For many years, the National Center for Nuclear Research has been a leading producer of radioactive iodine used in medical treatment and diagnosis. The latest irradiation method will allow to increase the activity of the material obtained, reduce the amount of heat released during production, and reduce the amount of radioactive waste.
The processes of this production are being investigated and improved by scientists from the Reactor Research Division.
Iodine-131 is a widely used radioisotope that decomposes by emitting a beta particle. It is used in the treatment of hyperthyroidism and some thyroid cancers that have the ability to absorb this ingredient. Iodine-131 is also used as a marker in radiotherapy, for example metaodobenzylguanine -131I (131I-MIBG) in the treatment of pheochromocytoma and neuroblastoma – the NCBJ is mentioned in the version sent to PAP.
Currently, tellurium dioxide, used as a target in the production of iodine-131, is the most frequently irradiated material in the Maria reactor, explains the engineer. I quote Anna Talarowska from the Reactor Research Department in the statement. Approximately one hundred forty tanks of TeO2 are loaded into its channels. More than 3000 containers are irradiated annually in the vertical ducts of the Maria reactor. After treatment in OR POLATOM, iodine is delivered in the form of radiopharmaceuticals or radiochemical solutions to recipients all over the world. Will be allowed. Modernizing tellurium irradiation process with more efficient production.
Iodine-131 is formed as a result of the transformation of the unstable β-tellurium isotope-131mTe. The latter is produced by capturing an atom of tellurium-130 neutrons. The conditions for neutron capture by 130 Te prevail in research reactors such as the MARIA reactor. The cores of these reactors are designed in such a way that it is possible to place the trays with the target material for a specific and ideal irradiation period.
“The so-called scientist explains natural tellurium, that is, which occurs naturally in nature. – It consists of eight stable isotopes. The isotope of 130Te is only about 34 percent. Natural tellurium. The remaining stable isotopes of tellurium have a neutron capture cross section greater than 130 Te.” Due to the high values of tellurium cross-sections in the field of thermal neutrons, especially epithelial neutrons, significant heat generation occurs as a result of intense nuclear reactions. This is especially true for the isotope of 123Te (0.9% of natural tellurium), where the active neutron capture cross-section is greater than 1,000 times in the case of 130Te. This means that neutrons react with 123Te much easier than with 130Te, and this is an unwanted effect.
The essence of the proposed change in the production method is irradiation of the disks with natural tellurium enriched in 130 to 95%. (Instead of the current rate of 33.8%). This will reduce the number of interactions of the neutrons with other tellurium isotopes, which are a non-useful part of the final product, and significantly increase the irradiation efficiency, explains NCBJ. He adds that the new method of irradiation of targets will allow greater activity for 131I, while reducing the amount of production waste and more efficient use of the reactor’s vertical channels.
“Increasing the activity of the final product, reducing the amount of waste and improving the use of channels is a step towards more efficient production, and thus wider access to this radioisotope. We are constantly analyzing the irradiation processes in order to maximize their effects as possible” – confirms the engineer. Talarosska.
According to the NCBJ, the results of the analyzes obtained so far allow to draw two main conclusions: the use of enriched tellurium significantly increases production efficiency and reduces heat generation in tanks.
“Experimental work is currently underway, and its results will allow for a final evaluation. From the Maria reactor point of view, it is necessary to prepare documentation, including instructions and procedures” – reads the release.
PAP – Science in Poland