Medical physicists use water tanks to verify the energy of heavy ion beams. Photo by Hai Bo Yuan.
Medical Heavy Ion Accelerator - Synchrotron. Photograph by Yuan Haibo.
Simulating three-dimensional dose spheres for heavy ion irradiation of tumor shapes. Image courtesy of the Institute of Modern Physics.
Development and Industrialization Team of Medical Heavy Ion Accelerator. Photo by Yuan Haibo ■ Ye Manshan, a journalist from this newspaper "Director Yang, I can eat normally now, walk around without any problems, and feel very good physically. Thank you all. Today, I can finally leave the hospital with peace of mind." At the Gansu Province Wuwei Heavy Ion Center, 69-year-old Mr. Huang is describing his condition to Deputy Chief Physician Yang Qianzi.
Mr. Huang suffered from advanced lung cancer. Due to the large size of the tumor in his lungs and its close proximity to his gastrointestinal tract, surgery was not feasible. On September 28, 2023, after undergoing minimally invasive surgery to place a separator (gauze pad) to separate the tumor from the gastrointestinal tract, followed by a high-dose heavy ion therapy, he was successfully treated.
Since the discovery of the Bragg peak, where high-speed ions release energy upon stopping in an object, humanity has been exploring the potential of using protons and heavy ions to treat cancer. From the initial proposal by American physicist Robert Wilson in 1946 to use proton beams for tumor treatment, to the establishment of the world's first heavy ion cancer treatment center in Chiba, Japan in 1994, a series of advancements have garnered global attention.
In this field, China is not lagging behind. Independently developed heavy ion cancer treatment devices have been established in multiple cities. This national treasure not only demonstrates China's leading strength in the field of heavy ion cancer treatment but also represents a significant leap forward in cancer treatment technology. With its unique advantages, heavy ions stand out in the field of cancer radiotherapy and are hailed as one of the most advanced, scientific, and effective therapies available today.
In 1988, the Institute of Modern Physics of the Chinese Academy of Sciences (hereinafter referred to as IMP) completed the construction of China's first large-scale heavy ion research device—the Lanzhou Heavy Ion Research Facility (HIRFL), which not only provided important experimental conditions for China's medium-energy heavy ion physics research but also marked the entry of China's cyclotron accelerator technology into the international forefront. In 1991, the Lanzhou Heavy Ion Accelerator National Laboratory was established. In 1992, the device won the first prize of the National Science and Technology Progress Award.
It was with the various types and energies of heavy ion beams provided by this device that scientists completed many scientific experiments, achieving significant results at the international advanced level, represented by the synthesis and research of new nuclides. This laid the foundation for subsequent heavy ion cancer treatment.
On a November day in 1993, while the cold wind was whistling outside, the atmosphere in the conference room of the Institute of Modern Physics was unusually heated because a seminar on how to apply the future of large scientific devices was being held here. Regarding how to utilize large scientific devices and maximize their value, each participant had different opinions.
At this time, Wei Zengquan, the director of the Heavy Ion Beam Application Room II, took the stage. His presentation was titled "Life Science Research," in which he detailed his ideas about conducting research on heavy ion cancer treatment.
Wei Zengquan's speech ignited the enthusiasm of the researchers present like a spark. With dreams of exploring the immense potential of heavy ion biology effects, they put forward various ideas for conducting related basic research.
As a student of Wei Zengquan, Li Qiang, director of the Biomedical Center of the Institute of Modern Physics, still remembers the significance of this research initiative. "The reason we were determined to develop a heavy ion cancer treatment device was that under the empowerment of the accelerator, heavy ions, like precise surgical knives, can directly attack the lesion, releasing tremendous energy to annihilate cancer cells."
The heavy ion cancer treatment device not only effectively prevents residual and recurrent cancer cells but also has minimal toxic side effects on normal tissues, alleviating the pain caused by radiotherapy for patients. Therefore, heavy ion cancer treatment is called one of the world's cutting-edge radiotherapy technologies.
However, challenges and opportunities coexist. Due to the lack of relevant international standards and the weak research foundation domestically, researchers at the Institute of Modern Physics faced the daunting task of starting from scratch, catching up with international research trends, and achieving localization.
"At that time, although we knew the tremendous potential of heavy ion cancer treatment, as a research institution, developing large medical equipment was completely new to us," recalled Xiao Guoqing, former director of the Institute of Modern Physics and head of the medical heavy ion accelerator industrialization project. Despite numerous difficulties, all the researchers were determined to tackle this "tough bone" in order to achieve a breakthrough in domestic technology from zero.
