Non-radioactive Iodine Research Articles

Computational studies and synthesis of 131iodine-labeled nocardiotide A analogs as a peptide-based theragnostic radiopharmaceutical ligand for cancer targeting SSTR2.

Radiolabeled peptides belong to a highly specific group of radiotracers used in oncology, particularly for diagnostics and cancer therapy. With the notable advantages of high binding affinity and selectivity to cancer cells, they have proven to be very useful in nuclear medicine. As a result, efforts have been focused on discovering new peptide sequences for radiopeptide preparation. Nocardiotide A, a cyclic hexapeptide comprising the amino acids cyclo-Trp-Ile-Trp-Leu-Val-Ala (cWIWLVA) isolated from Nocardiopsis sp., has shown significant cytotoxicity against cancer cells, rendering it a suitable candidate for the process. Therefore, the present study aimed to design a stable and effective radiopeptide by labeling nocardiotide A with iodine-131 (131I), ensuring that its affinity to SSTR2 is not compromised. In silico study showed that structural modification of nocardiotide A labeled with 131iodine exhibited good affinity value, forming hydrogen bonds with key residues, such as Q.102 and T.194, which are essential in SSTR2. Based on the results, cyclic hexapeptides of cWIWLYA were selected for further synthesis, and its peptide product was confirmed by the presence of an ionic molecule peak m/z [M + Na]+ 855.4332 (yield, 25.60%). In vitro tests conducted on cWIWLYA showed that cWIWLYA can bind to HeLa cancer cells. Radiopeptide synthesis was initiated with radiolabeling of cWIWLYA by 131I using the chloramine-T method that showed a radiochemical yield of 93.37%. Non-radioactive iodine labeling reaction showed that iodination was successful, which detected the presence of di-iodinated peptide (I2-cWIWLYA) with m/z [M + Na]+ 1107.1138. In summary, a radiopeptide derived from nocardiotide A showed great potential for further development as a diagnostic and therapeutic agent in cancer treatment.

Comparing therapeutic outcomes: radioactive iodine therapy versus non-radioactive iodine therapy in differentiated thyroid cancer.

Radioactive iodine (RAI) has been utilized for nearly 80 years in treating both hyperthyroidism and thyroid cancer, and it continues to play a central role in the management of differentiated thyroid cancer (DTC) today. Recently, the use of RAI therapy for indolent, low-risk DTC has generated considerable debate. This case-control study evaluated the therapeutic response in DTC patients, comparing outcomes between those who received RAI therapy and those who did not. The study included individuals diagnosed with either indolent or aggressive histological types of DTC who either underwent RAI therapy or did not. For each patient, information regarding demographics (age, sex, background), clinical data, laboratory parameters, pathological exam, history of RAI therapy, thyroid ultrasound findings, and loco-regional or distant metastasis was extracted. All group comparisons were made using a two-sided test at an α level of 5%. Out of 104 patients diagnosed with DTC, 76 met the inclusion criteria and were subsequently divided into two primary groups based on their history of RAI ablation. The majority of patients underwent RAI therapy (76.3%). Most patients had a good biochemical (68.4%, p = 0.246) and structural control (72.4%, p = 0.366), without a significant difference between the two groups. RAI therapy significantly protected against incomplete biochemical control in the overall population (p = 0.019) and in patients with histological indolent DTC (p = 0.030). Predictive factors for incomplete biochemical control included male sex (p = 0.008) and incomplete structural control (p = 0.002) across all patients, regardless of the histological type. While RAI therapy has traditionally been used to manage DTC, our study found no significant difference in biochemical and structural responses between patients who received RAI therapy and those who did not. However, RAI therapy emerged as a protective factor against incomplete biochemical control, even in histological indolent DTC cases. These findings suggest that while RAI therapy may not be universally necessary, it could be beneficial in reducing the risk of biochemical recurrence in select patient subgroups, such as those with incomplete structural control or male patients. Thus, a personalized approach to RAI therapy, tailored to individual risk factors, may improve patient outcomes without overtreatment.

