1. a. Radiation Therapy Center丨 b. Department of Medical Equipment, Nanjing First Hospital, Nanjing Medical University,
Nanjing 210006, China丨 2. Center of Medical Physics, Nanjing Medical University, Nanjing Jiangsu 210029, China
Abstract：Four-dimensional computed tomography (4D-CT), which combines temporal and spatial information, can display the
range of motion of patients’ tumor target. It is increasingly used in radiotherapy. However, due to the complexity of 4D-CT related
equipment and technique, there are many problems in the specific application of radiotherapy simulation, which hinder the further
promotion and application of this technique. In terms of 4D-CT scanning using the Siemens CT simulator combined with the Varian
real-time position management system, this paper first introduced problems that exist in the process of using the above-mentioned
equipment to perform 4D-CT simulation for radiotherapy patients. Then in view of the above problems, referring to the experience
of our department, the corresponding specific solutions were introduced, including making square openings in thermoplastic mask,
making foam wedge blocks, adjusting infrared cameras, removing metal jewelry, evaluating patient breathing curves, making the
radiotherapy 4D-CT scan protocol, etc. In the last section, the paper explained the application effect of the above solutions. The
solutions introduced in this paper provide useful reference and guidance for the staff to perform radiotherapy simulation for patients
using 4D-CT.
