>
		<tr>
			<td>Conical centrifuge tubes (15 mL)</td>
			<td>Corning Inc., Glendale, AZ, USA</td>
			<td>352096</td>
			<td>Falcon 15 mL high-clarity polypropylene (PP) conical centrifuge tubes</td>
		</tr>
		<tr>
			<td>Dendritic cells</td>
			<td>The American Type Culture Collection, Manassas, VA, USA</td>
			<td>CRL-11904</td>
			<td></td>
		</tr>
		<tr>
			<td>DFO-Bn-NCS</td>
			<td>Macrocyclics, Inc., Plano, TX, USA</td>
			<td>B-705</td>
			<td>p-SCN-Bn-Deferoxamine</td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Sigma-Aldrich, Inc., St. Louis, MO</td>
			<td>276855</td>
			<td></td>
		</tr>
		<tr>
			<td>Dose calibrator</td>
			<td>Mirion Technologies (Capintec), Inc., Florham Park, NJ, USA</td>
			<td>5130-3234</td>
			<td>CRC -55tR Dose Calibrator&#160;</td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s modified Eagle&#8217;s medium&#160;</td>
			<td>The American Type Culture Collection, Manassas, VA, USA</td>
			<td>30-2002</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>The American Type Culture Collection, Manassas, VA, USA</td>
			<td>30-2020</td>
			<td></td>
		</tr>
		<tr>
			<td>Hanks Balanced Salt solution (HBSS)</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, MA, USA</td>
			<td>14025092</td>
			<td>For preparation of H-HBSS</td>
		</tr>
		<tr>
			<td>Hydrochloric Acid (trace metal basis grade)</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, MA, USA</td>
			<td>A508P212</td>
			<td></td>
		</tr>
		<tr>
			<td>Melanoma cells</td>
			<td>The American Type Culture Collection, Manassas, VA, USA</td>
			<td>CRL-6475</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma-Aldrich, Inc., St. Louis, MO</td>
			<td>34860</td>
			<td></td>
		</tr>
		<tr>
			<td>Microcentrifuge tube</td>
			<td>Eppendorf, Hamburg, Germany</td>
			<td>30108442</td>
			<td>Protein LoBind microcentrifuge tube</td>
		</tr>
		<tr>
			<td>Murine GM-CSF</td>
			<td>R&#38;D Systems, Inc., Minneapolis, MN USA</td>
			<td>415-ML-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, MA, USA</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline without Ca2+ and Mg2+</td>
			<td>Thermo Fisher Scientific, Inc., Waltham, MA, USA</td>
			<td>10010023</td>
			<td>For washing cells</td>
		</tr>
		<tr>
			<td>Saline</td>
			<td>Covidien LLC, Mansfield, MA, USA</td>
			<td>1020</td>
			<td>0.9% Sterile Saline Solution</td>
		</tr>
		<tr>
			<td>Shaker&#160;</td>
			<td>Eppendorf, Hamburg, Germany</td>
			<td>T1317</td>
			<td>Thermomixer</td>
		</tr>
		<tr>
			<td>Silica gel-rad-TLC paper sheet&#160;</td>
			<td>Agilent Technologies Inc., Santa Clara, CA, USA</td>
			<td>SGI0001</td>
			<td>iTLC-SG</td>
		</tr>
	</tbody>
</table>

positron emission tomography imaging of cell trafficking: a method of cell radiolabeling

Stem cell and chimeric antigen receptor (CAR) T-cell therapies are emerging as promising therapeutics for organ regeneration and as immunotherapy for various cancers. Despite significant progress having been made in these areas, there is still more to be learned to better understand the pharmacokinetics and pharmacodynamics of the administered therapeutic cells in the living system. For noninvasive, in vivo tracking of cells with positron emission tomography (PET), a novel [89Zr]Zr-p-isothiocyanatobenzyl-desferrioxamine ([89Zr]Zr-DBN)-mediated cell radiolabeling method has been developed utilizing 89Zr (t1/2 78.4 h). The present protocol describes a [89Zr]Zr-DBN-mediated, ready-to-use, radiolabeling synthon for direct radiolabeling of variety of cells, including mesenchymal stem cells, lineage-guided cardiopoietic stem cells, liver regenerating hepatocytes, white blood cells, melanoma cells, and dendritic cells. The developed methodology enables noninvasive PET imaging of cell trafficking for up to 7 days post-administration without affecting the nature or the function of the radiolabeled cells. Additionally, this protocol describes a stepwise method for the radiosynthesis of [89Zr]Zr-DBN, biocompatible formulation of [89Zr]Zr-DBN, preparation of cells for radiolabeling, and finally the radiolabeling of cells with [89Zr]Zr-DBN, including all the intricate details needed for the successful radiolabeling of cells.

