A total of 17 RAIR-DTC patients with lymph node metastasis who were hospitalized at the Northern Theater Command General Hospital and received 125I seed implantation from December 2016 to January 2019 were collected, including 8 males and 9 females, with a median age of 58 years. The range was 22 to 70 years old，andall ofthemwere digonisedaspapillary thyroid carcinoma (PTC). 22 metastatic lymph nodes were diagnosed pathologically by needle biopsy, of which 5 patients had 2 lymph node metastases, 12 cases of them has 1 lymph node metastasis. Each patient took 131I with a cumulative dose of >22.2 GBq and received 125I seed implantation at least half a year after 131I treatment. (This study was reviewed and approved by the Medical Ethics Committee of our hospital, and all patients signed an informed consent form.)Inclusion criteria: (1) Complete thyroidectomy or near-total resection before operation, according to functional neck dissection and extended radical resection of cervical lymph nodes, confirmed by pathology as DTC metastasis, it was identified as RAIR-DTC according to the 2015 American Thyroid Association (ATA) guidelines ; (2) WBC count≥3.5×109/L, Hb≥90 g/L, prothrombin activity>40 %, PLT＞100×109/L, normal electrocardiogram, serum alanine aminotransferase and serum aspartate aminotransferase in liver function test Enzyme value does not exceed 3 times the normal upper limit; (3) Karnofsky performance status (KPS) scor≥70, with detailed clinicopathological data and follow-up data, survival time of more than 1 year; (4) no further transfer. Exclusion criteria: (1) Thyroglobulin antibody (TgAb) positive; (2) Severe heart, lung, liver and kidney dysfunction; (3) Severe coagulation dysfunction; (4) General condition is very poor or cachexia.
A 64-slice CT with Discovery VCT PET/CT produced by GE in the United States was used for routine scanning. The implant gun and the push thimble are flat-head general-purpose types produced by Zhejiang Xiangshan Jinheng Machinery Manufacturing Co., Ltd. The 15-20 cm×18 G puncture needle produced by Yako Co.; Ltd. is used. The particle TPS is provided by Beijing Feitian Zhaoye Technology Co., Ltd. The 125I radioactive particle source is produced by Beijing Atom Technology Co., Ltd. The particle length is 4.5 mm, the diameter is 0.8 mm, and the fully enclosed titanium shell. The particle activity is 14.8-25.9 MBq, the half-life is 59.6 d, and the tissue penetration distance is 17 mm. Steam sterilization. The whole body 131I imaging adopts the Symbia T16 SPECT/CT instrument of Siemens company in Germany. Five items of thyroid function (free triiodothyronine, free thyroxine, TSH, TgAb, anti-thyroid peroxidase autoantibody) and thyroglobulin (Tg) are detected by chemiluminescence method. The instrument and kit are composed of Soling Diagnostics (Italy) Co., Ltd. provides: Soling-LIAISON Chemiluminescence Analyzer, Soling-LIAISON Kit.
Preparation before surgery
Complete various laboratory tests before surgery, including blood routine, ABO and RH blood types, coagulation, liver and kidney function, four items of infectious diseases, five items of thyroid function, Tg, electrocardiogram, etc.; inform patients and their families complications and precautions that may occur during and after the operation and sign the informed consent; Stopdrinking for 2~4 hours before local anesthesia, establishing thevenous access; performing breathing training to reduce the intervention caused by the patient’s respiratory activity during the operation Implant deviation; patients with pain intolerance can be given tramadol analgesia (oral 50-100 mg/time) 30 min before surgery, and codeine phosphate tablets (oral, 15-30 mg/time) can be given for irritation cough.
