Micro Imager
Application Notes
Ex vivo control of visual stimuli in rat
brains by 18FDG imaging
Laurent Besret, Anne-Sophie Hérard (URA CEA-CNRS 2210, Orsay), Fabrice Beau (CEA-DSV, Orsay), Serge Maîtrejean (Biospace Lab, Paris)
In vivo imaging is rapidly developing as a direct consequence of improvements in dedicated instrumentation, superimposed upon decades of experience of in vitro imaging of tissues and molecular processes obtained, respectively, from histopathology and autoradiography. Examples are the strong association of in vivo optical microscopy with histopathology or PET/SPECT imaging with digital autoradiography. Ex vivo imaging of PET-labeled tissue sections after in vivo PET experiments is of particular interest for the precise measurement of molecular concentration or for tissue identification at high spatial resolution. While PET imaging now reaches voxel resolution in the (1-2 mm) range, pixel resolution in tissue sections by ex vivo imaging is one to two orders of magnitude better - in the (10-500 μm) range depending on the technique used.
The present study was focused on the increase of FDG uptake in the left colliculus of the brain after lateral visual stimulus. One goal was to evaluate the resolution and contrast performance of popular techniques available for ex vivo imaging of beta+-labeled tissue sections. Tested were film, phosphor imaging, and two real-time digital imagers, the Micro ImagerTM and the Beta ImagerTM, both products of Biospace Lab, Paris. The comparisons were carried out on brain tissue sections for which accurate localization is of particular interest.
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Laurent Besret, Anne-Sophie Hérard (URA CEA-CNRS 2210, Orsay), Fabrice Beau (CEA-DSV, Orsay), Serge Maîtrejean (Biospace Lab, Paris)
In vivo imaging is rapidly developing as a direct consequence of improvements in dedicated instrumentation, superimposed upon decades of experience of in vitro imaging of tissues and molecular processes obtained, respectively, from histopathology and autoradiography. Examples are the strong association of in vivo optical microscopy with histopathology or PET/SPECT imaging with digital autoradiography. Ex vivo imaging of PET-labeled tissue sections after in vivo PET experiments is of particular interest for the precise measurement of molecular concentration or for tissue identification at high spatial resolution. While PET imaging now reaches voxel resolution in the (1-2 mm) range, pixel resolution in tissue sections by ex vivo imaging is one to two orders of magnitude better - in the (10-500 μm) range depending on the technique used.
The present study was focused on the increase of FDG uptake in the left colliculus of the brain after lateral visual stimulus. One goal was to evaluate the resolution and contrast performance of popular techniques available for ex vivo imaging of beta+-labeled tissue sections. Tested were film, phosphor imaging, and two real-time digital imagers, the Micro ImagerTM and the Beta ImagerTM, both products of Biospace Lab, Paris. The comparisons were carried out on brain tissue sections for which accurate localization is of particular interest.
Read more...
Comprehensive functional imaging of
metabolism, perfusion and interstitial fluid
on histopathologic slices of infarcted
myocardium
S. Poussier, F. Maskali, P. Y. Marie, F. Carbillet, A. Bertrand, P. Olivier, F. Plenat, L. Antunes , D. Meng, H. Boutley, G. Karcher,S. Maitrejean
Histopathologic slices from infarcted hearts allow the assessment of the repartition of structural abnormalities and molecules involved in repairing processes. However, it is likely that these results depend on local variations in the functional status of myocardium and especially on the levels of tissue perfusion and cell viability. If available, such functional information might markedly enhance the understanding of histopathologic analyses.
In vivo, three main techniques may be used for assessing metabolism and perfusion of myocardium: glucose uptake (PET-18FDG), tissue perfusion (SPECT Sestamibi or Thalium), and extracellular fluid volume (MRI DTPA).
All these tracers may be labelled with beta emitter tracers. Therefore, using a high resolution imager for beta emitters, the Micro ImagerTM, it was postulated that the distribution of such tracers could be, simultaneously, precisely imaged and quantified on histopathologic slices with a high spatial resolution (~ 20 μm). The Micro ImagerTM is a high resolution radioactive disintegration imaging/counting system that allows the recording of data in the list mode. This records includes spatial coordinates as well as the time at which each disintegration occurs.
The aim of this study was to determine whether a global and comprehensive functional imaging of metabolism, perfusion and interstitial fluid could be provided by the Micro ImagerTM on histopathologic slices of infarcted myocardium from rats. In a first step, the ability of the Micro ImagerTM to separate activities provided by 3 different tracers (18F, 99mTc and 111In), using the time information recorded by the instrument, was tested on phantoms.
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S. Poussier, F. Maskali, P. Y. Marie, F. Carbillet, A. Bertrand, P. Olivier, F. Plenat, L. Antunes , D. Meng, H. Boutley, G. Karcher,S. Maitrejean
Histopathologic slices from infarcted hearts allow the assessment of the repartition of structural abnormalities and molecules involved in repairing processes. However, it is likely that these results depend on local variations in the functional status of myocardium and especially on the levels of tissue perfusion and cell viability. If available, such functional information might markedly enhance the understanding of histopathologic analyses.
In vivo, three main techniques may be used for assessing metabolism and perfusion of myocardium: glucose uptake (PET-18FDG), tissue perfusion (SPECT Sestamibi or Thalium), and extracellular fluid volume (MRI DTPA).
