Conventional two-dimensional (2-D) ultrasound is the standard method for the investigation of thyroid morphology. Volume calculations need model assumptions and are observer dependent. The present study performed with a commercially available three-dimensional (3-D) system Freescan added to a conventional ultrasound scanner compares the accuracy of conventional thyroid volumetry to several methods of 3-D volume determination. In vitro measurements were performed on thyroid phantoms with known volumes. The standard deviation of the normalized differences was 8.0% (3-D segmentation) and 10.5% (conventional). For the accuracy of volume determination in human thyroids we performed a postmortem study. The thyroid volume was calculated conventionally by the ellipsoid model and by two 3-D methods (segmentation and the newly developed multiplanar volume approximation). The reference volume was determined after resection by submersion. The standard deviation of the normalized differences was 26.9% for the conventional method, 9.7% for 3-D segmentation and 11.5% for the multiplanar volume approximation, showing significant better results for both 3-D methods and no significant difference between the 3-D methods. The 3-D system, therefore, achieves a better accuracy for thyroid volumetry than the conventional volumetry using planar images. In addition, the 3-D images are stored electronically and can be used for follow-up studies.

Summary Aim: In this study the incidence rate of familial nonmedullary thyroid carcinoma was investigated in the first and second grade relatives of patients registered at the Clinic and Policlinic for Nuclear Medicine, University of Würzburg. Patients and Methods: In this study 596 patients with differentiated thyroid carcinoma were enclosed, who were treated between 01.01.81 and 31.12.95. The data concerning a familial occurrence were studied by a retrospective survey-based analysis. These data were compared to a literature analysis for familial non-meduilary thyroid carcinoma. Results: 14 patients of the 596 patients treated showed a familial occurrence (2,3%). All these patients suffered from papillary thyroid carcinoma. According to the prognostic factors (tumor state, lymph node involvement, metastastic disease) no differences could be evaluated in the different groups (sporadic versus familial non-medullary thyroid disease). Conclusion: A familial occurrence of differentiated thyroid carcinomas is not frequently observed, but should be considered due to further genetic diseases.

Sialorrhoea is a socially disabling problem in bulbar amyotrophic lateral sclerosis (ALS). Botulinum toxin A (BoNT/A) was injected into the salivary glands in five patients with bulbar ALS and sialorrhoea. The effect of BoNT/A was measured by the number of paper handkerchiefs used each day and by salivary gland scintigraphy. BoNT/A ameliorated sialorrhoea and quality of life without major adverse effects. BoNT/A may be a relatively safe and effective treatment for sialorrhoea in selected patients.

The objective of this study was to estimate the reproducibility of Tc-99m-mercaptoacetyltriglycine (Tc-99m-MAG3) clearance calculated using a single-sample method. Methods: One hundred forty-seven patients with urological or ear, nose and throat cancer were analyzed in a retrospective study. Each patient had at least two clearance studies with Tc-99m-MAG3 before chemotherapy treatments to monitor renal function. Up to five clearance studies per patient were considered. The reproducibility was estimated by comparing two consecutive investigations. Pairs of investigations with a change in split renal function of more than 5% or an interval of more than 50 days were excluded. Clearance was determined using the Bubeck method. For each pair of consecutive clearance data, the difference between the first and the second measurements was expressed as a percentage of the mean value of the two measurements. The mean of these normalized differences represents the systematic deviation, and the s.d. represents the reproducibility of the compared clearances. Results: After the selection, 242 pairs of consecutive clearance data remained for comparison. Significantly different clearances were observed only between investigations 0 and 1 and between 4 and 5. The systematic deviation of these comparisons totaled -3.8% and -5.7%, respectively. In the other comparisons, no significant deviation induced by the chemotherapy was found. The reproducibility calculated for all comparisons totaled 11.7%. Conclusion: The error of reproducibility of Tc-99m-MAG3 clearance using the Bubeck method was less than or equal to 11.7%. This was an acceptable value, taking into account the greater fluctuation of tubular function compared with the glomerular filtration rate.

Radioiodinated meta-iodobenzylguanidine (MIBG), an analogue of norepinephrine, has been used in management of neuroendocrine tumors. Recent studies reveal that distribution of radioiodinated MIBG in animals depends on the specific activity of this radiopharmaceutical. In order to clarify the effect of specific activity on organ uptake of radioiodinated MIBG. the kinetics of no-carrier-added (n.c.a.) [I-123]MIBG (greater than or equal to 7.4 TBq/mu mol) were compared with those of commercial (com.) [I-123]MIBG (similar to 74 MBq/mu mol) in 3 healthy volunteers by serial imaging and blood sampling. The organ uptake of radioiodinated MIBG did not remarkably differ between the two specific activities. Due to rapid degradation a more pronounced accumulation of radioactivity was present in plasma alter n.c.a. than after com. [I-123]MIBG resulting in a higher background and thyroid activity. In addition due to a prolonged residence time of the radioactivity, the radiation exposure to organs was in general slightly higher with n.c.a. [I-123]MIBG as compared to com. [I-123]MIBG. This finding highlights the higher in vivo deiodination of n.c.a. [I-123]MIBG than of com. [I-123]MIBG in humans. In the treatment of children suffering from neuroblastoma, therefore, degradation of n.c.a. [I-123]MIBG may decrease the concentration of radioiodinated MIBG available for binding at tumor sites and result in higher radiation exposure of non-tumor tissue.