The flexible EDAN-based covalent organic frameworks constructed by flexible knots and 4,4′-ethylenedianiline as a linker for adsorping and fluorescence sensing iodine

In this paper, 4,4′-ethylenedianiline as a linker, flexible 2,4,6-tris(4-formylphenoxy)- 1,3,5-triazine (TPT−3−CHO) and hexa(4-formyl-phenoxy)cyclotriphosphazene (NOP−6−CHO) as knots were selected to construct the new flexible EDAN-based COFs (TEDAN and HEDAN) through Schiff base reactions of aldehyde and amine. The as-prepared flexible EDAN-based COFs have high crystallinity, sizable surface area, and thermal stability. With porous properties, abundant electron-rich heteroatoms as well as large π-conjugated network structures that can provide effective binding sites, TEDAN and HEDAN exhibit good reversible vapor-trapped iodine with the adsorption capacities of 4.64 and 2.25 g g−1, respectively. The aromatic networks of nitrogen-rich units in TEDAN provide many binding sites with guest iodine molecules than that of HEDAN, resulting in higher equilibrium uptake capacity of iodine for TEDAN. In addition, the flexible EDAN-based COFs show “turn-off” detection of non-radioactive iodine in the dispersion state with quenched constants (KSV) of 5.59 × 104 and 2.35 × 104 L mol−1. The fluorescence quenching of the flexible TEDAN-based COFs can be attributed to both the photo-induced electron transfer mechanism and the energy transfer transfer mechanism. The sensitivity of HEDAN is higher than that of TEDAN.

Rare Columnar Cell Variant Papillary Thyroid Carcinoma with Metastasis to Pancreas and Lungs at Initial Presentation: A Case Report and Review of Literature

AbstractPapillary thyroid cancer (PTC) is the most common endocrine malignancy, accounting for 85% of differentiated thyroid cancers. A small percentage of PTC variants are considered more aggressive, such as the tall cell variant associated with the V600E mutation in the BRAF gene and the rarer columnar variant, which is described in only 0.2% of cases and has a poor prognosis. Although locoregional metastases to neck lymph nodes are common, distant metastases of PTC are rare at presentation with only 5 to 7% reported in the literature. We present a very rare case of columnar cell variant PTC with synchronous metastasis to the lungs and indolent focus in the pancreas at initial diagnosis, which has never been reported in the literature. Our patient presented with non-radioactive iodine (RAI) responsive PTC with diffuse metastases to the lungs and one synchronous focal metastatic lesion in the pancreas. After multidisciplinary discussions, pancreatectomy/metastasectomy was deferred due to the disseminated PTC with multiple metastases to the lungs, lack of pancreas-related symptoms in the patient, and inherent complication risks. The patient was treated with systemic therapy using a tyrosine kinase inhibitor (lenvatinib), which is the standard of care for non-RAI responsive PTC and showed a complete radiologic resolution of the pancreatic lesion, however, with partial yet nonprogressive metastatic disease in the lungs.

Synthesis and evaluation of radiolabeled porphyrin derivatives for cancer diagnoses and their nonradioactive counterparts for photodynamic therapy.

Radioiodinated porphyrin derivatives and the corresponding nonradioactive iodine introduced compounds, [125I]I-TPPOH ([125I]3), [125I]I-l-tyrosine-TPP ([125I]9), I-TPPOH (3), and I-l-tyrosine-TPP (9) were designed, synthesized, and evaluated by in vitro and in vivo experiments. In cytotoxicity assays, 3 and 9 exhibited significant cytotoxicity under light conditions but did not show significant cytotoxicity without light irradiation. Biodistribution experiments with [125I]3 and [125I]9 showed similar distribution patterns with high retention in tumors. In photodynamic therapeutic (PDT) experiments, 3 and 9 at a dose of 13.6 μmol kg-1 weight with 50 W single light irradiation onto the tumor area significantly inhibited tumor growth. These results indicate that the iodinated porphyrin derivatives [123/natI]3 and [123/natI]9 are promising cancer theranostic agents.

A Novel Reagent for Radioiodine Labeling of New Chemical Entities (NCEs) and Biomolecules.

Radioiodine labeling of peptides and proteins is routinely performed by using various oxidizing agents such as Chloramine T, Iodobeads, and Iodogen reagent and radioactive iodide (I−), although some other oxidizing agents were also investigated. The main objective of the present study was to develop and test a novel reagent, inorganic monochloramine (NH2Cl), for radioiodine labeling of new chemical entities and biomolecules which is cost-effective, easy to make and handle, and is selective to label amino acids, peptides, and proteins. The data presented in this report demonstrate that the yields of the non-radioactive iodine labeling reactions using monochloramine are >70% for an amino acid (tyrosine) and a cyclic peptide (cyclo Arg-Gly-Asp-d-Tyr-Lys, cRGDyK). No evidence of the formation of N-chloro derivatives in cRGDyK was observed, suggesting that the reagent is selective in iodinating the tyrosine residue in the biomolecules. The method was successfully translated into radioiodine labeling of amino acid, a peptide, and a protein, Bovine Serum Albumin (BSA).

