The authors would like to aknowledge the colleagues and people involved in the different steps of the project. The colleagues in the JRC Karlsruhe design office, Messrs. Dietrich Knoche and Volkmar Ernest, in the JRC Karlsruhe Workshop Messrs. Christian Diebold and Joachim K&#252;st for the design and manufacturing of the lab on valve (LOV) manifold and Ringwald GmbH for the software implementation of the stopped-flow detection mode technique.

Note: Solutions were prepared from high-purity water (18.2 M&#937; cm) using devices designed for ultratrace analysis. Nitric acid was purified using a quartz sub-boiling distillation unit. Both the water purification system and the sub-boiling distillation unit were operated in a clean room.
Caution: 90Sr is acutely toxic and carcinogenic. Appropriate safety practices are essential when performing the experiments, including both engineering control systems and personal protective equipment.
1. Experiment Preparation
Note: A detailed description regarding the software architecture and its functionalities can be found elsewhere23.
<ol>
	<li>Connect the Modular Valve Position exit port to the entry port of the radio flow detector.</li>
	<li>Connect the Trigger line to selected detector.</li>
	<li>Ensure that the LOV ports are properly connected. Ensure that adequate volumes of working solutions are available for the entire protocol and that liquid sampling tubing will remain submerged.</li>
	<li>Ensure that the Autosampler is on, start the autosampler software, and via the software interface, initialize the autosampler. Click the Initialize button to generate the communication between the apparatus and the PC.</li>
	<li>Ensure the AutoRAD software has been started, check the communication ports using the options tab and initialize the software via the user interface. Refer to Discussion section for more details regarding the software graphical interface.</li>
	<li>Ensure that the analysis sequence is programmed in the detector Software. Program vew sequences using the Method editor tab in the AutoRAD software, by entering the number of steps needed and the tasks and speed for each device. 
	Note: A detailed description of the software operation can be found in previous publication23.</li>
	<li>Consult the local radioprotection officer and employ the radioprotection measurements needed for the complete procedure using 90Sr.</li>
</ol>
2. System Cleaning
<ol>
	<li>Load 10 mL of 18.2 M&#937; cm water from the flask to the syringe at 90 mL&#183;min-1. Ensure that the syringe valve position is set to the In position for this step. In this position, loading occurs directly to the syringe and not through the LOV.</li>
	<li>Drop the water to the waste via the holding coil at a flow rate of 90 mL&#183;min-1.</li>
	<li>Load 3 mL of ethanol to the holding coil at a flow rate of 3 mL&#183;min-1. Set the syringe valve position to Out.</li>
	<li>Drop the ethanol to the detector coil at a flow rate of 3 mL&#183;min-1.</li>
</ol>
3. Load Resin to the LOV
<ol>
	<li>While stirring the resin suspension in water (12 mg&#183;mL-1), pick up 3 mL via the LOV. Set the flow to 3 mL&#183;min-1</li>
	<li>Drop the resin suspension into the column channel at a flow rate of 1.2 mL&#183;min-1</li>
	<li>Clean the holding coil and drop the resin residues onto the column channel. For this, load 9 mL of 18.2 M&#937; cm water from the flask to the syringe at a flow rate of 90 mL&#183;min-1. Ensure that the syringe valve position is in the In position. Drop the water to the waste via the holding coil at a flow rate of 3 mL&#183;min-1.</li>
</ol>
4. Analysis Sequence
<ol>
	<li>Column conditioning
	<ol>
		<li>Load 2 mL of HNO3 (4 M) via the LOV to the holding coil. Set the flow to 6 mL&#183;min-1.</li>
		<li>Drop the HNO3 onto the column at a flow rate of 1.2 mL&#183;min-1.</li>
	</ol>
	</li>
	<li>Sample loading and elimination of interferences
	<ol>
		<li>Load sample (1.3 mL) from the autosampler to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Drop the sample onto the column at a flow rate of 1.2 mL&#183;min-1.</li>
		<li>Load 0.5 mL of HNO3 (4 M) to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Rinse the column with 0.5 mL of HNO3 (4 M) to elute matrix interferences at a flow rate of 1.2 mL&#183;min-1.</li>
	</ol>
	</li>
	<li>Elution of the sample and measurement
	<ol>
		<li>Load 5 mL of 18.2 M&#937; cm water to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Trigger the detector. Set the flow rate of the scintillation liquid to 2 mL&#183;min-1 in the detector software. Set the dwell to 10 s. The sample coil has a volume of 2 mL.</li>
		<li>Rinse the column.</li>
	</ol>
	</li>
	<li>rinsing of the sample probe and holding coil
	<ol>
		<li>Load 0.6 mL of HNO3 (1%) to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Load 0.6 mL of air to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Discharge 1.2 mL of the mixture to the waste.</li>
	</ol>
	</li>
	<li>Resin replacement
	<ol>
		<li>Load 0.2 mL of ethanol to the holding coil at a flow rate of 3 mL&#183;min-1.</li>
		<li>Rinse the column with 0.2 mL of ethanol at a flow rate of 1.2 mL&#183;min-1.</li>
		<li>Flush the column channel with 0.5 mL of water at a flow rate of 0.45 mL&#183;min-1.</li>
		<li>Discharge the used resin to the waste.</li>
	</ol>
	</li>
</ol>

