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1. Validation of stationary phases in (111)In-pentetreotide planar chromatography.

Author

Moreno-Ortega E, Mena-Bares LM, Maza-Muret FR, Hidalgo-Ramos FJ, and Vallejo-Casas JA

Subjects
Chromatography, Paper instrumentation, Chromatography, Thin Layer instrumentation, Drug Contamination, Paper, Reference Values, Silica Gel, Somatostatin analysis, Chromatography, Paper methods, Chromatography, Thin Layer methods, Indium Radioisotopes analysis, Radiopharmaceuticals analysis, Somatostatin analogs & derivatives
Abstract

Introduction: Since Pall-German stopped manufacturing ITLC-SG, it has become necessary to validate alternative stationary phases., Objective: To validate different stationary phases versus ITLC-SG Pall-Gelman in the determination of the radiochemical purity (RCP) of (111)In-pentetreotide ((111)In-Octreoscan) by planar chromatography., Material and Methods: We conducted a case-control study, which included 66 (111)In-pentetreotide preparations. We determined the RCP by planar chromatography, using a freshly prepared solution of 0,1M sodium citrate (pH 5) and the following stationary phases: ITLC-SG (Pall-Gelman) (reference method), iTLC-SG (Varian), HPTLC silica gel 60 (Merck), Whatman 1, Whatman 3MM and Whatman 17. For each of the methods, we calculated: PRQ, relative front values (RF) of the radiopharmaceutical and free (111)In, chromatographic development time, resolution between peaks. We compared the results obtained with the reference method. The statistical analysis was performed using the SPSS program. The p value was calculated for the study of statistical significance., Results: The highest resolution is obtained with HPTLC silica gel 60 (Merck). However, the chromatographic development time is too long (mean=33.62minutes). Greater resolution is obtained with iTLC-SG (Varian) than with the reference method, with lower chromatographic development time (mean=3.61minutes). Very low resolutions are obtained with Whatman paper, essentially with Whatman 1 and 3MM. Therefore, we do not recommend their use., Conclusions: Although iTLC-SG (Varian) and HPTLC silica gel 60 (Merck) are suitable alternatives to ITLC-SG (Pall-Gelman) in determining the RCP of (111)In-pentetreotide, iTLC-SG (Varian) is the method of choice due to its lower chromatographic development time., (Copyright © 2012 Elsevier España, S.L. and SEMNIM. All rights reserved.)

Published
2013
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2. A rapid chromatographic method for quality control of technetium-99m-bicisate.

Author

Amin KC, Saha GB, and Go RT

Subjects
Acetates chemistry, Cysteine isolation & purification, Organotechnetium Compounds isolation & purification, Oxides analysis, Paper, Radiochemistry, Radiopharmaceuticals isolation & purification, Sodium Pertechnetate Tc 99m analysis, Sodium Pertechnetate Tc 99m chemistry, Solvents chemistry, Technetium analysis, Technetium chemistry, Technetium Compounds analysis, Time Factors, Chromatography, Paper, Cysteine analogs & derivatives, Organotechnetium Compounds analysis, Quality Control, Radiopharmaceuticals analysis
Abstract

Unlabelled: The purpose of this work was to develop a simple and rapid method to determine the radiochemical purity of 99mTc-bicisate., Methods: A rapid paper chromatographic (PC) method was developed to determine the radiochemical purity of 99mTc-bicisate and compare the results with those of the manufacturer's recommended method. The present PC method included Whatman 3MM paper as the solid phase and ethyl acetate as the solvent., Results: The time for chromatography by this technique was 4-5 min compared to about 23 min by the manufacturer's method. The Rf value of 99mTc-bicisate (Rf = 0.9-1.0) was widely different from those of 99mTcO4- and reduced 99mTc (Rf = 0.0 for both) so the chromatographic strip after development could be readily cut into two segments, in order to determine the labeling yield., Conclusion: No significant difference in labeling yields was found between the present method and the manufacturer's method. The PC method using Whatman 3MM paper and ethyl acetate is a simple and fast technique to determine the radiochemical purity of 99mTc-bicisate and may be substituted for the manufacturer's recommended method to save time.

Published
1997

3. Rapid miniaturized chromatography for technetium-99m-tetrofosmin.

Author

McKay BF, Zimmer AM, and Spies SM

Subjects
Acetates chemistry, Microchemistry, Micromanipulation, Miniaturization, Organophosphorus Compounds isolation & purification, Organotechnetium Compounds isolation & purification, Paper, Quality Control, Radiochemistry, Radiopharmaceuticals isolation & purification, Sodium Pertechnetate Tc 99m analysis, Solvents chemistry, Technetium analysis, Time Factors, Chromatography, Paper methods, Organophosphorus Compounds analysis, Organotechnetium Compounds analysis, Radiopharmaceuticals analysis
Abstract

Unlabelled: The purpose of this investigation was to develop and evaluate a new and rapid miniaturized chromatography system that would accurately assess the radiochemical purity of 99mTc-tetrofosmin without the problems of solvent ratios and time requirements associated with the manufacturer's recommended procedure., Methods: The migration of the radiochemical components of 99mTc-tetrofosmin was evaluated using various chromatography media with ethyl acetate as the solvent. After optimization of the miniaturized system, radiochemical purity assessments were performed simultaneously on 23 99mTc-tetrofosmin preparations using both recommended and miniaturized chromatography systems., Results: A miniaturized chromatography system consisting of Whatman 1 chromatography paper with ethyl acetate was developed for the radiochemical purity assessment of 99mTc-tetrofosmin. Radiochemical purity results for 99mTc-tetrofosmin preparations were similar with both recommended and miniaturized chromatography methods, with a mean difference of 1.5% +/- 1.2% (s.d.). Differences in radiochemical purity results between the two chromatography systems were less than 2% (20 of 23 evaluations) with most preparations., Conclusion: Radiochemical purity results for 99mTc-tetrofosmin preparations were similar with both the manufacturer's recommended chromatography and miniaturized chromatography systems. The miniaturized chromatography system is easier to use, and the time required to perform radiochemical purity assessments is substantially reduced.

