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This paper aims to determine the levels of exposure to neutron and photon radiation among the personnel engaged in cyclotron operation and the personnel engaged in the production of radiopharmaceuticals, with the use of the environmental radiation monitoring system (RMS) installed in the positron emission tomography laboratory. The annual exposures of employees operating the cyclotron measured with the use of the RMS system are: 1.39 ± 0.16 mSv in case of photon radiation and 2.61 ± 0.14 mSv in case of neutron radiation. In the case of employees in the radiopharmaceuticals’ production zone, the annual exposures measured by means of the RMS system are 0.15 ± 0.03 mSv in case of photon radiation and 0.11 ± 0.01 mSv in case of neutron radiation. The exposure levels among the personnel engaged in cyclotron operation and the personnel engaged in the production of radiopharmaceuticals are below the permissible radiation dose limits.

Skeletal tumour burden is a biomarker of prognosis and survival in cancer patients. This study proposes a novel method based on the linear quadratic model to predict the reduction in metastatic tumour burden as a function of the absorbed doses delivered from molecular radiotherapy treatments. The range of absorbed doses necessary to eradicate all the bone lesions and to reduce the metastatic burden was investigated in a cohort of 22 patients with bone metastases from castration-resistant prostate cancer. A metastatic burden reduction curve was generated for each patient, which predicts the reduction in metastatic burden as a function of the patient mean absorbed dose, defined as the mean of all the lesion absorbed doses in any given patient. In the patient cohort studied, the median of the patient mean absorbed dose predicted to reduce the metastatic burden by 50% was 89 Gy (interquartile range: 83–105 Gy), whilst a median of 183 Gy (interquartile range: 107–247 Gy) was found necessary to eradicate all metastases in a given patient. The absorbed dose required to eradicate all the lesions was strongly correlated with the variability of the absorbed doses delivered to multiple lesions in a given patient (r = 0.98, P

Cerenkov radiation (CR) is the emission of UV-vis light generated by the de-excitation of the molecules in the medium, after being polarized by an excited particle traveling faster than the speed of light. When β particles travel through tissue with energies greater than 219 keV, CR occurs. Tissues possess a spectral optical window of 600 to 1100 nm. The CR within this range can be useful for quantitative preclinical studies using optical imaging and for the in-vivo evaluation of Lu177-radiopharmaceuticals (β-particle emitters). The objective of our research was to determine the experimental emission light spectrum of Lu177-CR and evaluate its transmission properties in tissue as well as the feasibility to applying CR imaging in the preclinical studies of Lu177-radiopharmaceuticals. The theoretical and experimental characterizations of the emission and transmission spectra of Lu177-CR in tissue, in the vis-NIR region (350 to 900 nm), were performed using Monte Carlo simulation and UV-vis spectroscopy. Mice Lu177-CR images were acquired using a charge-coupled detector camera and were quantitatively analyzed. The results demonstrated good agreement between the theoretical and the experimental Lu177-CR emission spectra. Preclinical CR imaging demonstrated that the biokinetics of Lu177-radiopharmaceuticals in the main organs of mice can be acquired.

Positron emission tomography (PET) using 18F-fluoromisonidazole (FMISO) is a promising technique for imaging tumour hypoxia, and a potential target for radiotherapy dose-painting. However, the relationship between FMISO uptake and oxygen partial pressure (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}${{P}_{{{\text{O}}_{2}}}}$ \end{document}PO2) is yet to be quantified fully. Tissue oxygenation varies over distances much smaller than clinical PET resolution (

The aims of this study were to determine how different background regions of interest (ROIs) around the kidney represent true background activity in over- and underlying tissues in (177)Lu-DOTA-octreatate ((177)Lu-DOTATATE) treatments and to determine the influence of the background positions on the kidney activity concentration estimates by the conjugate view (ConjV) and posterior view (PostV) methods. The analysis was performed in single-photon emission computed tomography (SPECT) images of 20 patients, acquired 24 h post injection of a (177)Lu-DOTATATE treatment, by a computer algorithm that created planar images from the SPECT data. The ratio between the activity concentration in the background and the true background varied from 0.36 to 2.08 [coefficient of variation (CV) = 25-181 %] and from 0.44 to 1.52 (CV = 16-70 %) for the right and left kidneys, respectively. The activity concentration estimate in the kidneys was most accurate with the PostV method using a background ROI surrounding the whole kidney, and this combination might be an alternative planar method for improved kidney dosimetry in the (177)Lu-DOTATATE treatments.

