Thyroid Remnant Research Articles

Effect of Thyroid Remnant Volume on the Risk of Hypothyroidism After Hemithyroidectomy: A Prospective Study.

Hypothyroidism is a common sequel after a hemithyroidectomy. Although various risk factors leading to hypothyroidism have been reported, the effect of the contralateral lobe's volume has been understudied. This study aimed to examine the association between the preoperative contralateral lobe's volume and the risk of postoperative hypothyroidism. During a 2-year period, 150 eligible patients undergoing a hemithyroidectomy were evaluated. The volume of the contralateral nonexcised lobe was estimated preoperatively by independent assessors on ultrasonography using the following formula: width (in cm) × depth (in cm) × length (in cm) × (π/6), adjusted for the body surface area (BSA). Postoperative hypothyroidism was defined as serum thyroid-stimulating hormone (TSH) exceeding 4.78 mIU/L. Any significant characteristics in the univariate analysis were entered into the multivariate analysis to determine independent factors. After a mean follow-up period of 53.5 ± 9.4 months, 44 patients (29.3 %) experienced postoperative hypothyroidism, and 10 of these patients required thyroxine replacement. Hypothyroidism was associated with a higher preoperative TSH level (p < 0.001), a smaller BSA-adjusted volume (p < 0.001), fewer ipsilateral nodules (p = 0.037), and the presence of thyroiditis (p = 0.050). After adjustment for thyroiditis, preoperative TSH (p < 0.001), number of ipsilateral nodules (p = 0.048), and BSA-adjusted volume (p < 0.001) were independent factors for hypothyroidism. Patients with a BSA-adjusted volume smaller than 3.2 ml had a threefold greater hypothyroidism risk than those with a BSA-adjusted volume of 3.2 ml or more (p < 0.001). A significant inverse association between the preoperative contralateral lobe's volume and hypothyroidism risk was observed after hemithyroidectomy. Together with a higher preoperative TSH level and fewer ipsilateral nodules, a smaller BSA-adjusted volume measured by preoperative ultrasonography independently predicted hypothyroidism.

Imaging of spatially extended hot spots with coded apertures for intra-operative nuclear medicine applications

Coded aperture imaging transcends planar imaging with conventional collimators in efficiency and Field of View (FOV). We present experimental results for the detection of 141 keV and 122 keV γ-photons emitted by uniformly extended 99mTc and 57Co hot-spots along with simulations of uniformly and normally extended 99mTc hot-spots. These results prove that the method can be used for intra-operative imaging of radio-traced sentinel nodes and thyroid remnants. The study is performed using a setup of two gamma cameras, each consisting of a coded-aperture (or mask) of Modified Uniformly Redundant Array (MURA) of rank 19 positioned on top of a CdTe detector. The detector pixel pitch is 350 μm and its active area is 4.4 × 4.4 cm2, while the mask element size is 1.7 mm. The detectable photon energy ranges from 15 keV up to 200 keV with an energy resolution of 3–4 keV FWHM. Triangulation is exploited to estimate the 3D spatial coordinates of the radioactive spots within the system FOV. Two extended sources, with uniform distributed activity (11 and 24 mm in diameter, respectively), positioned at 16 cm from the system and with 3 cm distance between their centers, can be resolved and localized with accuracy better than 5%. The results indicate that the estimated positions of spatially extended sources lay within their volume size and that neighboring sources, even with a low level of radioactivity, such as 30 MBq, can be clearly distinguished with an acquisition time about 3 seconds.

Thyroid cancer in lingual thyroid and thyroglossal duct cyst

Ectopy is the most common embryogenetic defect of the thyroid gland, representing between 48 and 61% of all thyroid dysgeneses. Persistence of thyroid tissue in the context of a thyroglossal duct remnant and lingual thyroid tissue are the most common defects. Although most cases of ectopic thyroid are asymptomatic, any disease affecting the thyroid may potentially involve the ectopic tissue, including malignancies. The prevalence of differentiated thyroid carcinoma in lingual thyroid and thyroglossal duct cyst is around 1% of patients affected with the above thyroid ectopies. We here review the current literature concerning primary thyroid carcinomas originating from thyroid tissue on thyroglossal duct cysts and lingual thyroid.

