On January 30, a reporter from the Global Times learned from the China National Nuclear Corporation that on the same day, the construction of the world's highest-power solution-type medical isotope reactor designed and built by the China Nuclear Power Research and Design Institute (hereinafter referred to as the Nuclear Power Institute), a subsidiary of the China National Nuclear Corporation, officially started construction. It is understood that once the isotope reactor is completed and put into operation, the annual production capacity of molybdenum-99 and iodine-131 medical isotopes can be achieved by 100,000 curies and 20,000 curies respectively in the future, which will solve the problem of long-term dependence on imports and restrictions on the two isotopes, meet the needs of tens of millions of domestic nuclear medicine diagnosis and treatment, and drive the output value of downstream industries to more than 4 billion yuan.
Medical isotopes are a successful application of radioisotopes in the medical field. In daily physical examinations, the carbon-14 used in the breath test for the detection of Helicobacter pylori is a typical medical isotope.
Carbon-14 isotope developed by CNNC Nuclear Power Institute (Source: CNNC)
Zhao Guang, director of the medical isotope project department of the Nuclear Power Institute, told the Global Times that dozens of medical isotopes, including carbon-14, iodine-131, iodine-125 and strontium-89, are important forces for the detection and treatment of major diseases. "Take iodine-131, for example, a medical isotope that is an important element in the treatment of thyroid disease. It can be concentrated, oxidized and organicized by thyroid follicular cells, and can destroy thyroid cells through ionization, which is used to treat hyperthyroidism and differentiated thyroid cancer, and does not produce rays that cause damage to the human body during the treatment process, which is very safe. ”
However, for a long time, the mainland has mainly relied on imports of medical isotopes, and a research report provided by the Nuclear Power Institute shows that in recent years, the mainland has relied on imports for more than 90% of the medical isotopes produced through nuclear reactors, and the variety is small. For example, technetium-99m and molybdenum-99, which are required for routine nuclear medicine diagnosis, are 100% imported, and the most effective targeted therapy for the treatment of hyperthyroidism and thyroid cancer, radionuclide iodine-131, 80%, and other important nuclide iodine-125, yttrium-90, lutetium-177, radium-223, etc., all rely on imports.
Correspondingly, the domestic demand for medical isotopes is gradually rising. According to the above research report, the global use of molybdenum-99 will be about 480,000 curies in 2023, the domestic use will be about 22,000 curies, and the global market demand for molybdenum-99 is expected to reach 650,000 curies in 2030, and the domestic market demand is expected to reach 40,000 curies. According to the incidence of thyroid disease in recent years, it is expected that the demand for iodine-131 in the international market will reach 110,000 curies in 2030, and China is currently the country with the largest use of iodine-131 in the world, with the demand for iodine-131 in the Chinese market being 20,000 curies per year in 2023 and 42,000 curies per year in 2030.
"At present, the research and development of medical isotopes in mainland China mainly relies on engineering research nuclear reactors, but because these nuclear reactors also shoulder other production tasks, the ability to produce medical isotopes is very limited. However, the domestic market demand for medical isotopes and their compounds is growing at a rate of 25%-30% per year. The extremely limited scale of production of reactors is simply not enough to meet the growing market demand. Yao Gang, president of the Nuclear Power Institute, told the Global Times.
This passive situation of imbalance between supply and demand not only seriously hinders the development of nuclear medicine in the mainland, but also endangers the lives and health of the people. In 2009, Canada's NRU reactor, the world's largest supplier of carbon-14, stopped production, causing China's carbon-14 supply to be cut off, which suddenly exposed the "bottleneck" problem to the public.
"For a long time, Canada and other Western countries have firmly grasped the right to speak on medical isotopes, and most of the mainland's medical isotopes rely on imports. In an interview with the Global Times, Wang Conglin, Secretary of the Party Committee of the Nuclear Power Institute, said that due to the development of the medical isotope industry, there is a significant gap between the application level of nuclear medicine in the mainland and that of developed countries. In terms of the frequency of nuclear medicine diagnosis and treatment, the number of nuclear medicine instruments per capita, and the amount of radioactive drugs used, developed countries such as Europe, the United States and Japan are dozens of times that of the mainland. In developed countries, about 1/5 of patients need to use medical isotopes, but the current situation in this field in the mainland is worrying, molybdenum-99, iodine-125, lutetium-177 and other large amounts of medical isotopes all rely on imports, carbon-14, iodine-131 and other small number of isotopes have achieved localization, but can not meet the needs of the domestic medical market.