Separation of iodine using neem oil-cashew nut shell liquid based-phenol formaldehyde resin modified lignocellulosic biomatrices: Batch and column study

BackgroundManagement and separation of radioactive iodine from wastewater of nuclear power plants is time-dependent and needs lot of efforts. Changes of surface chemistry due to radioactive irradiations are the major issue for developing an efficient adsorbent for separation of radionuclei from wastewater. MethodsThis article presented a promising case of separation of non-radioactive iodine from aqueous solution using neem oil phenolic resin treated lignocellulosic biomass. The resin was prepared with some ingredients with known properties of radiation absorption. FindingsThe data pointed that the treated biomass has the efficacy of iodine separation from aqueous solution within wide range of pH. The iodine sorption followed the Langmuir isotherm indicating a monolayer surface adsorption reaction. The maximum iodine removal efficacy of the resin treated biomass was 3.64 mg/g. The iodine adsorption was found to follow the pseudo second order reaction. The kinetic analysis also indicated that both surface adsorption and intraparticle diffusion were likely to control the rate of iodine-adsorbent. The treated adsorbent also showed iodine removal efficacy in column mode. The resin used for the treatment of lignocellulosic biomass was prepared using cashew nut shell liquid and phenol-formaldehyde that are known for their radiation adsorption and antioxidant properties. Thus, neem oil cashew nut shell liquid containing phenol formaldehyde resin treated biomass is expected to be stable under radioactive radiation. As radioactive iodine generation is a common phenomenon for nuclear power plant the bio-based chemical modified lignocellulosic adsorbent could be a promising alternative. However, more detail investigations with radioactive iodine containing real wastewater from nuclear power plant is needed for validation of our statement.

Chronic administration of pharmacological doses of angiotensin 1-7 and iodoangiotensin 1-7 has minimal effects on blood pressure, heart rate, and cognitive function of spontaneously hypertensive rats.

Cardiovascular diseases are the principal cause of death worldwide, with hypertension being the most common cardiovascular disease risk factor. High blood pressure (BP) is also associated with an increased risk of poor cognitive performance and dementia including Alzheimer's disease. Angiotensin 1–7 (Ang 1‐7), a product of the renin‐angiotensin system (RAS), exhibits central and peripheral actions to reduce BP. Recent data from our lab reveals that the addition of a non‐radioactive iodine molecule to the tyrosine in position 4 of Ang 1‐7 (iodoAng 1‐7) makes it ~1000‐fold more potent than Ang 1‐7 in competing for the 125I‐Ang 1‐7 binding site (Stoyell‐Conti et al., 2020). Moreover, the addition of the non‐radioactive iodine molecule increases (~4‐fold) iodoAng 1‐7’s ability to bind to the AT1 receptor (AT1R), the primary receptor for Ang II. Preliminary data indicates that iodoAng 1‐7 can also compete for the 125I‐Ang IV binding site with a low micromolar IC50. Thus, our aims were to compare the effects of chronic treatment of the Spontaneously Hypertensive Rat (SHR) with iodoAng 1‐7 (non‐radioactive iodine isotope) and Ang 1‐7 on arterial pressure, heart rate, and cognitive function. For this study, male SHRs were divided into three groups and treated with Saline, Ang 1‐7, or iodoAng 1‐7 administrated subcutaneously using a 28‐day osmotic mini pump. Systolic BP was measured non‐invasively by the tail‐cuff technique. Cognitive function was assessed by Y‐Maze test and novel object recognition (NOR) test. We have demonstrated in SHRs that subcutaneous administration of high doses of iodoAng 1‐7 prevented the increase in heart rate with age, while Ang 1‐7 showed a trend toward preventing the increase in heart rate, possibly by improving baroreflex control of the heart. Conversely, neither Ang 1‐7 nor iodoAng 1‐7 administered subcutaneously affected BP nor cognitive function.