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The authors have nothing to disclose.

Radiological characterization and protection are critical issues during all phases of a nuclear facility life cycle. The need for radionuclide determination during the decommissioning of nuclear facilities requires continuous improvement of analytical procedures. This entails the enhancement of selectivity and sensitivity, and shortening the analysis time . The AUTORAD prototype fulfils these requirements. In addition, the prototype is portable and allows on-site determination. The proposed automated on-line method was successfully applied for the determination of 90Sr activity in aqueous samples.
Figure 1 shows a schematic diagram of the AutoRAD system. Communication with the prototype was achieved using the commercial graphical programming language LabVIEW 2014. The Virtual Instrument Software Architecture (VISA) mode for configuring, programming and controlling interfaces was deployed. Figure 2 shows the graphical user interface screen where the port configuration can be verified prior to system initialization. The VISA mode is independent on the operating system and program environment, so it provides exceptional versatility. The basic structure and features of the developed software have been widely discussed in previous publication24. Improvements have been achieved by controlling the burettes by the PC using an RS232 interface, thus allowing enhanced control of both burettes simultaneously and the possibility to perform measurements in stop flow mode. In contrast, the RS232 connection reacts quickly when the system backpressure increases. This can lead to system error and measurement stop. Therefore, special attention has to be paid in the process of resin loading and ionic strength of the samples.
The optimization of the experimental conditions was achieved in a set of experiments using the strontium stable isotope 86Sr as a surrogate for the radioactive 90Sr, and by coupling the AUTORAD system to an ICP-MS rather than a beta detctcor system. Figure 3 shows the ICP-MS 86Sr elution profiles. The obtained 86Sr elution profiles are in full agreement with previously reported results for total strontium using low pressure separation devices25, and have been blank subtracted. The least squares linear regression method was used to generate a fit for the purpose curve which does not introduce an extra uncertainty component. The linearity obtained was 0.995, with p-values less than the significance level. The LOD of 2 pg&#183;g-1was determined by repeated measurements of the blank according to Currie26. The reproducibility of the method, based on the relative standard deviation of the peak area calculated on the basis of three repeated runs, was always less than 4% in the range of 10 to 120 pg&#183;g-1. The shoulder witnessed in the elution profiles is most likely an artefact due to non-optimal packing of the column in the automated AUTORAD configuration.
Figure 4 shows the 90Sr profile using the the radio flow detector. The AUTORAD system is able to effectively separate 90Sr in aqueous samples.
Figure 5 shows the dependence of the 90Sr concentration with the signal is linear in the range of interest. The derived detection limit is in the fg. g-1 range, enabling, without further modification, the determination of radiostrontium in nuclear decommissioning and waste characterization samples. Reproducibility of the method, using the flow scintillation detector and based on the relative standard deviation of the peak area, is around 30% in the studied concentration range. The current set-up of the prototype, however, limits its application to environmental samples, essentially due to the short time counting in the detector. Furthermore, complex matrices might saturate the resin in the mini column.
The stopped-flow technique, where both Hamilton and radio flow detector pump are stopped during the measurement, will be implemented. This feature will improve the sensitivity by extending the residence time in the largest part of the sample zone within the flow cell. Thus, a statistically meaningful signal is acculated before the sample exits the detector. This approach will improve both the counting statistics and the detection limits. In addition, a new application is being developed including an additional ion-exchange mini-column for the removal of matrix components that could affect the retention and separation of different radionuclides in complex matric samples.