Thyroid cancer in lingual thyroid and thyroglossal duct cyst

Ectopy is the most common embryogenetic defect of the thyroid gland, representing between 48 and 61% of all thyroid dysgeneses. Persistence of thyroid tissue in the context of a thyroglossal duct remnant and lingual thyroid tissue are the most common defects. Although most cases of ectopic thyroid are asymptomatic, any disease affecting the thyroid may potentially involve the ectopic tissue, including malignancies. The prevalence of differentiated thyroid carcinoma in lingual thyroid and thyroglossal duct cyst is around 1% of patients affected with the above thyroid ectopies. We here review the current literature concerning primary thyroid carcinomas originating from thyroid tissue on thyroglossal duct cysts and lingual thyroid.

Toxoplasmosis lymphadenitis of parotid gland concurrent with papillary thyroid carcinoma

We report a case of toxoplasmosis lymphadenitis simulating a parotid mass concurrent with a papillary thyroid carcinoma. A 55-year-old male presented symptomless masses in the left lower neck and right preauricular region for 2 months. Physical examination revealed a 2 cm × 2-cm firm mass in the right parotid region and a 3-cm diameter soft mass in the left lobe of thyroid gland. Computed tomography confirmed a lobulated nodule, embedded in the right parotid gland, and; a left thyroid nodule, which resembled a papillary thyroid carcinoma. Fine-needle aspiration (FNA) of the left thyroid lobe suggested a papillary thyroid carcinoma. A radical thyroidectomy, central neck lymph node dissection, and right superficial parotidectomy were performed. Histopathological examination of the surgical specimen supported the diagnosis of a papillary carcinoma of the left thyroid lobe and toxoplasmosis lymphadenitis in the right parotid gland. Specific serum immunoglobulin tests suggested a current infection with Toxoplasma gondii. The patient was administered pyrimethamine and sulfadiazine for 4 weeks and underwent I-131 ablation for the functional thyroid remnants in the anterior neck. At a 16-month follow-up, the patient was clinically fit and recurrence free. This case highlights the importance of remaining clinically vigilant to differentiate an unusual metastatic carcinoma from inflammation of the parotid gland. A consideration of toxoplasmosis lymphadenitis by thorough history taking, appropriate serologic tests, and selective use of FNA may provide combined preoperative information for differential diagnosis of a parotid mass and help avoid an unnecessary surgical procedure.

Serial stimulated thyroglobulin measurements are more specific for detecting distant metastatic differentiated thyroid cancer before radioiodine therapy

ObjectivePreablative stimulated thyroglobulin (ps-Tg) has the potential to be used in identifying distant metastatic differentiated thyroid carcinoma (DM-DTC), but its single level can be affected by remnant thyroid tissue and thyrotropin (TSH). The objective of this retrospective study was to evaluate the value of serial ps-Tg measurements in identifying DM-DTC specifically.MethodsA total of 317 DTC patients with serial measurements of ps-Tg, TSH and anti-Tg antibody were divided into M1 (n=72) and M0 (n=245) according to the presence of distant metastasis (DM) or not. The initial ps-Tg measurement, with a corresponding TSH exceeding 30 μIU/mL, was marked as Tg1, and ps-Tg measured right before radioactive iodine (RAI) therapy was defined as Tg2, with a median interval of 8 days. ΔTg denotes Tg2–Tg1, and ΔTSH denotes TSH2–TSH1. Tg1, Tg2, ΔTg, and ΔTg/ΔTSH were tested for efficacy in identifying DM-DTC using receiver operating characteristic (ROC) curve analysis, and further compared with chest computed tomography (CT) and posttreatment whole-body RAI scan (RxWBS).ResultsCompared with single ps-Tg measurement (Tg1 or Tg2), both ΔTg and ΔTg/ΔTSH were more narrowly distributed around zero in the M0 group, which made their distribution in the M1 group more distinguished in a relatively dispersed way. ΔTg/ΔTSH manifested a higher accuracy (88.64%) and specificity (90.20%) in identifying DM-DTC than Tg1 or Tg2 measurements, with a much higher specificity than chest CT (90.20% vs. 66.00%) and a much higher sensitivity than RxWBS (83.33% vs. 61.11%). ConclusionsSerial ps-Tg measurements even over as short an interval as 8 days hold incremental value in identifying DM-DTC. ΔTg/ΔTSH is a specific early biochemical marker for DM-DTC.

