Recently, the world's first integrated CT-linac, independently developed by United Imaging, was officially unveiled at the 14th National Radiation Oncology Academic Conference held by the Chinese Medical Association. It is known that, in terms of structure, linac and CT are truly integrated with first co-bed coaxial technology and diagnostic CT for accurate simulation of positioning, high-definition video guidance. In terms of the system, the five major systems (treatment planning system, oncology information management system, CT Sim system, image guidance system, and radiotherapy system) operated back and forth on multiple devices in the past are highly integrated and now all data processing can be completed on one device.

For example, the abdominal radiotherapy, it was a double "technical project" which needed the doctor's experience and eyesight in the past. That means patients were checked with CT in radiology and then did radiotherapy in radiotherapy department, and ribs, bone structure were always used for registration. However, the body metabolizes at every moment, and the lesion may slightly deviate from the original bone registration even when you stand up or lie down. To solve this problem, the most direct way is to conduct CT scanning and radiotherapy on the same device! Compared with the possible error of bone registration, the diagnostic CT with high-resolution images, when successfully using organ and soft tissue as the reference registration of the lesion, it can accurately calculate the target location and dose of radiotherapies.

On the left side is the CT picture taken by the integrated CT-linac and the right is the kV-CBCT picture. The comparison pictures come from the similar site of another patient.

This not only improves the accuracy of radiotherapy, but also alleviates the physical and psychological stress of patients. Patients do not need to go back and forth between radiology and radiotherapy departments. The whole process of radiotherapy, patient registration, CT simulation positioning, radiotherapy plan, radiotherapy quality control, treatment process management, image-guided radiotherapy, treatment recording, efficacy evaluation can be completed at one time. At the same time, the high-resolution images presented by the diagnostic CT make the radiotherapy process different from the previous one ——a radiotherapy plan throughout a treatment course, but accurately determine the target position and its changes of each radiotherapy according to real-time CT images. Thus adjustments for treatment plans and radiation dose can be made to tailor individualized treatment plans to patients. In addition, CT-linac's wireless mobile terminal application can let you use the stylus instead of the mouse to accurately outline the target area, which can minimize the damage of radiotherapy to normal tissue. Moreover, remote radiotherapy can also support cloud sharing of data and cloud interconnection between senior and lower hospitals, and senior physicians can physically guide the whole process of developing patients’ treatment plans, which can alleviate the current shortage of radiologist and physicists.

Xie Conghua, Director of Cancer Radiation and Chemotherapy Department of Zhongnan Hospital, Wuhan University, said: "From the installation inspection, we conducted a 6 months’ QA (Quality Assurance) and QC (Quality Control) monitoring for the equipment according to the TG-142 report with the focus on the quality monitoring, including isocenter accuracy, positioning accuracy of components, and dose stability and other equipment performances. Careful QA was also performed on each treatment plan with quite good results, including the uARC treatment plan made by United Imaging, and the data were superior to the recommended standards of SRS and IMRT in TG-142. At the same time, the new integrated CT-linac device makes new directions on clinical applications such as quality control, meticulous dose monitoring and more. In the near future, the individualized radiotherapy proposed by United Imaging will play an important role in the development of radiotherapy! ＂