Home About us Contact
|
Home About us Contact | ||
|
|
||
PET Imaging (pet + imaging)
Selected AbstractsChemInform Abstract: New Synthesis and Evaluation of Enantiomers of 7-Methyl-2-exo-(3,-iodo-5,-pyridinyl)-7-azabicyclo[2.2.1]heptane as Stereoselective Ligands for PET Imaging of Nicotinic Acetylcholine Receptors.CHEMINFORM, Issue 14 2009Yongjun Gao Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Imaging studies of biodistribution and kinetics in drug developmentDRUG DEVELOPMENT RESEARCH, Issue 2 2003Marc S. Berridge Abstract Although the intravenous route of administration is rarely used for drugs, it is by far the most common route for PET and SPECT radiotracers. This article discusses the use of planar and tomographic nuclear medicine technologies to image and quantify the distribution of drugs after local administration. In principle, this would include topical dermatologic, otic, ophthalmic, rectal, and vaginal administration, as well as the intramuscular, oral, and inhalation routes, although precedents do not yet exist for all of these. The studies reviewed focus mainly on oral ingestion and oral and nasal inhalation. The use of nondrug tracers for formulations is discussed, principally with planar imaging or SPECT using radionuclides such as 99mTc, as well as PET imaging where the active ingredient of a formulation can be labeled with 11C or sometimes 18F. An example of the latter type is a study of the deposition and kinetics in the lungs and airways of triamcinolone acetonide, an antiinflammatory steroid used for topical treatment of allergic rhinitis and asthma, dispensed from an inhaler. PET has high potential for evaluation of different formulations and delivery devices in the development of topically applied drugs. Drug Dev. Res. 59:208,226, 2003. © 2003 Wiley-Liss, Inc. [source] Molecular imaging: The application of small animal positron emission tomographyJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S39 2002Douglas J. Rowland Abstract The extraordinary advances in genomic technologies over the last decade have led to the establishment of new animal models of disease. The use of molecular imaging techniques to examine these models, preferably with non-destructive imaging procedures, such as those offered by positron emission tomography (PET), are especially valuable for the timely advancement of research. With the use of small animal PET imaging it is possible to follow individual subjects of a sample population over an extended time period by using highly specific molecular probes and radiopharmaceuticals. In this Prospect small animal PET imaging will be described, specifically focusing on the current technologies, its applications in molecular imaging and the logistics of performing small animal PET. J. Cell. Biochem. Suppl. 39: 110,115, 2002. © 2002 Wiley-Liss, Inc. [source] Synthesis of 1-(2,4-dichlorophenyl)-4-cyano-5-(4-[11C]methoxyphenyl)- N -(piperidin-1-yl)-1H -pyrazole-3-carboxamide ([11C]JHU75528) and 1-(2-bromophenyl)-4-cyano-5-(4-[11C]methoxyphenyl)- N -(piperidin-1-yl)-1H -pyrazole-3-carboxamide ([11C]JHU75575) as potential radioligands for PET imaging of cerebral cannabinoid receptorJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 12 2006Hong Fan Abstract Two novel ligands for cerebral cannabinoid receptor (CB1), 1-(2,4-dichlorophenyl)-4-cyano-5-(4-methoxyphenyl)- N -(piperidin-1-yl)-1H -pyrazole-3-carboxamide (JHU75528) and 1-(2-bromophenyl)-4-cyano-5-(4-methoxyphenyl)- N -(piperidin-1-yl)-1H -pyrazole-3-carboxamide (JHU75575) have been synthesized. Both JHU75528 and JHU75575 display a combination of higher binding affinity and lower lipophilicity than those of Rimonabant (SR141716), a high affinity CB1 selective antagonist, and AM281, the only available ligand for emission tomography imaging of CB1 in human subjects. Radiolabeled [11C]JHU75528 and [11C]JHU75575 were prepared by reaction of [11C]methyl iodide with nor-methyl precursors. The average radiochemical yield, specific radioactivity, and radiochemical purity of [11C]JHU75528 were 16%, 235 GBq/µmol (6360 mCi/µmol), and 99%, respectively; those of [11C]JHU75575 were 8%, 196 GBq/µmol (5308 mCi/µmol), and 99%, respectively. Both ligands hold promise as PET radioligands for imaging CB1 receptor. Copyright © 2006 John Wiley & Sons, Ltd. [source] Radiosynthesis of 2- exo -(2,-[18F]Fluoro-3,-(4-fluorophenyl)-pyridin-5,-yl)-7-azabicyclo[2.2.1]heptane ([18F]F2PhEP), a potent epibatidine-based radioligand for nicotinic acetylcholine receptor PET imagingJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 6 2006Gaëlle Roger Abstract 2- exo -(2,-Fluoro-3,-(4-fluorophenyl)-pyridin-5,-yl)-7-azabicyclo[2.2.1]heptane (F2PhEP), a novel, epibatidine-based, ,4,2-selective nicotinic acetylcholine receptor antagonist of low toxicity, as well as the corresponding N- Boc-protected chloro- and bromo derivatives as precursors