Abstract:
Targeted radionuclide therapy (TRT), the use of radiopharmaceuticals to target and irradiate tumour cells, has become an important method for cancer treatment. The radiolanthanide Lutetium-177 (
177Lu) is a medium-energy beta radionuclide with a suitable electron energy range for treatment of small tumors, and has been widely used in clinical targeted radionuclide therapy. The radiolanthanide terbium-161 (
161Tb) isotope has similar decay properties, biochemical properties, and in vivo characteristics to
177Lu, and it releases more Auger electrons and internal conversion electrons than
177Lu. It has been proposed, and preclinically demonstrated, that
161Tb is a better alternative to
177Lu for the treatment of small prostate cancer lesions. According to the conferences and published articles on nuclear medicine in recent years, more and more attention has been paid to the preparation of
161Tb nuclides and the development of its labeled drugs in the field of radiopharmaceuticals. However, there is no mature production process for
161Tb internationally, which has seriously hindered the clinical research of
161Tb-labeled drugs. Currently, there are two main methods for the preparation research of
161Tb. One is to produce
161Tb through an accelerator, and the other is to produce carrier-free
161Tb using a high-throughput reactor or a fission neutron source via the reaction
160Gd(n, γ)
161Gd→
161Tb. Commercial production of
161Tb using an accelerator is very difficult. The most common method internationally is to irradiate enriched
160Gd
2O
3 target material with a reactor or a fission neutron source to produce carrier-free
161Tb. According to the investigation, there are several research institutes or companies at home and abroad are carrying out relevant research on the preparation of
161Tb. Chengdu Gaotong Isotope Co., Ltd. (CNNC) used enriched
160Gd
2O
3 target material irradiated by a reactor with neutron flux of about 1-2×10
14 n·cm
−2·s
−1 to separate a large amount of irradiated
160Gd by a two-column method to prepare no carrier-added
161TbCl
3 nuclide solutions. Chengdu Gaotong Isotope Co., Ltd. has carried out many experiments on the preparation of
161Tb from
160Gd target material enriched. After separation and purification, the radionuclide purity, radiochemical purity and activity of
161TbCl
3 nuclide solution were detected by high purity germanium gamma spectrometer, activity meter and other instruments and equipment. The results showed that the radionuclide solution of
161TbCl
3 with radionuclide purity greater than or equal to 99.9%, radiochemical purity greater than 99% and chemical purity was obtained after the separation and purification of
161Gd target material enriched by irradiation in the reactor.