Association between serum TSH concentration and bone mineral density: an umbrella review.

INTRODUCTION: The aim of this study was to summarize the results of previous studies, standardize the data, and present new statistical results in order to provide physicians with clinically significant outcomes regarding the association between serum TSH concentration and bone mineral density (BMD). METHODS: To perform this umbrella review, a systematic search was conducted in which major online medical databases, such as PubMed, Web of Science, Embase, Scopus, Cochrane Library, and Google Scholar, were searched for meta-analyses and systematic reviews regarding the effect of TSH on BMD. Furthermore, all primary studies were screened for statistical analysis. RESULTS: The statistical outcomes of the present study were based on the data of 75,898 patients. The pooled risk ratio of any kind of fracture in patients with subclinical hyperthyroidism was estimated to be 1.36 (95% CI: 1.18-1.56; p < 0.001). The SMD for BMD in the distal radius in male patients receiving L-thyroxine suppression therapy was estimated to be -0.61 (95% CI: -1.10-(-0.11); p = 0.02). Furthermore, the pooled risk ratio of any fracture in patients receiving L-thyroxine suppression therapy was estimated to be 1.98 (95% CI: 0.98 - 3.98; p = 0.06). In these patients, the BMD may significantly differ from that in non-treated patients. However, the difference depends on the type of bone. CONCLUSIONS: Our data confirmed that subclinical hyperthyroidism has a detrimental effect on bones, causing decreased BMD. Based on the obtained results, the authors suggest that a reduced TSH serum level itself may be an individual factor associated with decreased BMD and, thus, with a greater risk of bone fracture. Nevertheless, it should be noted that the effects of TSH suppression therapy differ between areas of interest for assessing BMD. Furthermore, the results have shown that this issue may, in specific areas, concern not only postmenopausal women but also male patients. These conclusions should contribute to a careful consideration of the application of TSH suppressive therapy in all patients. Particular attention should be given to patients after DTC, while all the advantages and disadvantages of implementing L-thyroxine therapy should be individually considered.

A patient with advanced breast cancer and hyperthyroidism associated with struma ovarii.

Not required for Clical Vignettes.

Diagnosis and treatment of thyroid cancer in adult patients - Recommendations of Polish Scientific Societies and the National Oncological Strategy. 2022 Update [Diagnostyka i leczenie raka tarczycy u chorych doroslych - Rekomendacje Polskich Towarzystw Naukowych oraz Narodowej Strategii Onkologicznej. Aktualizacja na rok 2022].

The guidelines Thyroid Cancer 2022 are prepared based on previous Polish recommendations updated in 2018. They consider international guidelines - American Thyroid Association (ATA) 2015 and National Comprehensive Cancer Network (NCCN); however, they are adapted according to the ADAPTE process. The strength of the recommendations and the quality of the scientific evidence are assessed according to the GRADE system and the ATA 2015 and NCCN recommendations. The core of the changes made in the Polish recommendations is the inclusion of international guidelines and the results of those scientific studies that have already proven themselves prospectively. These extensions allow de-escalation of the therapeutic management in low-risk thyroid carcinoma, i.e., enabling active surveillance in papillary microcarcinoma to be chosen alternatively to minimally invasive techniques after agreeing on such management with the patient. Further extensions allow the use of thyroid lobectomy with the isthmus (hemithyroidectomy) in low-risk cancer up to 2 cm in diameter, modification of the indications for postoperative radioiodine treatment toward personalized approach, and clarification of the criteria used during postoperative L-thyroxine treatment. At the same time, the criteria for the preoperative differential diagnosis of nodular goiter in terms of ultrasonography and fine-needle aspiration biopsy have been clarified, and the rules for the histopathological examination of postoperative thyroid material have been updated. New, updated rules for monitoring patients after treatment are also presented. The updated recommendations focus on ensuring the best possible quality of life after thyroid cancer treatment while maintaining the good efficacy of this treatment.

A rare case of aggressive, hereditary paraganglioma associated with a pathogenic variant in SDHD.

Not required for Clinical Vignette.

Current iodine nutrition status in Poland (2017): is the Polish model of obligatory iodine prophylaxis able to eliminate iodine deficiency in the population?