for labelling with fluorine-18 were synthesized from 7- tert -butoxycarbonyl-7-azabicyclo[2.2.1]hept-2-ene in 13, 19 and 8% overall yield, respectively. [18F]F2PhEP was prepared in 8,9% overall yield (non-decay-corrected) using 1 mg of the bromo derivative in the following two-step radiochemical process: (1) no-carrier-added nucleophilic heteroaromatic ortho- radiofluorination with the activated K[18F]F-Kryptofix®222 complex in DMSO using microwave activation at 250 W for 90 s, followed by (2) quantitative TFA-induced removal of the N -Boc protective group. Radiochemically pure (>95%) [18F]F2PhEP (1.48,1.66 GBq, 74,148 GBq/µmol) was obtained after semi-preparative HPLC (Symmetry® C18, eluent aqueous 0.05 M NaH2PO4 CH3CN: 78/22 (v:v)) in 75,80 min starting from an 18.5 GBq aliquot of a cyclotron-produced [18F]fluoride production batch. Copyright © 2006 John Wiley & Sons, Ltd. [source] Synthesis and 11C-labelling of (E,E)-1-(3,,4,-dihydroxystyryl)-4-(3,-methoxy-4,-hydroxystyryl) benzene for PET imaging of amyloid deposits,,JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2002Yanming Wang Abstract Carboxylic acid derivatives of the amyloid-binding dye Congo red do not enter the brain well and are thus unable to serve as in vivo amyloid-imaging agents. A neutral amyloid probe, (E,E)-1-(3,,4,-dihydroxystyryl)-4-(3,-methoxy-4,-hydroxystyryl)benzene (3), devoid of any carboxylate groups has been designed and synthesized via a 12-step reaction sequence with a total yield of 30%. The unsymmetric compound 3 has also been labelled with C-11 via [11C]methyl iodide ([11C]CH3I) methylation of a symmetric 4,4,-dimesyl protected precursor followed by deprotection. Preliminary evaluation indicated that compound 3 selectively stained plaques and neurofibrillary tangles in post-mortem AD brain, and exhibited good binding affinity (Ki=38±8 nM) for A,(1,40) fibrils in vitro. In vivo pharmacokinetic studies indicated that [11C]3 exhibited higher brain uptake than its carboxylic acid analogs and good clearance from normal control mouse brain. [11C]3 also exhibited specific in vivo binding to pancreatic amyloid deposits in the NOR-beta transgenic mouse model. These results justify further investigation of 3 and similar derivatives as surrogate markers for in vivo quantitation of amyloid deposits. Copyright © 2002 John Wiley & Sons, Ltd. [source] Highly efficient synthesis of [11C]S12968 and [11C]S12967, for the in vivo imaging of the cardiac calcium channels using PETJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2001Frédéric Dolle Abstract The dihydrophyridines S12968 ((,)-S11568, absolute configuration S) and S12967 ((+)-S11568, absolute configuration R), 3-ethyl 5-methyl (,/+)-2-[(2-(2-aminoethoxy)ethoxy)methyl]-4-(2,3-dichlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate, have both an in vitro profile of high potency and of high selectivity for the low-voltage-dependent L-type calcium channel. In this paper, the radiosynthesis of both enantiomers, S12968 and S12967, with carbon-11, a positron-emitting isotope (half-life : 20.4 min) was investigated and oriented towards the preparation of multi milliCuries of radiotracer. Typically, 130,250 mCi (4.81,9.25 GBq) of [11C]S12968 and [11C]S12967 were obtained within 30 min of radiosynthesis (HPLC purification included) with specific radioactivities ranging from 500 to 1000 mCi/,mol (18.5,37.0 GBq/,mol) using no-carrier-added [11C]methyl triflate as the alkylating agent and the appropriate, enantiomerically pure carboxylic acid precursor at 100°C for 1 min. Based on preliminary PET experiments, only the levo enantiomer S12968 ((,)-[11C]-1) appears to be suitable for myocardial PET imaging as demonstrated in vivo in beagle dogs: with S12968, 85% of the uptake of [11C]S12968 could be inhibited in pretreatment experiments and up to 70% of [11C]S12968 could be displaced. Further investigations are currently underway in order to provide an absolute quantification of ventricular calcium channels with PET. Copyright © 2001 John Wiley & Sons, Ltd. [source] Review of non-positron emission tomography functional imaging of primary musculoskeletal tumours: Beyond the humble bone scanJOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, Issue 6 2005YY Ho Summary Bone and soft tissue tumours are rare neoplasms. There are five major roles of imaging in the management of primary musculoskeletal tumours, that is, to differentiate between benignity and malignancy, to evaluate for local tumour extension, to screen for metastases, to judge the effect of chemotherapy, and to monitor for recurrence. To accomplish this, multiple modalities are required because no single examination is able to complete all these tasks. These modalities include plain radiography, CT, MRI, conventional nuclear medicine as well as positron emission tomography (PET) imaging. Elsewhere, PET imaging has been