Introduction: Radioactive Iodine therapy is an established therapeutic application of well-differentiated thyroid cancer. However, the proven benefits of ionizing radiation of Iodine-131 also carry potential toxicities to other normal exposed tissues. Good water hydration during the course of RAI therapy is one of the radiation protection measures to minimize toxicities, directed to increase excretion of unbound iodine from the body. Apparently, a number of recognized medical societies had different recommendations on the amount of water intake during radioactive iodine therapy. Objective: To determine if there is a significant difference in the decrease of exposure rate, total effective dose equivalent, and length of stay of differentiated thyroid cancer patients undergoing high dose RAI when comparing between different amounts of water intake per day (<3L/day vs > 3 L/day). Methods: This study employed a prospective cohort design. Patients with differentiated thyroid cancer (DTC) admitted for high-dose RAI therapy at Jose R. Reyes Memorial Medical Center were included in the study. Dose rate and water intake volume were measured and total effective dose equivalent was computed every 24-hrs until discharged. Student t test was used to compare two water intake levels on quantitative variables while fisher exact test for categorical data. Results: A total of 47 participants were included in the study with 28 patients under > 3L/day group and 19 patients under < 3L/day with a mean consumption of 4.9 L/day and 2.3 L/day, respectively. There was no significant difference on the mean exposure rate between those who consumed at least 3L (15.3 mR/hr) against those who consumed less than 3L (17.3 mR/hr) during the time of intake, after the 24 hours (p=.9935) and 48 hours (p=.7523). Likewise, there is no significant difference on their mean total effective dose equivalent [in per day during intake (p=.9678), 24 hours (p=.4141) and 48 hours (p=.6706)]. The mean length of hospital stay is also the same for both groups with 1.7 days. Conclusion The study concludes that consuming different volume of water per day (> 3 L/day vs < 3L/ day) have the same rate of decreased in exposure rate, total effective dose equivalent (TEDE) as well as the same length of hospital
Thyroid Neoplasms ; Adenocarcinoma ; Iodine Radioisotopes

The use of high- or low-dose radio-iodine therapy (RAIT) for initial thyroid remnant ablation in post-thyroidectomised patients diagnosed with differentiated thyroid cancer (DTC) with no distant metastases has long been a subject of much debate. Meta-analyses and systematic reviews have been previously made using both randomised control trials (RCTs) and observational studies without due regard to differences in study design. Hence, amore focused meta-analysis of available RCTs alone was conducted to determine the presence of a compelling difference between the initial remnant ablation success rates of high- and low-dose RAIT in post-thyroidectomised DTC patient without distant demtastases. An extensive search of PubMed and Cochrane Central register of RCTs (up to August 2013) was performed by two reviewers, which was completed by hand search of referencesfrom releveangt articles and review papers published from 1996 to 2012. The two reviewers independtly selected eligible studies, with disagreement resolved by consensus. The inclusion criteria were as follows: (a) randomised controlled trials, (b) post-thyroidectomised adult subjects diagnosed with well differentiated thyroid cancer and no evidence of distant metastases, and (c) subject randomisation into 30-50 mCi or 100 mCi 131I treatment groups. Studies were exluded if (a) the full text of the study is not available, (b) the study is in another language other than English, and (c) if the data on relative risk was not available or could not be derived from the study. Of eight published RCTs on radio-iodine therapy as of August 2013, only 5 were eligible for this meta-analysis; namely those by JOhansen et al. (1991), Bal et al. (1996), Zaman et al. (2006), Maenpaa et al. (2008) and Caglar et al. (2012). The same two reviewers independenty extracted data from the full text of the selected five studies. Two-by-two tables comparing frequencies of successful and failed remnant ablation using low-dose (30-60 mCi) and high-dise (100 mCi) RAIT were derived from the published results of the included studies, and the weighted and pooled relative risks for successful remnant ablation were computed via the Mantel-Haenszel method using a fixed effects model (cx = 5%). Subgroup analyses were performed based on different definitions of a successful remnant ablation. The pooled relative risk (-0.03) was statistically insignificant (p=0.54) and had poor precision (95% confidence interval of {-0.12,0.06}) even when adjustments to the varied definitions of a successful ablation were performed. Thus, using available RCTs that compare high- and low-dose RAIT for remnant ablation of DTC, there is an apparent trend favoring higher success rates using high-dose RAIT. However, the lack of well designed RCTs precludes recommending high-dose initial RAI ablation, and encourages the present practice of individualized.
Meta-Analysis ; Thyroid Neoplasms ; Iodine Radioisotopes

Introduction: No clear consensus exists as to the optimal timing for conducting whole body scintigraphy (WBS) after radioactive iodine (RAI) therapy for differentiated thyroid carcinoma. Objective: This study aimed to compare the utility of early versus delayed post-therapy WBS in identifying residual lesions and metastases. Methods A systematic review of existing literature was done, yielding 6 observational studies relevant to the subject. Meta-analyses were done comparing lesion detecting rates of early (3-4 days post-RAI) and delayed (7-11 days post-RAI) post-therapy WBS for thyroid remnants and metastases in the lymph nodes, lungs, and bone using a random-effects model with odds ratios (OR) and 95% confidence intervals (CIs). A subgroup analysis was also done relating to the type of collimator used in imaging.
Iodine-131 ; Thyroid Neoplasms ; Iodine Radioisotopes ; Radionuclide Imaging

