ObjectiveTo investigate the value of integrin αvβ3 targeted microPET/CT imaging with 68Ga-NODAGA-RGD2 as radiotracer for the detection of osteosarcoma and theranostics of osteosarcoma lung metastasis.MethodsThe 68Ga-NODAGA-RGD2 and 177Lu-NODAGA-RGD2 were prepared via one-step method and their stability and integrin αvβ3 binding specificity were investigated in vitro. Forty-one nude mice were injected with human MG63 osteosarcoma to established the animal model bearing subcutaneous osteosarcoma (n=21), osteosarcoma in tibia (n=5), and osteosarcoma pulmonary metastatic (n=15). The microPET-CT imaging was carried out in 3 animal models at 1 hour after tail vein injection of 68Ga-NODAGA-RGD2. Biodistribution study of 68Ga-NODAGA-RGD2 was performed in animal model bearing subcutaneous osteosarcoma at 10, 60, and 120 minutes. The animal model bearing pulmonary metastatic osteosarcoma was injected with 177Lu-NODAGA-RGD2 at 7 weeks after model establishment to observe the therapeutic effect of pulmonary metastatic osteosarcoma. Histological and immunohistochemistry examinations were also done to confirm the establishment of animal model and integrin β3 expression in animal models bearing subcutaneous osteosarcoma and bearing pulmonary metastatic osteosarcoma.Results68Ga-NODAGA-RGD2 and 177Lu-NODAGA-RGD2 had good stability in vitro with the 50% inhibitory concentration value of (5.0±1.1) and (6.5±0.8) nmol/L, respectively. The radiochemical purity of 68Ga-NODAGA-RGD2 at 1, 4, and 8 hours was 98.5%±0.3%, 98.3%±0.5%, and 97.9%±0.4%; while the radiochemical purity of 177Lu-NODAGA-RGD2 at 1, 7, and 14 days was 99.3%±0.7%, 98.7%±1.2%, and 96.0%±2.8%. 68Ga-NODAGA-RGD2 microPET-CT showed that the accumulation of 68Ga-NODAGA-RGD2 in animal models bearing subcutaneous osteosarcoma and osteosarcoma in tibia and in lung metastasis as small as 1-2 mm in diameter of animal model bearing pulmonary metastatic osteosarcoma. Biodistribution study of 68Ga-NODAGA-RGD2 in animal model bearing subcutaneous osteosarcoma revealed rapid clearance from blood with tumor peak uptake of (3.85±0.84) %ID/g at 120 minutes. The distribution of 177Lu-NODAGA-RGD2 in lung metastasis was similar with 68Ga-NODAGA-RGD2. The number and size of osteosarcoma metastasis decreased at 2 weeks after 177Lu-NODAGA-RGD2 administration and integrin targeting specificity was confirmed by pathology examination.Conclusion68Ga-NODAGA-RGD2 was potential for positive imaging and early detection of osteosarcoma and metastasis. Targeted radiotherapy with 177Lu-NODAGA-RGD2 was one potential alternative for osteosarcoma lung metastasis.
ObjectiveTo compare the effectiveness of anterior subcutaneous pelvic internal fixator (INFIX) and plate internal fixation in treatment of unstable anterior pelvic ring fractures.MethodsThe clinical data of 48 patients with unstable anterior pelvic ring fractures who met the selection criteria between June 2014 and December 2019 were retrospectively analyzed. Among them, 21 cases were treated with INFIX (INFIX group), and 27 cases were treated with plate (plate group). There was no significant difference in gender, age, body mass index, cause of injury, time from injury to operation, Injury Severity Score (ISS), and fracture type between the two groups (P>0.05). The operation time, intraoperative blood loss, fracture healing time, partial weight-bearing time, and complete weight-bearing time were recorded and compared between the two groups. Matta standard was used to evaluate the quality of fracture reduction, and Majeed score system was used to evaluate the functional recovery of pelvic fracture after operation.ResultsThe patients in both groups were followed up for an average of 12.5 months (range, 6-16 months). The operation time and intraoperative blood loss in INFIX group were significantly lower than those in plate group (t=−11.965, P=0.000; t=−20.105, P=0.000). There was no significant difference in the quality of fracture reduction, fracture healing time, partial weight-bearing time, and complete weight-bearing time between the two groups (P>0.05). At 14 weeks after operation, there was no significant difference in the scores of pain, working, standing and walking, and total scores between INFIX group and plate group (P>0.05), but there were significant differences in sitting and sexual intercourse scores (t=−4.250, P=0.003; t=−6.135, P=0.006). The incidences of lateral femoral cutaneous nerve injury, femoral nerve injury, and heterotopic ossification were significantly higher in INFIX group than in plate group (P<0.05), while the incidence of incision infection was lower in INFIX group than in plate group (P<0.05).ConclusionCompared with the plate internal fixation, the INFIX internal fixation can obtain the similar effectiveness for the unstable anterior pelvic ring fracture and has the advantages of shorter operation time, less blood loss, and lower risk of infection.