[en] Introduction: The aim of the present study was to develop and demonstrate a viable method for the reactor production of ¹⁶⁹Er with acceptable specific activity using moderate flux reactor and its purification from ¹⁶⁹Yb following electrochemical pathway based on mercury-pool cathode to avail ¹⁶⁹Er in radionuclidically pure form essential for its therapeutic use. Methods: Erbium-169 was produced in reactor by neutron bombardment of isotopically enriched (98.2% in ¹⁶⁸Er) erbium target at a thermal neutron flux of ∼ 8 × 10¹³ n.cm^-2.s^-1 for 21 d. A thorough optimization of irradiation parameters including neutron flux, irradiation time and target cooling time was carried out. The influence of different experimental parameters for the quantitative removal ¹⁶⁹Yb from ¹⁶⁹Er was investigated, optimized and based on the results; a two-cycle electrochemical separation procedure was adopted. The suitablility of purified ¹⁶⁹Er for application in radiation synovectomy and bone pain palliation was ascertained by carrying out radiolabeling studies with hydroxypaptite (HA) particles and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminomethylene phosphonic acid (DOTMP), respectively. Results: Thermal neutron irradiation of 10 mg of isotopically enriched (98.2% in ¹⁶⁸Er) erbium target at a flux of ∼ 8 × 10¹³ n.cm^-2.s^-1 for 21 d followed by a two-step electrochemical separation of ¹⁶⁹Yb impurity yielded ∼ 3.7 GBq (100 mCi) of ¹⁶⁹Er with a specific activity of ∼ 370 MBq/mg (10 mCi/mg) and radionuclidic purity of > 99.99%. The reliability of this approach was amply demonstrated by performing several production batches, where the performance of each batch remained consistent. The utility of the purified ¹⁶⁹Er was demonstrated in the radiolabeling studies with HA particles and DOTMP, wherein both the radiolabeled products were obtained with high radiolabeling yield (> 99%). Conclusions: A viable strategy for the batch production and purification of ¹⁶⁹Er, suitable for therapeutic applications, has been developed and demonstrated

[en] ¹⁸⁸ReN-DEDC/lipiodol (DEDC – diethyldithiocarbamate) is a clinically established agent for the therapy of unresectable hepatocellular carcinoma (HCC). The original two-vial method for the preparation of ¹⁸⁸ReNDEDC/ lipiodol involved compulsory addition of stipulated amount of glacial acetic acid (GAA), which was cumbersome in a busy radiopharmacy. Moreover, an error in glacial acetic acid volume had significant impact on overall yield of ¹⁸⁸ReN-DEDC complex. Herein, we present a two-vial kit for quick, efficient and glacial acetic acid free preparation of ¹⁸⁸ReN- DEDC/lipiodol. Sterile two-vial freeze-dried kits, vial 1 containing N-methyl-S-methyl dithiocarbazate (DTCz) (2 mg), SnCl2.2H2O (0.8 mg), oxalic acid (28 mg), sodium ascorbate (10 mg) and vial 2 containing DEDC (100 mg), were prepared in a clean room facility. In the first step, ¹⁸⁸ReN-core was prepared by adding freshly eluted sodium perrhenate (1-5 mL, ~3700 MBq), obtained from a tungsten-¹⁸⁸/rhenium-¹⁸⁸ generator, into kit vial 1. Vial 1 was gently shaken to dissolve the contents and incubated at room temperature for 5 min. In the second step, kit vial 2 was reconstituted with 2 mL of physiological saline. About 1 mL of the reconstituted solution was transferred into kit vial 1. Subsequently, vial 1 was sequentially incubated at room temperature for 15 min, at 65C for 5 min and then cooled to room temperature. To extract ¹⁸⁸ReN-DEDC complex, lipiodol (2-3 mL) was added into kit vial 1 and the contents are mixed for 10 min. Clear separation of two layers was achieved by centrifugation of vial 1 at 1600g for another 10 min. Subsequently, lipiodol layer containing ¹⁸⁸ReN-DEDC was carefully separated for further use. The quality control of ¹⁸⁸ReN-DEDC/lipiodol was carried out by TLC in dichloromethane. Developed strip was analysed on a TLC scanner and radiochemical purity (RCP) was determined from peak area measurements.