The representative results presented in this manuscript were compiled from the previous [89Zr]Zr-DBN synthesis and cell radiolabeling studies18,19,22,23,24,25. In brief, 89Zr can be successfully complexed with DFO-Bn-NCS in ~30-60 min at 25-37 &#176;C using 7.5-15 &#181;g of DFO-Bn-NCS (Table 2</...

Watch this Scientific Journal Video about Positron Emission Tomography Imaging of Cell Trafficking: A Method of Cell Radiolabeling at JoVE.com

Positron Emission Tomography Imaging of Cell Trafficking: A Method of Cell Radiolabeling

Presented here is a protocol to radiolabel cells with a positron emission tomography (PET) radioisotope, 89Zr (t1/2 78.4 h), using a ready-to-use radiolabeling synthon, [89Zr]Zr-p-isothiocyanatobenzyl-desferrioxamine ([89Zr]Zr-DBN). Radiolabeling cells with [89Zr]Zr-DBN allows noninvasive tracking and imaging of administered radiolabeled cells in the body with PET for up to 7 days post-administration.

Stem cell and chimeric antigen receptor (CAR) T-cell therapies are emerging as promising therapeutics for organ regeneration and as immunotherapy for ...

This protocol describes a stepwise method for radiolabeling of cells and zirconium-89-DBN and its non-invasive tracking by PET. This technique also provides a reliable and a stable method for radiolabeling cells by a covalent conjugation of zirconium-89-DBN to the primary means of the cell surface proteins. Physicians and scientists working with cell therapies for neurological diseases and various cancers will find this protocol instrumental in understanding the pharmacokinetics of cell-based therapies via non-invasive PET imaging.The detailed protocol provides guidance to new users to learn and adopt this radiolabeling technique. Additional nodes included at the critical steps will help troubleshooting problems for a new user. To begin, prepare a column with approximately 100 milligrams of hydroxamate resin, and activate it by washing the column with eight milliliters of pure anhydrous acetonitrile followed by a flush with five to six milliliters of air.Pass two milliliters of 0.5 normal hydrochloric acid to the column. After passing an additional flush of five to six milliliters of air, load the solution containing both zirconium-89 and natural yttrium to the hydroxamate resin slowly. Wash the unbound natural yttrium from the hydroxamate resin with 20 milliliters of two normal hydrochloric acid, followed by 10 milliliters of deionized water.For eluding zirconium in the form of zirconium-89 hydrogen phosphate, add 0.5 milliliters of 1.2 molar dipotassium phosphate potassium dihydrogen phosphate buffer to the column and allow it to sit on the column for 30 minutes. Add an additional 1.5 milliliters of 1.2 molar buffer to elute the zirconium from the column. Next, take around 120 microliters of zirconium-89 hydrogen phosphate formulated in the buffer and neutralize the solution with HEPES-KOH and potassium carbonate to achieve a pH of 7.528.Add four microliters of freshly prepared five millimolar DFO-Bn-NCS to around 285 microliters of neutralized zirconium-89 hydrogen phosphate. And mix the solution by pipetting. After isolating zirconium from yttrium, add 0.5 milliliters of one molar oxalic acid to the column and allow it to sit on the column for one minute to elute zirconium in the form of zirconium-89 oxalate.Add an additional 2.5 milliliters of one molar oxalic acid to the column. To convert zirconium-89 oxalate into zirconium-89 chloride, wash the anion exchange column with six milliliters of acetonitrile, followed by a flush with five to six milliliters of air. Then, wash the column with 10 milliliters of saline followed by another flush of air.Slowly, load the solution containing zirconium-89 oxalate onto the activated anion exchange column before rewashing it with air. Then, wash the column with 50 milliliters of deionized water to remove the unbound oxalate ion. For eluding zirconium in the form of zirconium-89 chloride, add 0.1 milliliters of one normal hydrochloric acid to the column and allow it to sit on the column for one minute.Elute the zirconium from the column with an additional 0.4 milliliters of one normal hydrochloric acid. Dry the eluded zirconium-89 chloride in a V-shaped vial by placing it in a heating block at 65 degrees Celsius under a steady flow of nitrogen gas for 10 to 30 minutes, and then reconstitute the dried zirconium-89 chloride in water. Prepare 500 microliters of cell suspension with approximately 6 million cells in 500 microliters