SPECT imaging with [123I]-beta-CIT in Parkinsonism: comparison of SPECT images obtained by a single-headed and a three-headed gamma camera.

Single photon emission computed tomography (SPECT) imaging of dopamine transporters by using the cocaine derivative [123I]-(1R)-2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane ([123I]-beta-CIT) has been shown to be useful in patients with Parkinsonism. The aim of this study was to compare beta-CIT imaging with single-headed (SHS) and three-headed gamma camera systems (THS). In 17 patients with Parkinsonism, SPECT imaging with an SHS and a THS was performed 24 h after injection of 180 MBq of [123I]-beta-CIT. The SPECT studies were evaluated by visual assessment of the caudate nucleus (CN) and the putamen (PT) and the calculation of the striatal/cerebellar (S/C) ratios (with additional comparison to clinical symptoms measured by the Unified Parkinson's Disease Rating Scale (UPDRS)). The S/C ratios measured by the SHS and THS showed highly significant correlation (two-tailed P < 0.01) with Spearman correlation coefficients (SCCs) of 0.864 for the right side, 0.676 for the left side, and 0.761 for both sides. By the SHS, a sufficient visual differentiation between the CN and the PT could not be achieved. A significantly better distinction could be achieved by using the THS (Wilcoxon P<0.05). The S/C ratios of the THS only showed a significant (P < 0.05) SCC of -0.514 comparing to the UPDRS. Pathological alterations in the beta-CIT uptake pattern could be identified by using the SHS, but a significantly better differentiation of CN and the PT was possible by using the THS. The significant correlation of the S/C ratios measured by THS only emphasizes the value of THS in beta-CIT imaging.

Technetium-99m-furifosmin in the follow-up of differentiated thyroid carcinoma.

UNLABELLED: Tumor scintigraphy with flow tracers, such as 201TI-chloride, has an established role in the follow-up of differentiated thyroid cancer. We investigated a new tracer, 99mTc-furifosmin (Technescan Q12, Mallinckrodt Diagnostika, Hennef, Germany), in patients with elevated thyroglobulin levels or sonographic suspicion of lymph node metastases or recurrent disease. METHODS: In a prospective study, we examined 20 patients with 99mTc-furifosmin. All patients underwent a 18F-fluorodeoxyglucose (FDG) PET scan of the neck and chest. Positive 99mTc-furifosmin findings were validated by biopsy, (131)I scan, CT or 18F-FDG PET examinations. RESULTS: In three patients with cervical lymph node metastases detected on a planar 99mTc-furifosmin scan, we found a rapid tracer accumulation in the tumor (maximum < 2 min) and a significant washout in 2 of 3 patients after 4 hr. The visual contrast and the tumor-to-nontumor ratio was rather poor (average 1.2:1). In 3 additional patients, 3 pulmonary and 2 mediastinal lymph node metastases were detected by the 99mTc-furifosmin SPECT scan. Two patients were true-negative, and in 13 of 18 patients, the tumor could be localized by 18F-FDG PET (10 cervical, 6 mediastinal, 4 pulmonary metastases, 1 bone metastasis); 5 patients were false-negative. In 3 of these false-negative cases we could not localize the tumor with other diagnostic methods. Two patients had a true-negative PET examination. CONCLUSION: The statistical analysis of our data on 99mTc-furifosmin reveals that the sensitivity and 95% confidence interval of 33% (11%-56%) on a patient-by-patient basis and of 34% (17%-57%) for the lesion-by-lesion analysis is significantly lower than the sensitivity and 95% confidence interval of 72% (50%-89%) on a patient-by-patient basis and of 91% (78%-100%) on lesion-by-lesion basis for 18F-FDG. The sensitivity of 99mTc-furifosmin appears to be poor, even for cervical and mediastinal tumor manifestations where the value of 201TI-chloride is established.

Diagnostic use of daytime polysomnography versus nocturnal polysomnography in sleep apnea syndrome.

The usefulness of daytime polysomnography (DPSG) in the diagnosis of sleep apnea syndrome (SAS) is examined. Diagnostic use was investigated by conducting DPSG of two different time periods (Group M, 11.00-14.00 h, and Group A, 15.00-18.00 h). The subjects were 30 patients (28 men and two women; mean age, 54.0 years). Nocturnal polysomnography (NPSG) and DPSG were investigated by comparing indices of sleep, apnea index (AI) and arterial oxygen saturation (SaO2). There was no significant difference among these indices but there was a significant positive correlation between NPSG and DPSG in all variables related to sleep apnea. Moreover, there was no significant difference in the frequency of each type of apnea between NPSG and DPSG in either group. These findings suggest that DPSG is useful not only in diagnosing SAS but in evaluating its severity.

Non-invasive measurement of thyroidal iodine content (TIC) by X-ray fluorescence analysis (XFA).

The determination of thyroidal iodine content by X-ray fluorescence analysis is based on the phenomenon that the gamma radiation of Americium-241 excites stable iodine atoms to emit a characteristic fluorescence radiation which is proportional to the amount of iodine present in the gland. To study this, a stationary system has been developed which consists of a 11.1 GBq Am-241 source and a high-purity Germanium detector with spectrum analysator. Lower limit of detectability of this system corresponds to 0.013 mg per ml of thyroid volume measured sonographically; in-vivo precision given as coefficient of variation of duplicate measurements amounts to 12%. The thyroid is exposed with a radiation dose of 60 microSvs per measurement (approximately 5 % of a Tc-99m scan). Studies carried out in 149 volunteers and 173 patients showed a mean iodine concentration of 0.325 +/- 0.134 mg/ml in healthy persons; decreased iodine concentrations were found in euthyroid goitre patients and hyperthyroid patients with focal functional autonomy or Graves' disease. Iodine concentrations correlated negatively with age and goitre volume. The method is well suited for individual follow-up studies exploring different treatment modalities because of its sensitivity, high reproducibility and low radiation exposure.

[Radiation exposure from diagnostic nuclear medicine in Germany 1992 (the former Federal Republic)]. / Die Strahlenexposition durch nuklearmedizinische Untersuchungen in in Deutschland 1992 (alte Bundesländer).

Up to now, exact data on the frequency and collective effective dose of nuclear medicine examinations were missing for Germany. On the basis of official reimbursement statistics for outpatients, compiled by the Kassenärztliche Bundesvereinigung, the total frequency of nuclear medicine examinations is estimated. 2.3 million examinations have been performed in 1992 in the western part of Germany, corresponding to 35 examinations per 1000 inhabitants. 77% of the patients examined were older than 40 years. Thyroid scintigraphy leads the frequency statistics with 51%, followed by bone scintigraphy (28%) and myocardial perfusion scans (7%). The mean effective dose per examination according to ICRP 53, amounts to 3.5 mSv which corresponds to 0.12 mSv per caput. The major contributions to the collective effective dose derive from bone scintigraphy (39%) and myocardial perfusion scintigraphy (35%); the contribution of thyroid scintigraphy to the collective effective dose is only 10%. If the data are corrected for sex and age, the collective effective dose is reduced to 1.4 mSv per examination and to 0.05 mSv per caput, respectively.