About 150 commercial nuclear power plants (NPP) are undergoing decommissioning, but the total number of nuclear facilities is much greater if research and reprocessing facilities are taken into consideration1. Decommissioning of nuclear facilities is very costly and involves transport and off site measurement of contaminated material. Savings are possible by adopting on-site and flexible measurement techniques1. There is therefore an urgent need for rapid on site analytical methods supporting the decommissioning of old nuclear facilities. Gamma-emitters can be easily and selectively determined using gamma-spectroscopy, but there is a deficiency in on-site analytical methods for the hard-to-measure (HTM) radionuclides2. Among the HTM, 90Sr is of great interest due to its toxicity and high energy emission. Its determination is time consuming and requires the separation from interferences and quantification using LSC or spectroscopic methods3,4,5,6,7,8,9,10,11,12,13.
Standard radiochemical methods are time-consuming and often require repetitions to obtain an adequate yield of strontium. Therefore, there is an urgent need for faster and accurate methods. Besides the standard separation protocols, flow injection techniques are applied in the purification and/or pre-concentration of radioisotopes5,14,15. Lab-on-Valve (LOV) devices are a further development in flow techniques. They are programmable, flow-based platforms with different coupling modes and exhibit high versatility16. Such devices allow the automatic separation and pre-concentration of the analytes prior to the detection, thus increasing reproducibility and repeatability8,17,18,19. LOV systems coupled to multisyringe flow pumps have been widely used for the detection of radionuclides, due to the minimization of the reagent consumption and waste generation8,10,17,18,19,20. Nevertheless, reported studies regarding online detection at ultra-trace levels are sparse8,17.
On-site measurements of radioactive materials have many benefits and advantages, but there is no application of flow scintillation to 90Sr monitoring. Basically, quantification is achieved using an online detector that mixes the eluate coming from the LOV device with the scintillating cocktail11,21,22. The mixture is then pumped through the counting cell and measurement is made using paired photomultipliers. Due to the small volume of the cell, the measurement time is in the seconds scale.
The aim of this research is the development of a fully automated method for on-line strontium detection over a large working range, covering both environmentally relevant concentrations and also those found in nuclear industry waste streams. The platform is mobile and can be mounted in a vehicle to perform on-site analysis of aqueous samples.

<table><tbody><tr><td>microLAB 600 series</td><td>Hamilton</td><td>ML600EE6910</td><td>Two dual syringe pump system, equiped with two 10 mL glass syringes. The instruments are interconnected using the CAN port (daisy chain).</td></tr><tr><td>FlowLogic U</td><td>LabLogic</td><td>SG-BXX-05</td><td>Liquid scintillator with high flash point</td></tr><tr><td>&amp;szlig;-RAM 5</td><td>LabLogic</td><td></td><td>flow detector, 2000 &amp;mu;L coiled Teflon flow cell.Software Laura 4.2.8 (LabLogic, England) run on desktop PC and connected to the detector via USB</td></tr><tr><td>SC-&amp;mu; DX Autosampler</td><td>Elemental Scientific Instruments (ESI)</td><td></td><td></td></tr><tr><td>Cheminert selector</td><td>Valco Instruments Co. Inc.</td><td></td><td>in-house made Lab-on-Valve has been mounted on this selector</td></tr><tr><td>Modular Valve&lt;br/&gt; Positioner (MVP)</td><td>Hamilton</td><td></td><td></td></tr><tr><td>mini magnetic stirrer</td><td>IKA</td><td></td><td></td></tr><tr><td>Nitric Acid Suprapur 65%</td><td>Merck</td><td>1.00441.1000</td><td>purified using quartz sub-boiling distillation unit</td></tr><tr><td>Sr-resin</td><td>Eichchrom Tecnologies, Inc</td><td>SR-B100-A</td><td>particle size 100-150 &amp;micro;m</td></tr><tr><td>Water system Elix 3 in combination with Mili-Q Element A10</td><td>Millipore</td><td></td><td>high-purity water (18.2 M&amp;Omega; cm)</td></tr><tr><td>Sr-90 standard</td><td>Eckert &amp;amp; Ziegler</td><td>7090</td><td>Sr-90 concentration 1.915 kBq/g &amp;plusmn; 3.0%, reference date 15-May-2016 12:00 PST</td></tr><tr><td>MLS quartz sub-boiling distillation unit</td><td>MLS GmbH</td><td></td><td>Subboiling unit for the purification of HCl and nitric acid</td></tr></tbody></table>

automated 90sr separation and preconcentration in a lab-on-valve system at ppq level