A comparison of thyroidal protection by stable iodine or perchlorate in the case of acute or prolonged radioiodine exposure

In the case of a nuclear power plant accident, repetitive/prolonged radioiodine release may occur. Radioiodine accumulates in the thyroid and by irradiation enhances the risk of cancer. Large doses of non-radioactive iodine may protect the thyroid by inhibiting radioiodine uptake into the gland (iodine blockade). Protection is based on a competition at the active carrier site in the cellular membrane and the Wolff–Chaikoff effect, the latter being, however, only transient (24–48 h). Perchlorate may alternatively provide protection by a carrier competition mechanism only. Perchlorate has, however, a stronger affinity to the carrier than iodide. Based on an established biokinetic–dosimetric model developed to study iodine blockade, and after its extension to describe perchlorate pharmacokinetics and the inhibition of iodine transport through the carrier, we computed the protective efficacies that can be achieved by stable iodine or perchlorate in the case of an acute or prolonged radioiodine exposure. In the case of acute radioiodine exposure, perchlorate is less potent than stable iodine considering its ED50. A dose of 100 mg stable iodine has roughly the same protective efficacy as 1000 mg perchlorate. For prolonged exposures, single doses of protective agents, whether stable iodine or perchlorate, offer substantially lower protection than after acute radioiodine exposure, and thus repetitive administrations seem necessary. In case of prolonged exposure, the higher affinity of perchlorate for the carrier in combination with the fading Wolff–Chaikoff effect of iodine confers perchlorate a higher protective efficacy compared to stable iodine. Taking into account the frequency and seriousness of adverse effects, iodine and perchlorate at equieffective dosages seem to be alternatives in case of short-term acute radioiodine exposure, whereas preference should be given to perchlorate in view of its higher protective efficacy in the case of longer lasting radioiodine exposures.

A simple method for quantifying iodate and iodide fractions in solution using Ag+-impregnated activated carbon

The speciation of iodine in environment must be known in order to properly assess its geological fate and to study potential remediation materials for the decontamination of water containing radioactive iodine. In this study, the utilization of silver-impregnated granular activated carbon for separation between two iodine species, iodate and iodide, from each other was studied in different solution matrices with batch and column experiments. A high separation of the iodine species was achieved in the high concentrations of interfering ions, e.g. chloride, and in both μM and trace iodine concentrations. The method is suitable for both radioactive and non-radioactive iodine.

Development of New Biokinetic-Dosimetric Models for the Simulation of Iodine Blockade in the Case of Radioiodine Exposure in Man.

In the case of nuclear incidents, radioiodine may be liberated. After incorporation it accumulates in the thyroid and by internal irradiation enhances the risk of cancer occurrence. By administering a large dose of non-radioactive iodine the uptake of radioiodine into the gland can be inhibited ("iodine blockade"). Biokinetic models using first order kinetics are not suited to simulate iodine blockade, as the uptake into the gland is mediated by a saturable active transport. Therefore, we integrated an uptake mechanism described by a Michaelis-Menten kinetic into a simple ICRP biokinetic model. We moreover added a total uptake blocking mechanism representing the Wolff-Chaikoff effect becoming active when the gland is saturated with iodine. The validity of the model was ascertained by comparison with IMBA software. The competition of radioiodine and stable iodine at the membrane carrier site was modeled according to the rate law for monomolecular reactions for competing substrates. Our simulations show that competition for the uptake at the membrane carrier site accounts for about 60% and the saturation of the gland with iodine for over 35% of the total protective efficacy that exceeds 95%. Following acute radioiodine exposure, it is preferable to administer a single large dose of stable iodine. In the case of continuous radioiodine exposure, a single dose of stable iodine is less effective than after an acute exposure and splitting the total available dose and shortening the dosage intervals enhance efficacy. Model-based simulations may be a useful tool to develop antidote dosage schemes for uncommon emergencies.