Published
1997

4. Accuracy of single‐photon emission computed tomography in differentiating frontotemporal dementia from Alzheimer's disease

Author

H. J. Testa, D. M. A. Mann, A. R. Varma, R McNeill, J S Snowden, M Manoharan, G M Sare, and David Neary

Subjects
Paper, Male, medicine.medical_specialty, Neurology, Single-photon emission computed tomography, Sensitivity and Specificity, Diagnosis, Differential, Technetium Tc 99m Exametazime, Neuroimaging, Alzheimer Disease, medicine, Dementia, Humans, Neuropsychological assessment, Aged, Retrospective Studies, Tomography, Emission-Computed, Single-Photon, medicine.diagnostic_test, business.industry, Brain, Middle Aged, medicine.disease, Temporal Lobe, Frontal Lobe, Psychiatry and Mental health, Regional Blood Flow, Surgery, Female, Neurology (clinical), Alzheimer's disease, Differential diagnosis, Radiopharmaceuticals, Psychology, Nuclear medicine, business, Frontotemporal dementia
Abstract

Background: Alzheimer’s disease (AD) and frontotemporal dementia (FTD) are the commonest causes of presenile dementia. In the absence of a biological marker, diagnosis is reliant on clinical evaluation. Confirmation is often sought from neuroimaging, including single-photon emission computed tomography (SPECT). Most previous SPECT studies lack pathological validation. Aim: To examine the accuracy of SPECT in differentiating FTD from AD in patients with subsequent pathological confirmation. Methods: Technetium-99-labelled hexamethyl propylene amine oxime SPECT images obtained at initial evaluation in 25 pathologically confirmed cases of FTD were examined. These images were visually rated by an experienced blinded nuclear medicine consultant and compared with those of 31 patients with AD, also with pathological validation. Results: A reduction in frontal cerebral blood flow (CBF) was more common in FTD and was of diagnostic value (sensitivity 0.8, specificity 0.65 and likelihood ratio (LR) 2.25; 95% CI 1.35 to 3.77). A pattern of bilateral frontal CBF reduction without the presence of associated bilateral parietal CBF change is diagnostically more accurate (sensitivity 0.80, specificity 0.81 and +LR 4.13, 95% CI 1.96 to 8.71). Diagnostic categorisation (FTD or AD) on the basis of SPECT alone was less accurate than clinical diagnosis (based on neurology and detailed neuropsychological evaluation). One patient with FTD was initially clinically misdiagnosed as AD, owing to the lack of availability of full neuropsychological assessment. However, SPECT correctly diagnosed this patient, providing a diagnostic gain of 4%. Conclusion: Technetium-99-labelled hexamethyl propylene amine oxime SPECT CBF patterns provide valuable information in the diagnosis of FTD and AD. These data can be better used as an adjunct to clinical diagnosis if pathology is to be correctly predicted in life.

Published
2006

5. Relationship between regional cerebral metabolism and consciousness disturbance in traumatic diffuse brain injury without large focal lesions: an FDG‐PET study with statistical parametric mapping analysis

Author

Noriyuki Nakayama, Jun Shinoda, Ayumi Okumura, Toshihiko Nakashima, and Toru Iwama

Subjects
Paper, Adult, Male, medicine.medical_specialty, Pathology, Thalamus, Central nervous system, Statistical parametric mapping, Brain mapping, Severity of Illness Index, Gyrus, Fluorodeoxyglucose F18, Internal medicine, medicine, Humans, Radionuclide Imaging, Brain Mapping, medicine.diagnostic_test, Minimally conscious state, Brain, Middle Aged, medicine.disease, Psychiatry and Mental health, medicine.anatomical_structure, Glucose, Positron emission tomography, Brain Injuries, Consciousness Disorders, Cardiology, Surgery, Female, Neurology (clinical), Radiopharmaceuticals, Psychology, Cognition Disorders
Abstract

Background: The cerebral metabolism of patients in the chronic stage of traumatic diffuse brain injury (TDBI) has not been fully investigated. Aim: To study the relationship between regional cerebral metabolism (rCM) and consciousness disturbance in patients with TDBI. Methods: 52 patients with TDBI in the chronic stage without large focal lesions were enrolled, and rCM was evaluated by fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) with statistical parametric mapping (SPM). All the patients were found to have disturbed consciousness or cognitive function and were divided into the following three groups: group A (n = 22), patients in a state with higher brain dysfunction; group B (n = 13), patients in a minimally conscious state; and group C (n = 17), patients in a vegetative state. rCM patterns on FDG-PET among these groups were evaluated and compared with those of normal control subjects on statistical parametric maps. Results: Hypometabolism was consistently indicated bilaterally in the medial prefrontal regions, the medial frontobasal regions, the cingulate gyrus and the thalamus. Hypometabolism in these regions was the most widespread and prominent in group C, and that in group B was more widespread and prominent than that in group A. Conclusions: Bilateral hypometabolism in the medial prefrontal regions, the medial frontobasal regions, the cingulate gyrus and the thalamus may reflect the clinical deterioration of TDBI, which is due to functional and structural disconnections of neural networks rather than due to direct cerebral focal contusion.

Published
2006