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Lu M, Yang Z, Wang F, Drake G, Chen LM, Gore JC, Yan X. Optimization of a quadrature birdcage coil for functional imaging of squirrel monkey brain at 9.4T. Magn Reson Imaging 2021; 79:45-51. [PMID: 33741436 DOI: 10.1016/j.mri.2021.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/17/2022]
Abstract
A quadrature transmit/receive birdcage coil was optimized for squirrel monkey functional imaging at the high field of 9.4 T. The coil length was chosen to gain maximum coil efficiency/signal-to-noise ratio (SNR) and meanwhile provide enough homogenous RF field in the whole brain area. Based on the numerical simulation results, a 16-rung high-pass birdcage coil with the optimal length of 9 cm was constructed and evaluated on phantom and in vivo experiments. Compared to a general-purpose non-optimized coil, it exhibits approximately 25% in vivo SNR improvement. In addition to the volume coil, details about how to design and construct the associated animal preparation system were provided.
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Affiliation(s)
- Ming Lu
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; College of Nuclear Equipment and Nuclear Engineering, Yantai University, Yantai, Shandong, China
| | - Zhangyan Yang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gary Drake
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Xinqiang Yan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
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Devic S, Mohammed H, Tomic N, Aldelaijan S, De Blois F, Seuntjens J, Lehnert S, Faria S. FDG-PET-based differential uptake volume histograms: a possible approach towards definition of biological target volumes. Br J Radiol 2016; 89:20150388. [PMID: 27007269 DOI: 10.1259/bjr.20150388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE Integration of fluorine-18 fludeoxyglucose ((18)F-FDG)-positron emission tomography (PET) functional data into conventional anatomically based gross tumour volume delineation may lead to optimization of dose to biological target volumes (BTV) in radiotherapy. We describe a method for defining tumour subvolumes using (18)F-FDG-PET data, based on the decomposition of differential uptake volume histograms (dUVHs). METHODS For 27 patients with histopathologically proven non-small-cell lung carcinoma (NSCLC), background uptake values were sampled within the healthy lung contralateral to a tumour in those image slices containing tumour and then scaled by the ratio of mass densities between the healthy lung and tumour. Signal-to-background (S/B) uptake values within volumes of interest encompassing the tumour were used to reconstruct the dUVHs. These were subsequently decomposed into the minimum number of analytical functions (in the form of differential uptake values as a function of S/B) that yielded acceptable net fits, as assessed by χ(2) values. RESULTS Six subvolumes consistently emerged from the fitted dUVHs over the sampled volume of interest on PET images. Based on the assumption that each function used to decompose the dUVH may correspond to a single subvolume, the intersection between the two adjacent functions could be interpreted as a threshold value that differentiates them. Assuming that the first two subvolumes spread over the tumour boundary, we concentrated on four subvolumes with the highest uptake values, and their S/B thresholds [mean ± standard deviation (SD)] were 2.88 ± 0.98, 4.05 ± 1.55, 5.48 ± 2.06 and 7.34 ± 2.89 for adenocarcinoma, 3.01 ± 0.71, 4.40 ± 0.91, 5.99 ± 1.31 and 8.17 ± 2.42 for large-cell carcinoma and 4.54 ± 2.11, 6.46 ± 2.43, 8.87 ± 5.37 and 12.11 ± 7.28 for squamous cell carcinoma, respectively. CONCLUSION (18)F-FDG-based PET data may potentially be used to identify BTV within the tumour in patients with NSCLC. Using the one-way analysis of variance statistical tests, we found a significant difference among all threshold levels among adenocarcinomas, large-cell carcinoma and squamous cell carcinomas. On the other hand, the observed significant variability in threshold values throughout the patient cohort (expressed as large SDs) can be explained as a consequence of differences in the physiological status of the tumour volume for each patient at the time of the PET/CT scan. This further suggests that patient-specific threshold values for the definition of BTVs could be determined by creation and curve fitting of dUVHs on a patient-by-patient basis. ADVANCES IN KNOWLEDGE The method of (18)F-FDG-PET-based dUVH decomposition described in this work may lead to BTV segmentation in tumours.