PO-022 Benzamide class of HDACi differentially enhance sodium iodide symporter expression in breast cancer

IntroductionSodium iodide symporter (hNIS) expression is reported across all subtypes of breast cancer (BC) and is a potential endogenous gene target for radioiodine therapy [PlosOne8(1:e54055, 2012]. Successful clinical application however relies on very high expression of functional NIS in BC cells. We have been exploiting various transcriptional regulation approaches for NIS, of which use of HDAC inhibitors (HDACi) have shown promising amplification of endogenous NIS expression in BC [Scientific Reports6:19341, 2016]. Here, we show that differential induction of NIS expression in BC is possible using Benzamide class of HDACi (bHDACi) with minimal off-target effects on other cell types.Material and methodsThe effect of bHDACi, i.e. CI-994, Chidamide, MS-275 and AR-42, on NIS gene transcription was verified on a panel of human cancer cells by RTPCR. Functional in vitro assessment was done by non-radioactive iodine uptake. I131therapeutic efficacy was measured by clonogenic assay. Promoter binding transcription factor (TF) profiler array was done to identify novel TFs responsible for differential activation in BC cells. Further, in vivo therapeutic efficacy was monitored by bioluminescence imaging (BLI) of ZR-75–1-fl2.tdt orthotopic model.Results and discussionsUsing a non-toxic, low dose of bHDACi(s) treatment on a cancer cell panel, including breast, thyroid, lung, glioma, fibrosarcoma and ovarian, a significant induction of NIS expression (p<0.05) was observed only in BC cells. Observed differences of NIS expression was confirmed by protein expression and functional assessment on BC cells. Further, novel TFs (FOXA1, FOXOF2 etc.) were identified which show differential activation in BC after CI-994 treatment. Only in case of BC cells pre-treated with bHDACi(s), cell survival assay results showed enhanced cell death on exposure to I131. Further, AR-42 drug was tested in vivo which showed similar results. AR-42 pre-treated ZR-75–1 fl2tdt orthotopic tumour showed increased NIS expression. In comparison to untreated and only I131 treated group, a combination treatment of AR-42 with 1mCi I131, BLI imaging showed 20% and 30% signal drop on day1 and day 2 respectively indicating specific radio-ablation effect.ConclusionbHDACi(s) show differentially higher regulation of endogenous NIS with minimal effect on non-breast tissues and thus may potentially benefit NIS-based radioablation therapy trials in BC patients with low/moderate expression of NIS.

Analysis of Iodine Content in Salts and Korean Sauces for Low-Iodine Diet Education in Korean Patients with Thyroid Cancer Preparing for Radioiodine Therapy.

A low-iodine diet is necessary in patients about to undergo radioiodine therapy for thyroid cancer to decrease the competitive absorption of ingested nonradioactive iodine. This study aimed to assess the iodine concentrations in salts and basic Korean sauces, and to provide fundamental data for guidelines on a low-iodine diet before radioiodine therapy. The iodine contents of refined salts, solar sea salts, fish sauces, and commonly used Korean sauces with added refined salt were determined by ICP-MS. The iodine content of refined salts was found to be very low (0.033±0.05μg/100g) compared with that of solar sea salts (434±73.6μg/100g). The iodine contents of Korean soy sauce, Korean soybean paste, Gochujang seasoned with refined salt were also very low (0.010, 0.044, 0.002μg/100g, respectively). However, the mean iodine contents of the shrimp and fish Jeots analyzed in this study were found to be 41.3 ± 4.2 and 24.8 ± 4.5μg/100g, respectively. This study is the first to investigate the iodine contents of the salts and basic sauces used in Korea. The results show that refined salts and Korean traditional sauces seasoned with them can be safely used in low-iodine diets before radioiodine therapy.

Prognosis of Differentiated Thyroid Carcinoma with Initial Distant Metastasis: A Multicenter Study in Korea.

BackgroundMost patients with differentiated thyroid cancer (DTC) have a favorable prognosis. However, patients with DTC and initial distant metastasis have not been commonly found, and their clinical characteristics have seldom been reported. In this study, we analyzed the clinical features and prognosis of patients with DTC and initial distant metastasis in Korea.MethodsWe retrospectively reviewed the clinical data of 242 patients with DTC and initial distant metastasis treated from 1994 to 2013, collected from five tertiary hospitals in Korea.ResultsThe patients' median age was 51 years, and 65% were women. They were followed for a median of 7 years. Lung was the most common site of distant metastasis: only lung 149 patients (62%), only bone 49 (20%), other single site one (pleura), and combined sites 43 (40 were lung and bone, two were bone and other site, and one was lung and other site). At the time of diagnosis, 50 patients (21%) had non-radioactive iodine (RAI) avidity. Five-year disease-specific survival (DSS) was 85% and 10-year DSS was 68%, which were better than those in previous studies. After multivariate analysis, old age, male sex, metastatic site, and histologic type (follicular type) were significant factors for poor prognosis. However, negative RAI avidity status was not a significant prognostic factor after adjusting for other variables.ConclusionThe prognosis of Korean patients with DTC and initial distant metastasis was better than in previous studies. Old age, male sex, metastasis site, and histologic type were significant prognostic factors.

