Radiochemical Separation of 161Tb from Gd/Tb Matrix Using Ln Resin Column

Terbium-161 (161Tb) is a potential radiolanthanide due to its favorable properties for treatment small size of cancer. Preliminary study on radiochemical separation of 161Tb from Gd/Tb matrix using Ln resin column based on extraction chromatography method has been carried out. 161Tb radionuclide was produced by irradiation of natural Gd2O3 target through neutron thermal bombardment at G.A. Siwabessy Multipurpose Reactor. Fractions eluted from the column containing Gd/Tb matrix of irradiated natural Gd2O3 target were identified and quantified using a γ-rays spectrometer with HP-Ge detector coupled to a multichannel analyzer. The results show that the optimum condition on 161Tb separation from irradiated Gd2O3 target with radionuclide purity 99.27 ± 0.30% was obtained using HNO3 solution with concentration of 0.8 and 3 N to separate gadolinium and terbium isotope, respectively. The yield of 161Tb obtained from the separation was 61.21 ± 2.05% and Gd recovered was 97.15 ± 2.23%. Based on this experiment, 161Tb has been separated from irradiated natural gadolinium oxide target with high radionuclide purity.

KARAKTERISASI FISIKO-KIMIA RADIOISOTOP 149Pm HASIL IRADIASI BAHAN SASARAN 148Nd ALAM

ABSTRAK KARAKTERISASI FISIKO-KIMIA RADIOISOTOP 149Pm HASIL IRADIASI BAHAN SASARAN 148Nd ALAM. Penyakit kanker merupakan salah satu masalah utama yang dihadapi Indonesia di bidang kesehatan. Radioisotop pemancar-β- dengan aktivitas jenis tinggi dapat digunakan untuk penandaan biomolekul sebagai radiofarmaka spesifik target untuk terapi sel kanker. Promesium-149 (149Pm) merupakan salah satu radiolantanida pemancar-β- yang me-miliki energi beta (Eβ-)maksimum sebesar 1,07 MeV (95,9 %) dan dapat dipertimbangkan untuk digunakan pada terapi kanker berdasarkan sifat nuklir yang dimilikinya. Radioisotop 149Pm dapat dibuat dengan cara tidak langsung melalui reaksi inti (n,γ) di reaktor nuklir menggunakan bahan sasaran isotop 148Nd (neodymium-148) dan radioisotop 149Pm yang dihasilkan adalah bebas pengemban (carrier free) sehingga memiliki aktivitas jenis tinggi. Pada penelitian ini digunakan bahan sasaran Nd2O3 alam yang diiradiasi selama ± 4 hari di Central Irradiation Position (CIP) RSG-G.A.Siwabessy – Serpong pada fluks neutron termal ~1014 n.cm-2.det-1. Radioisotop 149Pm dipisahkan dari bahan sasaran Nd2O3 hasil iradiasi menggunakan metode kromatografi ekstraksi. Larutan radioisotop 149PmCl3 yang dihasilkan dikarakterisasi secara fisiko-kimia meliputi penentuan kemurnian radiokimia menggunakan metode kromatografi kertas dan elektroforesis kertas. Kemurnian radionuklida ditentukan menggunakan spektro-meter-γ dengan detektor HP-Ge yang dilengkapi multichannel analyzer (MCA). Larutan 149PmCl3 yang diperoleh berupa larutan jernih, memiliki pH 2 dan konsentrasi radioaktif 4,2 – 7,4 mCi/mL. Larutan 149PmCl3 memiliki kemurnian radiokimia 99,70 ± 0,23% dan kemurnian radionuklida setelah pendinginan selama 9 hari sebesar 98,58 ± 0,44%. Larutan 149PmCl3 stabil selama 2 minggu pada temperatur kamar. Larutan radioisotop 149PmCl3 memiliki karakteristik fisiko-kimia yang memenuhi persyaratan untuk digunakan dalam pembuatan radiofarmaka ABSTRACT PHYSICO - CHEMICAL CHARACTERIZATION OF 149Pm RADIOISOTOPE FROM IRRADIATED NATURAL 148Nd TARGET. Cancer is one of the major problems encountered in the field of health in Indonesia. A beta-emitting radioisotope with high specific activity can be used for labeling of biomolecules as a targeted radiopharmaceutical for cancer therapy. Promethium-149 (149Pm) is one of beta-emitting radiolanthanides with beta energy (Eβ-) maximum of 1.07 MeV (95.9%) and can be considered to be used for cancer therapy based on its nuclear properties. Radioisotope of 149Pm can be produced by indirect methode through (n,γ) reaction in nuclear reactor using 148Nd (neodymium-148) target material and 149Pm was produced as a carrier free radioisotope, so that it has high specific activity. In this study, natural Nd2O3 target was irradiated for ± 4 days in central irradiation position (CIP) of RSG-G.A. Siwabessy – Serpong at a thermal neutron flux of ~ 1014 n.cm-2.sec-1. Radioisotope of 149Pm was separated from irradiated of Nd2O3 target using extraction chromatography method. The physico-chemical characterization of 149PmCl3 solution was studied involves the determination of its radiochemical purity using paper chromatography and paper electrophoresis methods. The radionuclide purity was determined using a γ-spectrometer with HP-Ge detector and coupled with a multichannel analyzer (MCA). 149PmCl3 was obtained as a clear solution, has a pH of 2 and radioactive concentration of 4.2 to 7.4 mCi/mL. 149PmCl3 solution has radiochemical purity of 99.70 ± 0.23% and radionuclide purity after cooling for 9 days of 98.58 ± 0.44%. 149PmCl3 solution was stable for 2 weeks at room temperature. 149PmCl3 solution has the physico-chemical characteristics that meet requirements for use in preparation of radiopharmaceuticals.

Gamma-ray spectrometric measurement of radionuclide purity of radiopharmaceuticals contained in bottle samples

The radionuclide purity of a radiopharmaceutical product is usually measured by gamma-ray spectrometry with various measurement geometries. The importance of this test is that the radionuclide impurities, if present, result in an increase in the radiation dose to the patient without contributing to diagnostic information and in some cases may also interfere with the marking molecules and affect the proper conduct of diagnostic examination. In this work, gamma-ray spectrometry is used to determine the amounts of impurities by adopting as measurement geometry the same bottle containing eluted or prepared radiopharmaceuticals. In addition to high-purity germanium semiconductor detectors, the usefulness of NaI(Tl) and LaBr3(Ce) scintillators in routine operation is also examined. For the latter detectors, an evaluation of the minimum detectable activity was carried out and compared with the activity limits established by the regulation rules. The main cases considered are related to the first elution of 99Mo-99mTc generators and samples of 18F-FDG (fluoro-deoxy-glucose) to be used for positron emission tomography diagnostics.