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Affiliation(s)
- Slobodan Devic
- 1 Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Huriyyah Mohammed
- 1 Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Nada Tomic
- 1 Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Saad Aldelaijan
- 1 Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - François De Blois
- 1 Department of Radiation Oncology, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Jan Seuntjens
- 2 Department of Radiation Oncology, Montreal General Hospital, McGill University, Montréal, QC, Canada
| | - Shirley Lehnert
- 2 Department of Radiation Oncology, Montreal General Hospital, McGill University, Montréal, QC, Canada
| | - Sergio Faria
- 2 Department of Radiation Oncology, Montreal General Hospital, McGill University, Montréal, QC, Canada
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Smith TAD, Zanda M, Fleming IN. Hypoxia stimulates 18F-fluorodeoxyglucose uptake in breast cancer cells via hypoxia inducible factor-1 and AMP-activated protein kinase. Nucl Med Biol 2013; 40:858-64. [PMID: 23786679 DOI: 10.1016/j.nucmedbio.2013.05.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/10/2013] [Accepted: 05/12/2013] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Hypoxia can stimulate (18)F-fluorodeoxyglucose (FDG) uptake in cultured cells. A better understanding of the underlying molecular mechanism is required to determine the value of FDG for studying tumour hypoxia. METHODS The effect of hypoxia on FDG uptake, and key proteins involved in glucose transport and glycolysis, was studied in MCF7 and MDA231 breast cancer cell lines. RESULTS Hypoxia induced a dose- and time-dependent increase in FDG uptake. The FDG increase was transient, suggesting that FDG uptake is only likely to be increased by acute hypoxia (<24 h). Molecular analysis indicated that hypoxia upregulated glut1 and 6-phosphofructo-2-kinase, key proteins involved in regulating glucose transport and glycolysis, and that these changes were induced by Hypoxia-Inducible factor 1 (HIF1) upregulation and/or AMP-activated protein kinase activation. CONCLUSIONS FDG may provide useful information about the oxygenation status of cells in hypoxic regions where HIF1 upregulation is hypoxia-driven.
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Affiliation(s)
- Tim A D Smith
- Division of Applied Medicine, School of Medicine and Dentistry, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD
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Bartlett RM, Beattie BJ, Naryanan M, Georgi JC, Chen Q, Carlin SD, Roble G, Zanzonico PB, Gonen M, O'Donoghue J, Fischer A, Humm JL. Image-guided PO2 probe measurements correlated with parametric images derived from 18F-fluoromisonidazole small-animal PET data in rats. J Nucl Med 2012; 53:1608-15. [PMID: 22933821 DOI: 10.2967/jnumed.112.103523] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED (18)F-fluoromisonidazole PET, a noninvasive means of identifying hypoxia in tumors, has been widely applied but with mixed results, raising concerns about its accuracy. The objective of this study was to determine whether kinetic analysis of dynamic (18)F-fluoromisonidazole data provides better discrimination of tumor hypoxia than methods based on a simple tissue-to-plasma ratio. METHODS Eleven Dunning R3327-AT prostate tumor-bearing nude rats were immobilized in custom-fabricated whole-body molds, injected intravenously with (18)F-fluoromisonidazole, and imaged dynamically for 105 min. They were then transferred to a robotic system for image-guided measurement of intratumoral partial pressure of oxygen (Po(2)). The dynamic (18)F-fluoromisonidazole uptake data were fitted with 2 variants of a 2-compartment, 3-rate-constant model, one constrained to have K(1) equal to k(2) and the other unconstrained. Parametric images of the rate constants were generated. The Po(2) measurements were compared with spatially registered maps of kinetic rate constants and tumor-to-plasma ratios. RESULTS The constrained pharmacokinetic model variant was shown to provide fits similar to that of the unconstrained model and did not introduce significant bias in the results. The trapping rate constant, k(3), of the constrained model provided a better discrimination of low Po(2) than the tissue-to-plasma ratio or the k(3) of the unconstrained model. CONCLUSION The use of kinetic modeling on a voxelwise basis can identify tumor hypoxia with improved accuracy over simple tumor-to-plasma ratios. An effective means of controlling noise in the trapping rate constant, k(3), without introducing significant bias, is to constrain K(1) equal to k(2) during the fitting process.