Potentiometric measurement of urinary iodine concentration in patients with thyroid diseases with and without previous exposure to non-radioactive iodine

Extensive application of measurement of urinary iodine concentration (UIC) in several benign and malignant thyroid diseases could profit by the availability of rapid and inexpensive measuring techniques. Aim of this study was to apply a simple and inexpensive commercially available potentiometric method for the quantification of UIC based on iodine-specific ion-selective electrodes (ISE) in patients with thyroid diseases. This retrospective study included patients with differentiated thyroid cancer (n=286) and patients with hyperthyroidism of different etiologies (n=203). Within the whole sample (n=489) 20 patients had previously (1 week-6 months) been exposed to iodine overload, either from contrast media (n=8) or amiodarone (n=12). In patients not exposed to iodine, the histogram showed that the distribution of UIC violated normality. The peak of the curve occurred between 5.0 μmol/L and 6.0 μmol/L. Variability was sizeable (percent coefficient of variation, %CV: 66%, 95% confidence interval: 1.48-18.72 μmol/L). The group of exposed patients could be easily distinguished from not exposed patients (median UIC: 47.5 μmol/L vs. 5.42 μmol/L). UIC was significantly correlated to urinary creatinine concentration, but normalization to urinary creatinine increased the inter-subject variability of UIC (%CV=96% vs. 66%). In test-retest studies (n=25) the intra-class correlation coefficient was 0.73 for UIC, 0.82 for creatinine and 0.64 for the UIC: creatinine ratio. Iodine-specific ISE-based potentiometric methods can be successfully applied as an alternative to existing methods in patients with thyroid diseases. The promising characteristics of the method need to be confirmed in future larger prospective studies.

Removal of radioactive iodine and cesium in water purification

Radioactive iodine, one of the radionuclides released in the nuclear power plant accident on 11 March 2011, was detected in purified water at water purification plants (WPPs). However, information about removal of radioactive materials in actual water purification process was limited. Therefore, we investigated the removal of radioactive materials (iodine and cesium) immediately after the detection. It is found that non-radioactive iodine in water could be removed by the combined use of pre-chlorination and powdered activated carbon (PAC) treatment. The same result was also obtained in terms of radioactive iodine. Removal of non-radioactive iodine in WPPs was also investigated. Approximately, 60% of iodine was removed by combination of pre-chlorination (0.5–1.0 mg/L) and PAC (15–30 mg/L) in coagulation and sedimentation processes. In water purification process, cesium was mostly removed by coagulation and sedimentation; hence, radioactive cesium was not detected in purified water. It was confirmed that a thorough turbidity control is essential for the prevention of radioactive cesium contamination of purified water. Meanwhile, radioactive iodine in purified water has not been detected since 5 April 2011 and radioactive cesium since 22 March 2011, when the measurement was commenced. Moreover, dehydrated sludge including radioactive cesium has been treated in accordance with Japanese laws and regulations.

Structural Behavior of Tc and I Ions in Nuclear Waste Glass

Technetium-99 (Tc) and iodine-129 (I) are two long-lived fission products of high volatility, which makes their study in glass structure challenging. Both technetium and iodine have broad ranging multivalent chemistry and complex reactivity dependent on redox conditions; technetium and iodine redox may vary from Tc0 to Tc7+ and from I- to I7+. Relatively few studies have been done on their speciation in glass, in part because of their low retention at the temperatures required for glass melting. To better understand the redox and structural behavior of Tc and I in various nuclear waste glasses, a series of technetium- and iodine-containing borosilicate glasses of varied chemistry were prepared at scales ranging from a few grams to hundreds of kilograms. Technetium was included in both high-level and low-level nuclear waste glass formulations under a variety of redox conditions at concentrations ranging from 0.003 wt% to 0.06 wt%. Non-radioactive iodine glass samples were prepared in crucible melts using excess amounts of sodium or potassium iodide salts or ammonium iodate that resulted in concentrations ranging from 0.04 to 1.27 wt% iodine. These samples were also compared to glasses prepared in pilot-scale experiments in which the overall retentions reached 48% and 34% for technetium and iodine, respectively. Tc and I speciation in the resulting glasses were determined by X-ray absorption spectroscopy (XAS). While technetium was found as Tc0, Tc4+, and Tc7+, only I- was identified in these glasses. Previous studies of Tc local environment information inferred from K-edge XAS and Raman spectroscopy identified pertechnetate tetrahedra surrounded by network-modifying cations in oxidized glasses and octahedral TcO6 units in glasses prepared under reducing conditions. Conversely, iodine K-edge XAS of all glasses studied indicate iodide environments with lithium or sodium nearest-neighbors resembling disordered versions of octahedral sites in crystalline lithium or sodium iodide.