OBJECTIVE: The monitoring of the populations' iodine status is an essential part of successful programmes of iodine deficiency elimination. The current study aimed at the evaluation of current iodine nutrition in school children, pregnant and lactating women as a marker of the effectiveness and sustainability of mandatory iodine prophylaxis in Poland. DESIGN: The following iodine nutrition indicators were used: urinary iodine concentration (UIC) (all participants) and serum thyroglobulin (pregnant and lactating women). SETTING: The study was conducted in 2017 within the National Health Programme in five regions of Poland. PARTICIPANTS: The research included 300 pregnant women, 100 lactating women and 1000 school children (aged 6-12 years). RESULTS: In pregnant women, median UIC was 111·6 µg/l; there was no significant difference in median UIC according to the region of residence. In 8 % of pregnant women, thyroglobulin level was >40 ng/ml (median thyroglobulin 13·3 ng/ml). In lactating women, median UIC was 68·0 µg/l. A significant inter-regional difference was noted (P = 0·0143). In 18 % of breastfeeding women, thyroglobulin level was >40 ng/ml (median thyroglobulin 18·5 ng/ml). According to the WHO criteria, the investigated sample of pregnant and lactating women was iodine-deficient. Median UIC in school children was 119·8 µg/l (with significant inter-regional variation; P = 0·0000), which is consistent with iodine sufficiency. Ninety-four children (9·4 %) had UIC < 50 µg/l. CONCLUSIONS: Mandatory iodisation of household salt in Poland has led to a sustainable optimisation of iodine status in the general population. However, it has failed to assure adequate iodine nutrition during pregnancy and lactation.

Guidelines of Polish National Societies Diagnostics and Treatment of Thyroid Carcinoma. 2018 Update.

Significant advances have been made in thyroid can-cer research in recent years, therefore relevant clinical guidelines need to be updated. The current Polish guidelines "Diagnostics and Treatment of Thyroid Carcinoma" have been formulated at the "Thyroid Cancer and Other Malignancies of Endocrine Glands" conference held in Wisla in November 2015 [1].

Reference Values for TSH and Free Thyroid Hormones in Healthy Pregnant Women in Poland: A Prospective, Multicenter Study.

OBJECTIVES: The diagnosis and treatment of thyroid diseases in pregnant women remains a challenge. Various medical associations recommend establishing the reference intervals for thyroid hormones by a local laboratory. Considering differences within geophysical, socioeconomic conditions, and iodine prophylaxis in various populations, it is advisable to assess reference intervals for thyroid hormones specific to a region of residence. The objective was to assess trimester-specific reference intervals for TSH, fT3, and fT4 for pregnant women in the Polish population. METHODS AND RESULTS: We conducted a prospective study in 4 centers representing different regions of Poland (Krakow, Warsaw, Poznan, and Bialystok). Our study included consecutive, healthy pregnant women (172 patients), with an age range of 27-47 years. All women had a negative history for thyroid diseases, normal thyroid peroxidase antibody levels, and proper iodine prophylaxis. All newborns had TSH levels in the appropriate reference range. Serum TSH, fT3, fT4, and thyroid-peroxidase antibodies were measured in each trimester. The reference intervals were calculated using the percentile method, as recommended by the International Federation of Clinical Chemistry. The reference values calculated were 0.009-3.177, 0.05-3.442, and 0.11-3.53 mIU/L for TSH; 3.63-6.55, 3.29-5.45, and 3.1-5.37 pmol/L for fT3; and 11.99-21.89, 10.46-16.67, and 8.96-17.23 pmol/L for fT4 in consecutive trimesters of pregnancy. Reference intervals for pregnant women when compared to the general population showed a lower concentration of TSH in every trimester of pregnancy and lower fT4 in the 2nd and 3rd trimesters. CONCLUSIONS: Using appropriate trimester-specific reference intervals may improve care of pregnant women by preventing misdiagnosis and inadequate treatment.

99mTc Labeled Glucagon-Like Peptide-1-Analogue (99mTc-GLP1) Scintigraphy in the Management of Patients with Occult Insulinoma.