[en] ⁵⁴Mn, a reference standard required for calibration of radiation detectors and as a X-ray source is produced by (n,p) reaction on ⁵⁴Fe by neutron irradiation of natural Fe₂O₃ target. Radiochemical separation of ⁵⁴Mn from co-produced ⁵⁹Fe and ⁶⁰Co radionuclides and bulk iron was studied by a combination of anion exchange and solvent extraction in hydrochloric acid media to recover the respective radiochemicals. Preliminary uptake studies were carried out on the Dowex 1x8 anion exchanger and solvent extraction in diisopropyl ether using respective radiotracers at different hydrochloric acid concentrations to optimise the conditions of radiochemical separation of the individual radioisotopes produced. (author)

[en] MoO₃ samples procured from commercial sources were evaluated for their suitability as targets for regular production of ⁹⁹Mo by neutron activation in the reactor for use as a source of ^99mTc in nuclear medicine. The radionuclidic impurities produced along with ⁹⁹Mo were determined by gamma ray spectrometry. The possibility of these radionuclidic impurities and their decay products being carried into ^99mTc fraction during solvent extraction was studied to understand the implications. The presence of ⁵¹Cr, ⁵⁹Fe, ⁶⁰Co, ¹⁸⁸W impurities in ⁹⁹Mo produced was found to be undesirable as they are extracted with ^99mTc and however the levels of these impurities were found to be insignificant and comparable with the MoO₃ targets being used. (author)

[en] ¹⁸⁸Re (V)-Dimercaptosuccinicacid (DMSA) is a therapeutic radiopharmaceutical for treatment of medullary carcinoma of thyroid as well as some soft tissue tumours. Present work describes the development of a single-vial kit for the preparation of ¹⁸⁸Re (V)-DMSA at room temperature using ¹⁸⁸Re obtained from a ¹⁸⁸W-¹⁸⁸Re generator. Rhenium-188 activity in the form of Na¹⁸⁸ReO₄ was obtained from ¹⁸⁸W/¹⁸⁸Re generator (Polatom). Meso-DMSA, L-ascorbic acid, sodium oxalate were purchased from M/s. Sigma-Aldrich, USA. To prepare a batch of 10 lyophilized kits, 22 mg DMSA, 55 mg of ascorbic acid and 55 mg sodium oxalate were dissolved in 4.5 mL of 53 mM sodium bicarbonate solution. To this, 4.4 mg of SnCl_2.2H₂O dissolved in 1 mL of 1.0 M HCl was added and thoroughly mixed. The solution was then filtered through 0.22 micron Millipore filter and 0.5 mL aliquots were dispensed into 10 mL autoclaved glass vials. The contents of the glass vials were frozen in a dry ice bath and subsequently lyophilized. Radiochemical purity (RCP) of the complex was determined by TLC in acetone and saline as well as by HPLC analyses (C18 reversed phase column, solvent A = water with 0.1% trifluroacetic acid; solvent B = acetonitrile with 0.1% TFA; Gradient - 0 min - 10% B, 5 min - ,10% B, 15 min - 25% B, 25 min - 25% B). Conventional method of ¹⁸⁸Re (V)-DMSA preparation involves heating in boiling water bath for 30 min to obtain acceptable RCP. However, presence of oxalate in the reaction mixture could significantly enhance the complexation kinetics and acceptable level of RCP could be achieved by incubating at room temperature for 15 min. Under optimized conditions, 2 mg of DMSA, 5 mg of ascorbic acid, 5 mg sodium oxalate and 0.4 mg SnCl_2.2H₂O at pH 2, when incubated at room temperature for 15 min resulted in ¹⁸⁸Re (V)-DMSA complex with >95% RCP. Same formulation was subsequently transformed into a lyophilized kit. To prepare ¹⁸⁸Re (V)-DMSA using lyophilized kit, 1 mL of freshly eluted Na¹⁸⁸ReO₄ was added to the vial and incubated at room temperature for 15 minutes. RCP of ¹⁸⁸Re (V)-DMSA was determined by TLC in acetone (Rf (¹⁸⁸ReO₂ + ¹⁸⁸Re (V)DMSA) - 0; Rf (Na¹⁸⁸ReO₄) - 0.9) and saline (Rf (¹⁸⁸ReO₂) - 0; Rf (¹⁸⁸Re (V)DMSA + Na¹⁸⁸ReO₄) - 0.9). HPLC analysis of ¹⁸⁸Re (V)-DMSA complex prepared using the kit showed a mixture of four isomers which is as expected and also consistent with earlier reports. However, we observed that the ratio of the isomeric species formed are not the same as in the case of ¹⁸⁸Re (V)-DMSA prepared by conventional method and using the oxalate method. A single vial lyophilized kit for preparation of ¹⁸⁸Re (V)-DMSA at room temperature was developed. Using these kits, ¹⁸⁸Re (V)-DMSA could be prepared consistently in RCP >95%. Impact of difference in the isomeric ratio in ¹⁸⁸Re (V)-DMSA prepared by conventional method, without oxalate, and kit method can be ascertained only after comparing their in vivo distribution. (author)

