[Ultrastructural study on the facial nerve of rabbit after (125)I seed implantation].

OBJECTIVE: To investigate the ultrastructural variation of the facial nerve of rabbit with different dosage of (125)I seed brachytherapy. METHODS: Fifty-four big ear rabbits were divided into 3 groups randomly and given 40 Gy, 80 Gy, 120 Gy respectively. Radioactive seeds were implanted in one side of parotid gland, the other side was implanted with vacant shell as a control group. The facial nerves were obtained 2, 4, 6 months respectively after operation and the histological ultrastructural changes observed by electromicroscope. RESULTS: In the control group, epineurium was continuous, there was slight pitting edema under the epineurium, and axonal myelin was loose. In the test groups, there was slight pitting edema under the epineurium, and axonal myelin sheath was loose at 4th month. Macrophage and regenerated fibers were found in the 80 Gy group and myelin sheath lamellar separation, regeneration of nerve in the 120 Gy dosage. The myelin sheath lamellar was separated and axonal myelin loose in the test group at 6th month. Myelin sheath amellar separation and edema under the epineurium were found in the group of 80 Gy and 120 Gy. CONCLUSIONS: The ultrastructure of the facial nerve is damaged by the dosage of 40 Gy, 80 Gy brachytherapy with (125)I seeds. The higher dosage the nerve receives, the more serious the damage will be. Both of the epineurium and axonal myelin sheath are integral and continuous 6 months after operation with dosage of 120 Gy.

[Preliminary study of treating parotid gland malignant tumor with saving facial nerve (surgery associated with 125I seed implant brachytherapy)].

OBJECTIVE: To study the clinical effect of treating parotid gland malignant tumor with facial never-preserving surgery combined with 125I seed implant brachytherapy. METHODS: Thirty-two patients with parotid gland malignancy underwent tumor and parotid gland excision while preserving facial never. According to treating plan system (TPS), 125I seeds were implanted into the target area during or after operation. The patients were followed up after operation and the local tumor control and facial nerve function were observed. RESULTS: Tumor recurrence was not found in any patient treated after 12 to 44 months of follow up. All patients did not show obvious radiation-related complications. The facial never function of all patients was basically normal 6 months after operation. CONCLUSIONS: For parotid gland malignant tumor, surgery combined with 125I seeds implant brachytherapy can save facial nerve function, and the short-term effects were satisfactory.

[CT guided interstitial 125I seed implantation treatment for head and neck malignant tumor].

OBJECTIVE: To detect the methods and experience of CT guided interstitial mj seed implantation treatment for head and neck malignant tumor. METHODS: 5 patients with head and neck malignant tumor were treated by interstitial 125I seed implantation with CT guide, 3 of them were treated with operation and adjunct seeds implantation, the other two patients were implanted seed only. According the treatment plan, register needles were punctured firstly, based on CT scan, these needle' s position and depth were adjusted, then the seeds were implanted into the target area. Another CT scan was done for the dose verification. RESULTS: The procedure of 125I seeds implantation of five patients was successful. 5 of twelve register needles were adjusted. The dose distribution of the instant verification was the same as that of treatment plan. CONCLUSION: The CT guided seeds implantation of the head neck malignant tumors can practice the treatment plan accurately, and the dose verification can be done instantly.

[Radioactive seed implantation in treatment of oral and maxillofacial malignancy].

OBJECTIVE: To treat oral and maxillofacial malignant tumors with radioactive seed implantation and observe the therapeutic results and side effects. METHODS: Thirty-six patients with oral and maxillofacial malignancy were treated by radioactive seeds implanting (operation and seed implantation or seed implantation only). The treatment plans were designed before implanting by treatment plan system (TPS). All patients were followed up for 6 - 36 months with an average of 14 months and the results evaluated. RESULTS: In 3 patients treated only by seed implantation, the tumor size reduced obviously and the symptoms alleviated in 2 patients with advanced disease, and the tumor got complete remission in one patient with tongue cancer. In the other 33 patients who were implanted after operation, no recurrence was seen in the target area, but recurrence or lymph node metastasis was found outside the target area in 3 patients. There were no unusual complaint and external radiotherapeutic side effects except for skin hyperemia occurred in 8 patients. CONCLUSIONS: Radioactive seed implantation is very effective for preventing recurrence and metastasis of oral and maxillofacial malignancy.