Clinical efficacy of radioiodine therapy in multinodular toxic goiter, applying an implemented dose calculation algorithm.

Radioiodine is a common therapeutic option for Multinodular Toxic Goiter (MTG). We evaluated an algorithm for personalized radioiodine activity calculation. Ninety-three (28 male, 65 female; 43-84 years) patients with MTG eligible for radioiodine treatment (131I-iodide) were studied. The quantity of 131I-iodide to be administered was estimated by Thyroid Volume Reduction (TVR) algorithm, developed for Graves' disease. It takes into account 131I uptake, its effective half-life (T1/2eff), thyroid volume, and its expected reduction during treatment. A comparison with the activity calculated by other dosimetric protocols and the "fixed" activity method was performed. 131I uptake was measured by external counting, thyroid volume by ultrasonography (US), thyroid stimulating hormone (TSH), and thyroid hormones by standard immunometric methods. In a follow-up of 6-120 months, remission of hyperthyroidism after a single 131I-iodide treatment was observed in 76 patients (64 euthyroid, 12 hypothyroid). The thyroid volume reduction observed by US after the treatment fairly correlated with what predicted by our model; T1/2eff was highly variable and critically affected dose calculation. The administered activities (median 526 MBq, range 156-625 MBq) were slightly lower than the "fixed" activities (600 MBq) and with respect to the other protocols' prescriptions (-15/38%); the median 131I activity administered to relapsed patients (605 MBq) was significantly greater (P=0.01) with respect to the dose administered to cured patients (471 MBq). Our study shows that an effective cure of MTG can be obtained with relatively low 131I activities and probably with a relatively low incidence of hypothyroidism, using TVR method.

Long-term outcome of low-activity radioiodine administration preceded by adjuvant recombinant human TSH pretreatment in elderly subjects with multinodular goiter.

BACKGROUND: Large multinodular goiter (MNG) in elderly people is a common finding which can require intervention. The long-term effect of radioiodine therapy on thyroid volume (TV) and function after recombinant human (rh) TSH pre-treatment was evaluated. METHODS: After baseline evaluation, 40 subjects over 60 years old with a large MNG were treated with 131I up to the activity of 600 MBq. Nineteen patients were pretreated with rhTSH (0.1 mg on 2 consecutive days; group 1) while 21 subjects underwent treatment without rhTSH pretreatment (group 2). TV was monitored every 6-12 months by ultrasonography. The median follow-up period was 36 months. RESULTS: At the baseline, the groups matched in terms of TV, 24-h radioiodine uptake (RAIU), urinary iodine and neck complaints. The number of subjects pretreated with anti-thyroid drugs was significantly (P = 0.01) greater in group 2 than in group 1; TSH was more suppressed (P = 0.003) and f-T3 was more elevated (P = 0.005) in group 2 than in group 1 patients. RhTSH increased 24-h RAIU in group 1 up to the baseline level observed in group 2. The 131I activity administered was similar in both groups. Adverse events were slight and similar in both groups. A permanent post-radioiodine toxic condition was reported only in 2 patients in group 2. After radioiodine therapy, hypothyroidism was observed in significantly more group 1 patients than group 2 patients (P = 0.002). While TV was reduced in both groups, the percentage TV reduction recorded at the last examination was significantly higher (P = 0.03) in group 1 than in group 2. MNG-related complaints were significantly reduced in both group 1 (P = 0.0001 vs baseline) and group 2 (P = 0.001) patients. CONCLUSION: Low radioiodine activities after pretreatment with low-dosage rhTSH are able to reduce TV and improve MNG-related symptoms in elderly subjects.

Pharmacokinetics of Der p 2 allergen and derived monomeric allergoid in allergic volunteers.

BACKGROUND: Presently, sublingual immunotherapy is widely used as an alternative to the injection route for respiratory allergy, but its pharmacokinetics in humans is poorly known, and data are available only for Par j 1 allergen. We aimed at assessing the biodistribution of iodine-123-radiolabelled Der p 2 in allergic volunteers. METHODS: Purified Der p 2 and its monomeric allergoid were radiolabelled with iodine-123 and administered sublingually to 7 allergic volunteers. The subjects were allowed to swallow 6 min after administration. Dynamic (up to 10 min) and static scintigraphic images (30 min, 1, 2, 3 and 20 h) were recorded, and blood samples were obtained at different time points to measure the plasma radioactivity and to assess the presence of circulating radiolabelled species by gel chromatography. RESULTS: The local pharmacokinetics did not differ between allergen and allergoid. Plasma radioactivity began to increase only after swallowing and peaked at 1-2 h. Both the allergen and the allergoid persisted in the mouth for several hours, and traces could be detectable up to 20 h. At radioactivity plasma peak, gel chromatography showed that a fraction of the allergoid, but not the allergen, was absorbed as an intact molecule. CONCLUSIONS: These results indicate that the pharmacokinetics of sublingual administration is independent of the allergen used and characterized by the long persistence in the mouth. The contribution of enteric absorption of the allergoid in the mechanism of action of sublingual immunotherapy remains to be defined.

The usefulness of spiral Computed Tomography and colour-Doppler ultrasonography to predict portal-mesenteric trunk involvement in pancreatic cancer.

PURPOSE: The aim of this study was to determine the clinical utility of spiral computed tomography (CT) and colour Doppler ultrasonography (US) in the evaluation of portal-mesenteric trunk (PMT) involvement in pancreatic cancer. MATERIALS AND METHODS: Ninety-five patients with pancreatic cancer underwent preoperative assessment of the PMT with spiral CT and colour Doppler US. Five stages of vascular involvement were established. During surgery intraoperative US was performed to confirm the preoperative findings. RESULTS: Of the 95 patients observed, 82 (86.3%) underwent surgery. The sensitivity of spiral CT was 98%, specificity 79%, overall accuracy 80.2%. The positive predictive value was 87.5%; the negative predictive value 96%. The results of colour Doppler US were 92.3%, 72,7%, 72.8%, 79.5% and 88.8%, respectively. CONCLUSIONS: The results indicate that spiral CT is the gold standard in detecting PMT involvement in pancreatic cancer. Colour Doppler US is useful, but adds nothing to CT. Both of these techniques improve the possibility of predicting the resectability of pancreatic cancer.