of HEPES-buffered HBSS in a 1.5-milliliter micro centrifuge tube and add approximately 100 microliters of the formulated zirconium-89-DBN.Mix the zirconium-89-DBN and the cell suspension by gently pipetting the solution up and down with a micro pipette. Incubate the cells and zirconium-89-DBN mixture on a shaker at around 550 RPM at 25 to 37 degrees Celsius for 30 to 45 minutes for cell labeling. Perform radioactive TLC on the cell radiolabeling reaction using freshly prepared radioactive TLC solvent.Calculate the percentage of radioactivity at Rf equals 0.01 to 0.02 using the equation shown on the screen. In a separate 1.5 milliliter micro centrifuge tube, mix around 100 microliters of the formulated zirconium-89-DBN with around 500 microliters of HEPES-buffered HBSS to use it as a no-cell control for background correction. Calculate the percentage of radioactivity at Rf equals 0.01 to 0.02 using the equation shown on the screen, then calculate the effective cell radiolabeling by subtracting the two calculated radioactivity percentages.After confirming the completion of radiolabeling, add 600 microliters of chilled cell-appropriate complete medium to perform the quenching of the radiolabeling reaction. Centrifuge the cells at 96G for 10 minutes at four degrees Celsius. And discard the supernatant.Gently resuspend the pelleted cells in 500 microliters of the chilled medium by pipetting the medium up and down with a micro pipette. Centrifuge the cells at 96G for 10 minutes at four degrees Celsius and discard the supernatant. Next, calculate the final radiolabeling efficiency after all the washes using the equation shown on the screen.To ensure the quality of the radiolabeled cells, visually inspect the final suspension of radiolabeled cells, and if no clumps are present, perform a trypan blue exclusion viability test using 0.4%trypan blue solution prepared in PBS within one hour of radiolabeling and the washing steps. The chelation efficiency of DFO-Bn-NCS for zirconium-89 using zirconium-89 hydrogen phosphate and zirconium-89 chloride are different as measured by radioactive TLC. The stability of various cells radiolabeled with zirconium-89 over seven days is shown here.The retention of zirconium-89 radioactivity by radiolabeled cells was found to be stable in all the cells studied, with a negligible efflux observed over seven days post-labeling. The cell radiolabeling efficiencies in different cell types with zirconium-89-DBN are shown in this table. The cell radiolabeling efficiency varies from 20 to 50%as an uncorrected yield observed in the radiolabeled cell pellet after washing.The most critical step of this protocol are the addition of DFO-Bn-NCS to the chelation mixture and the quality assessment of radiolabeled cells. The application of this technique will help to understand the pharmacokinetics of cell-based therapies. It would also raise questions about any clinical need to alter the clearance profile of cell therapies.

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Research

JoVE Journal

Cancer Research

A Method of Targeted Cell Isolation via Glass Surface Functionalization

One of the limiting factors to the adoption and advancement of personalized medicine is the inability to develop diagnostic tools to probe individual nuances in expression from patient to patient. Current methodologies that try to separate cells to fill this niche result in disruption of physiological expression, making the separation technique useless as a diagnostic tool. In this protocol, we describe the functionalization and optimization of a surface for the cellular capture and release. This functionalized surface integrates biotinylated antibodies with a glass surface functionalized with an aminosilane (APTES), desthiobiotin and streptavidin. Cell release is facilitated through the introduction of biotin, allowing the recollection and purification of cells captured by the surface. This release is done through the targeting of the secondary moiety desthiobiotin, which results in a much more gentle release paradigm. This reduction in harsh reagents and shear forces reduces changes in cellular expression. The functionalized surface captures up to 80% of cells in a single cell mixture and has demonstrated 50% capture in a dual-cell mixture. Applications of this technology to xenografts and cancer separation studies are investigated. Quantification techniques for surface verification such as plate reader and ImageJ analyses are described as well.

