On this day, 29 years ago, on May 9, 1996 (March 22, 1996, the lunar calendar), my country developed the first domestically produced cyclotron. The first cyclotron independently developed by my country for producing radioisotopes passed the acceptance of the State Planning Commission on May 9, 1996. This shows that my country's cyclotron development technology has entered the international advanced level in the 1990s. The "high-current proton cyclotron and production medium-and short-life isotope device" accepted on the same day was successfully developed by China Academy of Atomic Energy Science. It is understood that accelerator development technology is a focus of competition in the world's high-tech field. Neutron-deficient isotopes produced by accelerators can be widely used in industry, agriculture and medicine, but cannot be produced in nuclear reactors. The use of neutron-deficient isotopes to diagnose and treat diseases is an important part of the world's most advanced medical science and technology. In the past, most of the neutron-deficient isotopes and their products or medicines used in my country relied on imports. However, due to the short life span of neutron-deficient isotopes and fierce international competition, my country's import of neutron-deficient isotopes is restricted. China Academy of Atomic Energy Science started this development work in 1988. Researchers have created a three-dimensional calculation method for magnetic fields, which exceeds the two-dimensional calculation technology mastered by advanced work. The production capacity of the developed cyclotron is five times higher than that of similar products. Chen Jiaer, academician of China Academy of Sciences and domestic accelerator expert who participated in the acceptance inspection, said that this device has the characteristics of "high flow strength, high efficiency, high intelligence, high starting point and oblique size. During more than a year of trial operation, seven radioactive isotopes, including cobalt 57, thallium 201, gallium 67, indium 111, germanium 68, cadmium 109 and fluorine 18, were produced. Some are used in hospitals in Beijing, Shanghai and other places, and their quality conforms to the China Pharmacopeia and reaches the level of international advanced countries. What is gratifying is that some isotopes have been exported to the United States and other countries and regions. my country's first base for mass production and supply of radioisotopes using accelerators has been established at China Academy of Atomic Energy Science.