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Results for “Iodine Isotopes”

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At least 19 recordsLinked to original sources
PubMed2004

Studies with natural and anthropogenic iodine isotopes: iodine distribution and cycling in the global environment.

Iodine is an important trace element in geological and biological processes. We summarize here recent results and new data of experiments and observations carried out to improve the understanding of concentration levels and behavior of natural and anthropogenic iodine nuclides in the global environment. The distribution of stable iodine in the Earth's crust was estimated using concentration data in a suite of representative samples and the influence of subduction on the marine iodine cycle was investigated using (129)I systematics on iodine-rich brines from Japan. The importance of microorganisms for the natural iodine cycle is shown in recent studies of iodine sorption on soil and of iodine volatilization from terrestrial and marine environments. Levels of anthropogenic (129)I were measured in samples collected around a spent fuel reprocessing plant in Japan.

Environmental Monitoring↗
PubMed1980

Iodine isotopes in radiation hygiene.

Radioactive isotopes of iodine rank among the factors of anthropogenic contamination of the biosphere. The review presents a radiation-hygienic survey of literary data and the author's own results of studies of the metabolism and biological effect of radioactive isotopes of iodine. The risk of their intake by human organism is evaluated. Particular attention is paid to 132-135I and 129I. Data on biological danger of these isotopes are scarce in the literature.

Animals↗
PubMed1982

Simple labeling of omega-phenylfatty acids by iodine isotope exchange.

Within 1 h 15-(p-iodophenyl)-pentadecanoic acid (p-IPPA) can easily be labeled with 123I by iodine-isotope exchange. In contrast to the electrophilic aromatic substitution procedure this method enables a 95% radiochemical yield. The so formed p-123IPPA can be used without the application of any complicated separation techniques. By comparison with commercially available 17-[123I]iodoheptadecanoic acid (123IHA) p-123IPPA shows a remarkably higher uptake in a rabbit heart. Additionally the background activity of p-123IPPA proved to be lower than that measured with 123IHA. p-123IPPA thus indicating its suitability for routine applications in nuclear medical heart diagnosis.

Animals↗
PubMed2002

PET quantitation and imaging of the non-pure positron-emitting iodine isotope 124I.

A series of PET studies using phantoms is presented to characterize the imaging and quantitative performance of the positron-emitting iodine isotope 124I. Measurements were performed on the 2D-PET scanner GE 4096+ as well as on the Siemens PET scanner HRR+ operated in both 2D and 3D modes. No specific correction was applied for the gamma-rays emitted together with the positrons. As compared to 18F, in studies with 124I there is a small loss of image resolution and contrast, and an increase in background. The quantitative results varied between different scanners and various acquisition as well as reconstruction modes, with an average relative difference of -6 +/- 13% (mean+/-SD) in respect of the phantom radioactivity as measured with gamma-ray spectroscopy. We conclude that quantitation of a radiopharmaceutical labelled with 124I is feasible and may be improved by the development of specific corrections.

Brain↗
PubMedDate not supplied

Synthesis of structurally identical fluorine-18 and iodine isotope labeling compounds for comparative imaging.

The synthesis of a benzophenone-based labeling compound designed for comparative imaging studies with both in vivo positron emission tomograph (PET) and single-photon computed tomography (SPECT) and ex vivo autoradiography is described. The new compound can be labeled with either F-18 or iodine radioisotopes to give two different radioisotopmers: N-[2-fluoro-5-(3-[I-131]iodobenzoyl)benzyl]-2-bromoacetamide (1) and N-[2-[F-18]fluoro-5-(3-iodobenzoyl)benzyl]-2-bromoacetamide (2). Compound 1 and 2 have a 2-bromoacetyl group, which can be used to conjugate with biomolecules through a nucleophilic substitution reaction. Compound 1 was synthesized from the corresponding tributyltin derivatives via an oxidative destannylation reaction, and compound 2 was prepared via a four-step radiosynthesis (nucleophilic aromatic substitution, reduction, oxidation, and alkylation) starting from 4-(N,N,N-trimethylammonio)-3-cyano-3'-iodobenzophenone triflate. A remarkably high radiochemical yield (>90%) was achieved for the F-18 nucleophilic aromatic substitution under mild conditions (room temperature in less than 10 min), indicating the structural advantage of the designed molecule to facilitate the F-18 for trimethylammonium substitution in the presence of two electron-withdrawing groups (nitrile and carbonyl). The overall radiosynthesis time for compound 2 is less than 3 h after end of bombardment (EOB) with an unoptimized radiochemical yield of about 2% (not decay corrected) and specific activity of 0.8 Ci/micromol at EOB. The radiolabeling precursors for compound 1 and 2 were synthesized via a carbon-carbon bond-forming reaction between 2-substituted-5-lithiobenzonitrile and 3-substituted benzaldehyde derivatives. Compounds 1 and 2 should allow us to label biomolecules with F-18 or iodine isotopes and gives structurally identical products, which are expected to have identical biological properties and should be useful for comparative imaging studies.

Acetamides↗
PubMed2005

Usefulness of combination of high-resolution ultrasonography and dual-phase dual-isotope iodine 123/technetium Tc 99m sestamibi scintigraphy for the preoperative localization of hyperplastic parathyroid glands in renal hyperparathyroidism.

BACKGROUND: The usefulness of both dual-phase dual-isotope iodine 123 ( 123 I)/technetium Tc 99m ( 99m Tc) sestamibi scintigraphy and ultrasonography for the detection of hyperplastic parathyroid glands secondary to renal hyperparathyroidism is rarely addressed; most studies focus on primary hyperparathyroidism. However, it may be crucial to identify and accurately localize hyperplastic glands before surgery. METHODS: To study the usefulness of high-resolution ultrasonography (performed by both the radiologist and surgeon) and dual-phase dual-isotope 123 I/ 99m Tc sestamibi scintigraphy in patients with renal hyperparathyroidism, a series of 20 patients consecutively referred for parathyroidectomy was studied prospectively. Results of both examinations, independently scored, were correlated with surgical and histopathologic findings for each hyperplastic parathyroid gland localization. RESULTS: All parathyroid glands except 1 were found during primary surgery consisting of a subtotal parathyroidectomy (success rate, 99%). The missed gland was removed successfully 1 month later. Neither supernumerary nor ectopic glands were found. Mean weight of totally removed parathyroid glands was 633 mg. Ultrasonography detected 75% of hyperplastic parathyroid glands; dual-phase 123 I/ 99m Tc sestamibi scintigraphy, 66%; and a combination of both, 88%. Most missed glands at scintigraphy corresponded to superior glands, whereas false-negative results at ultrasonography correlated with low gland weight. CONCLUSION: Combined ultrasonography and 123 I/ 99m Tc sestamibi scintigraphy should be considered for routine use to localize hyperplastic parathyroid glands in patients with renal hyperparathyroidism undergoing surgery. We suggest performing scintigraphy first, before ultrasonography, to guide the radiologist to areas of hyperfunctioning glands. In our experience, this proved very helpful in achieving a high surgical success rate in patients with renal hyperparathyroidism, especially when the surgeon visualizes the parathyroid glands at ultrasonography.

Adult↗