Ge 64 slice spiral ct scanner

In order to establish the 3D tumor model, the GE 64-slice spiral CT scanner (GE Medical Systems, Waukesha, WI, USA) was adopted with scanning from the pelvis to the foot where the slice thickness was 0.625 mm. The original image data were imported into Mimics 10.01 software (Materialise, Leuven, Belgium) in DICOM format. In order to build the 3D skeletal model, threshold selection and region growing function were used. The images were saved in STL format. Then Imageware 13.2 software (Media Cybernetics, Silver Springs, MD, USA) was used for the model matching and thus length, distal femur, proximal tibia, the diameter of the medullary cavity and other anatomic parameters were measured. CT scanning was performed on the allogeneic bone grafts (Orion Biomaterials Co., Ltd., Shaanxi, China), for repairing large bone defects. By the same method, the 3D model was also established in this case.

Radioactive seeds were ¹²⁵I with a half‐life of 60.2 days. The radioactivity of these seeds is 0.8 mCi (2.59 × 10⁷Bq), the energy of gamma‐ray radiation from the seed is 27–35 keV, and tissue penetration from the seed is around 1.7 cm in depth. The PD was 120 Gy.
The seeds and implantation equipment were obtained from Seeds Biological Pharmacy Ltd. (Tianjin, China) and the calibrator was obtained from the Image Processing Center of  University (Beijing,China). Single‐use implantation needles were manufactured and disinfected in Shanghai. Other equipment used included the treatment plan system (TPS) developed by Prowess Inc. (Concord, CA, USA) and a GE 64‐slice spiral CT scanner (GE Healthcare, Chicago, IL, USA).