Low-dose versus high-dose radioactive iodine ablation of differentiated thyroid carcinoma: a prospective randomized study

Purpose: Following total thyroidectomy of differentiated thyroid carcinoma (DTC), some patients are ablated with radioactive iodine I-131 (RAI). We compare the success of ablation with 30 millicurie (mCi) versus 80 mCi. Methods: We randomized the patients to 30 mCi or 80 mCi RAI after surgery. T1-T3, N0-N1, M0 tumors were included (based on the AJCC 7th edition). Pre-ablation baseline serum thyroglobulin (sTg), and thyroglobulin antibody (Tg Ab) were performed. Six months post-ablation successful thyroid ablation was defined as a negative whole body scan (WBS) and undetectable sTg. Results: Out of 50 patients with DTC, 45 patients fulfilled the eligibility criteria. Total thyroidectomy was performed in 27/ 45 (60%). 26/45 (57.8%) of patients received 30 mCi while 19/45 (42.2%) patients received 80 mCi. The median age was 37 and 36.5 years in the arms 80 and 30 mCi respectively. Papillary carcinoma predominated in 42/45 (93.3%) of patients. T2 tumors predominated in 10/19 (52.6%), and 15/26 (57.7%) of the 80 and 30 mCi arms respectively. According to the American Thyroid Association (ATA) risk classification, all of the patients had low risk disease. Success of ablation was achieved in 15/19 (78.9%), and in 15/26 (57. 7%) of the arms 80 and 30 mCi respectively. No patients developed distant metastases in both arms. The patients who received 80 mCi had longer hospital isolation than the 30 mCi arm (p 0.008). 6/26 (23.1%) patients in the 30 mCi arm were isolated for 2-4 days, whereas all the 80 mCi arm patients were isolated for 3-5 days. Conclusion: Both 80 mCi and 30 mCi RAI have similar success rate in the ablation of thyroid remnant of low risk DTC patients. The low dose is associated with fewer side effects, shorter hospital admission duration, and is less expensive in low risk DTC patients.

Outcome of radioiodine therapy in patients with papillary thyroid carcinoma concurrent with Hashimoto′s thyroiditis

Objective To evaluate the impact of low-dose 131I therapy and high-dose 131I therapy on the clinical outcome in PTC patients coexisting with Hashimoto′s thyroiditis (HT). Methods A total of 140 non-distant metastatic PTC patients (16 males, 124 females, age range: 16-66 years) from July 2010 to December 2014 were enrolled in this retrospective study. Patients concurrent with HT (n=84, group A) were divided into low-dose group (1 110 MBq, n=56, group A1) and high-dose group (5 550 MBq, n=28, group A2) according to 131I ablation dose. Patients without HT (n=56) were enrolled as control group (group B), and received 1 110 MBq of 131I. The thyroid remnant ablation outcome was evaluated according to 131I diagnostic whole-body scan (Dx-WBS), neck ultrasonography (US), serum Tg and TgAb level 6-8 months after 131I ablation therapy. The successful ablation rates were compared by χ2 test. Kruskal-Wallis rank sum test was also used. Results There were no significant differences among the 3 groups in terms of both clinicopathological features and postoperative remnant thyroid (H: 0.203-2.944, χ2: 0.271-0.970, all P>0.05). When negative Dx-WBS and US were deemed as successful ablation criterion, complete ablation rate was found significantly more in group B (94.6%, 53/56) than that in group A1 (82.1%, 46/56; χ2=4.264, P 0.05). When combining negative sTg (sTg 0.05), and no difference was observed between group A2 (12/15) and group A1 (χ2=1.320, P>0.05). Conclusion Non-distant metastatic PTC patients coexisting with HT has undesirable 131I ablation outcome compared with those without HT, increasing 131I dose is unhelpful to enhance efficiency of remnant ablation for PTC patients with HT. Key words: Thyroid neoplasms; Hashimoto disease; Radiotherapy; Iodine radioisotopes; Treatment outcome

Iodine-131: An Effective Method for Treating Lymph Node Metastases of Differentiated Thyroid Cancer.