This protocol describes customizable surface functionalization of the desthiobiotin, streptavidin, and APTES system in order to isolate specific cell types of interest. In addition, this manuscript covers the applications, optimization, and verification of this process.

One of the limiting factors to the adoption and advancement of personalized medicine is the inability to develop diagnostic tools to probe individual ...

A Mimic of the Tumor Microenvironment: A Simple Method for Generating Enriched Cell Populations and Investigating Intercellular Communication

Understanding the early heterotypic interactions between cancer cells and the surrounding non-cancerous stroma is important in elucidating the events leading to stromal activation and establishment of the tumor microenvironment (TME). Several in vitro and in vivo models of the TME have been developed; however, in general these models do not readily permit isolation of individual cell populations, under non-perturbing conditions, for further study. To circumvent this difficulty, we have employed an in vitro TME model using a cell growth substrate consisting of a permeable microporous membrane insert that permits simple generation of highly enriched cell populations grown intimately, yet separately, on either side of the insert&#39;s membrane for extended co-culture times. Through use of this model, we are capable of generating greatly enriched cancer-associated fibroblast (CAF) populations from normal diploid human fibroblasts following co-culture (120 hr) with highly metastatic human breast carcinoma cells, without the use of fluorescent tagging and/or cell sorting. Additionally, by modulating the pore-size of the insert, we can control for the mode of intercellular communication (e.g., gap-junction communication, secreted factors) between the two heterotypic cell populations, which permits investigation of the mechanisms underlying the development of the TME, including the role of gap-junction permeability. This model serves as a valuable tool in enhancing our understanding of the initial events leading to cancer-stroma initiation, the early evolution of the TME, and the modulating effect of the stroma on the responses of cancer cells to therapeutic agents.

We adapted a permeable microporous membrane insert to mimic the tumor microenvironment (TME). The model consists of a mixed cell culture, allows simplified generation of highly enriched individual cell populations without using fluorescent tagging or cell sorting, and permits studying intercellular communication within the TME under normal or stress conditions.

Understanding the early heterotypic interactions between cancer cells and the surrounding non-cancerous stroma is important in elucidating the events ...

Live-imaging of Breast Epithelial Cell Migration After the Transient Depletion of TIP60

The wound-healing assay is efficient and one of the most economical ways to study cell migration in vitro. Conventionally, images are taken at the beginning and end of an experiment using a phase-contrast microscope, and the migration abilities of cells are evaluated by the closure of wounds. However, cell movement is a dynamic phenomenon, and a conventional method does not allow for tracking single-cell movement. To improve current wound-healing assays, we use live-cell imaging techniques to monitor cell migration in real time. This method allows us to determine the cell migration rate based on a cell tracking system and provides a clearer distinction between cell migration and cell proliferation. Here, we demonstrate the use of live-cell imaging in wound-healing assays to study the different migration abilities of breast epithelial cells influenced by the presence of TIP60. As cell motility is highly dynamic, our method provides more insights into the processes of wound healing than a snapshot of wound closure taken with the traditional imaging techniques used for wound-healing assays.

Here, we present the real-time monitoring of cell migration in a wound-healing assay using TIP60-depleted MCF10A breast epithelial cells. The implementation of live-cell imaging techniques in our protocol allows us to analyze and visualize single-cell movement in real time and across time.

The wound-healing assay is efficient and one of the most economical ways to study cell migration in vitro. Conventionally, images are taken at the ...

