scholarly journals Attenuation Correction for Small Animal PET Images: A Comparison of Two Methods

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Daniela D'Ambrosio ◽  
Federico Zagni ◽  
Antonello E. Spinelli ◽  
Mario Marengo
Keyword(s):  
Attenuation Correction ◽  
Animal Studies ◽  
Spinal Column ◽  
Small Animal ◽  
Small Animal Pet ◽  
X Rays ◽  
Beam Hardening ◽  
Photon Attenuation ◽  
Bone Scans

In order to extract quantitative parameters from PET images, several physical effects such as photon attenuation, scatter, and partial volume must be taken into account. The main objectives of this work were the evaluation of photon attenuation in small animals and the implementation of two attenuation correction methods based on X-rays CT and segmentation of emission images. The accuracy of the first method with respect to the beam hardening effect was investigated by using Monte Carlo simulations. Mouse- and rat-sized phantoms were acquired in order to evaluate attenuation correction in terms of counts increment and recovery of uniform activity concentration. Both methods were applied to mice and rat images acquired with several radiotracers such asF18-FDG,11C-acetate,68Ga-chloride, andF18-NaF. The accuracy of the proposed methods was evaluated in heart and tumour tissues usingF18-FDG images and in liver, kidney, and spinal column tissues usingC11-acetate,Ga68-chloride, andF18-NaF images, respectively.In vivoresults from animal studies show that, except for bone scans, differences between the proposed methods were about 10% in rats and 3% in mice. In conclusion, both methods provide equivalent results; however, the segmentation-based approach has several advantages being less time consuming and simple to implement.

scholarly journals In Vivo Imaging of Peripheral Benzodiazepine Receptors in Mouse Lungs: A Biomarker of Inflammation

2005 ◽  
Vol 4 (4) ◽  
pp. 7290.2005.05133 ◽  
Author(s):  
Matthew J. Hardwick ◽  
Ming-Kai Chen ◽  
Kwamena Baidoo ◽  
Martin G. Pomper ◽  
Tomás R. Guilarte
Keyword(s):  
In Vivo Imaging ◽  
Ex Vivo ◽  
Inflammatory Diseases ◽  
Imaging Techniques ◽  
Benzodiazepine Receptors ◽  
Small Animal ◽  
Small Animal Pet ◽  
Planar Imaging ◽  
Peripheral Benzodiazepine Receptors

The ability to visualize the immune response with radioligands targeted to immune cells will enhance our understanding of cellular responses in inflammatory diseases. Peripheral benzodiazepine receptors (PBR) are present in monocytes and neutrophils as well as in lung tissue. We used lipopolysaccharide (LPS) as a model of inflammation to assess whether the PBR could be used as a noninvasive marker of inflammation in the lungs. Planar imaging of mice administrated 10 or 30 mg/kg LPS showed increased [123I]-( R)-PK11195 radioactivity in the thorax 2 days after LPS treatment relative to control. Following imaging, lungs from control and LPS-treated mice were harvested for ex vivo gamma counting and showed significantly increased radioactivity above control levels. The specificity of the PBR response was determined using a blocking dose of nonradioactive PK11195 given 30 min prior to radiotracer injection. Static planar images of the thorax of nonradioactive PK11195 pretreated animals showed a significantly lower level of radiotracer accumulation in control and in LPS-treated animals ( p < .05). These data show that LPS induces specific increases in PBR ligand binding in the lungs. We also used in vivo small-animal PET studies to demonstrate increased [11C]-( R)-PK11195 accumulation in the lungs of LPS-treated mice. This study suggests that measuring PBR expression using in vivo imaging techniques may be a useful biomarker to image lung inflammation.

scholarly journals An in vivo multimodal feasibility study in a rat brain tumour model using flexible multinuclear MR and PET systems

2020 ◽  
Author(s):  
Chang-Hoon Choi ◽  
Carina Stegmayr ◽  
Aliaksandra Shymanskaya ◽  
Wieland A. Worthoff ◽  
Nuno A da Silva ◽  
...  
Keyword(s):  
Brain Tumour ◽  
Small Animal ◽  
Optimal Combination ◽  
Small Animal Pet ◽  
Molecular Profile ◽  
Genetic Profile ◽  
Normal Brain ◽  
Valuable Insight ◽  
Wide Range