Objective: To relate cerebral perfusion abnormalities to subsequent changes in clinical status among patients with mild cognitive impairment (MCI). Methods: Perfusion single photon emission computed tomography (SPECT) images were acquired in 105 elderly patients without dementia with MCI, using 99mTc-HMPAO. Clinical outcome after a 5-year follow-up period was heterogeneous. Results: Baseline SPECT data differed in those patients with MCI who were later diagnosed with Alzheimer’s disease (the converter group) from those patients with MCI who experienced clinically evident decline but did not progress to a diagnosis of Alzheimer’s disease within the follow-up period (the decliner group), from patients with MCI who had no clinical evidence of progression (the stable group), and from a group of 19 normal subjects (the control group). The most consistent decreases in relative perfusion in converters compared with the normal, stable and decliner groups were observed in the caudal anterior cingulate, and in the posterior cingulate. In addition, converters showed increased relative perfusion in the rostral anterior cingulate in comparison to the stable and decliner groups. A group of patients with Alzheimer’s disease were also included for purposes of comparison. The group of patients with Alzheimer’s disease at baseline differed from each of the other groups, with temporoparietal regions showing the most significant reductions in perfusion. Conclusions: These results suggest that clinical heterogeneity in MCI is reflected in SPECT perfusion differences, and that the pattern of perfusion abnormalities evolves with increasing clinical severity.

Background: Clinically apparent Alzheimer's disease (AD) is thought to result when brain tissue damage exceeds a critical threshold of "brain reserve", a process possibly accelerated by the apolipoprotein E (ApoE) E4 allele. The interaction between onset age and ApoE genotype was investigated to assess whether early disease onset (

Declines in brain glucose metabolism have been described early in Alzheimer's disease (AD), and there is evidence that a genetic predisposition to AD contributes to accelerate this process. The epsilon 4 (e4) allele of the apolipoprotein E (ApoE) gene has been implicated as a major risk factor in this process. The aim of this FDG-PET study was to assess the ApoE e4 dose related effect on regional cerebral glucose metabolism (METglc) in clinical AD patients, with statistical voxel based methods.Eighty six consecutive mild to moderate AD patients included in the Network for Efficiency and Standardisation of Dementia Diagnosis database underwent FDG-PET scans at rest. PCR was used to determine the ApoE genotype. Patients were grouped as e4 non-carriers (n = 46), e3/e4 (n = 27) and e4/e4 (n = 13) carriers. A voxel-based mapping program was used to compare each AD subgroup with a database of 35 sex and age matched controls (p0.001, corrected for cluster extent) and also to compare between the subgroups (p0.001, uncorrected).No difference was found as to age at examination, age at onset, sex, disease duration, educational level, or severity of dementia between AD subgroups. Compared with controls, all AD subgroups had equivalent METglc reductions in the precuneus, posterior cingulate, parietotemporal, and frontal regions. Direct comparisons between AD subgroups indicated that patients with at least one e4 allele had METglc reductions within additional associative and limbic areas compared with e4 non-carriers.The present FDG-PET study showed different metabolic phenotypes related to the ApoE genotype in clinical AD patients, as revealed with voxel based statistical methods. The results suggest a generalised disorder in e4 carriers impairing metabolism globally, in addition to the more localised changes typical of AD patients.

Molecular imaging, the science that combines non-invasive in vivo imaging and molecular biology, has begun to use labelled oligonucleotides as radiotracers. Antisense oligonucleotides target gene expression at the RNA level, while aptamer oligonucleotides are designed to hit proteins of interest. Oligonucleotides for imaging cover a large range of applications, from the invention of new contrast agents for diagnosis to exquisite research tools for the development of new drugs.

Positron emission tomography with (18)F-fluoro-2-deoxyglucose is an imaging technology that is demonstrating increasing utility in the evaluation of gastrointestinal malignancies.

Objective: To compare the HMPAO SPECT cerebral perfusion patterns in early and late onset Alzheimer's disease. Methods: Twenty patients with early onset disease ( 65 years) were studied. All patients fulfilled NINCDS-ADRDA clinical criteria and had details of disease severity and length of history at the time of imaging. Technetium-99m HMPAO SPECT brain scans were acquired on a multi-detector gammacamera and analysed visually and with statistical parametric mapping (SPM99). Results: Patients with early onset disease had significantly greater posterior cortical association area involvement whereas those with late onset disease had significantly greater medial temporal hypoperfusion. These findings were unchanged after controlling for disease severity and length of illness. Discussion: These functional imaging findings of the differences between early and late onset Alzheimer's disease are supported by published findings that include histopathological and clinical evidence; namely late onset patients tend to present with the characteristic involvement of the medial temporal lobes producing marked memory loss whereas early onset patients present with predominant posterior cortical association area involvement. These age related findings should be borne in mind when clinically diagnosing, and interpreting functional brain imaging studies in, patients with suspected Alzheimer's disease.