Long-term Live-cell Imaging to Assess Cell Fate in Response to Paclitaxel

Live-cell imaging is a powerful technique that can be used to directly visualize biological phenomena in single cells over extended periods of time. Over the past decade, new and innovative technologies have greatly enhanced the practicality of live-cell imaging. Cells can now be kept in focus and continuously imaged over several days while maintained under 37 &#176;C and 5% CO2 cell culture conditions. Moreover, multiple fields of view representing different experimental conditions can be acquired simultaneously, thus providing high-throughput experimental data. Live-cell imaging provides a significant advantage over fixed-cell imaging by allowing for the direct visualization and temporal quantitation of dynamic cellular events. Live-cell imaging can also identify variation in the behavior of single cells that would otherwise have been missed using population-based assays. Here, we describe live-cell imaging protocols to assess cell fate decisions following treatment with the anti-mitotic drug paclitaxel. We demonstrate methods to visualize whether mitotically arrested cells die directly from mitosis or slip back into interphase. We also describe how the fluorescent ubiquitination-based cell cycle indicator (FUCCI) system can be used to assess the fraction of interphase cells born from mitotic slippage that are capable of re-entering the cell cycle. Finally, we describe a live-cell imaging method to identify nuclear envelope rupture events.

Live-cell imaging provides a wealth of information on single cells or whole populations that is unattainable by fixed cell imaging alone. Here, live-cell imaging protocols to assess cell fate decisions following treatment with the anti-mitotic drug paclitaxel are described.

Live-cell imaging is a powerful technique that can be used to directly visualize biological phenomena in single cells over extended periods of time. Over ...

Fluorescence Molecular Tomography for In Vivo Imaging of Glioblastoma Xenografts

Tumorigenicity is the capability of cancer cells to form a tumor mass. A widely used approach to determine if the cells are tumorigenic is by injecting immunodeficient mice subcutaneously with cancer cells and measuring the tumor mass after it becomes visible and palpable. Orthotopic injections of cancer cells aim to introduce the xenograft in the microenvironment that most closely resembles the tissue of origin of the tumor being studied. Brain cancer research requires intracranial injection of cancer cells to allow the tumor formation and analysis in the unique microenvironment of the brain. The in vivo imaging of intracranial xenografts monitors instantaneously the tumor mass of orthotopically engrafted mice. Here we report the use of fluorescence molecular tomography (FMT) of brain tumor xenografts. The cancer cells are first transduced with near infrared fluorescent proteins and then injected in the brain of immunocompromised mice. The animals are then scanned to obtain quantitative information about the tumor mass over an extended period of time. Cell pre-labeling allows for cost effective, reproducible, and reliable quantification of the tumor burden within each mouse. We eliminated the need for injecting imaging substrates, and thus reduced the stress on the animals. A limitation of this approach is represented by the inability to detect very small masses; however, it has better resolution for larger masses than other techniques. It can be applied to evaluate the efficacy of a drug treatment or genetic alterations of glioma cell lines and patient-derived samples.

Fluorescence Molecular Tomography for In Vivo Imaging of Glioblastoma Xenografts

Orthotopic intracranial injection of tumor cells has been used in cancer research to study brain tumor biology, progression, evolution, and therapeutic response. Here we present fluorescence molecular tomography of tumor xenografts, which provides real-time intravital imaging and quantification of a tumor mass in preclinical glioblastoma models.

Tumorigenicity is the capability of cancer cells to form a tumor mass. A widely used approach to determine if the cells are tumorigenic is by injecting ...

Multimodal Bioluminescent and Positronic-emission Tomography/Computational Tomography Imaging of Multiple Myeloma Bone Marrow Xenografts in NOG Mice

Multiple myeloma (MM) tumors engraft in the bone marrow (BM) and their survival and progression are dependent upon complex molecular and cellular interactions that exist within this microenvironment. Yet the BM microenvironment cannot be easily replicated in vitro, which potentially limits the physiologic relevance of many in vitro and ex vivo experimental models. These issues can be overcome by utilizing a xenograft model in which luciferase (LUC)-transfected 8226 MM cells will specifically engraft in the mouse skeleton. When these mice are given the appropriate substrate, D-luciferin, the effects of therapy on tumor growth and survival can be analyzed by measuring changes in the bioluminescent images (BLI) produced by the tumors in vivo. This BLI data combined with positronic-emission tomography/computational tomography (PET/CT) analysis using the metabolic marker 2-deoxy-2-(18F)fluoro-D-glucose (18F-FDG) is used to monitor changes in tumor metabolism over time. These imaging platforms allow for multiple noninvasive measurements within the tumor/BM microenvironment.