BackgroundThe aim of this study was to assess the efficacy of radioactive iodine-131 (131I) therapy for lymph node metastasis of differentiated thyroid cancer (DTC) and to identify influential factors using univariate and multivariate analyses to determine if identified factors influence the efficacy of treatment.Material/MethodsThis study included a retrospective review of 218 patients with histologically proven DTC in the post-operation stage. After thyroid tissue remnants were eliminated with 131I therapy, patients’ lymph node status was confirmed by ultrasound and by 131I whole body scan regarding lymph node metastasis, and then patients were treated with 131I as appropriate. The treatment efficacy was assessed and possible influencing factors were identified using univariate and multivariate analyses.ResultsThe total effective rate of 131I therapy was 88.07% (including a cure rate of 20.64% and an improvement rate of 67.43%). The non-effective rate was 11.93%. Of the total 406 lymph nodes of 218 patients, 319 lymph nodes (78.57%) were judged to be effectively cured, including 133 (32.75%) lymph nodes that were totally eliminated and 186 (45.82%) lymph nodes that shrank. Eighty-seven (21.43%) of the 406 lymph nodes had no obvious change. No lymph nodes were found to be in a continuously enlarging state. Distant metastasis, size of lymph node, human serum thyroglobulin (HTG) level, and condition of thyroid remnants ablation were identified as the independent factors influencing the efficacy of treatment using univariate and multivariate analyses.ConclusionsThe use of 131I is a promising treatment for lymph node metastasis of DCT. Distant metastasis, size of lymph nodes, HTG level, and condition of thyroid remnant ablation were independent factors influencing the treatment efficacy.

Application of ultrasensitive thyroglobulin assays in the follow-up of differentiated thyroid carcinoma

DTC is the most common endocrine carcinoma and its routine treatment consists of total thyroidectomy and 131I thyroid remnant ablation. Currently, standard follow-up for DTC comprises Tg measurement and neck ultrasound as well as an additional radioiodine scan when indicated. As thyroid cells are assumed to be the only source of Tg in serum, circulating Tg serves as an excellent marker of persistent or recurrent disease in DTC follow-up. With the development of highly sensitive Tg assays, now it is possible to detect very low Tg concentrations which reflect minimal amounts of thyroid tissue without the need for TSH stimulation. This review is to introduce clinical implications of highly sensitive Tg assays. Key words: Thyroid neoplasms; Thyroglobulin; Trends

Low- and high-dose radioiodine therapy for low-/intermediate-risk differentiated thyroid cancer: a preliminary clinical trial.