Background: Complaints of persistent cognitive deficits following mild head trauma are often uncorroborated by structural brain imaging and neuropsychological examination. Objective: To investigate, using positron emission tomography (PET), the in vivo changes in regional cerebral uptake of 2-[ 18 F]fluoro-2-deoxy-D-glucose (FDG) and regional cerebral blood flow (rCBF) in patients with persistent symptoms following mild head trauma. Methods: Five patients with mild head trauma and five age and education matched healthy controls were imaged using FDG-PET to measure differences in resting regional cerebral glucose metabolism. Oxygen-15 labelled water (H 2 15 O)-PET was also used to measure group differences in rCBF changes during a spatial working memory task. In addition, neuropsychological testing and self report of dysexecutive function and post-concussion symptoms were acquired to characterise the sample. Results: There was no difference between patients and controls in normalised regional cerebral FDG uptake in the resting state in frontal and temporal regions selected a priori. However, during the spatial working memory task, patients had a smaller increase in rCBF than controls in the right prefrontal cortex. Conclusions: Persistent post-concussive symptoms may not be associated with resting state hypometabolism. A cognitive challenge may be necessary to detect cerebral changes associated with mild head trauma.

Background PET/CT scanning can determine suitability for curative therapy and inform decision making when considering radical therapy in patients with non-small cell lung cancer (NSCLC). Metastases to central mediastinal lymph nodes (N2) may alter such management decisions. We report a 2 year retrospective series assessing N2 lymph node staging accuracy with PET/CT compared to pathological analysis at surgery. Methods Patients with NSCLC attending our centre (excluding those who had induction chemotherapy) who had staging PET/CT scans and pathological nodal sampling between June 2006 and June 2008 were analysed. For each lymph node assessed pathologically, the corresponding PET/CT status was determined. 64 patients with 200 N2 lymph nodes were analysed. Results Sensitivity of PET/CT scans for indentifying involved N2 lymph nodes was 39%, specificity 96% and overall accuracy 90%. For individual lymph node analysis, logistic regression demonstrated a significant linear association between PET/CT sensitivity and time from scanning to surgery (p=0.031) but not for specificity and accuracy. Those scanned 9 weeks, 0% ≥9 weeks, p=0.013) and more accurate (94%

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.

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.

Objective: To assess the accuracy and clinical usefulness of [123I]s-CIT (2s-carbomethoxy-3s-(4-iodophenyl)tropane) SPECT in the differential diagnosis of Parkinson's disease. Subjects: 185 consecutive patients with symptoms of movement disorder were studied. The diagnoses were Parkinson's disease (92), essential tremor (16), vascular parkinsonism (15), various Parkinson plus syndromes (P+) (12), dementia with Lewy bodies (DLB) (5), dystonia (5), drug induced movement disorder (12), and other diagnoses (8). A reference group (psychogenic parkinsonism) comprised 20 subjects with complaints suggesting extrapyramidal disease but with no unequivocal signs on clinical examination and no abnormalities on brain imaging. Results: s-CIT uptake was significantly lower in the whole striatum as well as separately in the putamen and in the caudate nucleus in Parkinson's disease than in the reference group or in drug induced movement disorder, essential tremor, or dystonia. The uptake of s-CIT in the vascular parkinsonism group was heterogeneous and mean s-CIT uptake fell between the reference group and the Parkinson's disease group. In the P+ and DLB groups the striatal uptake ratios overlapped those of the Parkinson's disease group. Conclusions: [123I]s-CIT SPECT may not be as useful a tool in the clinical differential diagnosis of Parkinson's disease as was previously believed, but it was 100% sensitive and specific for the diagnosis in younger patients (age 55 years) specificity was substantially lower (68.5%). This differential specificity reflected the different distribution of differential diagnostic disorders (P+, DLB, vascular parkinsonism) in the older and younger age groups.

