Experts consensus on 3D-printing template-assisted CT-guided radioactive iodine-125 seed implantation for recurrent soft tissue carcinoma in China

Permanent radioactive iodine-125 seed implantation (RISI), known as radioactive seed implantation, is a minimally invasive internal radiation technique. This method involves implanting 125I seeds (4.5 × 0.8 mm, encapsulated in a nickel-titanium alloy) into tumors under image guidance. The radionuclide continuously releases low energy γ-rays, effectively killing tumor cells. RISI delivers high local doses with minimal damage to surrounding normal tissues. It is performed through image-guided percutaneous puncture, accompanied by high precision, minimal trauma, and rapid recovery. In Western countries, RISI is primarily utilized for early-stage prostate cancer. In 2002, Professor Junjie Wang introduced computed tomography (CT)-guided technology for RISI, expanding its indications to head and neck, thoracic, abdominal, pelvic, and spinal tumors. In 2014, he proposed the concept of image-guided interventional brachytherapy, advancing minimally invasive brachytherapy. In 2015, he integrated three-dimensional 3D-printing template (3D-PT) with CT-guided technology, significantly enhancing the precision, quality, and efficiency of RISI, and introduced the concept of stereotactic brachytherapy. Over nearly 20 years, RISI has developed into a standardized procedure, involving preoperative planning, intraoperative optimization, and postoperative verification, highlighting its role in comprehensive cancer treatment. The main treatments for soft tissue sarcoma (STS) include surgery or surgery combined with radiotherapy and chemotherapy. However, STS is prone to local recurrence, and effective treatments are lacking after recurrence. Experts have conducted extensive trials on RISI for the treatment of recurrent STS (r-STS), accumulating significant clinical experience. This study aimed to establish standards and consensus on 3D-PT-assisted CT-guided RISI for the treatment of r-STS.