To compare the ablation results, therapeutic responses and adverse reactions between a low dose (1.1GBq) or high dose (3.7GBq) of 131I in low-/intermediate-risk differentiated thyroid cancer (DTC) patients. The factors influencing the ablation result and therapeutic response were also analyzed. The researchers used a random number table to randomly assign the enrolled patients to the low-dose group or high-dose group at a 1:1 ratio, and assessment of ablation result, therapeutic response, and adverse reactionsevaluated6±3months after therapy. A total of 140 patients were enrolled in the study through October 2014-June 2015. Until February 2016, 132 patients completed the trial. 99 patients were re-examined under thyroid-stimulating hormone (TSH) stimulation 3-9months after 131I therapy. For the low-dose and high-dose groups, the success rates of ablation were 52.7% (29/55) and 59.1% (26/44), respectively. The ablation results did not differ significantly between the two groups (P=0.548). One hundred and thirty two patients were re-examined 2-9months after 131I therapy. The low-dose group had an excellent response rate of~80% (53/66), an indeterminate response rate of~20% (13/66), and no cases with a biochemical incomplete response. The high-dose group had an excellent response rate of~85% (56/66), an indeterminate response rate of~11% (7/66), and a biochemical incomplete response rate of~4% (3/66). No significant differences in the therapeutic response were observed between the two groups (P=0.087). Patients in stage N1b had a significantly lower success rate of ablation than those in stage N0 (P=0.000). The success rate of ablation increased significantly with lower thyroglobulin (Tg) levels (P=0.000). A pre-treatment Tg level was significantly associated with a higher excellent response rate (P=0.002). Pre-treatment-stimulated Tg of 0.47 and 3.09μg/L were identified as cut-off values for predicting the ablation result and therapeutic response, respectively. The incidences of adverse reactions were 18% (12/66) and 39% (26/66) in the low-dose and high-dose groups, respectively, and this difference between the two groups was significant (P=0.007). The result of thyroid remnant ablation and the response to therapy did not differ significantly between the two groups. The low-dose group had a lower incidence of adverse reactions than the high-dose group. N1b and pre-treatment-stimulated Tg were factors influencing the ablation result, whereas pre-treatment-stimulated Tg was a factor influencing the therapeutic response. Pre-treatment-stimulated Tg of 0.47 and 3.09μg/L were identified as cut-off values for predicting the ablation result and therapeutic response, respectively. The study protocol was approved by the Clinical Trials and Biomedical Ethics Committee of our hospital and registered on the Chinese Clinical Trial Registry under the registration number ChiCTR-IOR-15006139.

Differentiated thyroid carcinoma: Incremental diagnostic value of 131I SPECT/CT over planar whole body scan after radioiodine therapy.

The purpose of this prospective study was to determine the incremental diagnostic value of single photon emission computed tomography/computed tomography with iodine-131 over planar whole body scan in the staging of patients with differentiated thyroid carcinoma. A total of 365 patients (270 female, 95 male) with differentiated thyroid carcinoma were treated with radioiodine therapy for thyroid remnant ablation with radical intent after thyroidectomy between January 2013 and November 2014. In addition to planar whole body scan, single photon emission computed tomography/computed tomography of neck and chest were performed. Each radioactive focus at whole body scan was classified as positive or equivocal with respect of specific territories: thyroid bed, cervical lymph nodes and distant metastases.Whole-body scan detected focal uptake in 353 patients and no uptake in 12. The location was considered equivocal in 100. Single photon emission computed tomography/computed tomography detected focal uptake in 356 patients and no uptake in nine. In three patients with negative wholebody scan, single photon emission computed tomography/computed tomography provided information about residual activity in the thyroid bed. By single photon emission computed tomography/computed tomography the location was equivocal in 18 patients only. Single photon emission computed tomography/computed tomography was helpful in 82 out of 100 patients with equivocal findings by whole body scan allowing a correct identification of the uptake sites. In a great number of equivocal whole body scan, due to high remnant activity, single photon emission computed tomography/computed tomography was able to differentiate between thyroid remnant and lymph nodes uptake. In 22 out of 100 patients with doubtful whole body scan, single photon emission computed tomography/computed tomography correctly identified nodal or distant metastases, and in 2/100 patients, focal uptake classified as metastatic by whole body scan was reclassified as para-physiological by single photon emission computed tomography/computed tomography. The TNM classification changed in 13 out of 22 patients. Single photon emission computed tomography/computed tomography improves detection and localization of the iodine-131 uptake after thyroidectomy in patients with differentiated thyroid carcinoma and it is more accurate than whole body scan to evaluate lymph nodes and to identify and characterize distant metastases. Single photon emission computed tomography/computed tomography aids assessment of lower/upper stage in a significant number of patients with differentiated thyroid carcinoma and it can affect therapy decision-making and patient management.