INTRODUCTION: The aim of this study was to assess the utility of [Lys40(Ahx-HYNIC-99mTc/EDDA)NH2]-exendin-4 scintigraphy in the management of patients with hypoglycemia, particularly in the detection of occult insulinoma. MATERIALS AND METHODS: Forty patients with hypoglycemia and increased/confusing results of serum insulin and C-peptide concentration and negative/inconclusive results of other imaging examinations were enrolled in the study. In all patients GLP-1 receptor imaging was performed to localise potential pancreatic lesions. RESULTS: Positive results of GLP-1 scintigraphy were observed in 28 patients. In 18 patients postsurgical histopathological examination confirmed diagnosis of insulinoma. Two patients had contraindications to the surgery, one patient did not want to be operated. One patient, who presented with postprandial hypoglycemia, with positive result of GLP-1 imaging was not qualified for surgery and is in the observational group. Eight patients were lost for follow up, among them 6 patients with positive GLP-1 scintigraphy result. One patient with negative scintigraphy was diagnosed with malignant insulinoma. In two patients with negative scintigraphy Munchausen syndrome was diagnosed (patients were taking insulin). Other seven patients with negative results of 99mTcGLP-1 scintigraphy and postprandial hypoglycemia with C-peptide and insulin levels within the limits of normal ranges are in the observational group. We would like to mention that 99mTc-GLP1-SPECT/CT was also performed in 3 pts with nesidioblastosis (revealing diffuse tracer uptake in two and a focal lesion in one case) and in two patients with malignant insulinoma (with the a focal uptake in the localization of a removed pancreatic headin one case and negative GLP-1 1 scintigraphy in the other patient). CONCLUSIONS: 99mTc-GLP1-SPECT/CT could be helpful examination in the management of patients with hypoglycemia enabling proper localization of the pancreatic lesion and effective surgical treatment. This imaging technique may eliminate the need to perform invasive procedures in case of occult insulinoma.

Diagnostics and Treatment of Thyroid Carcinoma.

Revised Guidelines of Polish National Societies Prepared on the initiative of the Polish Group for Endocrine Tumours approved in their final version between November 16th and 28th, 2015 by the Scientific Committee of the V Conference "Thyroid Cancer and other malignancies of endocrine glands" organised between November 14th and 17th, 2015 in Wisla, Poland; called by the following Societies: Polish Endocrine Society, Polish Society of Oncology, Polish Thyroid Association, Polish Society of Pathologists, Society of Polish Surgeons, Polish Society of Surgical Oncology, Polish Society of Clinical Oncology, Polish Society of Radiation Oncology, Polish Society of Nuclear Medicine, Polish Society of Paediatric Endocrinology, Polish Society of Paediatric Surgeons, Polish Society of Ultrasonography Gliwice-Wisla, 2015 DECLARATION: These recommendations are created by the group of delegates of the National Societies, which declare their willingness to participate in the preparation of the revised version of the Polish Guidelines. The members of the Working Group have been chosen from the specialists involved in medical care of patients with thyroid carcinoma. Directly before the preparation of the Polish national recommendations the American Thyroid Association (ATA) published its own guidelines together with a wide comment fulfilling evidence-based medicine (EBM) criteria. ATA Guidelines are consistent with National Comprehensive Cancer Network (NCCN) Recommendation. According to the members of the Working Group, it is necessary to adapt them to both the specific Polish epidemiological situation as well as to the rules referring to the Polish health system. Therefore, the Polish recommendations constitute a consensus of the experts' group, based on ATA information. The experts analysed previous Polish Guidelines, published in 2010, and other available data, and after discussion summed up the results in the form of these guidelines. It should be added that Part II, which constitutes a pathological part, has been available at the website of the Polish Society of Pathologists for acceptance of the members of the Society, and no essential comments have been proposed. The Members of the Group decided that a subgroup elected from among them would update the Guidelines, according to EBM rules, every year. The Revised Guidelines should help physicians to make reasonable choices in their daily practice; however, the final decision concerning an individual patient should be made by the caring physician responsible for treatment, or optimally by a therapeutic tumour board together with the patient, and should take into consideration the patient's health condition. It should be emphasised that the recommendations may not constitute a strict standard of clinical management imposed on medical staff. The data from clinical trials concerning numerous clinical situations are scarce. In such moments the opinion of the management may differ from the recommendations after considering possible benefits and disadvantages for the patient.

Laparoscopic adrenalectomy for pheochromocytoma is more difficult compared to other adrenal tumors.