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Affiliation(s)
- Rachel M Bartlett
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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Huang T, Civelek AC, Li J, Jiang H, Ng CK, Postel GC, Shen B, Li XF. Tumor microenvironment-dependent 18F-FDG, 18F-fluorothymidine, and 18F-misonidazole uptake: a pilot study in mouse models of human non-small cell lung cancer. J Nucl Med 2012; 53:1262-8. [PMID: 22717978 DOI: 10.2967/jnumed.111.098087] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED (18)F-FDG, (18)F-fluorothymidine, and (18)F-misonidazole PET scans have emerged as important clinical tools in the management of cancer; however, none of them have demonstrated conclusive superiority. The aim of this study was to compare the intratumoral accumulation of (18)F-FDG, (18)F-fluorothymidine, and (18)F-misonidazole and relate this to specific components of the tumor microenvironment in mouse models of human non-small cell lung cancer (NSCLC). METHODS We used NSCLC A549 and HTB177 cells to generate subcutaneous and peritoneal xenografts in nude mice. Animals were coinjected with a PET radiotracer, pimonidazole (hypoxia marker), and bromodeoxyuridine (proliferation marker) intravenously 1 h before animal euthanasia. Tumor perfusion was assessed by Hoechst 33342 injection, given 1 min before sacrifice. The intratumoral distribution of PET radiotracers was visualized by digital autoradiography and related to microscopic visualization of proliferation, hypoxia, perfusion, stroma, and necrosis. RESULTS NSCLC xenografts had complex structures with intermingled regions of viable cancer cells, stroma, and necrosis. Cancer cells were either well oxygenated (staining negatively for pimonidazole) and highly proliferative (staining positively for bromodeoxyuridine) or hypoxic (pimonidazole-positive) and noncycling (little bromodeoxyuridine). Hypoxic cancer cells with a low proliferation rate had high(18)F-FDG and (18)F-misonidazole uptake but low (18)F-fluorothymidine accumulation. Well-oxygenated cancer cells with a high proliferation rate accumulated a high level of (18)F-fluorothymidine but low (18)F-FDG and(18)F-misonidazole. Tumor stroma and necrotic zones were always associated with low (18)F-FDG, (18)F-misonidazole, and (18)F-fluorothymidine activity. CONCLUSION In NSCLC A549 and HTB177 subcutaneously or intraperitoneally growing xenografts, (18)F-fluorothymidine accumulates in well-oxygenated and proliferative cancer cells, whereas (18)F-misonidazole and (18)F-FDG accumulate mostly in poorly proliferative and hypoxic cancer cells. (18)F-FDG and (18)F-misonidazole display similar intratumoral distribution patterns, and both mutually exclude (18)F-fluorothymidine.
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Affiliation(s)
- Tao Huang
- Department of Medical Imaging, the Fourth Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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Abstract
Animal handling and preparation is one of the most critical aspects of in vivo NMR imaging in small animals, and involves a broad spectrum of challenges, any of which could affect data quality and reproducibility. This chapter will outline the most critical considerations in animal handling for in vivo MRI experimentation in rodent models. Highly accurate and reproducible positioning is one of the most important aspects, since sensitivity, motion and susceptibility artifacts, animal imaging throughput, and ease of data quantification are all dependent on it. A variety of devices exist today that assist in several aspects of animal handling and positioning, each with its own advantages and limitations. This chapter will detail many of the devices that are commercially available and how they have dealt with integration of RF coil technology, restraint, anesthesia, fiducial markers, warming, and physiological monitoring. The chapter will additionally detail various aspects of animal anesthesia, maintenance of core body temperature, physiological monitoring, intubation and ventilation, and systemic contrast agent administration. An increasingly important factor in running a small animal MRI laboratory, facility biosecurity, will also be reviewed.
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Affiliation(s)
- Patrick McConville
- Molecular Imaging Research, Inc., 800 Technology Drive, Ann Arbor, MI 48108, USA.
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Kokuryo D, Kimura Y, Obata T, Yamaya T, Kawamura K, Zhang MR, Kanno I, Aoki I. A small animal holding fixture system with positional reproducibility for longitudinal multimodal imaging. Phys Med Biol 2010; 55:4119-30. [PMID: 20601770 DOI: 10.1088/0031-9155/55/14/011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study presents a combined small animal holding fixture system, termed a 'bridge capsule', which provides for small animal re-fixation with positional reproducibility. This system comprises separate holding fixtures for the head and lower body and a connecting part to a gas anesthesia system. A mouse is fixed in place by the combination of a head fixture with a movable part made from polyacetal resin, a lower body fixture made from vinyl-silicone and a holder for the legs and tail. For re-fixation, a similar posture could be maintained by the same holding fixtures and a constant distance between the head and lower body fixtures is maintained. Artifacts caused by the bridge capsule system were not observed on magnetic resonance (MRI) and positron emission tomography (PET) images. The average position differences of the spinal column and the iliac body before and after re-fixation for the same modality were approximately 1.1 mm. The difference between the MRI and PET images was approximately 1.8 mm for the lower body fixture after image registration using fiducial markers. This system would be useful for longitudinal, repeated and multimodal imaging experiments requiring similar animal postures.
