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Aim: The use of radioiodine therapy is common in the treatment of benign thyroid disease. Council directive Euratom 97/43 requires that for all medical exposure of individuals for radiotherapeutic purposes exposures of target volumes should be individually planned. There are several strategies to accomplish this aim for radioiodine therapy including individual radioiodine uptake measurement and using either individual or mean effective radioiodine uptake and half-life. Although it is always simple to use standard activities, the effective thyroidal half-life and thyroidal uptake of I needs to be estimated individually to achieve optimal dosimetric results. We analyzed the radioiodine half-life and uptake in a large number of patients for use in a semi-individual calculation., Methods: Patients presenting consecutively between 1 January 2006 and 31 December 2007 were included in the study. Inclusion criteria were the control of hyperthyroidism and withdrawal of antithyroid drugs 2 days before preliminary radioiodine testing and therapy. Patients were treated for Graves' disease (n=363), nontoxic goitre (n=50), toxic goitre (n=639), or toxic uninodular adenoma (n=365). The effective half-life and uptake of I were estimated by uptake measurements after 24 h and 5 days during the preliminary radioiodine test, and serial measurements over 5 days during therapy., Results: The mean effective half-life of I measured during radioiodine therapy was 5.4 days in Graves' disease, 6.4 days in nontoxic goitre, 6.6 days in toxic goitre, and 5.7 days in toxic uninodular adenoma. The mean maximal uptake of I measured during radioiodine therapy was 64% in Graves' disease, 42% in nontoxic goitre, 38% in toxic goitre, and 31% in toxic uninodular adenoma., Conclusion: These actual values analyzed here might be used for a semi-individual calculation of therapeutic activity when an individual approach is not possible.

Objective: To evaluate the effect of radioiodine therapy for volume reduction in large goitres., Methods: A retrospective study was performed involving 88 patients treated between 2001 and 2007 with radioiodine for toxic or nontoxic goitres. The goitres were between 80 and 250 ml in volume (median 127 ml+/-38.57). Activities of I to be administered were calculated individually through radioiodine testing with uptake measurements over 5 days, the mean activity being 1721+/-440 MBq I (714-2395 MBq I), equivalent to a mean of 14+/-4.19 MBq I/g of thyroid tissue (6-24 MBq I/g of thyroid tissue). The designated dose was 150 Gy for the entire thyroid volume, and post-therapeutic dosimetry revealed a mean thyroid dose of 175+/-45.92 Gy (64-300 Gy). Control examinations were performed, including thyroid blood testing and thyroid ultrasound at 6 weeks and at 3, 6, 12, 24, 36, 48 and 72 months after radioiodine therapy., Results: The mean volume reduction was 41.9% after 3 months and 65.9% after 1 year. Thyroid volume reduction was highly significant (P<0.001) in the first year after radioiodine therapy. No volume increase was observed in any patient during follow-up. Unfortunately, many patients were lost during follow-up (n = 84 after 3 months, n = 38 after 1 year)., Conclusion: Radioiodine therapy is an effective treatment for both nontoxic and toxic goitres, resulting in a highly significant thyroid volume reduction of nearly 66% within 1 year.

Aim: The apoptotic and necrotic dose-response of thyroid carcinoma cells following irradiation with I was evaluated., Methods: In our in-vitro model, cells of well-differentiated papillary thyroid carcinoma (B-CPAP) were incubated with increasing activity concentrations of I for 2 days. Changes in cell viability and the extents of necrosis and apoptosis were evaluated both immediately and 2 days after irradiation., Results: Viability of B-CPAP cells diminished with increasing I activity concentration. No apoptosis was detectable immediately after irradiation. Two days after irradiation significant apoptosis was found. The lowest I activity concentration at which apoptosis was detectable corresponds to about 1 MBq . ml. At higher activity concentrations a larger percentage of cells became apoptotic but the proportion decreased again at activity concentrations >10 MBq . ml. Likewise, necrosis was minimal at low activity concentrations and showed an exponential increase with rising I activity concentrations (>5-10 MBq . ml). Necrosis was already detectable immediately after irradiation and was the predominant form of cell death at high activity concentrations., Conclusion: The data suggest that the nature of the cytotoxic effect of I and whether it leads to apoptotic or necrotic cell death is dose-dependent. High I doses seem to produce mainly necrotic phenomena, whereas at low I activity concentrations apoptotic phenomena prevail. The predominance of delayed apoptosis could explain why radioiodine therapy at lower doses is often linked to delayed onset and possible continuation of thyroid volume reduction over some months and even up to a year.