Abstract Background : In addition to the structural information afforded by 1 H MRI, the use of X-nuclei, such as sodium-23 ( 23 Na) or phosphorus-31 ( 31 P), offers important complementary information concerning physiological and biochemical parameters. By then combining this technique with PET, which provides valuable insight into a wide range of metabolic and molecular processes by using of a variety of radioactive tracers, the scope of medical imaging and diagnostics can be significantly increased. While the use of multimodal imaging is undoubtedly advantageous, identifying the optimal combination of these parameters to diagnose a specific dysfunction is very important and is advanced by the use of sophisticated imaging techniques in specific animal models.Methods : In this pilot study, rats with intracerebral 9L gliosarcomas were used to explore a combination of sequential multinuclear MRI using a sophisticated switchable coil set in a small animal 9.4 T MRI scanner and, subsequently, a small animal PET with the tumour tracer O-(2-[ 18 F]-fluoroethyl)-L-tyrosine ( 18 F-FET). This enabled in vivo multinuclear MR-PET experiments to be conducted without compromising the performance of either multinuclear MR or PET.Results : High-quality in vivo images and spectra including high-resolution 1 H imaging, 23 Na-weighted imaging, detection of 31 P metabolites and 18 F-FET uptake were obtained, allowing the characterisation of tumour tissues in comparison to a normal brain. These parameters have been shown to be useful in the identification of the genetic profile of gliomas, particularly concerning the mutation of the isocitrate hydrogenase gene, which is highly relevant for treatment strategy.Conclusions : The combination of multinuclear MR and PET in, for example, brain tumour models with specific genetic mutations will enable the physiological background of signal alterations to be explored and the identification of the optimal combination of imaging parameters for the non-invasive characterisation of the molecular profile of tumours.

scholarly journals Coregistration of Small Animal PET and Autoradiography for in vivo–ex vivo Comparison

2007 ◽  
pp. 822-830
Author(s):  
Soo-Min Song ◽  
Min-Jeong Kim ◽  
Joung-Min Lee ◽  
Hye-Jin Park ◽  
KyeongMin Kim ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Small Animal ◽  
Small Animal Pet ◽  
Animal Pet

scholarly journals New 55Co-labeled Albumin-Binding Folate Derivatives as Potential PET Agents for Folate Receptor Imaging

2019 ◽  
Vol 12 (4) ◽  
pp. 166 ◽  
Author(s):  
Lauren L. Radford ◽  
Solana Fernandez ◽  
Rebecca Beacham ◽  
Retta El Sayed ◽  
Renata Farkas ◽  
...  
Keyword(s):  
Folate Receptor ◽  
Small Animal ◽  
Small Animal Pet ◽  
Receptor Imaging ◽  
Albumin Binding ◽  
Liver Uptake ◽  
Biodistribution Studies ◽  
Positron Emission

Overexpression of folate receptors (FRs) on different tumor types (e.g., ovarian, lung) make FRs attractive in vivo targets for directed diagnostic/therapeutic agents. Currently, no diagnostic agent suitable for positron emission tomography (PET) has been adopted for clinical FR imaging. In this work, two 55Co-labeled albumin-binding folate derivatives-[55Co]Co-cm10 and [55Co]Co-rf42-with characteristics suitable for PET imaging have been developed and evaluated. High radiochemical yields (≥95%) and in vitro stabilities (≥93%) were achieved for both compounds, and cell assays demonstrated FR-mediated uptake. Both 55Co-labeled folate conjugates demonstrated high tumor uptake of 17% injected activity per gram of tissue (IA/g) at 4 h in biodistribution studies performed in KB tumor-bearing mice. Renal uptake was similar to other albumin-binding folate derivatives, and liver uptake was lower than that of previously reported [64Cu]Cu-rf42. Small animal PET/CT images confirmed the biodistribution results and showed the clear delineation of FR-expressing tumors.

Development of a novel radiation imaging detector system for in vivo gene imaging in small animal studies

1998 ◽  
Vol 45 (3) ◽  
pp. 1743-1749 ◽  
Author(s):  
A.G. Weisenberger ◽  
E.L. Bradley ◽  
S. Majewski ◽  
M.S. Saha
Keyword(s):  
Animal Studies ◽  
Small Animal ◽  
Detector System ◽  
Radiation Imaging ◽  
Imaging Detector

Implementation of 89Zr production and in vivo imaging of B-cells in mice with 89Zr-labeled anti-B-cell antibodies by small animal PET/CT

2011 ◽  
Vol 69 (6) ◽  
pp. 852-857 ◽  
Author(s):  
Martin Walther ◽  
Peter Gebhardt ◽  
Philipp Grosse-Gehling ◽  
Lydia Würbach ◽  
Ingo Irmler ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
In Vivo Imaging ◽  
Small Animal ◽  
Small Animal Pet ◽  
Animal Pet ◽  
Pet Ct

Effects of posture on regional pulmonary blood flow in rats as measured by PET

2010 ◽  
Vol 108 (2) ◽  
pp. 422-429 ◽  
Author(s):  
Torsten Richter ◽  
Ralf Bergmann ◽  
Jens Pietzsch ◽  
Inge Közle ◽  
Frank Hofheinz ◽  
...  
Keyword(s):  
Blood Flow ◽  
Pulmonary Blood Flow ◽  
Small Animal ◽  
Vertical Gradient ◽  
Human Albumin ◽  
Small Animal Pet ◽  
Longitudinal Measurements ◽  
Spatial Differences ◽  
Spontaneously Breathing