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Affiliation(s)
- Daisuke Kokuryo
- Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
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Li XF, Ma Y, Sun X, Humm JL, Ling CC, O'Donoghue JA. High 18F-FDG uptake in microscopic peritoneal tumors requires physiologic hypoxia. J Nucl Med 2010; 51:632-8. [PMID: 20351353 DOI: 10.2967/jnumed.109.071233] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
UNLABELLED The objective of this study was to examine (18)F-FDG uptake in microscopic tumors grown intraperitoneally in nude mice and to relate this to physiologic hypoxia and glucose transporter-1 (GLUT-1) expression. METHODS Human colon cancer HT29 and HCT-8 cells were injected intraperitoneally into nude mice to generate disseminated tumors of varying sizes. After overnight fasting, animals, breathing either air or carbogen (95% O(2) + 5% CO(2)), were intravenously administered (18)F-FDG together with the hypoxia marker pimonidazole and cellular proliferation marker bromodeoxyuridine 1 h before sacrifice. Hoechst 33342, a perfusion marker, was administered 1 min before sacrifice. After sacrifice, the intratumoral distribution of (18)F-FDG was assessed by digital autoradiography of frozen tissue sections. Intratumoral distribution was compared with the distributions of pimonidazole, GLUT-1 expression, bromodeoxyuridine, and Hoechst 33342 as visualized by immunofluorescent microscopy. RESULTS Small tumors (diameter, <1 mm) had high (18)F-FDG accumulation and were severely hypoxic, with high GLUT-1 expression. Larger tumors (diameter, 1-4 mm) generally had low (18)F-FDG accumulation and were not significantly hypoxic, with low GLUT-1 expression. Carbogen breathing significantly decreased (18)F-FDG accumulation and tumor hypoxia in microscopic tumors but had little effect on GLUT-1 expression. CONCLUSION There was high (18)F-FDG uptake in microscopic tumors that was spatially associated with physiologic hypoxia and high GLUT-1 expression. This enhanced uptake was abrogated by carbogen breathing, indicating that in the absence of physiologic hypoxia, high GLUT-1 expression, by itself, was insufficient to ensure high (18)F-FDG uptake.
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Affiliation(s)
- Xiao-Feng Li
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
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Christian N, Deheneffe S, Bol A, De Bast M, Labar D, Lee JA, Grégoire V. Is (18)F-FDG a surrogate tracer to measure tumor hypoxia? Comparison with the hypoxic tracer (14)C-EF3 in animal tumor models. Radiother Oncol 2010; 97:183-8. [PMID: 20304513 DOI: 10.1016/j.radonc.2010.02.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Revised: 01/17/2010] [Accepted: 02/22/2010] [Indexed: 10/19/2022]
Abstract
INTRODUCTION Fluorodeoxyglucose (FDG) has been reported as a surrogate tracer to measure tumor hypoxia with positron emission tomography (PET). The hypothesis is that there is an increased uptake of FDG under hypoxic conditions secondary to enhanced glycolysis, compensating the hypoxia-induced loss of cellular energy production. Several studies have already addressed this issue, some with conflicting results. This study aimed to compare the tracers (14)C-EF3 and (18)F-FDG to detect hypoxia in mouse tumor models. MATERIALS AND METHODS C3H, tumor-bearing mice (FSAII and SCCVII tumors) were injected iv with (14)C-EF3, and 1h later with (18)F-FDG. Using a specifically designed immobilization device with fiducial markers, PET (Mosaic®, Philips) images were acquired 1h after the FDG injection. After imaging, the device containing mouse was frozen, transversally sliced and imaged with autoradiography (AR) (FLA-5100, Fujifilm) to obtain high resolution images of the (18)F-FDG distribution within the tumor area. After a 48-h delay allowing for (18)F decay a second AR was performed to image (14)C-EF3 distribution. AR images were aligned to reconstruct the full 3D tumor volume, and were compared with the PET images. Image segmentation with threshold-based methods was applied on both AR and PET images to derive various tracer activity volumes. The matching index DSI (dice similarity index) was then computed. The comparison was performed under normoxic (ambient air, FSAII: n=4, SCCVII, n=5) and under hypoxic conditions (10% O(2) breathing, SCCVII: n=4). RESULTS On AR, under both ambient air and hypoxic conditions, there was a decreasing similarity between (14)C-EF3 and FDG with higher activity sub-volumes. Under normoxic conditions, when comparing the 10% of tumor voxels with the highest (18)F-FDG or (14)C-EF3 activity, a DSI of 0.24 and 0.20 was found for FSAII and SCCVII, respectively. Under hypoxic conditions, a DSI of 0.36 was observed for SCCVII tumors. When comparing the (14)C-EF3 distribution in AR with the corresponding (18)F-FDG-PET images, the DSI reached values of 0.26, 0.22 and 0.21 for FSAII and SCCVII under normoxia and SCCVII under hypoxia, respectively. CONCLUSION This study showed that FDG is not a good surrogate tracer for tumor hypoxia under either ambient or hypoxic conditions. Only specific hypoxia tracers should be used to measure tumor hypoxia.