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow injection analysis, has been developed. The concentrations of radioactive strontium were determined by flow scintillation counting, allowing for on-line and also on-site determination. The proposed system can determine radioactive strontium at industrial relevant levels without further modification using overall analysis time of less than 10 min per aqueous sample. The limit of the detection is 320 fg&#183;g-1 (1.7 Bq/g).

The fully automated AUTORAD platform operated by homemade LabVIEW-based software has been developed and implemented (Figure 1). The software allows sufficient flexibility for daily operation in a user-friendly environment (Figure 2). The versatility of the platform has been also demonstrated by coupling it to different detectors (Figure 3). The applicability of the method has been demonstrated in aqueous samples spiked with a 90Sr standard (Figure 4). The parameters linearity, linear range, limit of detection (LOD) and repeatability have been evaluated (Figure 5).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57722/57722fig1.jpg" /> 
Figure 1. Schematic representation of the AutoRAD system showing the port configuration and reagents used. The central port is connected to the syringe pump via the holding coil (10 mL); the methacrylate LOV was fabricated in house. <a href="/files/ftp_upload/57722/57722fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57722/57722fig2.jpg" /> 
Figure 2. AutoRAD Software options menu. The bottom right corner area shows the assigned ports. Via the scroll down menu, the user is able to make changes in the assignment. <a href="/files/ftp_upload/57722/57722fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57722/57722fig3.jpg" /> 
Figure 3. 86Sr elution peaks using an Inductively coupled plasma mass spectrometry (ICP-MS) as a detector. Strontium is eluted quantitatively from the column during the first 100 s of the elution. <a href="/files/ftp_upload/57722/57722fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57722/57722fig4.jpg" /> 
Figure 4. 34.5 &#177; 1 Bq 90Sr (6.6 pg&#183;g-1) elution peak using &#223;-RAM 5 as detector. The residence time in the coil was 40 s. The overall recovery rate of the proposed methodology for 90Sr is 70% &#177; 5%. <a href="/files/ftp_upload/57722/57722fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57722/57722fig5.jpg" /> 
Figure 5. Calibration curve for the count rate versus the concentration of radiostrontium. A good linearity was obtained (R2 = 0.997). The detection limit was calculated as 320 fg&#183;g-1 &#177; 5 (1.7 Bq) by three point three times standard deviation of the blank. <a href="/files/ftp_upload/57722/57722fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level at JoVE.com

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

Here, we present the portable autoRAD platform for quick radiometric separation and determination of 90Sr, an important fission product highly pertinent to nuclear waste.

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow ...

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7.9K Views.  European Commission, DG Joint Research Centre - JRC. Hier presenteren we de draagbare autoRAD platform voor snelle radiometrische scheiding en bepaling van 90Sr, een belangrijke kernsplijting product zeer relevant is voor het kernafval.

Video: Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular identity and function. Each of the seven PtdInsPs varies in their distribution and abundance, which are tightly regulated by specific kinases and phosphatases. The abundance of PtdInsPs can change abruptly in response to various signaling events or disturbance of the regulatory machinery. To understand how these events lead to changes in the amount of PtdInsPs and their resulting impact, it is important to quantify PtdInsP levels before and after a signaling event or between control and abnormal conditions. However, due to their low abundance and similarity, quantifying the relative amounts of each PtdInsP can be challenging. This article describes a method for quantifying PtdInsP levels by metabolically labeling cells with 3H-myo-inositol, which is incorporated into PtdInsPs. Phospholipids are then precipitated and deacylated. The resulting soluble 3H-glycero-inositides are further extracted, separated by high-performance liquid chromatography (HPLC), and detected by flow scintillation. The labeling and processing of yeast samples is described in detail, as well as the instrumental setup for the HPLC and flow scintillator. Despite losing structural information regarding acyl chain content, this method is sensitive and can be optimized to concurrently quantify all seven PtdInsPs in cells.