All these tracers may be labelled with beta emitter tracers. Therefore, using a high resolution imager for beta emitters, the Micro ImagerTM, it was postulated that the distribution of such tracers could be, simultaneously, precisely imaged and quantified on histopathologic slices with a high spatial resolution (~ 20 μm). The Micro ImagerTM is a high resolution radioactive disintegration imaging/counting system that allows the recording of data in the list mode. This records includes spatial coordinates as well as the time at which each disintegration occurs.
The aim of this study was to determine whether a global and comprehensive functional imaging of metabolism, perfusion and interstitial fluid could be provided by the Micro ImagerTM on histopathologic slices of infarcted myocardium from rats. In a first step, the ability of the Micro ImagerTM to separate activities provided by 3 different tracers (18F, 99mTc and 111In), using the time information recorded by the instrument, was tested on phantoms.
Read more...
Simultaneous dual-isotope imaging of
Technetium-99m and Thallium-201 using the
Micro ImagerTM
Laurent Riou (INSERM E0340, Grenoble), Carole Lartizien (ANIMAGE, Lyon), Alexis Broisat, Catherine Ghezzi (INSERM E0340, Grenoble), Serge Maitrejean (Biospace Lab, Paris), Daniel Fagret (INSERM E0340, Grenoble), Marc Janier (ANIMAGE, Lyon)
The development of new radiolabeled tracers requires the comparison of the newly proposed compound with the gold-standard molecule. 201Tl is the reference myocardial blood flow tracer and is being widely used for the diagnosis of coronary artery disease in patients. 99mTc-labelled tracers have been synthesized and proposed as substitutes for 201Tl because of the better physical characteristics offered by 99mTc (shorter half-life [6.02 hrs vs. 72 hrs for 201Tl] and better suited emission energy [140 vs. 69 keV for 201Tl]). The development of high-resolution imaging systems now allows the assessment of the myocardial uptake of a given flow tracer on small animal models such as the rat or the mouse. Specifically, the Micro ImagerTM provides a resolution of ~20 μm and a field-of-view compatible with rat or mouse ex vivo imaging of myocardial slices. Micro ImagerTM is a radioactive disintegration imaging/counting system that allows the recording of data in the list mode. This record include spatial coordinates but also the time at which each disintegration occurs. The objective of this study was to evaluate the potential of the time information recorded by the Micro ImagerTM for the simultaneous dual-isotope imaging of a 99mTc labeled perfusion tracer (99mTcN-NOET) and of 201Tl in rat myocardium. Such a capability would provide perfect image registration and excellent resolution for the quantitative comparison of ex vivo images obtained with 2 different radiolabeled tracers in an organ of interest.
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Laurent Riou (INSERM E0340, Grenoble), Carole Lartizien (ANIMAGE, Lyon), Alexis Broisat, Catherine Ghezzi (INSERM E0340, Grenoble), Serge Maitrejean (Biospace Lab, Paris), Daniel Fagret (INSERM E0340, Grenoble), Marc Janier (ANIMAGE, Lyon)
The development of new radiolabeled tracers requires the comparison of the newly proposed compound with the gold-standard molecule. 201Tl is the reference myocardial blood flow tracer and is being widely used for the diagnosis of coronary artery disease in patients. 99mTc-labelled tracers have been synthesized and proposed as substitutes for 201Tl because of the better physical characteristics offered by 99mTc (shorter half-life [6.02 hrs vs. 72 hrs for 201Tl] and better suited emission energy [140 vs. 69 keV for 201Tl]). The development of high-resolution imaging systems now allows the assessment of the myocardial uptake of a given flow tracer on small animal models such as the rat or the mouse. Specifically, the Micro ImagerTM provides a resolution of ~20 μm and a field-of-view compatible with rat or mouse ex vivo imaging of myocardial slices. Micro ImagerTM is a radioactive disintegration imaging/counting system that allows the recording of data in the list mode. This record include spatial coordinates but also the time at which each disintegration occurs. The objective of this study was to evaluate the potential of the time information recorded by the Micro ImagerTM for the simultaneous dual-isotope imaging of a 99mTc labeled perfusion tracer (99mTcN-NOET) and of 201Tl in rat myocardium. Such a capability would provide perfect image registration and excellent resolution for the quantitative comparison of ex vivo images obtained with 2 different radiolabeled tracers in an organ of interest.
Read more...
Microarray differential screening with two
radioactive probes on the
Micro ImagerTM
T. Vujasinovic, H. Salin, C. Menini, J. Mallet and S. Dumas (Hôpital Pitié Salpêtrière, Paris), S. Maitrejean (Biospace Lab)
There are several major technological challenges to use high-density probe arrays for largescale gene expression screenings:
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T. Vujasinovic, H. Salin, C. Menini, J. Mallet and S. Dumas (Hôpital Pitié Salpêtrière, Paris), S. Maitrejean (Biospace Lab)
There are several major technological challenges to use high-density probe arrays for largescale gene expression screenings:
- the analysis of very small quantities of tissues or cell populations,
- the detection of rare messenger RNAs (mRNA),
- the detection of small modulations of gene expression that may be of major biological significance,
- the detection and quantification, in a single sample and during the same experiment, of numerous mRNAs the amounts of which may differ by several orders of magnitude.
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