INTRODUCTION: Laparoscopic adrenalectomy is the gold standard for the treatment of benign adrenal tumors. However, some authors raise the problem of differences in surgery for pheochromocytoma in comparison to other lesions. AIM: To compare laparoscopic adrenalectomy for pheochromocytoma and for other tumors. MATERIAL AND METHODS: Four hundred and thirty-seven patients with adrenal tumors were included in the retrospective analysis. Patients were divided into two groups: 1 (124 patients treated for pheochromocytoma) and 2 (313 patients with other types of tumor). The two groups were compared with respect to mean operative time, intraoperative blood loss, conversion rate, complication rate and the relationship of tumor size with operative time. RESULTS: The mean operative time in group 1 was 91 min, and in group 2 it was 82 min (p = 0.016). In both groups 1 and 2, tumor size correlated with operative time (p < 0.0001 and p = 0.0003, respectively). The mean blood loss in groups 1 and 2 was 117 ml and 54 ml, respectively (p = 0.0011). The complication rate in groups 1 and 2 was 4% and 4.2%, respectively (p = 0.9542). In groups 1 and 2, conversion was necessary in 2 (1.6%) and 5 (1.6%) cases, respectively (p = 0.9925). CONCLUSIONS: Longer operative time and higher blood loss after laparoscopic adrenalectomy for pheochromocytoma indicate its greater difficulty. However, despite these drawbacks, minimally invasive surgery still seems to be an effective and safe method.

Unraveling the functions of type II-prohibitins in Arabidopsis mitochondria.

In yeast and mammals, prohibitins (PHBs) are considered as structural proteins that form a scaffold-like structure for interacting with a set of proteins involved in various processes occurring in the mitochondria. The role of PHB in plant mitochondria is poorly understood. In the study, the model organism Arabidopsis thaliana was used to identify the possible roles of type-II PHBs (homologs of yeast Phb2p) in plant mitochondria. The obtained results suggest that the plant PHB complex participates in the assembly of multisubunit complexes; namely, respiratory complex I and enzymatic complexes carrying lipoic acid as a cofactor (pyruvate dehydrogenase, 2-oxoglutarate dehydrogenase and glycine decarboxylase). PHBs physically interact with subunits of these complexes. Knockout of two Arabidopsis type-II prohibitins (AtPHB2 and AtPHB6) results in a decreased abundance of these complexes along with a reduction in mitochondrial acyl carrier proteins. Also, the absence of AtPHB2 and AtPHB6 influences the expression of the mitochondrial genome and leads to the activation of alternative respiratory pathways, namely alternative oxidase and external NADH-dependent alternative dehydrogenases.

Are RECIST criteria sufficient to assess response to therapy in neuroendocrine tumors?

MATERIAL AND METHODS: Within the group of 47 patients treated with peptide receptor radionuclide therapy (PRRT), four patients were chosen: three with inoperable tumors without liver metastases and one with two lesions in the pancreas and metastases. RESULTS: In all patients, after PRRT, the changes in the sum of the longest diameters of tumors were between -1% and -21%, resulting in stable disease reported [strict Response Evaluation Criteria in Solid Tumors (RECIST)]. But the measurements of tumor volume and attenuation in computed tomography and the tumor to nontumor ratio in somatostatin receptor scintigraphy resulted in different response assessments. CONCLUSIONS: The RECIST standard may be not sufficient to properly assess the therapy response in patients with neuroendocrine tumors.

Reference values for thyroid volume established by ultrasound in Polish schoolchildren.

INTRODUCTION: A frequency in excess of 5% of goitre in children is an approved WHO marker of iodine deficiency. As thyroid ultrasound remains the main method of thyroid volume (TV) assessment, the choice of adequate normative values is important for the proper interpretation of epidemiologic data. There is disagreement as to whether local or international normative values should be used. The aim of this study was to establish Polish local TV normative values in children aged 6-12 years. MATERIAL AND METHODS: The study was carried out in a group of 642 children aged 6-12 years (312 girls and 330 boys) living in the Polish seaside area with a proven history of best iodine supply. Inclusion criteria were: iodine concentration in casual morning urine samples above 100 µg/L, no goitre on palpation, no pathological findings on thyroid US, no history of thyroid disorders, no treatment affecting thyroid function, and written informed consent from the child's parents. TV was measured ultrasonographically with a 7.5 MHz linear transducer. Urinary iodine concentration (UIC) was measured in urine spot samples using the Sandell-Kolthoff method. RESULTS: Median UIC ranged according to age from 126.6 to 155.1 µg/L in girls, and from 132.23 to 157.62 µg/L in boys. TVs at P97 were: 3.96, 4.23, 4.33, 5.44, 6.07, 9.5, and 10.9 for girls and 3.99, 4.2, 4.79, 6.61, 7.38, 7.89, and 9.35 for boys. They were lower than the 1997 WHO normative values but higher than the 2004 reference currently adopted by the WHO. CONCLUSIONS: The obtained results may be adopted as normative TV values for Polish children.

