Side effects of CT-guided implantation of 125I seeds for recurrent malignant tumors of the head and neck assisted by 3D printing non co-planar template.

<bold>Background: </bold>For the recurrence of head and neck cancer after operation and radiotherapy, the local control of radioactive seed implantation is good, and it has a certain palliative effect. This study aims to investigate the acute and late side effects of a three-dimentional printing non co-planar template (3D-PNCT) for computed tomography (CT)-guided radioactive 125I seed (RIS) implantation in recurrent cancer of the head and neck.<bold>Methods: </bold>Between January 2016 and December 2016, forty-two patients with local recurrent malignant tumors of the head and neck received 3D-PNCT-assisted RIS implantation. The prescribed dose was 110-160 Gy. Preoperative planning design, production of individual guide plates, RIS implantation, postoperative dose evaluation, and follow-up were completed for all patients. Side effects in the skin, mucous membranes, blood and spinal cord were evaluated.<bold>Results: </bold>All patients underwent surgery successfully. Duration of follow-up was 4-14 (median, of 8.5) months. The activity of a single RIS was 0.34-0.7 (median, 0.6) mCi. The number of RIS was 10-126 (median, 34). The number of implantation needles was 4-31 (median, 11). The mean D2cc (dose to the most exposed 2-cc volume) and D0.1cc (dose to the most exposed 0.1-cc volume) of the skin were 24.9 (7.1-85.5) and 47.5 (9.4-167.2), respectively, whereas those of the spinal cord were 8.4 (4.5-33.3) and 14.2 (13.6-63.0), mucosa were 35.1 (4.2-82.8) and 87.0 (6.6-214.1), parotid glands were 16.2 (12.8-19.7) and 29.8 (26.1-33.4) and those of the trachea were 17.9 (2.5-45.9) and 32.7 (3.9-83.9), respectively. No case had an acute reaction of grade ≥ 3. Three cases had a grade-1 skin reaction. Blood toxicity did not occur, nor spinal-cord injury. Xerostomia was not aggravated than that of before brachytherapy. One case had a grade-3 nerve response.<bold>Conclusions: </bold>3D-PNCT-assisted RIS implantation can provide good accuracy for positioning. For local recurrent malignant tumor of head and neck, there were no obvious adverse reactions. [ABSTRACT FROM AUTHOR]