Phosphoinositides are signaling lipids whose relative abundance rapidly changes in response to various stimuli. This article describes a method to measure the abundance of phosphoinositides by metabolically labeling cells with 3H-myo-inositol, followed by extraction and deacylation. Extracted glycero-inositides are then separated by high-performance liquid chromatography and quantified by flow scintillation.

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular ...

Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a 15N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the 1H isotope in depths up to about 2 &#956;m from the target surface. Surface H coverages are measured with a sensitivity in the order of ~1013 cm-2 (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~1018 cm-3 (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal 15N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, 1H(15N,&#945;&#947;)12C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of 15N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100).

We illustrate the application of 1H(15N,&#945;&#947;)12C resonant nuclear reaction analysis (NRA) to quantitatively evaluate the density of hydrogen atoms on the surface, in the volume, and at an interfacial layer of solid materials. The near-surface hydrogen depth profiling of a Pd(110) single crystal and of SiO2/Si(100) stacks is described.

Nuclear reaction analysis (NRA) via the resonant 1H(15N,&#945;&#947;)12C reaction is a highly effective method of depth profiling that quantitatively and ...

Engineering

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. They offer new possibilities for the characterization of living systems and are particularly appropriate for detecting, localizing and quantifying the presence of metal oxide nanoparticles both in biological specimens and the environment. Indeed, these techniques all meet relevant requirements in terms of (i) sensitivity (from 1 up to 10 &#181;g.g-1 of dry mass), (ii) micrometer range spatial resolution, and (iii) multi-element detection. Given these characteristics, microbeam chemical element imaging can powerfully complement routine imaging techniques such as optical and fluorescence microscopy. This protocol describes how to perform a nuclear microprobe analysis on cultured cells (U2OS) exposed to titanium dioxide nanoparticles. Cells must grow on and be exposed directly in a specially designed sample holder used on the optical microscope and in the nuclear microprobe analysis stages. Plunge-freeze cryogenic fixation of the samples preserves both the cellular organization and the chemical element distribution. Simultaneous nuclear microprobe analysis (scanning transmission ion microscopy, Rutherford backscattering spectrometry and particle induced X-ray emission) performed on the sample provides information about the cellular density, the local distribution of the chemical elements, as well as the cellular content of nanoparticles. There is a growing need for such analytical tools within biology, especially in the emerging context of Nanotoxicology and Nanomedicine for which our comprehension of the interactions between nanoparticles and biological samples must be deepened. In particular, as nuclear microprobe analysis does not require nanoparticles to be labelled, nanoparticle abundances are quantifiable down to the individual cell level in a cell population, independently of their surface state.

In Situ Detection and Single Cell Quantification of Metal Oxide Nanoparticles Using Nuclear Microprobe Analysis

We describe a procedure for the detection of chemical elements present in situ in human cells as well as their in vitro quantification. The method is well-suited to any cell type and is particularly useful for quantitative chemical analyses in single cells following in vitro metal oxide nanoparticles exposure.

Micro-analytical techniques based on chemical element imaging enable the localization and quantification of chemical composition at the cellular level. ...

Preparation and Evaluation of 99mTc-labeled Tridentate Chelates for Pre-targeting Using Bioorthogonal Chemistry

Pre-targeting combined with bioorthogonal chemistry is emerging as an effective way to create new radiopharmaceuticals. Of the methods available, the inverse electron demand Diels-Alder (IEDDA) cycloaddition between a radiolabeled tetrazines and trans-cyclooctene (TCO) linked to a biomolecule has proven to be a highly effective bioorthogonal approach to imaging specific biological targets. Despite the fact that technetium-99m remains the most widely used isotope in diagnostic nuclear medicine, there is a scarcity of methods for preparing 99mTc-labeled tetrazines. Herein we report the preparation of a family of tridentate-chelate-tetrazine derivatives and their Tc(I) complexes. These hitherto unknown compounds were radiolabeled with 99mTc using a microwave-assisted method in 31% to 83% radiochemical yield. The products are stable in saline and PBS and react rapidly with TCO derivatives in vitro. Their in vivo pre-targeting abilities were demonstrated using a TCO-bisphosphonate (TCO-BP) derivative that localizes to regions of active bone metabolism or injury. In murine studies, the 99mTc-tetrazines showed high activity concentrations in knees and shoulder joints, which was not observed when experiments were performed in the absence of TCO-BP. The overall uptake in non-target organs and pharmacokinetics varied greatly depending on the nature of the linker and polarity of the chelate.