Efficacy and safety of 90Y-DOTATATE therapy in neuroendocrine tumours.

BACKGROUND: The aim of this study was to assess the efficacy and toxicity of peptide receptor radionuclide therapy (PRRT) with the use of the high affinity somatostatin receptor subtype 2 analogue, (90)Y labelled Tyr3-octreotate, ((90)Y-DOTATATE) in neuroendocrine tumours (NETs). MATERIAL AND METHODS: 46 patients with disseminated or non-operable NET were enrolled in this study. The (90)Y-DOTATATE therapeutic activity was calculated per total body surface area up to a total of 7.4 GBq/m(2) administered in three to five cycles, repeated every four to nine weeks. Before and after the therapy, blood tests for haematology, kidney and liver function, and chromogranin A were performed. RESULTS: Out of 46 (90)Y-DOTATATE treated patients, one died before completing the therapy and 16 died after completing the therapy, among them one due to myocardial infarction. After 12 month follow-up, stabilisation of disease was observed in 47%, partial remission in 31%, and progression in 9% of the 45 patients who completed the therapy. Five patients died before completion of 12 months of follow-up. One of the patients died due to myocardial infarction. In one case, the information after 12 months is incomplete. The progression free survival was 37.4 months. During 12 months follow-up, transient decrease of PLT, WBC and haemoglobin values was observed. A transient increase of creatinine level (within normal ranges) and decrease of GFR values were found. CONCLUSIONS: NETs (90)Y-DOTATATE therapy results in symptomatic relief and tumour mass reduction. The mild critical organ toxicity does not limit the PRRT of NETs.

[Management of thyroid diseases during pregnancy]. / Postepowanie w chorobach tarczycy u kobiet w ciazy.

The management of thyroid disorders during pregnancy is one of the most frequently disputed problems in modern endocrinology. It is widely known that thyroid dysfunction may result in subfertility, and, if inadequately treated during pregnancy, may cause obstetrical complications and influence fetal development. The 2007 Endocrine Society Practice Guideline endorsed with the participation of the Latino America Thyroid Association, the American Thyroid Association, the Asia and Oceania Thyroid Association and the European Thyroid Association, greatly contributed towards uniformity of the management of thyroid disorders during pregnancy and postpartum. Despite the tremendous progress in knowledge on the mutual influence of pregnancy and thyroid in health and disease, there are still important areas of uncertainty. There have been at least a few important studies published in the last 3 years, which influenced the thyroidal care of the expecting mother. It should also be remembered that guidelines may not always be universally applied in all populations with different ethnical, socio-economical, nutritional (including iodine intake) background or exposed to different iodine prophylaxis models. The Task Force for development of guidelines for thyroid dysfunction management in pregnant women was established in 2008. The expert group has recognized the following tasks: development of the coherent model of the management of thyroid dysfunction in pregnant women, identification of the group of women at risk of thyroid dysfunction, who may require endocrine care in the preconception period, during pregnancy and postpartum - that is in other words, the development of Polish recommendations for targeted thyroid disorder case finding during pregnancy, and the development of Polish trimester-specific reference values of thyroid hormones. Comprehensive Polish guidelines developed by the Task Force are to systematize the management of the thyroid disorders in pregnant women in Poland.

[The risk assessment of lungs' apices injury in patients after radioactive iodine therapy due to hyperthyroidism]. / Ocena ryzyka uszkodzenia szczytów pluc u pacjentów po leczeniu radiojodem z powodu nadczynnosci tarczycy.

In the light of recent research data hypothesis on radioactive iodine therapy leading to inflammatory reaction in lungs' apices has lately gained wider acceptance among pulmonologists. The study published of late showed that in one female patient previously treated with radioiodine due to toxic multinodular goiter 99mTc-Tectreotide uptake was found in the lung apex. The aim of study was evaluation of the risk assessment of inflammatory reaction in lungs' apices among patients treated with radioactive iodine due to hyperthyroidism. The study was carried out in 15 female patients (mean age 75 years +/-10 years) with large toxic multinodular goiter and fine needle aspiration biopsy negative for malignancy and who did not qualify for thyreoidectomy. Mean radioactive iodine therapeutic dose used in the study was 940 MBq. Chest SPECT scan (99mTc-Tectreotide) was performed one year after radioiodine therapy. Trace uptake in lung apex has been noted only in one patient. In 14 out of 15 patients in the study tectreotide uptake has not been found in any lungs' apices. All of 15 patients became euthyroid six months after radioactive iodine therapy and had their thyroid gland shrinked. No significant correlation between inflammatory reaction in lung apices and radioiodine therapy in patients with hyperthyroidism and large multinodular goiter was found in conducted study.