discussed at length, because it is likely to be superior in the assessment of bone and soft tissue tumours over conventional nuclear medicine procedures. However, conventional nuclear medicine may be of value when PET is unavailable. In this review, an overview of anatomical imaging will be given and the role of non-PET functional imaging will be discussed in detail. A variety of illustrative cases will be presented. [source] Preclinical evaluation of carcinoembryonic cell adhesion molecule (CEACAM) 6 as potential therapy target for pancreatic adenocarcinoma,THE JOURNAL OF PATHOLOGY, Issue 3 2009Laura A Strickland Abstract Despite the availability of new targeted therapies, ductal pancreatic adenocarcinoma continues to carry a poor prognosis. Carcinoembryonic antigen-related cell adhesion molecule (CEACAM)6 has been reported as a potential biomarker and therapy target for this malignancy. We have evaluated CEACAM6 as a potential therapy target, using an antibody,drug conjugate (ADC). Expression of CEACAM6 in pancreatic adenocarcinomas was determined using immunohistochemistry on tissue microarrays. The expression pattern in granulocytes and granulocytic precursors was measured by flow cytometry. Murine xenograft and non-human primate models served to evaluate efficacy and safety, respectively. Robust expression of CEACAM6 was found in > 90% of invasive pancreatic adenocarcinomas as well as in intraepithelial neoplastic lesions. In the granulocytic lineage, CEACAM6 was expressed at all stages of granulocytic maturation except for the early lineage-committed precursor cell. The anti-CEACAM6 ADC showed efficacy against established CEACAM6-expressing tumours. In non-human primates, antigen-dependent toxicity of the ADC consisted of dose-dependent and reversible depletion of granulocytes and their precursors. This was associated with preferential and rapid localization of the antibody in bone marrow, as determined by sequential in vivo PET imaging of the radiolabelled anti-CEACAM6. Localization of the radiolabelled tracer could be attenuated by predosing with unlabelled antibody confirming specific accumulation in this compartment. Based on the expression pattern in normal and malignant pancreatic tissues, efficacy against established tumours and limited and reversible bone marrow toxicity, we propose that CEACAM6 should be considered for an ADC-based therapy approach against pancreatic adenocarcinomas and possibly other CEACAM6-positive neoplasms. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] Bilateral thoracoscopy, mediastinoscopy and laparoscopy, in addition to CT, MRI and PET imaging, are essential to correctly stage and treat patients with mesothelioma prior to trimodality therapy,ANZ JOURNAL OF SURGERY, Issue 10 2009John M. Alvarez Abstract Background:, Trimodality therapy (TMT; extrapleural pneumonectomy (EPP), chemotherapy and radiation therapy) offers the potential of optimal survival in selected patients with Brigham stage I,II epitheliod mesothelioma based on CT, MRI and PET scanning. We hypothesized that these scanning modalities were inadequate to accurately stage these patients. Methods:, Patients suitable for TMT, in addition to CT, MRI and PET scanning, prior to EPP, underwent bilateral thoracoscopy, mediastinoscopy and laparoscopy (surgical staging). Follow-up CT scans were performed, six monthly, quality of life assessments yearly. Results:, From 1 June 2004 to 28 February 2007, 34 patients were referred; mean age was 66 years (range: 44,69). Surgical staging was performed in 30 patients; 24 patients were confirmed as Brigham Stage I,II. However, six were upstaged, five as stage IV disease (one contralateral chest, two contralateral chest and abdomen, two abdomen) and one as mediastinal node positive; two further patients were reclassified histologically (one sarcomatoid, one biphasic). These eight patients fared poorly, 50% dying within 1 year from mesothelioma. Following surgical staging, 3 patients declined further surgery; thus, 19 patients proceeded to surgery, 3 were unresectable and 16 received EPP. Follow-up of all 34 patients is complete. Conclusion:, Surgical staging identified 26% of patients who would have received no benefit from TMT. [source] 34 In vivo tumour hypoxia and carbonic anhydrase IX expression in xenografted human renal cell carcinoma animal models using probes, 124I-G250 pet, biodistribution and immunohistochemistry immunobiodistribution, and oxygen studiesBJU INTERNATIONAL, Issue 2006N. LAWRENTSCHUK Introduction:, Hypoxia stimulates angiogenesis and has been demonstrated in tumours where it correlates with resistance to treatment and poor prognosis. We have previously demonstrated hypoxia in human Renal Cell Carcinoma (RCC). The purpose of animal models was to further evaluate oxygen levels within RCC whilst also focusing on expression of the protein carbonic