Cytogenetic Damage in the Peripheral Blood Lymphocytes of Thyroid Cancer Patients during Pre and Post 131I Therapy

Aim: 131 I therapy is widely used in patients of differentiated thyroid carcinoma for the ablation of remnant thyroid tissue post thyroidectomy as well as metastasis. These patients are in hypothyroid state with consequent reduction in renal clearance of 131 I thereby increasing the extent of whole body exposure. Present study was carried out to assess the DNA damage due to the presence of thyroid carcinoma as well as posttherapeutic 131 I exposure at 72h by measuring micronuclei (MN) frequency in peripheral blood lymphocytes (PBLs) in patients of differentiated thyroid cancer. Methods: The study group consisted of 25 differentiated thyroid carcinoma patients and 35 healthy donors. The blood samples of the patients were collected pre and post 131 I therapy (1.6-9.3 GBq) and processed for PBL MN frequency by cytokinesis-block MN assay. Results: The mean basal MN frequency was significantly high in thyroid cancer patients as compared to the healthy donors (p< 0.001). 131 I exposed patients demonstrated significant increase in the MN frequency at 72h after therapeutic 131 I exposure compared to their basal MN index ( p<0.001 ). However the percent increase in MN frequency post 131 I therapy did not show any correlation with administered dose in thyroid cancer patients. Conclusion: The study has revealed significant DNA damage in PBLs as indicated by increased PBL MN frequency post 131 I therapy. However marked individual variations were observed in the DNA damage response to 131 I therapy.

Parameters Influencing Curative Effect of 131I Therapy on Pediatric Differentiated Thyroid Carcinoma: A Retrospective Study.

BACKGROUND This study aimed to investigate the parameters influencing the effectiveness of first 131I thyroid remnant ablation and then 131I treatment of metastatic lesions in children and adolescents with differentiated thyroid carcinoma (DTC). MATERIAL AND METHODS A total of 88 children and adolescents with DTC were divided into 2 groups: 56 in the complete-ablation group and 32 in the incomplete-ablation group for the first 131I ablation; 32 in the incomplete-ablation group were further divided: 19 in the complete-remission group and 13 in the incomplete-remission group for subsequent 131I treatment of metastatic lesions. Influential parameters were analyzed using t test, t' test, rank-sum test, χ2-test, and Fisher exact test, and logistic regression analysis was performed. Radioactive iodine uptake (RAIU), lymph node metastases, and pulmonary metastases were selected as influential parameters. RESULTS After logistic regression analysis, RAIU, only lymph node metastases, and pulmonary metastasis were significantly associated with the complete-ablation rate. High levels of RAIU and serum thyroglobulin (Tg) were not conducive to disease remission after subsequent 131I treatment of metastatic lesions. The remission rate of patients with pulmonary metastasis was lower than the rate of patients with lymph node metastases or no metastases. CONCLUSIONS Results demonstrated that a high remission rate is associated with low postoperative RAIU and Tg. Lymph node metastasis and pulmonary metastasis reduce the complete-remission rate of first 131I ablation therapy. Pulmonary metastasis reduces the remission rate of subsequent 131I treatment. Also, 131I treatment for pediatric DTC with pulmonary metastasis achieved progression-free survival.

Absorbed dose estimation to family members of patients treated with radioiodine for thyroid cancer

Introduction Thyroid remnant ablation with radioiodine is a well-established treatment for patients with Differentiated Thyroid Carcinoma (DTC) following thyroidectomy. After 3–4 days of hospitalization, these patients return home, presenting a possible radiation hazard to their family members. Purpose This work aims at estimating the radiation burden to the cohabitants of DTC patients treated with radioiodine, after hospital release. Materials and methods 724 patients (183/541 men/women) suffering from DTC were treated with radioiodine activities ranging from 1850 to 9250MBq. Thyroid Hormone Withdrawal (THW) was applied in 305 patients (42.1%), whereas 419 (57.9%) patients were prepared with recombinant human TSH (rhTSH). Radioiodine T eff was calculated from dose rate measurements at 1 and 2 m from the patients, performed at regular time intervals throughout their hospitalization. All patients were discharged 3–4 days post-treatment and were provided with written and oral instructions about radiation protection precautions. Patients were grouped according to their family status and radiation doses to their cohabitants were estimated based on appropriate exposure scenarios. Results Mean radioiodine T eff was 15.3 h (range 1.9–37.5 h). T eff in the rhTSH group was lower than the THW group (14.5 h and 17.1 h respectively, p〈0.05). Mean absorbed doses to all family members were estimated to be well below the corresponding dose constraints. Maximum dose to any child was slightly above 0.5 mSv, whereas maximum dose to any non-relative co-traveller was Conclusion Provided necessary precautions are followed, radiation burden to the family members of DTC patients treated with radioiodine following thyroidectomy can be kept lower than the corresponding dose constraints.