Using small animal PET with 68Ga-radiolabeled human albumin microspheres (Ga-68-microspheres), we investigated the effect of posture on regional pulmonary blood flow (PBF) in normal rats. This in vivo method is noninvasive and quantitative, and it allows for repeated longitudinal measurements. The purpose of the experiment was to quantify spatial differences in PBF in small animals in different postures. Two studies were performed in anesthetized, spontaneously breathing Wistar rats. Study 1 was designed to determine PBF in the prone and supine positions. Ga-68-microspheres were given to five prone and eight supine animals. We found that PBF increased in dorsal regions of supine animals (0.75) more than in prone animals (0.70; P = 0.037), according to a steeper vertical gradient of flow in supine than in prone animals. No differences in spatial heterogeneity were detected. Study 2 was designed to determine the effects of tissue distribution on PBF measurements. Because microspheres remained fixed in the lung, PET was performed on animals in the position in which they received Ga-68-microsphere injections and thereafter in the opposite posture. The distribution of PBF showed a preference for dorsal regions in both positions, but the distribution was dependent on the position during administration of the microspheres. We conclude that PET using Ga-68-microspheres can detect and quantify regional PBF in animals as small as the rat. PBF distributions differed between the prone and supine postures and were influenced by the distribution of lung tissue within the thorax.

scholarly journals Preliminary Experience with Small Animal SPECT Imaging on Clinical Gamma Cameras

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
P. Aguiar ◽  
J. Silva-Rodríguez ◽  
M. Herranz ◽  
A. Ruibal
Keyword(s):  
Animal Studies ◽  
Small Animal ◽  
Spect Imaging ◽  
Portable Device ◽  
Preclinical Research ◽  
Preclinical Imaging ◽  
Gamma Cameras ◽  
Widespread Availability ◽  
Phantom Experiments

The traditional lack of techniques suitable forin vivoimaging has induced a great interest in molecular imaging for preclinical research. Nevertheless, its use spreads slowly due to the difficulties in justifying the high cost of the current dedicated preclinical scanners. An alternative for lowering the costs is to repurpose old clinical gamma cameras to be used for preclinical imaging. In this paper we assess the performance of a portable device, that is, working coupled to a single-head clinical gamma camera, and we present our preliminary experience in several small animal applications. Our findings, based on phantom experiments and animal studies, provided an image quality, in terms of contrast-noise trade-off, comparable to dedicated preclinical pinhole-based scanners. We feel that our portable device offers an opportunity for recycling the widespread availability of clinical gamma cameras in nuclear medicine departments to be used in small animal SPECT imaging and we hope that it can contribute to spreading the use of preclinical imaging within institutions on tight budgets.

scholarly journals Radiosynthesis and Evaluation of Cyclohexyl (5-(2-[11C-Carbonyl]acetamidobenzo[d]thiazol-6-yl)-2-Methylpyridin-3-yl)Carbamate ([11C]PK68) As a New Radioligand For Imaging Receptor-Interacting Protein 1 Kinase

2022 ◽  
Author(s):  
Tomoteru Yamasaki ◽  
Katsushi Kumata ◽  
Atsuto Hiraishi ◽  
Yiding Zhang ◽  
Hidekatsu Wakizaka ◽  
...  
Keyword(s):  
Acetyl Chloride ◽  
Radiochemical Purity ◽  
Specific Binding ◽  
Small Animal ◽  
Small Animal Pet ◽  
Interacting Protein ◽  
Molar Activity ◽  
Positron Emission ◽  
Key Enzyme

Abstract Background: Receptor-interacting protein 1 kinase (RIPK1) is a key enzyme in the regulation of cellular necroptosis. Recently, cyclohexyl (5-(2-acetamidobenzo[d]thiazol-6-yl)-2-methylpyridin-3-yl)carbamate (PK68, 5) has been developed as a potent inhibitor of RIPK1. Herein, we radiosynthesized [11C]PK68 as a new positron emission tomography (PET) ligand for imaging RIPK1 and evaluated its potential in vivo.Results: We synthesized [11C]PK68 by reacting amine precursor 14 with [11C]acetyl chloride. At the end of synthesis, we obtained [11C]PK68 of 1200–1790 MBq (n = 10) with >99% radiochemical purity and a molar activity of 37–99 GBq/μmol starting from 18–33 GBq of [11C]CO2. The fully automated synthesis took 30 min from the end of irradiation. In a small-animal PET study, [11C]PK68 was rapidly distributed in the liver and kidneys of healthy mice after injection, and was subsequently cleared from their bodies via hepatobiliary excretion and the intestinal reuptake pathway. Although there was no obvious specific binding of RIPK1 in the PET study, [11C]PK68 demonstrated relatively high stability in vivo, and may be used as a lead compound for further candidate development.Conclusions: In the present study, we successfully radiosynthesized [11C]PK68 and evaluated its potential in vivo. We are planning to optimize the chemical structure of [11C]PK68 and conduct further PET studies on it using pathological models.

Sign in / Sign up

Export Citation Format

Share Document