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Affiliation(s)
- Nicolas Christian
- Center for Molecular Imaging and Experimental Radiotherapy, Université catholique de Louvain, St-Luc University Hospital, Brussels, Belgium
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Strobel K, Bergmann R, Meister S, van den Hoff J, Pietzsch J. Improved multimodality imaging using alginate molding in xenograft tumor models. J Magn Reson Imaging 2010; 31:747-52. [DOI: 10.1002/jmri.22090] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Chang J, Wen B, Kazanzides P, Zanzonico P, Finn RD, Fichtinger G, Ling CC. A robotic system for 18F-FMISO PET-guided intratumoral pO2 measurements. Med Phys 2010; 36:5301-9. [PMID: 19994538 DOI: 10.1118/1.3239491] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
An image-guided robotic system was used to measure the oxygen tension (pO2) in rodent tumor xenografts using interstitial probes guided by tumor hypoxia PET images. Rats with approximately 1 cm diameter tumors were anesthetized and immobilized in a custom-fabricated whole-body mold. Imaging was performed using a dedicated small-animal PET scanner (R4 or Focus 120 microPET) approximately 2 h after the injection of the hypoxia tracer 18F-fluoromisonidazole (18F-FMISO). The coordinate systems of the robot and PET were registered based on fiducial markers in the rodent bed visible on the PET images. Guided by the 3D microPET image set, measurements were performed at various locations in the tumor and compared to the corresponding 18F-FMISO image intensity at the respective measurement points. Experiments were performed on four tumor-bearing rats with 4 (86), 3 (80), 7 (162), and 8 (235) measurement tracks (points) for each experiment. The 18F-FMISO image intensities were inversely correlated with the measured pO2, with a Pearson coefficient ranging from -0.14 to -0.97 for the 22 measurement tracks. The cumulative scatterplots of pO2 versus image intensity yielded a hyperbolic relationship, with correlation coefficients of 0.52, 0.48, 0.64, and 0.73, respectively, for the four tumors. In conclusion, PET image-guided pO2 measurement is feasible with this robot system and, more generally, this system will permit point-by-point comparison of physiological probe measurements and image voxel values as a means of validating molecularly targeted radiotracers. Although the overall data fitting suggested that 18F-FMISO may be an effective hypoxia marker, the use of static 18F-FMISO PET postinjection scans to guide radiotherapy might be problematic due to the observed high variation in some individual data pairs from the fitted curve, indicating potential temporal fluctuation of oxygen tension in individual voxels or possible suboptimal imaging time postadministration of hypoxia-related trapping of 18F-FMISO.
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Affiliation(s)
- Jenghwa Chang
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10021, USA.
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Molecular imaging of hypoxia with radiolabelled agents. Eur J Nucl Med Mol Imaging 2009; 36:1674-86. [PMID: 19565239 PMCID: PMC2758191 DOI: 10.1007/s00259-009-1195-9] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 06/07/2009] [Indexed: 01/29/2023]
Abstract
Tissue hypoxia results from an inadequate supply of oxygen (O2) that compromises biological functions. Structural and functional abnormalities of the tumour vasculature together with altered diffusion conditions inside the tumour seem to be the main causes of tumour hypoxia. Evidence from experimental and clinical studies points to a role for tumour hypoxia in tumour propagation, resistance to therapy and malignant progression. This has led to the development of assays for the detection of hypoxia in patients in order to predict outcome and identify patients with a worse prognosis and/or patients that would benefit from appropriate treatments. A variety of invasive and non-invasive approaches have been developed to measure tumour oxygenation including oxygen-sensitive electrodes and hypoxia marker techniques using various labels that can be detected by different methods such as positron emission tomography (PET), single photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), autoradiography and immunohistochemistry. This review aims to give a detailed overview of non-invasive molecular imaging modalities with radiolabelled PET and SPECT tracers that are available to measure tumour hypoxia.
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Abstract
Multimodality small-animal molecular imaging has become increasingly important as transgenic and knockout mice are produced to model human diseases. With the ever-increasing number and importance of human disease models, particularly in rodents (mice and rats), the ability of high-resolution multimodality molecular imaging instrumentation to contribute unique information is becoming more common and necessary. Multimodality imaging with high spatial resolution and good sensitivity, which combines modalities and records sequentially or simultaneously complementary information, offers many advantages in certain research experiments. This article discusses the current trends and new horizons in preclinical multimodality imaging in-vivo and its role in biomedical research.
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Affiliation(s)
- David B Stout
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine at UCLA, 570 Westwood Plaza, CNSI Building, Room 2151, Los Angeles, CA 90095, USA
| | - Habib Zaidi
- Division of Nuclear Medicine, Geneva University Hospital, CH-1211 Geneva, Switzerland.