Preparation and Evaluation of 99mTc-labeled Tridentate Chelates for Pre-targeting Using Bioorthogonal Chemistry

Here, we describe a protocol for radiolabeling and in vivo testing of tridentate 99mTc(I) chelate-tetrazine derivatives for pre-targeting and bioorthogonal chemistry.

Pre-targeting combined with bioorthogonal chemistry is emerging as an effective way to create new radiopharmaceuticals. Of the methods available, the ...

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

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological targets and processes. However, the increasing number of different tracers creates challenges for their production at radiopharmacies. While historically it has been practical to dedicate a custom-configured radiosynthesizer and hot cell for the repeated production of each individual tracer, it is becoming necessary to change this workflow. Recent commercial radiosynthesizers based on disposable cassettes/kits for each tracer simplify the production of multiple tracers with one set of equipment by eliminating the need for custom tracer-specific modifications. Furthermore, some of these radiosynthesizers enable the operator to develop and optimize their own synthesis protocols in addition to purchasing commercially-available kits. In this protocol, we describe the general procedure for how the manual synthesis of a new PET tracer can be automated on one of these radiosynthesizers and validated for the production of clinical-grade tracers. As an example, we use the ELIXYS radiosynthesizer, a flexible cassette-based radiochemistry tool that can support both PET tracer development efforts, as well as routine clinical probe manufacturing on the same system, to produce [18F]Clofarabine ([18F]CFA), a PET tracer to measure in vivo deoxycytidine kinase (dCK) enzyme activity. Translating a manual synthesis involves breaking down the synthetic protocol into basic radiochemistry processes that are then translated into intuitive chemistry &#34;unit operations&#34; supported by the synthesizer software. These operations can then rapidly be converted into an automated synthesis program by assembling them using the drag-and-drop interface. After basic testing, the synthesis and purification procedure may require optimization to achieve the desired yield and purity. Once the desired performance is achieved, a validation of the synthesis is carried out to determine its suitability for the production of the radiotracer for clinical use.

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

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.

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological ...

Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh

A methodology is described to generate an isotopically pure 229Th ion beam in the 2+ and 3+ charge states. This ion beam enables one to investigate the low-lying isomeric first excited state of 229Th at an excitation energy of about 7.8(5) eV and a radiative lifetime of up to 104 seconds. The presented method allowed for a first direct identification of the decay of the thorium isomer, laying the foundations to study its decay properties as prerequisite for an optical control of this nuclear transition. High energy 229Th ions are produced in the &#945;&#160;decay of a radioactive 233U source. The ions are thermalized in a buffer-gas stopping cell, extracted and subsequently an ion beam is formed. This ion beam is mass purified by a quadrupole-mass separator to generate a pure ion beam. In order to detect the isomeric decay, the ions are collected on the surface of a micro-channel plate detector, where electrons, as emitted in the internal conversion decay of the isomeric state, are observed.

Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh

We present a protocol for the generation of an isotopically purified low-energy 229Th ion beam from a 233U source. This ion beam is used for the direct detection of the 229mTh ground-state decay via the internal-conversion decay channel. We also measure the internal conversion lifetime of 229mTh as well.

A methodology is described to generate an isotopically pure 229Th ion beam in the 2+ and 3+ charge states. This ion beam enables one to investigate the ...

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

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands for in vivo investigations. Within this protocol, a robust and reliable remote-controlled radiosynthesis of [11C]SNAP-7941, an antagonist to the melanin-concentrating hormone receptor 1, is described. The radiosynthesis starts with cyclotron produced [11C]CO2 that is subsequently further reacted via a gas-phase transition to [11C]CH3OTf. Then, this reactive intermediate is introduced to the precursor solution and forms the respective radiotracer. Chemical as well as the radiochemical purity are determined by means of RP-HPLC, routinely implemented in the radiopharmaceutical quality control process. Additionally, the molar activity is calculated as it is a necessity for the following real-time kinetic investigations. Furthermore, [11C]SNAP-7941 is applied to MDCKII-WT and MDCKII-hMDR1 cells for evaluating the impact of P-glycoprotein (P-gp) expression on cell accumulation. For this reason, the P-gp expressing cell line (MDCKII-hMDR1) is either used without or with blocking prior to experiments by means of the P-gp substrate (&#177;)-verapamil and the results are compared to the ones observed for the wildtype cells. The overall experimental approach demonstrates the importance of a precise time-management that is essential for every preclinical and clinical study using PET tracers radiolabelled with short-lived nuclides, such as carbon-11 (half-life: 20 min).