To examine the range of clinical phenotypes, tumour associations, relevant investigations, response to therapy and outcome in a large series of non-selected patients with paraneoplastic neurological disease (PND) affecting the central nervous system (CNS) in the United Kingdom.Data were obtained on patients either through direct referral or through the British Neurological Surveillance Unit (BNSU) from February 2000 to January 2001. Physicians were asked to supply information about age and sex of patients, presenting neurological syndromes, the basis of the diagnosis of PND, any associated malignancy, and treatment. Case notes were reviewed and follow up data obtained where possible one year after notification.A total of 63 patients (48 females, 15 males) were identified, 48 through the BNSU and 15 through direct referral. Of these 52 were diagnosed as having definite PND, 10 probable PND, and 1 possible PND. The median age of onset of PND was 66 years (range 30-80 years) and only 7 patients (11%) were less than 50 years at presentation. In 53 patients (84%) the PND preceded the diagnosis of cancer. Paraneoplastic sensory neuronopathy, paraneoplastic encephalomyelitis, and paraneoplastic cerebellar degeneration (PCD) were the most common syndromes reported. The benefit of magnetic resonance imaging in the diagnosis of the disease was limited, while fluorodeoxyglucose positron emission tomography was shown to be useful for the detection of an occult malignancy in 10 out of 14 patients. Antineuronal antibodies were positive in 44/57 (77%) of cases. The following tumours were diagnosed: small cell lung cancer (30%), breast cancer (14%), ovarian cancer (8%), non-small cell lung cancer (8%), Hodgkin's lymphoma (6%), other (16%). With the exception of PCD associated with mesothelioma all other tumours diagnosed in these patients had been previously documented as being associated with PND. Only treatment of the tumour was found to be associated with a stable or improved neurological outcome at last follow up (Fisher's exact test = 4.7, p0.03). Median survival time was 43 months (95% CI 28 to 57) from onset of neurological disease as calculated using the Kaplan-Meier survival analysis.PND has a striking female preponderance usually affecting patients in their sixth decade and above. The median survival in our study was 43 months. The majority of patients with PND are not known to have cancer at the time of diagnosis. Our study confirms the importance of diagnosing and treating the underlying tumour.

Background:The term "posterior cortical atrophy" (PCA) refers to a clinical syndrome in which higher order visual processing is disrupted owing to a neurodegenerative disorder, the most commonly associated pathology being Alzheimer's disease. Objective:To map the topography of hypometabolic brain regions in a group of subjects with PCA who had undergone detailed neuropsychological characterisation. Methods:Resting cerebral metabolism was measured with (18F)fluorodeoxyglucose-positron emission tomography (FDG-PET) in patients with PCA (n = 6), typical Alzheimer's disease (n = 10), and healthy controls (n = 10). The data were analysed using statistical parametric mapping (SPM99) and region of interest techniques. Results:Clinically, the PCA subjects showed predominant visuospatial deficits (including features of Balint's syndrome) consistent with damage to the dorsal stream of visual processing. Compared with the controls, the PCA group showed marked glucose hypometabolism primarily affecting the posterior cerebral hemispheres (right worse than left). In addition, the PCA group showed two symmetrical areas of hypometabolism in the region of the frontal eye fields. Compared with typical Alzheimer's disease, the PCA group had selective hypometabolism in the occipito-parietal region (right much worse than left). Conclusions:The neuropsychological and PET findings are consistent with damage predominantly to the dorsal stream of visual processing. Frontal eye field hypometabolism secondary to loss of input from the occipito-parietal region may be the mechanism for the ocular apraxia seen in Balint's syndrome.

Objectives: To evaluate cerebral glucose metabolism, assessed by 18-fluorodeoxyglucose positron emission tomography (FDG-PET), in patients with chronic fatigue syndrome (CFS), using an observer independent analytical approach; and to characterise any observed alterations by correlating them with neuropsychological deficits. Methods: 26 patients (13 female, 13 male) were examined. They all fulfilled the CDC diagnostic criteria for CFS. Their ages ranged from 26 to 61 years (mean (SD) age, 43 (9.3) years). They underwent extensive psychometric testing including the hospital anxiety and depression scale (HADS) and the short form 36 item health questionnaire (SF-36). Brain FDG-PET was done in all the subjects. After stereotactic normalisation, single subject comparisons with an age and sex matched normal database (n = 18) and a group comparison between the patients and normal controls were undertaken, along with additional correlation analyses between brain metabolism and psychometric test scores. Results: 12 of the 26 patients showed no significant decrease in FDG uptake compared with the controls. Of the remaining 14, 12 showed hypometabolism bilaterally in the cingulate gyrus and the adjacent mesial cortical areas. Five of these 12 patients also had decreased metabolism in the orbitofrontal cortex. The two remaining patients had hypometabolism in the cuneus/praecuneus. Correlation analyses showed significant correlations between some test scores (anxiety, depression, health related quality of life) but not fatigue and regional reductions in glucose metabolism. Conclusions: Although abnormalities in FDG-PET were only detectable in approximately half the CFS patients examined, and no specific pattern for CFS could be identified, PET may provide valuable information in helping to separate CFS patients into subpopulations with and without apparent alterations in the central nervous system.