Radioiodine therapy after recombinant human tsh administration or hormone withdrawal: Is there a difference in I-131 effective half-life?

Introduction The release of thyroidectomized patients treated with radioactive iodine I-131 from the treating facility is predominantly judged on the basis of the residual I-131 activity which is dictated by the effective half-life of I-131. Purpose To determine the effective half-life of I-131 (Teff1/2 in thyroidectomized patients subjected to radioiodine therapy after either recombinant human TSH administration or hormone therapy withdrawal. Materials and methods A series of 88 consecutive patients administered with I-131 following thyroidectomy was investigated. Recombinant human TSH has been administered in 32 patients (group A), while the rest 56 patients (group B) had been subjected to hormone therapy withdrawal. Measurements of the dose rate emitted by the patient at mid-thoracic height at a distance of 1 m were obtained 0, 6, 24 and 30 h after I-131 administration. The T1/2 was determined from the exponential fit of measured data. Data regarding age, sex, weight, height, diet, administered dose, volume of water drunk, and size of remnant thyroid tissue were recorded. Results The mean I-131 Teff1/2 was found 8.8 h for group A and 12.4 h for group B, with difference being statistically significantly (p Conclusion Administration of recombinant human TSH instead of hormone thyroid withdrawal prior to radioiodine therapy of thyroidectomized patients may enhance elimination rate of residual I-131 activity, and accelerate release from treating facility.

Variants and pitfalls on radioiodine scans in pediatric patients with differentiated thyroid carcinoma.

Potentially false-positive findings on radioiodine scans in children with differentiated thyroid carcinoma can mimic functioning thyroid tissue and functioning thyroid carcinomatous tissue. Such false-positive findings comprise variants and pitfalls that can vary slightly in children as compared with adults. To determine the patterns and frequency of these potential false-positive findings on radioiodine scans in children with differentiated thyroid carcinoma. We reviewed a total of 223 radioiodine scans from 53 pediatric patients (mean age 13.3years, 37 girls) with differentiated thyroid carcinoma. Focal or regional activity that likely did not represent functioning thyroid tissue or functioning thyroid carcinomatous tissue were categorized as variants or pitfalls. The final diagnosis was confirmed by reviewing the concurrent and follow-up clinical data, correlative ultrasonography, CT scanning, serum thyroglobulin and antithyroglobulin antibody levels. We calculated the frequency of these variants and pitfalls from diagnostic and post-therapy radioiodine scans. The most common variant on the radioiodine scans was the thymic activity (24/223, 10.8%) followed by the cardiac activity (8/223, 3.6%). Salivary contamination and star artifact, caused by prominent thyroid remnant, were the most important observed pitfalls. Variants and pitfalls that mimic functioning thyroid tissue or functioning thyroid carcinomatous tissue on radioiodine scan in children with differentiated thyroid carcinoma are not infrequent, but they decrease in frequency on successive radioiodine scans. Potential false-positive findings can be minimized with proper knowledge of the common variants and pitfalls in children and correlation with clinical, laboratory and imaging data.

Safety of Completion Thyroidectomy for Initially Misdiagnosed Thyroid Carcinoma.