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

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.

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands ...

Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol

The kynurenine pathway (KP) is a primary route for tryptophan metabolism. Evidence strongly suggests that metabolites of the KP play a vital role in tumor proliferation, epilepsy, neurodegenerative diseases, and psychiatric illnesses due to their immune-modulatory, neuro-modulatory, and neurotoxic effects. The most extensively used positron emission tomography (PET) agent for mapping tryptophan metabolism, &#945;-[11C]methyl-L-tryptophan ([11C]AMT), has a short half-life of 20 min with laborious radiosynthesis procedures. An onsite cyclotron is required to radiosynthesize [11C]AMT. Only a limited number of centers produce [11C]AMT for preclinical studies and clinical investigations. Hence, the development of an alternative imaging agent that has a longer half-life, favorable in vivo kinetics, and is easy to automate is urgently needed. The utility and value of 1-(2-[18F]fluoroethyl)-L-tryptophan, a fluorine-18-labeled tryptophan analog, has been reported in preclinical applications in cell line-derived xenografts, patient-derived xenografts, and transgenic tumor models.
This paper presents a protocol for the radiosynthesis of 1-(2-[18F]fluoroethyl)-L-tryptophan using a one-pot, two-step strategy. Using this protocol, the radiotracer can be produced in a 20 &#177; 5% (decay corrected at the end of synthesis, n &#62; 20) radiochemical yield, with both radiochemical purity and enantiomeric excess of over 95%. The protocol features a small precursor amount with no more than 0.5 mL of reaction solvent in each step, low loading of potentially toxic 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (K222), and an environmentally benign and injectable mobile phase for purification. The protocol can be easily configured to produce 1-(2-[18F]fluoroethyl)-L-tryptophan for clinical investigation in a commercially available module.

Radiosynthesis of 1-2-[18F]Fluoroethyl-L-Tryptophan using a One-pot, Two-step Protocol

Here, we describe the radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-tryptophan, a positron emission tomography imaging agent for studying tryptophan metabolism, using a one-pot, two-step strategy in a radiochemistry synthesis system with good radiochemical yields, high enantiomeric excess, and high reliability.

The kynurenine pathway (KP) is a primary route for tryptophan metabolism. Evidence strongly suggests that metabolites of the KP play a vital role in tumor ...

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

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.

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 ...

Cancer Research

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

A fast, efficient method has been developed on the GAIA synthesis module for automated gallium-68 radiolabeling of 3BP-3940, a molecular imaging probe targeting the fibroblast activation protein for positron emission tomography imaging of the tumor microenvironment. The reaction conditions involved acetate buffer (final concentration: 0.1 M), methionine as an anti-radiolysis agent (final concentration: 5.4 mg/mL), and 30 &#181;g of 3BP-3940, with heating for 8 min at 98 &#176;C. A final purification step on a C18 cartridge was necessary to obtain a radiolabeled product of high purity. In contrast, the generator-produced 68Ga was used directly without a concentration step on a cation exchange cartridge. The production of three validation batches confirmed the method&#39;s reliability, allowing the synthesis of [68Ga]Ga-3BP-3940 in 22.3 &#177; 0.6 min with high radiochemical purity (RCP), as determined by both radio-HPLC (99.1% &#177; 0.1%) and radio-TLC (99.2% &#177; 0.1%). The average radiochemical yield, based on RCP values measured by radio-HPLC, was 74.4% &#177; 3.3%. The stability of the radiolabeled product was demonstrated for up to 4 h after preparation. This protocol provides a reliable, rapid, and efficient methodology for the preparation of [68Ga]Ga-3BP-3940, which can easily be transposed to a clinical setting.

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.

A fast, efficient method has been developed on the GAIA synthesis module for automated gallium-68 radiolabeling of 3BP-3940, a molecular imaging probe ...

Automated ⁹⁰Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

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