Single, very low dose (0.03 mg) of recombinant human thyrotropin (rhTSH) effectively increases radioiodine uptake in the I-131 treatment of large nontoxic multinodular goiter.

BACKGROUND: Radioiodine therapy (RIT) in patients with large nontoxic multinodular goiter (MNG) recently becomes more common method in comparison to surgery (especially in elderly patients and with contraindications because of severe chronic diseases other systems). Repeatedly low thyroid radioactive iodine uptake (RAIU) decreases effectiveness of RIT or makes it impossible. The recombinant human thyrotropin can increase RAIU and improve the results of RIT. THE AIM OF THE STUDY: was to assess the influence of a single very low dose (0.03 mg) of rhTSH on RAIU and thyroid function in euthyroid (MNG-EU) and subclinical hyperthyroid (MNG-SC) patients with a large multinodular goiter. MATERIAL AND METHODS: 40 patients (14 male, 26 female, age 57-80 yr) with large non-toxic MNG over 80 grams and with baseline RAIU < 40% were included into the double-blind randomized study and divided into two groups: rhTSH-group and control group. First group received the single intramuscular injection of 0.03 mg rhTSH and the second received placebo. The RAIU were measured 24 and 48 hours after the rhTSH and then all the patients were administered therapeutic doses of I-131. TSH and free thyroxine levels were measured at 1st and 2nd day after the injection of rhTSH and later, at 4 and 8 weeks after the RIT. RESULTS: The mean RAIU increased significantly from 30.44 ± 7.4% to 77.22 ± 8.7% (p < 0.001). There were no statistically significant differences in RAIU between euthyroid (MNG-EU) and subclinically hyperthyroid (MNG-SC) patients. The peak of serum TSH was noticed 24 hours after rhTSH injection and in MNG-EU patients it has remained within normal range, similarly as fT4. In the MNG-SC group the administration of rhTSH resulted in a significant increase in the TSH values after 24 hours, whose mean level slightly exceeded the upper limit of the normal range with normalization at 48 hours. 8 weeks after the RIT, the TSH and fT4 levels did not exceed the normal range and did not differ in a statistically significant way. CONCLUSIONS: Even the single very low dose of rhTSH increases the values of RAIU in significant way, in euthyroid and subclinically hyperthyroid patients. The administration of rhTSH is well-tolerated. Neoadjuvant administration of a low dose (0.03 mg) of rhTSH before I-131 seems to be an optimal method of management which may increase the effectiveness of RIT and decrease the exposure of the patients to absorbed doses of ionizing radiation.

Radioiodine therapy for Graves' disease - retrospective analysis of efficacy factors.

INTRODUCTION: Radioiodine ((131)I) isotope therapy is the method of choice in the treatment of Graves' disease relapse. The efficiency of this method is dependent on many factors; therefore, the present paper aims to identify the parameters that have a crucial impact on the efficacy of radioiodine therapy for Graves' disease. MATERIAL AND METHODS: The authors performed a retrospective analysis of the medical documentation of 700 Graves' disease sufferers treated with (131)I. The patients were divided into three groups depending on the thyroid-absorbed dose of (131)I: group I - 100 Gy, II - 150 Gy, and III - 200 Gy. The authors assessed the influence of gender, age, presence of orbitopathy, TRab titres, thyroid mass, iodine uptake after 24 and 48 hours, and the absorbed dose on the treatment efficacy at one year post-(131)I administration. RESULTS: The volume of thyroid gland (P < 0.002) and the thyroid-absorbed dose (P < 0.001) were the only factors that had a significant impact on the outcome of the treatment. The likelihood of hyperthyroidism persisting (odds ratio: 3.71, 95% confidence interval: 2.4-5.87) was greatest in patients from group I. In group II, with thyroid volume amounting both to 25 mL and to 25-50 mL, the percentage of hyperthyroidism was lowest (1 and 0%). However, with thyroid volume > 50 mL, the percentage of hyperthyroidism was lowest in group III (10%). CONCLUSIONS: The absorbed dose of (131)I and the volume of the thyroid gland are two parameters that have a significant influence on the efficacy of radioiodine therapy for Graves' disease. 150 Gy is the optimal dose for glands < 50 mL. A goitre > 50 mL requires an absorbed dose of 200 Gy in order to minimise the risk of recurrent hyperthyroidism.

Parathyroid gland function after radioiodine ((131)I) therapy for toxic and non-toxic goitre.