Here we use bioluminescent, X-ray, and positron-emission tomography/computed tomography imaging to study how inhibiting mTOR activity impacts bone marrow-engrafted myeloma tumors in a xenograft model. This allows for physiologically relevant, non-invasive, and multimodal analyses of the anti-myeloma effect of therapies targeting bone marrow-engrafted myeloma tumors in vivo.

Multiple myeloma (MM) tumors engraft in the bone marrow (BM) and their survival and progression are dependent upon complex molecular and cellular ...

Live-Cell Imaging Assays to Study Glioblastoma Brain Tumor Stem Cell Migration and Invasion

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include rapid proliferation and pervasive invasion into the normal brain. Recurrence is thought to result from the presence of radio- and chemo-resistant brain tumor stem cells (BTSCs) that invade away from the initial cancerous mass and, thus, evade surgical resection. Hence, therapies that target BTSCs and their invasive abilities may improve the otherwise poor prognosis of this disease. Our group and others have successfully established and characterized BTSC cultures from GBM patient samples. These BTSC cultures demonstrate fundamental cancer stem cell properties such as clonogenic self-renewal, multi-lineage differentiation, and tumor initiation in immune-deficient mice. In order to improve on the current therapeutic approaches for GBM, a better understanding of the mechanisms of BTSC migration and invasion is necessary. In GBM, the study of migration and invasion is restricted, in part, due to the limitations of existing techniques which do not fully account for the in vitro growth characteristics of BTSCs grown as neurospheres. Here, we describe rapid and quantitative live-cell imaging assays to study both the migration and invasion properties of BTSCs. The first method described is the BTSC migration assay which measures the migration toward a chemoattractant gradient. The second method described is the BTSC invasion assay which images and quantifies a cellular invasion from neurospheres into a matrix. The assays described here are used for the quantification of BTSC migration and invasion over time and under different treatment conditions.

Here, we describe live-cell imaging techniques to quantitatively measure the migration and invasion of glioblastoma brain tumor stem cells over time and under multiple treatment conditions.

Glioblastoma (GBM) is an aggressive brain tumor that is poorly controlled with the currently available treatment options. Key features of GBMs include ...

Management of Respiratory Motion Artefacts in 18F-fluorodeoxyglucose Positron Emission Tomography using an Amplitude-Based Optimal Respiratory Gating Algorithm

Positron emission tomography (PET) combined with X-ray computed tomography (CT) is an important molecular imaging platform that is required for accurate diagnosis and clinical staging of a variety of diseases. The advantage of PET imaging is the ability to visualize and quantify a myriad of biological processes in vivo with high sensitivity and accuracy. However, there are multiple factors that determine image quality and quantitative accuracy of PET images. One of the foremost factors influencing image quality in PET imaging of the thorax and upper abdomen is respiratory motion, resulting in respiration-induced motion blurring of anatomical structures. Correction of these artefacts is required for providing optimal image quality and quantitative accuracy of PET images.
Several respiratory gating techniques have been developed, typically relying on acquisition of a respiratory signal simultaneously with PET data. Based on the respiratory signal acquired, PET data is selected for reconstruction of a motion-free image. Although these methods have been shown to effectively remove respiratory motion artefacts from PET images, the performance is dependent on the quality of the respiratory signal being acquired. In this study, the use of an amplitude-based optimal respiratory gating (ORG) algorithm is discussed. In contrast to many other respiratory gating algorithms, ORG permits the user to have control over image quality versus the amount of rejected motion in the reconstructed PET images. This is achieved by calculating an optimal amplitude range based on the acquired surrogate signal and a user-specified duty cycle (the percentage of PET data used for image reconstruction). The optimal amplitude range is defined as the smallest amplitude range still containing the amount of PET data required for image reconstruction. It was shown that ORG results in effective removal of respiration-induced image blurring in PET imaging of the thorax and upper abdomen, resulting in improved image quality and quantitative accuracy.