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Cho H, Ackerstaff E, Carlin S, Lupu ME, Wang Y, Rizwan A, O'Donoghue J, Ling CC, Humm JL, Zanzonico PB, Koutcher JA. Noninvasive multimodality imaging of the tumor microenvironment: registered dynamic magnetic resonance imaging and positron emission tomography studies of a preclinical tumor model of tumor hypoxia. Neoplasia 2009; 11:247-59, 2p following 259. [PMID: 19242606 PMCID: PMC2647727 DOI: 10.1593/neo.81360] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 12/20/2008] [Accepted: 12/22/2008] [Indexed: 11/18/2022]
Abstract
In vivo knowledge of the spatial distribution of viable, necrotic, and hypoxic areas can provide prognostic information about the risk of developing metastases and regional radiation sensitivity and may be used potentially for localized dose escalation in radiation treatment. In this study, multimodality in vivo magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging using stereotactic fiduciary markers in the Dunning R3327-AT prostate tumor were performed, focusing on the relationship between dynamic contrast-enhanced (DCE) MRI using Magnevist (Gd-DTPA) and dynamic (18)F-fluoromisonidazole ((18)F-Fmiso) PET. The noninvasive measurements were verified using tumor tissue sections stained for hematoxylin/eosin and pimonidazole. To further validate the relationship between (18)F-Fmiso and pimonidazole uptake, (18)F digital autoradiography was performed on a selected tumor and compared with the corresponding pimonidazole-stained slices. The comparison of Akep values (kep = rate constant of movement of Gd-DTPA between the interstitial space and plasma and A = amplitude in the two-compartment model (Hoffmann U, Brix G, Knopp MV, Hess T and Lorenz WJ (1995). Magn Reson Med 33, 506-514) derived from DCE-MRI studies and from early (18)F-Fmiso uptake PET studies showed that tumor vasculature is a major determinant of early (18)F-Fmiso uptake. A negative correlation between the spatial map of Akep and the slope map of late (last 1 hour of the dynamic PET scan) (18)F-Fmiso uptake was observed. The relationships between DCE-MRI and hematoxylin/eosin slices and between (18)F-Fmiso PET and pimonidazole slices confirm the validity of MRI/PET measurements to image the tumor microenvironment and to identify regions of tumor necrosis, hypoxia, and well-perfused tissue.
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Affiliation(s)
- HyungJoon Cho
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Ellen Ackerstaff
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Sean Carlin
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Mihaela E Lupu
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Ya Wang
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Asif Rizwan
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Joseph O'Donoghue
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - C Clifton Ling
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - John L Humm
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Pat B Zanzonico
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Jason A Koutcher
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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15
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Abstract
The recent wave of enthusiasm for image guidance in radiation therapy is largely due to the advent of on-line imaging devices. The current narrow definition of image-guided radiotherapy (IGRT), in fact, essentially connotes the use of near real-time imaging during treatment delivery to reduce uncertainties in target position and should therefore be termed IGRT-D. However, a broader (and more appropriate) context of image-guidance should include: (1) detection and diagnosis, (2) delineation of target and organs at risk, (3) determining biological attributes, (4) dose distribution design, (5) dose delivery assurance and (6) deciphering treatment response through imaging i.e. the 6 D's of IGRT. Strategies to advance these areas will be discussed.
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16
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Zhang M, Huang M, Le C, Zanzonico PB, Claus F, Kolbert KS, Martin K, Ling CC, Koutcher JA, Humm JL. Accuracy and reproducibility of tumor positioning during prolonged and multi-modality animal imaging studies. Phys Med Biol 2008; 53:5867-82. [PMID: 18827321 DOI: 10.1088/0031-9155/53/20/021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Dedicated small-animal imaging devices, e.g. positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI) scanners, are being increasingly used for translational molecular imaging studies. The objective of this work was to determine the positional accuracy and precision with which tumors in situ can be reliably and reproducibly imaged on dedicated small-animal imaging equipment. We designed, fabricated and tested a custom rodent cradle with a stereotactic template to facilitate registration among image sets. To quantify tumor motion during our small-animal imaging protocols, 'gold standard' multi-modality point markers were inserted into tumor masses on the hind limbs of rats. Three types of imaging examination were then performed with the animals continuously anesthetized and immobilized: (i) consecutive microPET and MR images of tumor xenografts in which the animals remained in the same scanner for 2 h duration, (ii) multi-modality imaging studies in which the animals were transported between distant imaging devices and (iii) serial microPET scans in which the animals were repositioned in the same scanner for subsequent images. Our results showed that the animal tumor moved by less than 0.2-0.3 mm over a continuous 2 h microPET or MR imaging session. The process of transporting the animal between instruments introduced additional errors of approximately 0.2 mm. In serial animal imaging studies, the positioning reproducibility within approximately 0.8 mm could be obtained.