The influence of non-radioactive iodine (127I) on the outcome of radioiodine (131I) therapy in patients with Graves’ disease and toxic nodular goitre

The aim of the study was to achieve an effective target dose in the thyroid by increasing the effective half-life (Teff) of (131)I by use of iodide ((127)I) two days after (131)I therapy in patients with hyperthyroidism with low Teff. The study was carried out in two groups. Group A - 41 patients, and Group B - 14 patients, all the patients were with hyperthyroidism with Teff less than 3 days qualified for (131)I therapy. Only group A patients received 600 μg of iodide a day for 3 days, two days after (131)I therapy. Radioiodine uptake (RAIU) after 24 and 48 hours, thyroid scintiscan and ultrasonography were done before and after 12 months of (131)I therapy. In group A a significant increase was seen in the Teff (5 days on average) resulting in an increase in the energy target dose by 28% and 37%, in patients with Graves' disease (GD) and toxic nodular goitre (TNG), respectively. After one year of therapy 50% of GD and 93% of TNG patients achieved euthyroidism; 28% of GD and 3% of TNG patients were in hypothyroidism. In Group B, all the patients had radioiodine treatment failure and received a second therapeutic dose of (131)I. Administration of (127)I after (131)I treatment can lead to an increase in its effective half-life. This will also increase the absorbed energy dose in thyroid tissue, thereby improving therapeutic outcome without administration of a higher or second dose of (131)I. This may minimize whole-body exposure to radiation and reduces the cost of treatment.

Nonradioactive Iodine-Labeled Antibodies-Inductively Coupled Plasma Mass Spectrometry for Immunoassay

In the present study, the system of nonradioactive iodine-labeled-antibodies linking inductively coupled plasma mass spectrometry for immunoassay was reported. The goat-anti-Escherichia coli and goat anti rabbit were considered as simulant antigen and antibody respectively in order to establish a new method of immunoassay by inductively coupled plasma mass spectrometry which has the advantage of high sensitivity, low detection limit and preferable linearity range. During the experiment, the N-bromosuccinimide, a mild oxidant, was used to oxidize the non-radioactive iodine (127 I) that labeled the protein. The method of nonradioactive iodine labeled protein was established and the best labeling condition was explored. The compound of I was purified by Sephadex G50 column chromatography, then the stability and activity were examined. The results showed that the labeling program was simple, reaction time was within two minutes, the labeling yield achieved 63.12% and none of I shed from the compound after 96 hours. The simulant antigen and antibody reacted on polystyrene microtiter plate and the I was detected by ICP-MS, the detection limit of the method was 0.12 mg x L(-1), relative standard deviation (n = 9) was less than 3% and the linearly dependent coefficient was 0.998 7. This system can also be used in analysis of other protein, nucleic acid and so on.

Iodine measurement in porous matrices based on calcium phosphate compounds

Porous ceramic materials based on calcium phosphate compounds (CFC) have been studied and developed for several biomedical applications such as implants, controlled drug delivery, and radioactive sources for brachytherapy. Two kinds of hydroxyapatite (HAp) powders and their ceramic bodies were characterized. In this study, non-radioactive iodine was incorporated in two types of biodegradable hydroxyapatite-based porous matrices (HA and HACL). The results reveal that both systems present a high capacity of incorporating iodine. The quantity of incorporated iodine was measured by neutron activation analysis (NAA). The porous ceramic matrices based on hydroxyapatite demonstrated a great potential for uses in low dose rate (LDR) brachytherapy.