The direct purchase from abroad, seems to save R & D time and money, but under the "shortcut", the disadvantages are also exposed, Wang Conglin further said that relying on foreign procurement, has always faced the problem of high prices and can not guarantee on-time supply.
Some people in the industry said that the cost of isotopes in a single treatment is as high as tens of thousands of yuan when using imported medical isotope treatment. To make matters worse, there are also supply problems in the international market. According to the above research report, in recent years, the global supply of medical isotopes has relied on a few medical research reactors in Canada, the Netherlands, Belgium, France, South Africa, Australia and other countries, most of which have been out of service and are facing a series of problems such as high maintenance costs, difficult waste decomposition, and safety risks, and are expected to be shut down around 2025. Among them, France's OSIRIS reactor and Canada's national general research reactor have permanently ceased production in 2015 and 2018, respectively, which caused the global supply of molybdenum-99 production to be reduced by about 30% at the end of 2016, and this shortage will continue beyond 2025, and the price of clinical molybdenum-technetium (99Mo-99mTc) generator applications will continue to rise.
"It can be said that the construction of medical isotope nuclear reactors is an imperative that we have to do. Xu Yu, vice president of the Nuclear Power Institute, said in an interview with the Global Times that the construction of a new type of medical isotope production reactor will not only alleviate the tight domestic supply and demand, but also create favorable conditions for the international market.
Schematic diagram of the world's highest-power solution-type medical isotope reactor designed and built by the Nuclear Power Institute of China National Nuclear Corporation (Photo source: China National Nuclear Corporation)
"After the completion of the medical isotope nuclear reactor, it will achieve an annual output of 100,000 curies of molybdenum-99 and 20,000 curies of iodine-131, which exceeds the current domestic demand. Li Qing, chief designer of the medical isotope nuclear reactor project, told the Global Times that the medical isotope nuclear reactor uses uranyl nitrate aqueous solution as fuel, and uranyl nitrate aqueous solution is also a target material for the production of isotopes, and its inherent characteristics determine that it has innate advantages far beyond conventional reactors in the field of nuclear safety and environmental protection. "Medical isotope nuclear reactors have low parameters and low power, so they are safer. ”
However, the advantages of medical isotope nuclear reactors go far beyond that. Li Qing further introduced that the construction cost of medical isotope nuclear reactors is one-third of that of ordinary nuclear reactors, and the consumption of nuclear fuel is four-thousandths of that of existing technology. "Ordinary high-throughput nuclear reactors use the method of 'solid target' to produce medical isotopes, that is, the raw materials of the target are placed in the irradiation channel and turned into nuclides of medical isotopes through irradiation. But there is a prerequisite for this approach, which is that the reactor must be operational. So we usually produce medical isotopes in a 'hitchhiking' way when we are doing other experiments, but if ordinary high-throughput nuclear reactors are used to produce medical isotopes alone, because nuclear fuel is very expensive, the cost is sky-high. ”
In addition, one of the advantages of medical isotope stacks is that they are very flexible in the way they operate. "The production of medical isotopes in the way of 'solid targets' must follow the 'rhythm' of the reactor, and cannot affect the running schedule of the reactor, while the medical isotope reactor is a dedicated production reactor, and you can let it run for a few days if you want it to run for a few days, and you can arrange the running time of the reactor according to the requirements of drug production. Li Qing said that medical isotope stacks mainly produce molybdenum-99 and iodine-131, both of which are products with short half-lives, such as molybdenum-99, with a half-life of only more than 60 hours. Therefore, the reactor operation plan and production tasks can be formulated according to the target nuclide and the demand for the target nuclide, and the more that is needed can be done, and the less that is needed can be done less, according to the needs of the market.
Zhang Jinsong, head of medical isotope R&D technology at the Nuclear Power Institute, told the Global Times that the construction period of the medical isotope reactor is 42 months, and it is expected to be completed and put into operation in 2027. After the completion of the reactor, it will help the two most commonly used isotopes in medical treatment, iodine-131 and molybdenum-99, achieve a breakthrough in production capacity, and turn the mainland from an importer to an exporter in one fell swoop. At the same time, it can also reduce the price of domestic medical isotope drugs, so that more people can use and afford it.
"We will actively implement the 'Healthy China' strategy, solve the demand for some domestic isotopes and drugs in short supply in the early stage, basically meet domestic demand in the medium term, realize the localization of several new medical isotopes, and reach the international leading position in the long term, completely solve the problem of domestic medical isotope shortage and nuclear medicine development, and become an important supply base for global medical isotopes and drugs, reduce the pain of diseases and benefit the people. Zhang Jinsong said.