OBJECTIVE: To investigate the feasibility of using thyroid ^99mTcO₄^- imaging ROI ratio instead of 24 h radioactive iodine uptake (RAIU) for estimating ¹³¹I dose in individualized treatment of hyperthyroidism. METHODS: We retrospectively analyzed the clinical data of 132 patients receiving ¹³¹I treatment in our department between January and June, 2019. According to their 3 h/24 h RAIU peak ratio, the patients were divided into peak forward (≥80%) group and no peak forward (< 80%) group. In the former group, the therapeutic ¹³¹I dose was calculated based the Marinelli formula (¹³¹I dose=thyroid mass×planned amount/24 h RAIU), and in the latter group, the correlation between the ROI ratio and the 24 h RAIU was analyzed, and the ¹³¹I dose was calculated using a modified Marinelli formula where 24 h RAIU was replaced by a converted ROI ratio. The two groups of patients were compared for antithyroid drug type and discontinuation time, thyroid hormones and related antibodies, thyroid area, thyroid mass and ¹³¹I dose. All the patients were and followed up for one year to analyze the treatment efficacy. The ROI ratios after the treatment were analyzed in the two groups using ROC curves. RESULTS: There was a significant positive correlation between the ROI ratio and 24 h RAUI in the no peak forward group (Y=58.13 + 0.2X, R²=0.118, P < 0.05), and the formula for calculating ¹³¹I dose was converted into: ¹³¹I dose=thyroid mass× planned amount/(58.13+0.2×ROI ratio)%. Before the treatment, therapeutic ¹³¹I dose, thyroid hormone levels, TRAb, 3 h and 24 h RAIU, thyroid area, thyroid mass, and ROI ratio all differed significantly between the two groups (P < 0.05). At 3 months after treatment, thyroid hormone levels, TRAb, TPOAb, thyroid area, thyroid mass, ROI ratio, response rate, hypothyroidism rate, cure rate, remission rate, and nonresponse rate were similar between two groups (P>0.05). At the 1-year follow-up, the composition ratios of hyperthyroidism, hypothyroidism and cured cases remained similar between two groups (P>0.05). ROC curve analysis showed that at 3 months after treatment, the optimal cutoff values of ROI ratio for predicting hyperthyroid recurrence and hypothyroidism were 15.79 and 6.33, respectively. CONCLUSION Thyroid ^99mTcO₄^- imaging ROI ratio can be used for calculating ¹³¹I dose in individualized treatment of hyperthyroidism and for prognostic evaluation of the patients.
Humans ; Iodine Radioisotopes/therapeutic use* ; Retrospective Studies ; Thyroid Neoplasms ; Hypothyroidism

OBJECTIVETo investigate the changes in thyroglobulin antibodies (TgAb) and its influencing factors in differentiated thyroid cancer (DTC) patients with positive TgAb (>115 U/ml) after total thyroidectomy and radioiodine (¹³¹I) therapy.

METHODSWe collected the clinical data of 118 DTC patients with positive TgAb and analyzed their TgAb levels before surgery, before ¹³¹I therapy, and after ¹³¹I therapy with a median follow-up of 2.3 months and 5.2 months. Multiple linear regression (MLR) was applied to analyze the time of TgAb concentration decreased by more than 50% (T₅₀) and its influencing factors.

RESULTSCompared with the previous TgAb levels, TgAb decreased significantly 2.3 months and 5.2 months after surgery or after ¹³¹I therapy, respectively (both P=0.000). The proportions of patients with TgAb decreased by more than 50% in each stage were 28.6%,33.3%, and 37.2%,respectively. The negative conversion ratios were 23.4%,48.9%, and 62.8%,respectively. MLR showed that only the interval between surgery and ¹³¹I therapy was correlated with T₅₀ (B=1.125, P=0.000).

CONCLUSIONSThe TgAb levels in DTC patients remarkably decrease after surgery and after ¹³¹I therapy. The interval between surgery and ¹³¹I therapy remarkably influences the lowering speed of TgAb levels. Prompt application of ¹³¹I therapy after surgery helps to lower TgAb levels.

Adenocarcinoma ; Autoantibodies ; Humans ; Iodine Radioisotopes ; Thyroglobulin ; Thyroid Neoplasms ; Thyroidectomy

We report a facile and effective method for radioiodine-labeled radiopharmaceuticals via copper (I)-catalyzed click chemistry route. In the novel radioiodination method, 5-iodo ((125/131)I)-1, 2, 3-triazoles were synthesized after a 24-h click reaction in organic solvent with a radiochemical yield of 13%. However, in the aqueous phase, the radiochemical yield of the conjugation radioiodine to RGD via click chemistry was 0. This suggested an exchange between hydrogen ion and iodine ion in aqueous phase so that no enough radioiodine was left to conjugate with RGD. We propose different mechanisms of Cu (I)-catalyzed cycloaddition of organic azides and 1-iodo-alkynes in organic phase and aqueous phase.
Click Chemistry ; Iodine Radioisotopes ; Radiopharmaceuticals ; chemical synthesis ; Triazoles ; chemical synthesis