OBJECTIVES: To examine the validity of [(123)I]beta-CIT SPECT for monitoring the progression of dopaminergic degeneration in Parkinson's disease; to investigate the influence of short term treatment with D(2)receptor agonists on striatal [(123)I]beta-CIT binding; and to determine the sample size and frequency of SPECT imaging required to demonstrate a significant effect of a putative neuroprotective agent. METHODS: A group of 50 early stage Parkinson's disease patients was examined. Two SPECT imaging series were obtained, 12 months apart. The mean annual change in the ratio of specific to non-specific [(123)I]beta-CIT binding to the striatum, putamen, and caudate nucleus was used as the outcome measure. RESULTS: A decrease in [(123)I]beta-CIT binding ratios between the two images was found in all regions of interest. The average decrease in [(123)I]beta-CIT binding ratios was about 8% in the whole striatum, 8% in the putaminal region, and 4% in the caudate region. Comparison of scans done in nine patients under two different conditions-in the off state and while on drug treatment-showed no significant alterations in the expression of striatal dopamine transporters as measured using [(123)I]beta-CIT SPECT. Power analysis indicated that to detect a significant (p < 0.05) effect of a neuroprotective agent with 0.80 power and 30% of predicted protection within two years, 216 patients are required in each group when the effects are measured in the whole putamen. CONCLUSIONS: [(123)I]beta-CIT SPECT seems to be a useful tool to investigate the progression of dopaminergic degeneration in Parkinson's disease and may provide an objective method of measuring the effectiveness of neuroprotective treatments. Short term treatment with a D(2)agonist does not have a significant influence on [(123)I]beta-CIT binding to dopamine transporters. If the latter finding is replicated in larger groups of patients, it supports the suitability of [(123)I]beta-CIT SPECT for examining the progression of neurodegeneration in patients being treated with D(2)receptor agonists

Objectives: The differential diagnosis between typical idiopathic Parkinson's disease (PD) and the striatonigral variant of multiple system atrophy (MSA-P) is often difficult because of the presence of signs and symptoms common to both forms of parkinsonism, particularly at symptom onset. This study investigated striatal and midbrain findings in MSA-P and PD patients in comparison with normal controls with the use of positron emission tomography (PET) and three dimensional magnetic resonance imaging (3D MRI) based volumetry to increase the differential diagnostic accuracy between both disease entities. Methods: Nine patients with MSA-P, 24 patients with PD, and seven healthy controls were studied by MRI and PET with 6-[18F]-fluoro-L-dopa (FDOPA), [18F]fluoro-deoxyglucose (FDG), and 11-C-Raclopride (RACLO). Striatal and extrastriatal volumes of interest (VOI) were calculated on the basis of the individual MRI data. The PET data were transferred to the VOI datasets and subsequently analysed. Results: MSA-P differed significantly from PD patients in terms of decreased putaminal volume, glucose metabolism, and postsynaptic D2 receptor density. The striatal FDOPA uptake was equally impaired in both conditions. Neither MRI volumetry nor PET imaging of the midbrain region further contributed to the differential diagnosis between PD and MSA-P. Conclusions: The extent and spatial distribution of functional and morphological changes in the striatum permit the differentiation of MSA-P from PD. Both, multi-tracer PET and 3D MRI based volumetry, may be considered equivalent in the assessment of different striatal abnormality in both disease entities. In contrast, MRI and PET imaging of the midbrain does not provide a further gain in diagnostic accuracy.

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.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.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.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.

The purpose of this work was to develop a simple and rapid method to determine the radiochemical purity of 99mTc-bicisate.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.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.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.

Objectives: To elucidate the factors associated with severity of cardiac sympathetic nerve involvement in idiopathic Parkinson’s disease (PD). Methods: 123 I-metaiodobenzylguanidine uptake was examined in 88 patients with PD. The ratio of the uptake in the heart ( H ) to that in the mediastinum (M) (the H / M ratio) was calculated and correlated with age at onset, age at examination, and disease severity and duration. Twenty five healthy people were also examined as a control. Results: There was a mild but significant negative correlation between H / M ratio and age at onset (early, r = −0.33, p = 0.002; delayed, r = −0.34, p = 0.001) and between Hoehn and Yahr (H-Y) stage (early, r = −0.30, p = 0.006; delayed, r = −0.32, p = 0.003). There was no significant correlation between disease duration and H / M ratio. When patients with PD were classified into four subgroups on the basis of age at onset (> 62 or III or H-Y ⩽ II), the median H / M ratio of the older and more severe group was significantly lower than that of the younger and less severe group (p = 0.005). Conclusion: This study suggests that late onset, high severity PD is associated with myocardial sympathetic dysfunction.