Purpose: To evaluate a novel strategy of immunolocalization of human neuroblastoma by targeting the neural cell adhesion molecule (NCAM), which is over-expressed on neuroblastoma., Methods: NCAM expression on the cell surface of established neuroblastoma cells was shown by flow cytometry. A SCID mouse model using IMR5-75 neuroblastoma cells to induce subcutaneous tumour growth was established. 131I was used to label monoclonal NCAM specific ERIC1 antibodies generating the 131I-ERIC1 antibody, which showed a high affinity to NCAM also after labelling (KD=9 x 10(-8) mol . l(-1))., Results: Measurement of organ-specific radioactivity showed low organ-specific uptake (5.33%ID/g (percent of injected dose per gram of tissue) after 72 h), which continuously decreased over the 96 h investigation period, demonstrating clearance of radioactivity. In contrast, tumours accumulated radioactivity continuously up to a peak of 42.07%ID/g at the 96 h time point (31.07%ID/g at 72 h). This specific uptake could be blocked by application of unlabelled ERIC1 antibodies. Measurement of blood specific radioactivity revealed a characteristic clearance over the first 72 h. With 37 Gy, tumour-specific radioactivity reached therapeutic doses after 96 h., Conclusions: These results indicate that 131I-labelled ERIC1 has the ability to probe NCAM-expressing tumour cells in vivo with high efficiency and is a promising reagent for the diagnosis and treatment of NCAM-positive human tumours, especially for neuroblastoma.

Aim: This in-vitro study investigated the influence of the contrast agents iothalamate (Conray) and special preparations of iotrolan (Isovist) and iopromide (Ultravist) without ethylenediaminetetraacetic acid (EDTA), the anaesthetic Scandicain and the glucocorticoid triamcinolone on the stability of 90Y-, 169Er- and 186Re-radiocolloids used for radiation synovectomy., Methods: Vials of 1 ml of synovial fluid and 0.02 ml of radiocolloid suspension (0.56-3.6 MBq) were mixed with 0.06, 0.6 and 1.0 ml of each contrast agent. In an additional series, 0.1 ml of Scandicain and 0.1 ml of triamcinolone were tested. Thin layer chromatography and ultrafiltration/centrifugation were performed between 1 h and 15 days after incubation with negative and positive controls., Results: Within 24 h, 0.6 and 1.0 ml of Conray had mobilized 5-20% of the 90Y and 169Er out of the colloids. No interference between 186Re-colloids and Conray was visible before the ninth day after incubation. Iotrolan and iopromide without EDTA had no effect on the stability at shorter incubation periods of up to 6 days. The addition of Scandicain did not produce low-molecular 90Y or 169Er in the presence of synovial fluid. The fraction of low-molecular 186Re reached 4% after 24 h. Triamcinolone did not have any effect on stability in the presence of synovial fluid., Conclusion: The disintegration of the radioactive colloids can be attributed to either the formation of EDTA complexes or radiolytic effects. The volume of the injected contrast agent should be as small as possible to confirm correct intra-articular distribution.

Background: The extent of thyroid resection and the necessity of lymph node dissection has become an issue of controversy in patients with incidental multifocal papillary microcarcinoma., Method: Between 1993 and 2001 a total of 4120 patients underwent surgery for thyroid diseases: 142 patients showed papillary thyroid cancer of < or = 1 cm, multifocal microcarcinomas were found in 22 patients (15.5%). Twenty patients (17 women, three men, aged 26-71 years) met the inclusion criterion of having pre- and intraoperatively no indication of malignancy (incidentaloma). A limited surgical procedure ranging from bilateral subtotal (n=15), ipsilateral total, contralateral subtotal (n=4) to bilateral total (n=1) thyroidectomy without lymph node dissection was performed. The mean volume of thyroid remnants was 4.3 ml., Results: In 16/20 (80%) patients, the thyroid remnant was ablated by the first dose of 131I, using 3.7 GBq 131I in 15 patients and 1.85 GBq 131I in one patient. Three patients received a second, and one patient a third radioiodine ablation. All 20 patients remained free from relapse or metastasis, documented by negative 131I whole-body scintigraphy and unmeasurable thyroglobulin levels after thyroid hormone withdrawal in hypothyroidism. One patient died 7 years after the diagnosis of thyroid cancer from primary lung cancer. Median follow-up was 65 months (range, 24-120 months)., Conclusion: Subtotal thyroidectomy followed by radioiodine therapy without completion thyroidectomy and lymphadenectomy is a possible option in incidental multifocal microcarcinomas.