IntroductionCompletion thyroidectomy is defined as the surgical removal of the remnant thyroid tissue following procedures of less than total or near-total thyroidectomy. Whether thyroid reoperations are associated with an increased complication risk is controversial.ObjectiveA retrospective analysis was done of patients undergoing completion thyroidectomy for cancer of the thyroid who had undergone surgery elsewhere for solitary thyroid nodule. The incidence of surgical complications in these patients after reoperation was investigated in this study.Material and methodsThe study included a total of 53 patients who had undergone thyroid lobectomy for a solitary nodule as initial surgery elsewhere and were referred to our institute for completion thyroidectomy when the histopathology revealed malignancy.ResultsThere were 53 patients, 43 females and 10 males. Their mean age was 34.7±12.12 years (range 19–65 years). After initial surgery, the histopathology revealed papillary carcinoma in 46 patients (86.8%), follicular carcinoma in 7 (13.2%). Fourteen out of 53 patients had recurrent laryngeal nerve palsy after initial surgery (26.4%). None of the patients had clinical hypocalcemia after the first surgery. One or more parathyroid glands were identified and preserved in 52 patients (98.1%) in the process of completion thyroidectomy. No patient had additional recurrent nerve injury at the second surgery. The mean serum calcium value preoperatively was 8.96±0.39 mg/dL, and six months after surgery serum calcium was 8.74±0.56 mg/dL. Mean follow-up was 18 months. Transient hypoparathyroidism occurred in 24.5% patients. Five patients were lost to follow-up. Permanent and symptomatic hyperparathyroidism occurred in eight patients (16.67%).ConclusionsCompletion thyroidectomy is a safe and appropriate option in the management of well-differentiated thyroid cancer. It removes disease on the ipsilateral and contralateral side of the thyroid and carries a low risk of recurrent laryngeal nerve damage, but a higher risk of permanent hypoparathyroidism.

Reappraisal of the indication for radioiodine thyroid ablation in differentiated thyroid cancer patients.

Radioactive iodine therapy is administered to patients with differentiated thyroid cancer (DTC) for eradication of thyroid remnant after total thyroidectomy or, in patients with metastatic disease, for curative or palliative treatment. In past years, thyroid remnant ablation was indicated in almost every patient with a diagnosis of DTC. Nowadays, careful revision of patients' outcome has introduced the concept of risk-based selection of patients candidate to thyroid remnant ablation. The present review aims to underline the indications for thyroid remnant ablation and to address methodologies to be employed.

Outcome of Well-Differentiated Thyroid Carcinoma Patients Receiving a Cumulative Doses of ? 600 mCi (22GBq) of I-131

Background: There is no maximum limit for cumulative dose of I-131 for persistent disease in well-differentiated thyroid carcinoma (DTC) patients. However, most remissions are obtained with cumulative activity equal to or lower than 600 mCi (22 GBq). On the other hand a significantly increased risk of leukemia and secondary cancers has been reported with high cumulative dose of I-131 (? 600 mCi). Above this cumulative activity further radioiodine therapy should be taken on an individualized basis.Objective: The aim of the study was to see the outcome of patients with well differentiated thyroid carcinoma receiving a cumulative doses (CDs) of ? 600 mCi I-131.Patient and Method: A retrospective study of 72 patients with DTC receiving a CDs of ?600 mCi I-131 in the National Institute of Nuclear Medicine and Allied Sciences (NINMAS), Dhaka during the period of January 1994 up to December 2007 was carried out. Initially all patients were treated by thyroidectomy followed by radioiodine therapy as adjusted by standard protocol. The mean period of follow up was 8.9 ± 6 years. From the medical files, age, gender, histopathological variant, thyroid remnant and radio ablation doses, follow up data were recorded. Age was further categorized as &lt;45 and ?45 years. Thyroid bed remnant was designated as significant if the thyroid bed uptake was ?5% after surgery. Dose was categorized in ?5 dose and &gt; 5 doses to find its association with status on last follow up. Disease free (DF) was established as: undetectable or suppressed serum Tg levels &lt;2.0 ng/mL and stimulated serum Tg level &lt;10 ng/mL, two consecutive negative whole body scans.Results: A total of 38 patients had papillary carcinoma, eight had follicular variant of papillary carcinoma and 26 had follicular carcinoma. Age range at diagnosis was nine to 72 years. There were 22 males and 50 females giving a M: F ratio of about 1:2. Among the 72 patients 25 patients had lymph node metastases, eight had lung metastases and 20 had bone metastases at presentation. Twenty-one patients died during the whole observation period and 20 of them were cancer related. Two patients developed second malignancy.Conclusion: DTC patients with follicular variant, ? 45 years of age, having bone metastasis and significant thyroid remnant have less favourable outcome in spite of high cumulative doses of radioiodine. DTC patients with higher TNM stage and bone metastasis require higher and more radioiodine doses.Bangladesh J. Nuclear Med. 17(2): 114-119, July 2014