In June 1995, the Heavy Ion Cancer Treatment Technology Research Project "Basic Research on Advanced Technologies in Nuclear Medicine and Radiotherapy" was selected as part of the National Climbing Program B, receiving support and cooperation from the state and local authorities. Various departments provided a variety of human tumor specimens for research, enabling the Institute of Modern Physics to establish laboratories equipped with cutting-edge instruments and equipment, comprehensively carrying out radiobiology, medical physics experimental research, and animal experiments.
In the early exploration stage, a key issue was how to precisely match the required energy based on the depth and size of the tumor. This was like a precise missile strike, ensuring that the energy penetrates deeply into the tumor while avoiding damage to healthy tissues.
Wei Zengquan's team first investigated the different energy levels of ion beams needed for tumors at different depths. At the same time, to address the issue that the shape of the ion beam irradiation must be equivalent to the shape of the tumor, they adjusted the collimators and modulated the beam, creating a three-dimensional dose sphere that matched the shape of the tumor. Thus, methods for controlling the energy and shape of the heavy ion beam were born.
Due to limited funding, researchers could only build a small chamber for animal experiments to meet basic experimental needs.
"Among many heavy ions, which one produces the best experimental results? Is it carbon ions, nitrogen ions, or argon ions?" Wei Zengquan's team chose animal tumor cells as the experimental subjects. With the support and cooperation of the biology department of Lanzhou University, after multiple experiments, summaries, and gradual improvements, they finally discovered that carbon ions produced the best results among all heavy ions.
The success at that moment greatly excited Wei Zengquan. This meant that his idea proposed in 1993 had finally become a reality, boosting the team's confidence. Subsequent series of exciting experimental results confirmed that heavy ion therapy was equally effective against human tumor cells. These basic research efforts accumulated valuable data for clinical research on heavy ion cancer treatment and laid a solid foundation for the development of subsequent treatment technologies.
On March 1, 2006, China's first shallow tumor heavy ion treatment device passed expert evaluation and acceptance. This meant that conditions for clinical trials of shallow tumor heavy ion treatment were met.
In November of the same year, the research team conducted preliminary clinical trials using heavy ion treatment technology on four cancer patients for the first time. The smooth progress of the clinical trials made China the fourth country in the world to successfully conduct clinical treatment of heavy ion therapy.
In the following year, the research team cooperated closely with hospitals to use the heavy ion treatment device to treat more than 70 cancer patients with a variety of tumor types, including esophageal cancer, lung cancer, and liver cancer, achieving a cure rate of 70%.
In March 2008, the Heavy Ion Treatment Center of the Institute of Modern Physics, the first heavy ion cancer treatment center in China, was officially opened, marking the beginning of a new era in heavy ion cancer treatment in China.
Xiao Guoqing, who has witnessed the development of heavy ion cancer treatment from scratch, said with emotion, "After years of hard work, the first heavy ion cancer treatment center in China was finally established. From initial exploration to the establishment of the center, we have gone through twists and turns, and our team has encountered numerous challenges and difficulties. However, we have always adhered to the belief that heavy ion cancer treatment will bring hope to countless cancer patients."
As of 2019, more than 10,000 patients have received heavy ion therapy at the Heavy Ion Treatment Center of the Institute of Modern Physics, with remarkable therapeutic effects and minimal side effects. From the original heavy ion treatment of esophageal cancer and lung cancer to the treatment of pancreatic cancer, breast cancer, and other types of cancer, the heavy ion treatment center has continuously expanded its treatment scope and improved its treatment technology.
At present, heavy ion cancer treatment technology has been widely used in clinical practice in China. The number of heavy ion cancer treatment centers has increased from one to six, covering regions such as Shandong, Gansu, Anhui, and Sichuan.
The number of heavy ion therapy patients is increasing year by year, and the treatment effect is remarkable. According to statistics from the National Cancer Center, the five-year survival rate of patients with lung cancer, liver cancer, and esophageal cancer treated with heavy ion therapy exceeds 70%.
More importantly, heavy ion therapy has significant advantages over traditional radiotherapy and chemotherapy in terms of therapeutic effects and side effects. It has become an important supplementary means of cancer treatment, providing hope for patients who are not suitable for surgery and radiotherapy.
"Since I started treating patients with heavy ions in 2007, I have witnessed countless miracles. Many patients who were once desperate have regained hope because of heavy ion therapy." Sun Xian, deputy director of the Heavy Ion Treatment Center of the Institute of Modern Physics, said emotionally.
As a cancer patient, Mr. Huang deeply understands the importance of heavy ion therapy. "When I was diagnosed with lung cancer, I thought it was a death sentence. However, heavy ion therapy gave me a new lease on life. I am deeply grateful to the medical staff for their hard work and dedication. Without them, I would not have survived."
In the future, China's heavy ion cancer treatment technology will continue to develop and improve, benefiting more cancer patients and contributing to the cause of human health.