Import the enhanced or plain CT scan images 1 week before the operation into the TPS system for design, avoiding important tissues and organs (such as large blood vessels, heart, spinal cord, etc.) as much as possible. Delineate the gross tumor volume (GTV) and planning target volume (PTV). The PTV range includes the tumor itself and surrounding tissues that may infiltrate (such as burr signs around the tumor). Set an appropriate prescription dose of 110~140 Gy and particle activity (14.8~25.9 MBq) , follow the principle of 0.5~1.0 cm between particles, 1 cm between needle tracks, Making 90% of GTV received prescription dose (D90)> matched peripheral dose (matched peripheral dose, MPD), and then calculate the number of particles and particle source distribution to simulate the best way to enter the needle. Obtain the preoperative planning parameters D90, D100, the volume percentage (V100, V150) of 100% and 150% of the prescribed dose received by GTV, and the dose-volume histogram (DVH).
Select different positions according to the lesion location, place an external positioning grating on the skin area corresponding to the lesion, select the puncture point by CT scan, and intramuscularly inject 2% lidocaine for local infiltration anesthesia, determine the depth and angle of the puncture path, and follow the TPS plan Needle cloth layer by layer. During the operation, the position and direction of the implanted needle were adjusted according to the CT scan, so that the depth of the needle into the lesion was through the center of the tumor and 0.5 cm from the edge of the tumor. Then, one particle was implanted every 0.5 to 1.0 cm in the backward way, and the particles were supplemented from the periphery to the center, and the needle was placed again referring to the position of the implanted needle, and the intraoperative real-time optimization until the implantation was completed. Care should be taken to avoid important blood vessels and nerves during implantation. During the operation, the patient's heart rate, blood pressure, respiration and blood oxygen saturation were monitored. At the same time, the patient's consciousness, pain, breathing, cough, hemoptysis and other conditions were observed, and timely symptomatic treatment was performed. After the operation is completed, press the puncture point for 10-20 minutes.
Post-operative verification plan
After the operation is completed, the CT images are immediately transferred to TPS for postoperative verification and particle identification, and D90, D100, V100, V150, DVH, and homogeneity index (HI) are counted. HI=(VT, ref-VT, 1.5ref)/VT, ref, VT, ref, VT, 1.5ref is the volume of the target area receiving the prescribed dose, and the volume of the target area receiving 150% of the prescribed dose (cm3); Larger, indicating that the target dose distribution is more uniform .
Postoperative review and short-term efficacy evaluation
(1) Efficacy judgment. Neck color Doppler ultrasound and neck CT were reviewed before treatment and 6 months after treatment to evaluate the effect of 125I seed implantation. According to the solid tumor efficacy evaluation standard (Response Evaluation Criteria in Solid Tumors, RECIST) 1.1 for efficacy evaluation . ①Complete remission (CR): The lesion completely disappeared, and there is no imaging suggestion of recurrence, tumor residual and metastasis, or only 125I particle metallic shadow; ②Partial remission (PR): The sum of the short diameter of the target lesion is at least The baseline short diameter of the lesion (the sum of the smallest diameters measured before treatment) was reduced by 30%; ③stable disease (SD): those who did not meet the criteria for either PR or progressive disease (PD); ④PD : Based on the minimum sum of the short diameters of the target lesions during the entire study, the diameter sum increased by ≥20%; or the absolute value of the diameter sum increased by ≥5 mm (the appearance of one or more new lesions is also regarded as PD).(2) Adverse reactions. After the operation, closely observe whether the patient has adverse reactions such as bleeding, hematoma, particle displacement, needle implantation, etc., and refer to the United States Tumor Radiotherapy Cooperation Group/European Organization for Research and Treatment of Cancer (Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer). (RTOG/EORTC) Acute Radiation Response Scoring Standard evaluates skin radiation damage caused by radioactive seed implantation , observes and evaluates complications during operation, postoperative and follow-up.
Use IBM SPSS 19.0 software to process data. Quantitative data conforming to the normal distribution are expressed as ±s, quantitative data not conforming to the normal distribution are expressed as M (P25, P75); qualitative data are expressed as frequency or percentage. The quantitative data before and after treatment were compared by paired t test or Wilcoxon signed rank test. P<0.05 indicates that the difference is statistically significant.