OBJECTIVE: To present a theoretical analysis of how the presence of bone in interstitial brachytherapy affects dose rate distributions with MCNP4C Monte Carlo code and to prepare for the next clinical study on the dose distribution of interstitial brachytherapy in head and neck neoplasm. METHODS: Type 6711,¹²⁵I brachytherapy source was simulated with MCNP4C Monte Carlo code whose cross section library was DLC-200. The dose distribution along the transverse axis in water and dose constant were compared with the American Association of Physicists in Medicine (AAPM) TG43UI update dosimetry formalism and current literature. The validated computer code was then applied to simple homogeneous bone tissue model to determine the affected different bone tissue had on dose distribution from ¹²⁵I interstitial implant. RESULTS: ¹²⁵I brachytherapy source simulated with MCNP4C Monte Carlo code met the requirements of TG43UI report. Dose rate constant, 0.977 78 cGy/(h×U), was in agreement within 1.32% compared with the recommended value of TG43UI. There was a good agreement between TG43UI about the dosimetric parameters at distances of 1 to 10 cm along the transverse axis of the ¹²⁵I source established by MCNP4C and current published data. And the dose distribution of ¹²⁵I photon emitting source in different bone tissue was calculated. Dose-deposition capacity of photons was in decreasing order: cortical bone, spongy bone, cartilage, yellow bone marrow, red bone marrow in the same medium depth. Photons deposited significantly in traversal axis among the phantom material of cortical bone and sponge bone relevant to the dose to water. In the medium depth of 0.01 cm, 0.1 cm, and 1 cm, the dose in the cortical bone was 12.90 times, 9.72 times, and 0.30 times of water respectively. CONCLUSION This study build a ¹²⁵I source model with MCNP4C Monte Carlo code, which is validated, and could be used in subsequent study. Dose distribution of photons in different bone medium is not the same as water, and its main energy deposits in bone medium surface, so we should consider the effect of bone medium when we design the target area adjacent to the bone tissue in ¹²⁵I sources implantation plan.
Brachytherapy ; Iodine Radioisotopes ; Monte Carlo Method ; Photons ; Radiotherapy Dosage

Radioactive iodine treatment (RAIT) after surgery reduces local recurrence and cancer related death. Cases of hyponatremia after preparation for RAIT have rarely been reported. We report 4 cases of hyponatremia which developed after RAIT. The cause of hyponatremia seemed to be related with over ingestion of free water which is recommended during RAIT. These cases highlighted the importance of weight adjusted water ingestion during RAIT.
Eating ; Humans ; Hyponatremia* ; Iodine Radioisotopes ; Iodine* ; Recurrence ; Thyroid Gland* ; Thyroid Neoplasms* ; Water ; Water Intoxication

OBJECTIVE: To determine the prevalence of menstrual and reproductive dysfunction among subjects who have undergone radioiodine treatment for thyroid carcinoma.
METHODOLOGY: This study enrolled adult women with Differentiated Thyroid Carcinoma who received the treatment at age 40 years and below. Data was processed using SAS program and evaluated using Fischer's test and Wilcoxon test.
RESULTS: The study enrolled 46 women. Three reported cycle irregularities, 4 reported changes in amount of bleeding and 1 had amenorrhea. The prevalence rate of menstrual abnormalities was 15.2%. These women received a significantly higher dose of radioactive iodine (RAI) (120 vs. 110 mCi, p = 0.0064). Eleven women tried to conceive and there were 5 births to 5 different subjects after radiation. There were no congenital anomalies and 1 miscarriage. Four women were menopausal with an average age of 44.4 years old.
CONCLUSION: This study showed that the prevalence of menstrual disturbances after high dose radioactive iodine treatment among thyroid cancer patients is 15.2%. The affected group received a significantly higher dose of radioactive iodine compared to the unaffected group.

Human ; Female ; Adult ; Abortion, Spontaneous ; Amenorrhea ; Iodine ; Iodine Radioisotopes ; Menopause ; Menstruation Disturbances ; Prevalence ; Radiation ; Thyroid Neoplasms

Most differentiated thyroid cancer (DTC) patients have an excellent prognosis. However, about one-third of DTC patients with recurrent or metastatic disease lose the hallmark of specific iodine uptake initially or gradually and acquire radioactive iodine-refractory DTC (RAIR-DTC) with poor prognosis. Due to the potentially severe complications from unnecessarily repeated RAI therapy and encouraging progress of multiple targeted drugs for advanced RAIR-DTC patients, it has become crucial to identify RAIR-DTC early. In this review, we focus on the progress and controversies regarding the defining of RAIR-DTC, further with subsistent approaches and promising molecular nuclear medicine imaging in identifying RAIR-DTC, which may shed light on the proper management methodsof such patients.
Humans ; Iodine Radioisotopes ; Iodine ; Molecular Imaging ; Nuclear Medicine ; Prognosis ; Thyroid Gland ; Thyroid Neoplasms