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Abstract  

This paper describes a method for the preparation of 125I brachytherapy sources. The process consist of surface oxidation of a silver rods [0.5 mm (ϕ) × 3 mm (1)], formation of a thin silver bromide over layer and finally replacement of bromide ions by 125I ions. The effect of various parameters such as 125I feed activity, iodide carrier concentration and reaction time were examined and optimized for maximum impregnation of 125I activity on the substrate. Sources containing 74–111 MBq (2–3 mCi) 125I on a silver matrix could be prepared and encapsulated in titanium capsules [0.8 mm (ϕ) × 4.75 mm (1)] using Nd: YAG laser. Quality assurance tests to ensure nonleachability, uniform distribution of activity and leak tightness that are necessary before application were evaluated.

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Abstract  

In the present study, ytterbium-169 was produced via the 169Tm(p, n)169Yb nuclear process at the AMIRS (Cyclone-30, IBA, Belgium) cyclotron, irradiating Tm2O3 with proton particles of 15 MeV primary energy and 20 μA current for 20 min. Deposition of Tm2O3 on Cu substrate was carried out via by the sedimentation method. The 543 mg of thulium(III)oxide with 108 mg of ethyl cellulose and 8 mL of acetone were used to prepare a Tm2O3 layer of 11.69 cm2. Yields of about 0.643 MBq 169Yb per μAh were experimentally obtained. 169Yb was separated in 80 ± 5% radiochemical yield using liquid–liquid extraction. Solvent extraction of no-carrier-added 169Yb from irradiated thulium(III)oxide target hydrochloric solution was investigated using di-(2-ethylhexyl)phosphoric acid (HDEHP).

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Abstract  

The Nitinol stent was bombarded in a cyclotron at a flux rate of 4 μA/cm2 to produce 48V via 48Ti (p, n) 48V reaction. In this study dose distribution of 48V radioactive stent was investigated for renal arteries. Version X-2.6 of the MCNP Monte Carlo radiation transport system code was employed to calculate dose distribution around the stent. As 48V is a mixed gamma and beta particle emitter, two separate runs of MCNP for both beta and gamma particles were performed and the total deposited dose was acquired by adding the two mentioned values. In order to verify the simulation, the calculated results have been compared with previous published data for the source. Calculated results show high dose gradient near the stent and the maximum amount of dose deposits at the vessel wall. According to (AAPM) TG-60/149 protocol, the dosimetric parameters, including geometry function, G(ρ,z), radial dose function, g L(ρ), and anisotropy function, F(ρ,z), were also determined.

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Abstract  

An indigenous technology for the production of 125I brachytherapy sources has been developed for the management of intraocular cancer. This indigenous method of producing 125I seeds represents a new paradigm, and a thorough quality evaluation of the seeds in accordance with Atomic Energy Regulatory Board (AERB) of India was carried to ensure their safety during therapy. In this current work, we describe an overview of our experience, the efforts made in establishing enviable quality analysis of 125I seeds to ensure their safety in episcleral plaque brachytherapy.

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Summary  

The radionuclide 192Ir has been increasingly used as a brachytherapy source and manufactured in different geometry forms (thin wires, hairpins, needles or point sources). A procedure for the characterization of the activity content of 192Ir wire sources was developed in order to establish the secondary standard activity measurement system based on the ionization chamber set up at Brazilian National Laboratory for Ionizing Radiation Metrology (LNMRI). Firstly, the ion current of the ionization chamber is measured and, subsequently, the activity is determined in a destructive analysis. This procedure enables obtaining the calibration factor for wire sources that can be used for further activity determination of similar sources in a non-destructive analysis. Accurate activity determination is needed for dosimetric measurements and for helping the manufacturers to improve its quality control programs.

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Abstract  

In order to develop an 125I seed for brachytherapy of prostate cancer, a carrier body consisting of Al2O3 and silver powder was developed. To optimize the adsorption conditions of 125I on the rods, various experiments were performed. The adsorption capacity was more than 95% after 4 hours at a volume of 50 μl containing about 5 mCi of 125I. Dosimetric properties were measured for the radial and longitudinal directions. Variations were below 11% in the longitudinal distribution and 5% in the radial distribution. This method is effective for the preparation of 125I seeds to be used in brachytherapy treatment.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Jiaheng He, Hu Song, Yuan Jian, Lin Jiang, Wenbin Zhong, Xinliang Li, Zongping Ma, and Guoping Liu

Abstract  

The adsorption of 125I on palladium coated silver wires was studied in this paper. The experimental conditions, e.g., reaction volume, carrier concentration, reaction time, reaction temperature, pH of the reaction mixture, were systematically optimized to obtain quantitative adsorption of 125I on palladium coated silver wires. The experiments were performed using potassium iodide 8–9 μg as carrier in a reaction volume of 100 μL incubated in ~50 °C water bath for ~1 h, and the pH of the reaction system was controlled at 2–2.5. The distribution of activity on palladium coated silver wire was uniform, and the source cores can be easily sealed by laser welding into titanium capsules.

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References 1 Hadjiev, J., Antal, G., Antalffy, Zs., et al.: A novel technique with a flexible applicator for MRI-based brachytherapy of cervical cancer

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A brachytherapia szerepe az ajak-szájüregi daganatok kuratív ellátásában

The role of brachytherapy in the curative treatment of oral cavity tumors

Orvosi Hetilap
Authors: Örs Ferenczi, Tibor Major, and Zoltán Takácsi-Nagy

] 5 Takácsi-Nagy Z, Martínez-Mongue R, Mazeron JJ, et al. American Brachytherapy Society Task Group report: combined external beam irradiation and interstitial brachytherapy for base of tongue

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CA Meeuwis 1997 A new applicator design for endocavitary brachytherapy of cancer of nasopharynx Radiother Oncol 45 95

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