Inclusion Criteria:
* Age: 18\~75 years old (including 18 and 75 years old);
* ECOG: 0-2 points;
* Expected survival of more than 3 months; Differentiated thyroid carcinoma undergoing total thyroidectomy or subtotal thyroidectomy and confirmed as locally recurrent or metastatic disease by imaging, serum tumor marker (tg), biopsy pathology; at least one measurable lesion (diameter of the tumor ≥10 mm), and meets the requirements of RECIST 1.1.
* Hemoglobin ≥80g/L, neutrophil ≥1.5×109/L, platelet count ≥80×109/L, serum creatinine ≤1.5× upper limit of normal or creatinine clearance ≥60ml/min, Blood urea nitrogen ≤2.5× upper limit of normal (ULN); Total bilirubin ≤1.5×ULN; Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5×ULN; If accompanied by liver metastasis, ALT and AST≤5×ULN albumin ≥25 g/L;
* Women of childbearing potential must have taken reliable contraceptive measures or undergone a pregnancy test (serum or urine) within 7 days prior to enrollment, with a negative result, and be willing to use appropriate contraceptive methods during the trial and for 1 year after the last dose of 131I (for women), or for 6 months after the last dose of 131I (for men);
* Participants voluntarily joined the study and signed informed consent, with good compliance and follow-up;
* Patients diagnosed with iodine-refractory/potentially iodine-refractory DTC after multidisciplinary team discussion.
Exclusion Criteria:
* Accompanied by pleural effusion or ascites, causing respiratory distress;
* Symptoms of brain metastasis cannot be controlled and treated in less than 2 months; there is a risk of suffocation due to excessively large neck metastatic masses; patients with spinal bone metastases have a risk of spinal cord compression paralysis; cardiac metastasis, heart failure, and patients at risk of acute cardiovascular events;
* Patients with severe and uncontrolled diseases, including: 1) Uncontrolled hypertension (despite optimal drug therapy, systolic blood pressure ≥140mmHg or diastolic blood pressure ≥90mmHg); 2) Poorly controlled arrhythmias of ischemic heart disease or myocardial infarction of grade II or above (including corrected QT interval (QTc) male ≥450 ms, female ≥470 ms) and ≥2 congestive heart failures (New York Heart Association (NYHA) classification); 3) Poorly controlled diabetes (fasting blood sugar \>10mmol/L); 4) Active or poorly controlled severe infections (according to Common Terminology Criteria for Adverse Events ≥ grade 2); 5) Patients with active hepatitis B or hepatitis C (hepatitis B: positive HBsAg and hepatitis B virus (HBV) DNA ≥500 IU/mL; hepatitis C: positive hepatitis C virus (HCV) RNA and abnormal liver function), or active infections requiring antimicrobial therapy (e.g., with antibiotics, antiviral drugs, antifungal drugs); 6) Renal insufficiency: urine routine shows urine protein ≥++ or confirmed 24-hour urine protein ≥1.0 g; 7) Patients with seizures requiring treatment.
* Received surgical treatment, incisional biopsy, or major trauma within 28 days prior to randomization;
* Unable to quit or with a history of psychiatric medication abuse;
* Allergic to the investigational drug (rhTSH or 131I) or its excipients;
* Had an infection within 4 weeks prior to screening, including bacterial, viral, or fungal infections, with ongoing symptoms at the time of screening;
* Received lipophilic iodine contrast agents (such as iodized oil, iodized benzene, etc.) within the past 3 months or received water-soluble iodine contrast agents (such as iohexol, iodinated glycerol, etc.) within the past 1 month prior to screening;
* Pregnant or lactating women, or women who engaged in unprotected sexual intercourse within the two weeks prior to screening, or women with a positive blood pregnancy test at screening;
* Male subjects (or their partners) or female subjects who have plans for fertility or donation of sperm or ova during the entire study period and within 6 months after the end of the study, and who are unwilling to adopt contraceptive measures during the study period and within 6 months after the end of the study;
* Researchers believe that the presence of any condition may harm the subjects or prevent them from meeting or fulfilling the study requirements.