[en] The aim of the present study was to develop and demonstrate a viable method for the reactor production of ¹⁶⁹Er with acceptable specific activity using moderate flux reactor and its purification from ¹⁶⁹Yb following electrochemical pathway based on mercury-pool cathode to avail ¹⁶⁹Er in radionuclidically pure form essential for its therapeutic use. Erbium-169 was produced in reactor by neutron bombardment of isotopically enriched (98.2% in ¹⁶⁸Er) erbium target at a thermal neutron flux of ~8´1013 n.cm^-2.s^-1 for 21 d. A thorough optimization of irradiation parameters including neutron flux, irradiation time and target cooling time was carried out. The influence of different experimental parameters for the quantitative removal ¹⁶⁹Yb from ¹⁶⁹Er was investigated, optimized and based on the results; a two-cycle electrochemical separation procedure was adopted. The suitability of purified ¹⁶⁹Er for application in radiation synovectomy and bone pain palliation was ascertained by carrying out radiolabeling studies with hydroxypaptite (HA) particles and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminomethylene phosphonic acid (DOTMP), respectively. Thermal neutron irradiation of 10 mg of isotopically enriched (98.2% in ¹⁶⁸Er) erbium target at a flux of ~8´1013 n.cm^-2.s^-1 for 21 d followed by a two-step electrochemical separation of ¹⁶⁹Yb impurity yielded ~3.7 GBq (100 mCi) of ¹⁶⁹Er with a specific activity of ~370 MBq/mg (10 mCi/mg) and radionuclidic purity of >99.99%. The reliability of this approach was amply demonstrated by performing several production batches, where the performance of each batch remained consistent. The utility of the purified ¹⁶⁹Er was demonstrated in the radiolabeling studies with HA particles and DOTMP, where in both the radiolabeled products were obtained with high radiolabeling yield (>99%). A viable strategy for the batch production and purification of ¹⁶⁹Er, suitable for therapeutic applications, has been developed and demonstrated. (author)

[en] Rhenium-188 is an attractive candidate for a wide variety of radiotherapeutic applications. Its high energy beta particle (E_β = 2.1 MeV) with concurrent emission of a gamma photon (E_γ = 155 keV) suitable for imaging as well as its versatile chemistry for radiolabeling with a variety of biological vectors, make "1"8"8Re an attractive radioisotope for treatment of a wide variety of cancers such as metastatic bone cancer, non-resectable liver cancer, non-melanoma skin cancers and radiosynovectomy of big joints. Pentavalent "1"8"8Re-dimercaptosuccinic acid ("1"8"8Re (V) DMSA) is a beta-emitting analogue of "9"9"mTc (V) DMSA, a tracer that is taken up in a variety of tumors and bone metastases. The aim of the present study is to evaluate the stability of ("1"8"8Re (V) DMSA), its uptake in human osteocarcinoma (MG-63) cells and human breast adenocarcinoma (MCF-7) cell lines as well as to assess its cellular toxicity

[en] The ability to radiolabel the bio-active molecule is an important consideration in separation of therapeutic radiopharmaceuticals. In this context, ¹¹¹Ag has suitable physical characteristic for being used in therapy. ¹¹¹Ag having t_1/2 7.45d, 1.09 MeV beta emission and 245.4 KeV (1.24%), 342.1KeV (6.68%) gamma ray emissions is suited for treatment of localized tumor in addition to its application as a radiochemical

[en] Radiation induced discolouration of three dyes namely basic yellow 11 (BY), basic red 29 (BR) and gentian violet (GV) has been carried out. Extent of discolouration varies with the nature of dye and its concentration. Presence of H₂O₂ increases the sensitivity of all the dyes studied. However there is an optimum concentration of H₂O₂ above which there is no further increase in sensitization with increasing concentration of H₂O₂. The sensitization effect of TiO₂ is dependent on nature of dye. (author)

[en] Time differential perturbed angular correlation (TDPAC) study of ¹⁸¹Hf in two room temperature ionic liquids, namely, 1-octyl, 3-methyl imidazolium bromide (aqueous soluble) and 1-octyl, 3-methyl imidazolium phosphorous hexafluoride (non-aqueous) has been carried out. The results of ¹⁸¹Hf in aqueous ionic liquid show static interaction of electrostatic nature between Hf⁴⁺ and the Br^- of the ionic liquid. In the case of aqueous insoluble ionic liquid, time dependent spectra were observed indicating the major role of the rotational dynamics. The correlation time obtained for the complex of Hf with TRPO from 30% TRPO in RTIL was found to be more than that from 30% TRPO in xylene. (author)