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Affiliation(s)
- Mutian Zhang
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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17
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Multimodality rodent imaging chambers for use under barrier conditions with gas anesthesia. Mol Imaging Biol 2008; 11:100-6. [PMID: 18679755 DOI: 10.1007/s11307-008-0165-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 04/23/2008] [Accepted: 05/06/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE The ability to reproducibly and repeatedly image rodents in noninvasive imaging systems, such as small-animal positron emission tomography (PET) and computed tomography (CT), requires a reliable method for anesthetizing, positioning, and heating animals in a simple reproducible manner. In this paper, we demonstrate that mice and rats can be reproducibly and repeatedly imaged using an imaging chamber designed to be rigidly mounted on multiple imaging systems. PROCEDURES Mouse and rat imaging chambers were made of acrylic plastic and aluminum. MicroCT scans were used to evaluate the positioning reproducibility of the chambers in multimodality and longitudinal imaging studies. The ability of the chambers to maintain mouse and rat body temperatures while anesthetized with gas anesthesia was also evaluated. RESULTS Both the mouse and rat imaging chambers were able to reproducibly position the animals in the imaging systems with a small degree of error. Placement of the mouse in the mouse imaging chamber resulted in a mean distance of 0.23 mm per reference point in multimodality studies, whereas for longitudinal studies the mean difference was 1.11 mm. The rat chamber resulted in a mean difference of 0.46 mm in multimodality studies and a mean difference of 4.31 mm in longitudinal studies per reference point. The chambers maintained rodent body temperatures at the set point temperature of 38 degrees C. CONCLUSIONS The rodent imaging chambers were able to reproducibly position rodents in tomographs with a small degree of variability and were compatible with routine use. The embedded anesthetic line and heating system was capable of maintaining the rodent's temperature and anesthetic state, thereby enhancing rodent health and improving data collection reliability.
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18
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Rommel D, Abarca-Quinones J, Christian N, Peeters F, Lonneux M, Labar D, Bol A, Gregoire V, Duprez T. Alginate moulding: an empirical method for magnetic resonance imaging/positron emission tomography co-registration in a tumor rat model. Nucl Med Biol 2008; 35:571-7. [DOI: 10.1016/j.nucmedbio.2008.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 03/27/2008] [Accepted: 04/03/2008] [Indexed: 11/30/2022]
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19
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FDG uptake, a surrogate of tumour hypoxia? Eur J Nucl Med Mol Imaging 2008; 35:1544-9. [PMID: 18509637 PMCID: PMC2491423 DOI: 10.1007/s00259-008-0758-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 02/18/2008] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Tumour hyperglycolysis is driven by activation of hypoxia-inducible factor-1 (HIF-1) through tumour hypoxia. Accordingly, the degree of 2-fluro-2-deoxy-D: -glucose (FDG) uptake by tumours might indirectly reflect the level of hypoxia, obviating the need for more specific radiopharmaceuticals for hypoxia imaging. DISCUSSION In this paper, available data on the relationship between hypoxia and FDG uptake by tumour tissue in vitro and in vivo are reviewed. In pre-clinical in vitro studies, acute hypoxia was consistently shown to increase FDG uptake by normal and tumour cells within a couple of hours after onset with mobilisation or modification of glucose transporters optimising glucose uptake, followed by a delayed response with increased rates of transcription of GLUT mRNA. In pre-clinical imaging studies on chronic hypoxia that compared FDG uptake by tumours grown in rat or mice to uptake by FMISO, the pattern of normoxic and hypoxic regions within the human tumour xenografts, as imaged by FMISO, largely correlated with glucose metabolism although minor locoregional differences could not be excluded. In the clinical setting, data are limited and discordant. CONCLUSION Further evaluation of FDG uptake by various tumour types in relation to intrinsic and bioreductive markers of hypoxia and response to radiotherapy or hypoxia-dependent drugs is needed to fully assess its application as a marker of hypoxia in the clinical setting.
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20
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Christian N, Lee JA, Bol A, De Bast M, Gallez B, Grégoire V. Immobilization device for in vivo and in vitro multimodality image registration of rodent tumors. Radiother Oncol 2008; 87:147-51. [DOI: 10.1016/j.radonc.2008.02.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 02/14/2008] [Accepted: 02/14/2008] [Indexed: 10/22/2022]
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21
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Haney CR, Fan X, Parasca AD, Karczmar GS, Halpern HJ, Pelizzari CA. Immobilization Using Dental Material Casts Facilitates Accurate Serial and Multimodality Small Animal Imaging. CONCEPTS IN MAGNETIC RESONANCE. PART B, MAGNETIC RESONANCE ENGINEERING 2008; 33B:138-144. [PMID: 20827425 PMCID: PMC2933927 DOI: 10.1002/cmr.b.20108] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Custom disposable patient immobilization systems that conform to the patient's body contours are commonly used to facilitate accurate repeated patient setup for imaging and treatment in radiation therapy. However, in small-animal imaging, immobilization is often overlooked or done in a way that is not conducive to reproducible positioning. This has a negative impact on the potential for accurate analysis of serial or multimodality imaging. We present the use of vinyl polysiloxane dental impression material for immobilization of mice for imaging. Four different materials were examined to identify any potential artifacts using magnetic resonance techniques. A water phantom placed inside the cast was used at 4.7 T with magnetic resonance imaging and showed no effect at the center of the image when compared with images without the cast. A negligible effect was seen near the ends of the coil. Each material had no detectable signal using electron paramagnetic resonance imaging at 9 mT. The use of dental material also greatly enhances the use of fiducial markers that can be embedded in the mold. Therefore, image registration is simplified as the immobilization of the animal and fiducials together helps in translating from one image coordinate system to another.