INTRODUCTION: The therapeutic effect of radioactive iodine ((131)I) on benign goitre consists of the emission of tissue-destructive beta-radiation. Since the range of beta (131)I radiation in tissue can reach 2.4 mm, it can affect the adjacent parathyroid glands. The purpose of this paper is to assess parathyroid function in patients with toxic and non-toxic goitres, up to five years following (131)I therapy. MATERIAL AND METHODS: The study sample consisted of 325 patients with benign goitres (220 with toxic nodular goitre (TNG), 25 with non-toxic nodular goitre (NTNG), and 80 with Graves' disease (GD) treated with (131)I. The therapeutic activity of (131)I for each patient was calculated using Marinelli's formula. The serum levels of fT3, fT4, TSH, iPTH and Ca(2+), Ca and phosphates were determined one week before (131)I administration, as well as every two months up to a year following the therapy, and then after three and five years post-treatment. RESULTS: After two months following the administration of (131)I, all the treated patients showed a statistically significant above normal increase in iPTH concentrations (amounting to a value almost twice the norm in patients with TNG), which remained stable up to ten months after treatment, to return to normal level in the following months. In all the patients, Ca(2+), Ca, phosphates concentration remained within normal range throughout the course of the study. The concentrations of fT3 and fT4 quickly returned to normal after (131)I administration, and remained within normal range until the completion of the study. CONCLUSION: Radioiodine treatment of benign thyroid disorders results in transient (up to ten months after (131)I administration) hyperparathyroidism. The condition does not influence the level of calcium and phosphates concentration in any significant way.

Iodine isotope ¹³¹I therapy for toxic nodular goitre: treatment efficacy parameters.

BACKGROUND: When planning radioactive iodine therapy, it frequently happens, both in Poland and world-wide, that inadequate attention is paid to such easily measurable parameter sas: 1) the serum concentration of thyrotropin (TSH) before administering radioiodine, which is a key factor for extranodular(non-autonomous) iodine uptake of the thyroid gland, 2) thyroid gland iodine uptake, and 3) the effective half-life of 131I (Teff.). The aim of the study is to evaluate the impact of the above factors on the efficacy of 131I treatment in hyperthyroid patients. METHODS: The material consisted of 4140 patients: 2190 with autonomous toxic nodules (ATN) and 1950 with toxic multinodular goitres (TMG). The patients were prepared for treatment in such a way that the concentration of TSH did not exceed 0.1 mU/land Teff.< 5 days. The therapeutic activity of 131I was calculated using Marinelli's formula. The selection of absorbed dose value was determined by the degree of suppression of extranodulart issue. Monitoring was performed every eight weeks. RESULTS: At one year after 131I administration showed that a euthyroid status was achieved in 94%, hypothyroidism was seen observed in 3%, while persistence or recurrence of hyperthyroidism in 3% of ATN patients and, respectively, 89%, 4% and 7% of TMG patients. CONCLUSIONS: Patients with toxic nodular goitre who are to be treated with radioiodine should have the lowest possible serum concentration of TSH. The suppression of extranodular determines the optimal value of absorbed dose for Marinelli's formula.

Bone scan in metabolic bone diseases. Review.

Metabolic bone disease encompasses a number of disorders that tend to present a generalized involvement of the whole skeleton. The disorders are mostly related to increased bone turnover and increased uptake of radiolabelled diphosphonate. Skeletal uptake of 99mTc-labelled diphosphonate depends primarily upon osteoblastic activity, and to a lesser extent, skeletal vascularity. A bone scan image therefore presents a functional display of total skeletal metabolism and has valuable role to play in the assessment of patients with metabolic bone disorders. However, the bone scan appearances in metabolic bone disease are often non-specific, and their recognition depends on increased tracer uptake throughout the whole skeleton. It is the presence of local lesions, as in metastatic disease, that makes a bone scan appearance obviously abnormal. In the early stages, there will be difficulty in evaluating the bone scans from many patients with metabolic bone disease. However, in the more severe cases scan appearances can be quite striking and virtually diagnostic.

[Subclinical hyperthyrodism, diagnosis and radioiodine therapy]. / Subkliniczna nadczynnosc tarczycy, diagnostyka i leczenie radioizotopowe.

Subclinical hyperthyroidism is a state of increased thyroid function with few or no clinical definitive signs or symptoms of hyperthyroidism. It is characterised by a decrease of serum (TSH) concentration below 0.1 mU/L, when serum levels of total and free thyroxin and triiodothyronin concentration are within normal reference ranges. It is not a rare finding and rates between 0.02% and 11.3% have been reported in different groups. The clinical diagnosis of subclinical hyperthyroidism is very difficult in the absence of the typical symptoms of hyperthyroidism. Therefore the diagnostic evaluation is important, especially with the use of radioisotope scan. In nuclear medicine department we can confirm the provisional diagnosis by the use of thyroid scan. Recent studies reported the effects of subclinical hyperthyroidism on cardiovascular system, skeletal system, cognitive function, on quality of life and life expectancy especially in the elderly patient. Treatment is indicated in the presence of palpitation, or atrial fibrillation, in postmenopausal osteoporosis in women not on hormone replacement therapy, and in elderly patients in whom surgery is contraindicated. According to the opinions of European clinicians and clinician members of the American Thyroid Association, the majority recommend radical treatment for these patients. Radioiodine therapy is considered to be the treatment of choice in most of the patients with nodular goiter.