Johannes W. van Isselt

Standardized radioiodine therapy in Graves' disease: the persistent effect of thyroid weight and radioiodine uptake on outcome

Abstract. Objective. To assess the incidence of hypothyroidism, euthyroidism, and recurrent hyperthyroidism following a standard dose of Na131I (3.7 MBq or 100 μCi) per g thyroid tissue, adjusted for radioiodine tracer uptake.

The success rate of I-131 ablation in differentiated thyroid cancer: comparison of uptake-related and fixed-dose strategies

INTRODUCTION The aim of the study was to compare the success rate of an uptake-related ablation protocol in which the dose depends on an I-131 24-h neck uptake measurement and a fixed-dose ablation protocol in which the dose depends on tumour stage. METHODS All differentiated thyroid carcinoma patients with M0 disease who had undergone (near-) total thyroidectomy followed by I-131 ablation were included. In the uptake-related ablation protocol, 1100 (uptake >10%), 1850 (uptake 5-10%) and 2800 MBq (uptake <5%) were used. In the fixed-dosage ablation strategy, 3700 (T1-3, N0 stage) and 5550 MBq (N1 and/or T4 stage) were applied. We used I-131 uptake on whole-body scintigraphy and thyroglobulin-off values to evaluate the ablation 6-12 months after treatment. RESULTS In the uptake-related ablation protocol, 60 out of 139 (43%) patients were successfully treated versus 111 out of 199 for the fixed-dose ablation protocol (56%) (P=0.022). The differences were not statistically significant for patients with T4 (P=0.581) and/or N1 (P=0.08) disease or for patients with T4N1 tumour stage (P=0.937). CONCLUSION The fixed-dose I-131 ablation protocol is more effective in ablation of the thyroid remnant in differentiated thyroid carcinoma patients than an uptake-related ablation protocol. This difference is not observed in patients with a N1 and/or T4 tumour stage.

The hot skull: Malignant or feminine?

Diffusely increased uptake in the calvarium on bone scintigraphy (a hot skull) is often present in patients with bone metastases and metabolic diseases. Excluding these known facts the prevalence of the hot skull and its relation with malignancy and, more specifically, with breast carcinoma have been studied in 673 patients. In women, the hot skull is clearly related to malignancy and to a lesser extent to breast carcinoma. However, antother remarkable feature of the hot skull is its predominance in women in general (compared to men) and, therefore, the data suggest that the hot skull can also represent a normal variant of the female skull. We conclude that the hot skull has no clinical value in screening protocols.

I-131 Accumulation in a Benign Cystic Mesothelioma in a Patient with Follicular Thyroid Cancer

Focal I-131 accumulation is generally a reliable indicator of functioning normal thyroid tissue or a differentiated thyroid cancer metastasis. However, physiologic accumulation of activity may also be observed in organs such as the intestinal tract, liver, and salivary glands. Extrathyroidal I-131 accumulation has been reported in various sites, such as ectopic gastric mucosa, gastrointestinal and urinary tract abnormalities, cysts (mammary, liver, kidney, and ovaries), and inflammation and infection foci. We report a case of focal I-131 accumulation in a benign cystic mesothelioma in a patient with follicular thyroid cancer.