Management of Respiratory Motion Artefacts in 18F-fluorodeoxyglucose Positron Emission Tomography using an Amplitude-Based Optimal Respiratory Gating Algorithm

Amplitude-based optimal respiratory gating (ORG) effectively removes respiratory-induced motion blurring from clinical 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) images. Correction of FDG-PET images for these respiratory motion artefacts improves image quality, diagnostic and quantitative accuracy. Removal of respiratory motion artefacts is important for adequate clinical management of patients using PET.

Positron emission tomography (PET) combined with X-ray computed tomography (CT) is an important molecular imaging platform that is required for accurate ...

Quantifying the Brain Metastatic Tumor Micro-Environment using an Organ-On-A Chip 3D Model, Machine Learning, and Confocal Tomography

Brain metastases are the most lethal cancer lesions; 10-30% of all cancers metastasize to the brain, with a median survival of only ~5-20 months, depending on the cancer type. To reduce the brain metastatic tumor burden, gaps in basic and translational knowledge need to be addressed. Major challenges include a paucity of reproducible preclinical models and associated tools. Three-dimensional models of brain metastasis can yield the relevant molecular and phenotypic data used to address these needs when combined with dedicated analysis tools. Moreover, compared to murine models, organ-on-a-chip models of patient tumor cells traversing the blood brain barrier into the brain microenvironment generate results rapidly and are more interpretable with quantitative methods, thus amenable to high throughput testing. Here we describe and demonstrate the use of a novel 3D microfluidic blood brain niche (&#181;mBBN) platform where multiple elements of the niche can be cultured for an extended period (several days), fluorescently imaged by confocal microscopy, and the images reconstructed using an innovative confocal tomography technique; all aimed to understand the development of micro-metastasis and changes to the tumor micro-environment (TME) in a repeatable and quantitative manner. We demonstrate how to fabricate, seed, image, and analyze the cancer cells and TME cellular and humoral components, using this platform. Moreover, we show how artificial intelligence (AI) is used to identify the intrinsic phenotypic differences of cancer cells that are capable of transit through a model &#181;mBBN and to assign them an objective index of brain metastatic potential. The data sets generated by this method can be used to answer basic and translational questions about metastasis, the efficacy of therapeutic strategies, and the role of the TME in both.

Here, we present a protocol for preparing and culturing a blood brain barrier metastatic tumor micro-environment and then quantifying its state using confocal imaging and artificial intelligence (machine learning).

Brain metastases are the most lethal cancer lesions; 10-30% of all cancers metastasize to the brain, with a median survival of only ~5-20 months, ...

Dynamic Imaging of Chimeric Antigen Receptor T Cells with [18F]Tetrafluoroborate Positron Emission Tomography/Computed Tomography

T cells genetically engineered to express chimeric antigen receptors (CAR) have shown unprecedented results in pivotal clinical trials for patients with B cell malignancies or multiple myeloma (MM). However, numerous obstacles limit the efficacy and prohibit the widespread use of CAR T cell therapies due to poor trafficking and infiltration into tumor sites as well as lack of persistence in vivo. Moreover, life-threatening toxicities, such as cytokine release syndrome or neurotoxicity, are major concerns. Efficient and sensitive imaging and tracking of CAR T cells enables the evaluation of T cell trafficking, expansion, and in vivo characterization and allows the development of strategies to overcome the current limitations of CAR T cell therapy. This paper describes the methodology for incorporating the sodium iodide symporter (NIS) in CAR T cells and for CAR T cell imaging using [18F]tetrafluoroborate-positron emission tomography ([18F]TFB-PET) in preclinical models. The methods described in this protocol can be applied to other CAR constructs and target genes in addition to the ones used for this study.

Dynamic Imaging of Chimeric Antigen Receptor T Cells with [18F]Tetrafluoroborate Positron Emission Tomography/Computed Tomography

This protocol describes the methodology for non-invasively tracking T cells genetically engineered to express chimeric antigen receptors in vivo with a clinically available platform.

T cells genetically engineered to express chimeric antigen receptors (CAR) have shown unprecedented results in pivotal clinical trials for patients with B ...