anhydrase IX (CA IX). This protein is stimulated by hypoxia and involved in angiogenesis and may be a potential tumour target for imaging and future therapies. Methods:, Balb/c nude mice had human RCC (SK-RC-52) xenografted subcutaneously. Tumours were grown to different volumes with oxygen levels measured. Further groups then had the radiolabelled monoclonal antibody 124I-G250 (that binds to CA IX) injected intravenously and had Positron Emission Tomography (PET), gamma counting and oxygen studies performed on days 0,1,2,3,5,7,10 and 14 post injection. Immunohistochemistry and autoradiography was also performed. Results:, An inverse relationship between tumour volume and hypoxia within the model was established (P < 0.001). Furthermore, CA IX was expressed by tumours with maximal uptake of 124I-G250 on days 2/3 by distribution with gamma counting that could be correlated with uptake on PET imaging. Conclusions:, The xenograft model confirms human RCC are hypoxic. Also, that the level of hypoxia is inversely proportional to tumour sise. A correlation was made between PET scanning with 124I-G250 and biodistribution within tumours by gamma counting confirming CAIX as an imaging and potential therapeutic target in RCC. [source] Prospective comparison of [18F]fluorodeoxyglucose positron emission tomography with conventional assessment by computed tomography scans and serum tumor markers for the evaluation of residual masses in patients with nonseminomatous germ cell carcinomaCANCER, Issue 9 2002Christian Kollmannsberger M.D. Abstract BACKGROUND To assess the ability of [18F]fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET) to predict the viability of residual masses after chemotherapy in patients with metastatic nonseminomatous germ cell tumors (GCT), PET results were compared in a blinded analysis with computed tomography (CT) scans and serum tumor marker changes (TUM) as established methods of assessment. METHODS Independent reviewers who were blinded to each other's results evaluated the PET results and corresponding CT scan and TUM results in 85 residual lesions from 45 patients. All patients were treated within prospective clinical trials and received primary/salvage, high-dose chemotherapy with autologous blood stem cell support for primary poor prognosis disease or recurrent disease. PET results were assessed both visually and by quantifying glucose uptake (standardized uptake values). Results were validated either by histologic examination of a resected mass and/or biopsy (n = 28 lesions) or by a 6-month clinical follow-up after evaluation (n = 57 lesions). RESULTS F-18 FDG PET showed increased tracer uptake in 32 of 85 residual lesions, with 29 true positive (TP) lesions and three false positive (FP) lesions. Fifty-three lesions were classified by PET as negative (no viable GCT), 33 lesions were classified by PET as true negative (TN), and 20 lesions were classified by PET as false negative (FN). In the blinded reading of the corresponding CT scan and TUM results, 38 residual lesions were assessed correctly as containing viable carcinoma and/or teratoma. Forty-six lesions were classified as nonsuspicious by CT scan/TUM (33 TN lesions and 14 falsely classified lesions). PET correctly predicted the presence of viable carcinoma in 5 of these 14 and the absence of viable carcinoma in 3 of these 14 lesions. Resulting sensitivities and specificities for the prediction of residual mass viability were as follows: PET, 59% sensitivity and 92% specificity; radiologic monitoring, 55% sensitivity and 86% specificity; and TUM, 42% sensitivity and 100% specificity. The positive and negative predictive values for PET were 91% and 62%, respectively. The diagnostic efficacy of PET did not improve when patients with teratomatous elements in the primary tumor were excluded from the analysis. In patients with multiple residual masses, a uniformly increased residual F-18 FDG uptake in all lesions was a strong predictor for the presence of viable carcinoma. CONCLUSIONS F-18 FDG PET imaging performed in conjunction with conventional staging methods offers additional information for the prediction of residual mass histology in patients with nonseminomatous GCT. A positive PET is highly predictive for the presence of viable carcinoma. Other useful indications for a PET examination include patients with multiple residual masses and patients with marker negative disease. Cancer 2002;94:2353,62. © 2002 American Cancer Society. DOI 10.1002/cncr.10494 [source] Presurgical lateralization of seizure focus and language dominant hemisphere with O-15 water PET imagingACTA NEUROLOGICA SCANDINAVICA, Issue 2 2000R. Tatlidil Objectives, The purpose of this study was to assess the value of same day blood flow PET in both the identification of the language dominant hemisphere and in the lateralization of the epileptic focus in patients who