"What we have done is simply to freeze the tumor to death at -196 ℃, and then completely inactivate it at 85 ℃," said Liu Jing, a researcher at the Institute of Physical and Chemical Technology of the Chinese Academy of Sciences. This "ice and fire dual sky" composite thermal ablation technology was conquered by his team after more than 20 years, and finally entered clinical practice in the form of a "Kangbo knife" for minimally invasive treatment of tumors. Time goes back to the 1990s. At that time, minimally invasive tumor cryoablation technology was still in its infancy, and only a few companies in the international market had mastered the core technology, using expensive argon and helium as working fluids. Among them, helium was still scarce in China and faced the risk of import supply interruption at any time. A set of equipment often costs tens of millions of yuan, and the gas cost alone for a single surgery is very high, which restricts the promotion of technology. More importantly, single cryoablation has congenital defects, such as incomplete treatment, easy needle bleeding, and the risk of tumor implantation and metastasis. Liu Jing began to ponder whether it was possible to adopt a different approach. He led the team to take a different approach, abandoning the internationally recognized high-pressure gas throttling refrigeration route and innovatively proposing a new tumor treatment equipment that integrates deep low-temperature freezing and high-temperature ablation, which later became commonly known as the "cold hot knife" (Kangbo knife). The refrigerant and heat medium were selected from low-cost and easily accessible liquid nitrogen and medical ethanol. However, this makes technology research and development very difficult. How to achieve stable delivery and precise control of liquid nitrogen in micro probes, ensuring that only a large amount of cold is released at the needle tip and adiabatic along the way, is a global challenge; At the same time, it is necessary to deliver high-temperature gaseous ethanol to the same location to release ultra-high heat, achieving flexible switching and precise melting between ice and fire, which is a technical challenge that has not been touched upon both domestically and internationally. During that time, we experimented repeatedly, failed repeatedly, and started from scratch again. ”Liu Jing recalls. After countless principle attempts, working fluid screening, process exploration, and prototype software and hardware development and evaluation optimization, the team finally broke through various technical bottlenecks of Kangbo Knife medical equipment from components to the whole machine. Later, together with Haijieya Company, the product was promoted to large-scale clinical applications. The breakthrough of Kangbo Knife medical equipment lies in not only achieving deep low-temperature freezing (-196 ℃), but also integrating high-intensity heating function (+85 ℃) in the same micro probe. This composite ablation mode of "freezing first and then heating" is the first proposed and implemented internationally, surpassing previous single cryotherapy or high-temperature ablation, and becoming a rapidly emerging tool for tumor treatment. Freezing causes tumor cells to form ice crystals, rupture and die, while releasing antigens; High temperature completely inactivates residual cells and effectively seals the needle passage to prevent bleeding and tumor metastasis. ”Liu Jing explained that "the ultra wide temperature difference of nearly 300 ℃ generates huge thermal stress inside the tumor, and its killing power far exceeds that of single freezing or heating." Based on this original breakthrough technology and his outstanding contributions to high/low temperature biological heat transfer over the years, Liu Jing has won one of the highest awards in the international heat transfer community, the William Begell Medal. The Kangbo knife has also broken the monopoly of traditional tumor cryotherapy equipment and opened a new era of composite cold and hot ablation technology. The most difficult aspect of transforming scientific research achievements is not the technology itself, but how to truly adapt the technology to clinical needs. ”Liu Jing said. To this end, he works closely with the Haijieya team and adheres to the research and development concept of "medical engineering integration". Every technical detail is polished based on real feedback from the clinical front line. The product design should conform to the operating habits of doctors, and the treatment plan should be optimized according to the characteristics of different tumors. Nowadays, Kangbo Knife has been clinically applied in more than 280 hospitals across the country, with a cumulative surgical volume exceeding 30000 cases. Overseas, Kangbo Knife has been exported to more than ten countries such as the UK, Germany, and France, completing hundreds of difficult surgeries. Doing research is not about publishing papers, but about solving problems. ”Liu Jing said, "If a result only stays in the laboratory and is not truly applied to patients, its value has not been fully realized." Today, Liu Jing is still active in the forefront of scientific research. His vision has already turned to a further future - the application of low-temperature biomedical technology in fields such as life preservation, cardiovascular and cerebrovascular diseases, regenerative medicine, and targeted immunity. Tumor treatment is just the starting point. ”He said, "There are still too many unknowns waiting for us to explore the power of 'Ice and Fire'