Graves' ophthalmopathy in patients treated with radioiodine 131-I.

BACKGROUND: Radioiodine treatment of hyperthyroidism in Graves' disease patients may cause or aggravate the course of ophthalmopathy (GO). We evaluated the activity and severity of ophthalmopathy in patients who acquired GO following radioiodine therapy. MATERIAL AND METHODS: Between 2003 and 2005, 763 Graves' disease patients (50.9% of the total number of 1,500 patients referred to our Department) were treated with radioiodine 131-I. This treatment was only offered to patients with NOSPECS score < 3 and CAS < 3. Following their radioiodine treatment, in 39 patients (5.1% of all Graves' disease patients), mean age 53.9 ± 11.6 years, onset of GO was observed within 12 months of post-treatment follow-up. RESULTS: In 39 patients who developed GO after 131-I treatment, median values of hTRAb and NOSPECS score were 15.4 U/L (IQR = 22.9) and 5.0 points (max = 8.0; min = 2.0), respectively, at the time of their GO onset. Patients were qualified for methylprednisolone pulse therapy (8.0 g) and subsequent radiotherapy (20 Gy). Median concentration of hTRAb and NOSPECS score at one, six and 12 months post-GO therapy were: 10.0 U/L (IQR = 21.6) and 4.0 (max = 6.0; min = 1.0); 7.5 U/L (IQR = 1.1) and 3.0 (max = 10.0; min = 0.0); 2.8 U/L (IQR = 8.3) and 3.0 (max = 6.0; min = 0.0), respectively. A positive association between hTRAb and NOSPECS score was observed over the control period. IL-6 and IL-2 concentration prior to and one month after treatment remained elevated. CONCLUSIONS: Since 5% of our Graves' disease patients developed severe GO following radioiodine treatment, an association between radioiodine therapy and severe ophthalmopathy cannot be excluded. IL-6 and IL-2 concentrations remained elevated after glucocorticoid therapy.

[Fusion SPECT/CT in clinical practice]. / Fuzja SPECT/TK w praktyce klinicznej.

Fusion consists in a combination of images obtained using different diagnostic techniques, usually functional (SPECT, PET) and structural (CT, MR) imaging. It may be performed as a software fusion of images obtained not the same time by different devices or as a hardware fusion of images obtained the same time using as a hybrid system enabling both the functional and structural imaging (SPECT/CT, PET/CT). Fusion enables precise anatomical location of lesions detected by SPECT, functional verification of lesions found by CT. It is a useful tool in the assessment of effectiveness and dosimetry for radioisotopic therapy. Additionally fusion of functional and structural examinations reduces diagnostic difficulties appearing in independent interpretation. In spite of inconveniences resulting from technical aspects of software fusion (positioning differences, spontaneous movements of internal organs) it is more and more commonly used in clinical practice in centers not possessing hybrid systems.

Biokinetics of ¹³¹I after endogenous and exogenous stimulation of TSH in patients with DTC.

BACKGROUND: The effective radioiodine treatment of patients with DTC is possible only after raising the TSH value over 30 µUI/ml. This effect might be obtained by either endogenous or exogenous stimulation. The aim of this study was to evaluate differences in (131)I biokinetics of selected regions of interest (ROIs) in cases of endogenous and exogenous stimulation. MATERIAL AND METHODS: Two groups of 50 patients were enrolled in the study. All patients were treated with 3.7 GBq of ¹³¹I; the first group after thyroid hormone withdrawal (THW), the second group after rhTSH administration (rhTSH). On the basis of post-treatment images, the uptake ratios over selected ROIs (thyroid remnants, mediastinum, liver, stomach, abdomen, and whole-body) were compared between groups. RESULTS: In the case of uptake over the whole-body and the liver, statistically significant higher values were received for the THW group. For the remaining regions, the differences between groups were statistically insignificant, but uptake ratios in the rhTSH group were generally numerically lower compared to the THW group. CONCLUSIONS: The revealed difference in radioiodine biokinetics after thyroid hormone withdrawal or administration of recombinant human TSH may influence many important aspects of patients with DTC treatment, such as the choice of proper therapeutic scheme, the cost of therapy, and the dose assessment.