were preoperatively evaluated for complex partial seizures. Methods, The charts of 24 patients who had temporal lobectomies for seizures were retrospectively reviewed. All PET scans were acquired by using O-15 water tracer (H215O) in both resting and language activation conditions. PET language laterality results were compared to Intracarotid amytal procedure (IAP) results. For epileptic focus lateralizations, regions of interest (ROI) analysis of temporal lobes was performed on resting scans. Results, IAP testing was discordant with PET language mapping in 1 out of 24 cases. This patient had a decline in cognitive abilities as measured by postoperative neuropsychologic testing. For epileptic focus lateralization, the PET was highly sensitive (87%) and specific (100%). Lateralizations with the PET were in agreement with surgical sites in all cases. Eighteen patients (75%) were seizure free and 4 patients (17%) were significantly improved after surgery. Conclusion, The results suggest that O-15 water PET is sensitive and specific in both the lateralization of epileptic focus and the language dominant hemisphere and can be a cost-effective and noninvasive method in presurgical evaluation of patients with complex partial seizures. [source] How Useful is PET/CT Imaging in the Management of Post-Transplant Lymphoproliferative Disease After Liver Transplantation?AMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2006L. McCormack Post-transplant lymphoproliferative disease (PTLD) is a serious and potentially life-threatening complication after solid organ transplantation. Here, we report our first experience with the use of PET/CT (positron emission tomography combined with computed tomogram) for the management of patients with PTLD after liver transplantation. Four patients with histologically proven PTLD were analyzed. Conventional work-up included physical examination and head-to-pelvis CT. PET/CT was used in one patient for initial staging and in all patients for follow-up. PET/CT positive findings underwent biopsy. Information provided by PET/CT resulted in a change of medical management in three of the four patients. Conventional work-up missed residual disease after surgery in one and failed to detect a tumor relapse in another patient. However, one patient disclosed a false positive PET/CT finding in the lungs. In conclusion, PET/CT may be a useful tool for staging and therapy monitoring of PTLD after liver transplantation. [source] Current use of 18F-Fluorodeoxyglucose Positron Emission Tomography and Combined Positron Emission Tomography and Computed Tomography in Squamous Cell Carcinoma of the Head and NeckTHE LARYNGOSCOPE, Issue 11 2005Lee A. Zimmer The history and physical examination, computed tomography (CT) and magnetic resonance imaging are the cornerstones for identifying new and recurrent cancers of the head and neck. The advent of positron emission tomography (PET) and combined PET/CT imaging technology is a promising development. These modalities have the potential to help stage patients presenting with head and neck cancer, identify responses to nonsurgical therapy, and allow earlier detection of recurrence in the hope of improving survival. The following paper provides a brief history of PET and PET/CT imaging. The current PET and PET/CT literature for squamous cell carcinoma of the head and neck is reviewed, and specific recommendations for its use are provided. [source] Giant cell arteritis on 18F-FDG PET/CTCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 5 2009Thomas F. Heston Summary Purpose:, We present a case of incidentally noted giant cell arteritis in a patient undergoing 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT imaging. The patient was originally referred to PET/CT for staging of his renal transitional cell carcinoma. Methods:, The patient was injected intravenously with 370 MBq of 18F-FDG. After a 60 min uptake period, PET/CT imaging was performed from the skull base to the mid thighs. Results:, A small para-aortic node in the region of the surgical bed showed increased tracer uptake of concern for malignancy. In addition, there were several non-calcified pulmonary nodules present, also concerning for malignancy. Incidentally noted was diffusely increased tracer uptake throughout the aorta and a thickened aortic wall on CT images. Diffuse tracer uptake was also present in the proximal branches of the aorta, including the carotid, iliac, femoral, and subclavian arteries. The patient had biopsy proven giant cell arteritis. Conclusion:, Increased 18F-FDG uptake by the aorta on PET/CT imaging is an abnormal finding that prompts a more thorough assessment for malignancy, and also can indentify important co-morbidities in cancer patients. Evaluation of aortic uptake should be a routine practice in the interpretation of 18F-FDG PET/CT scans. [source] | |||||||||||||