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Affiliation(s)
- Chad R. Haney
- Department of Radiology, The University of Chicago, MC 2026, Chicago, IL 60637-1463
| | - Xiaobing Fan
- Department of Radiology, The University of Chicago, MC 2026, Chicago, IL 60637-1463
| | - Adrian D. Parasca
- Department of Radiation and Cellular Oncology, The University of Chicago, MC 1105, Chicago, IL 60637-1463
| | - Gregory S. Karczmar
- Department of Radiology, The University of Chicago, MC 2026, Chicago, IL 60637-1463
| | - Howard J. Halpern
- Department of Radiation and Cellular Oncology, The University of Chicago, MC 1105, Chicago, IL 60637-1463
| | - Charles A. Pelizzari
- Department of Radiation and Cellular Oncology, The University of Chicago, MC 1105, Chicago, IL 60637-1463
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22
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Oswald J, Treite F, Haase C, Kampfrath T, Mäding P, Schwenzer B, Bergmann R, Pietzsch J. Experimental hypoxia is a potent stimulus for radiotracer uptake in vitro: comparison of different tumor cells and primary endothelial cells. Cancer Lett 2007; 254:102-10. [PMID: 17400370 DOI: 10.1016/j.canlet.2007.02.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 02/19/2007] [Accepted: 02/21/2007] [Indexed: 11/16/2022]
Abstract
Hypoxia causes upregulation of vascular endothelial growth factor (VEGF) which is a key regulator in tumor angiogenesis and essential for the proliferation of endothelial cells. Endothelial cells have been described to accumulate radiotracers like (18)F-FDG. However, the contribution of radiotracer uptake by endothelial cells to uptake measured in tumors by positron emission tomography (PET) is still unclear. In this study (18)F-FDG and (18)F-FMISO radiotracer uptake in various tumor and primary endothelial cells cultured at hypoxic conditions was investigated. Experimental hypoxia was confirmed by significant upregulation of VEGF mRNA. In comparison to normoxic conditions, cellular uptake of (18)F-FDG was significantly increased at hypoxic conditions in two of the tumor and all endothelial cells, whereas (18)F-FMISO uptake was only enhanced in tumor cell lines HT-29 and MCF-7. Our data showed a marked influence of experimental hypoxia on the metabolism and gene expression of tumor and endothelial cells in vitro. This indicates an important contribution of endothelial cells to (18)F-FDG radiotracer uptake in tumors and for the visualization of tumors by means of PET.
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Affiliation(s)
- Joachim Oswald
- Institute of Radiopharmacy, Research Center Dresden-Rossendorf, Dresden, Germany
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23
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Zanzonico PB. Broad-spectrum multi-modality image registration: from PET, CT, and MRI to autoradiography, microscopy, and beyond. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2006; 2006:1584-1588. [PMID: 17946908 DOI: 10.1109/iembs.2006.259650] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Image registration and fusion are increasingly important components of both clinical and small-animal imaging and have lead to the development of a variety of pertinent hardware and software tools, including multi-modality, e.g. PET-CT, devices. At the same time, advances in microscopic imaging, including phosphor-plate digital autoradiography and immunohistochemistry, now allow ultra-high (sub-100 microm)-resolution molecular characterization of tissue sections. To date, however, in vivo imaging of intact subjects and ex vivo imaging of harvested tissues sections have remained separate and distinct, making it difficult to reliably inter-compare the former and the latter. The Department of Medical Physics and the Radiation Biophysics Laboratory at Memorial Sloan-Kettering Cancer Center, under the direction of Dr. Clifton Ling, has now designed, fabricated, and tested a stereotactic imaging system for so-called "broad-spectrum" image registration, from coarser-resolution in vivo imaging modalities such as PET, CT, and MRI to ultra-high-resolution ex vivo imaging techniques such as histology, autoradiography, and immunohistochemistry.
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Affiliation(s)
- P B Zanzonico
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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