Purpose An accurate position of the needle is vitally important in low‐dose‐rate seed implantation brachytherapy. Our paper aims to implement a mixed reality navigation system to assist with the placement of the I125 seed implantation thoracoabdominal tumor brachytherapy needle and to validate the accuracy and quality of this type of method. Methods With the surgical navigation system, based on mixed reality through a novel modified multi‐information fusion method, the fusion of virtual organs and a preoperative plan for a real patient and the tracking of surgical tools in real time were achieved. Personalized image recognition and pose estimation were used to track needle punctures in real time and to perform registration processes. After a one‐time registration with a hexagonal prism tracker that used an iterative closest point algorithm, all information, including medical images and volume renderings of organs, needles, and seeds, was precisely merged with the patient. Doctors were able to observe the tumor target and to visualize the preoperative plan. This system was validated in both phantom and animal experiments. The accuracy of this system was validated by calculating the positional and rotational error of each needle insertion. The accuracy of implantation of each seed was determined in an animal experiment to test the accuracy in low‐dose‐rate brachytherapy. The efficiency of this system was also validated through time consumption assessments. Results In the phantom experiment, the average error of the needle locations was 0.664 mm and the angle error was 4.74°, average time consumption was 16.1 min with six needles inserted. Based on the results of the animal experiment, the accuracy of the needle insertion was 1.617 mm, while the angle error was 5.574° and the average error of the seed positions was 1.925 mm. Conclusions This paper describes the design and experimental validation of a novel surgical navigation system based on mixed reality for I125 seed brachytherapy for thoracoabdominal tumors. This system was validated through a series of experiments, including phantom experiments and animal experiments. Compared with the traditional image‐guided system, the procedure presented here is convenient, displays clinically acceptable accuracy and reduces the number of CT scans, allowing doctors to perform surgery based on a visualized plan. All the experimental results indicated that the procedure is ready to be applied in further clinical studies.

Purpose: The study evaluated the feasibility, clinical effectiveness, and quality of life of computed tomography (CT)-guided 125 I brachytherapy for locally recurrent nasopharyngeal carcinoma (NPC). Methods: We recruited 81 patients diagnosed with locally recurrent NPC after previous radiotherapy with or without chemotherapy. Thirty-nine patients received 125 I brachytherapy (group A) and 42 received re-irradiation (IMRT, group B). The evaluated outcomes were local control, complications, and quality of life. Cox proportional hazards regression analysis was used to compare local tumor progression-free survival (LTPFS) and overall survival (OS) in the two treatment groups. Results: The median follow-up was 30 months (range, 5-68 months), median LTPFS was 21 in group A and 17 months in group B. The 1-, 2-, and 3-year OS in group A were 84.6%, 51.3%, 30.7%, and 85.7%, 50.0%, and 32.6% in group B. In group A, 10/39 patients (25.6%) experienced at least one ≥grade III complication; no grade V complications occurred. In group B, 28/42 (66.7%) experienced at least one ≥grade III complication and 6/42 (14.3%) died of severe grade V complications. No significant between-group difference existed in the Quality of Life score on the EORTC QLQ-H&N35 questionnaire before treatment. In group A, quality of life was significantly improved after treatment; but did not improve, or even deteriorated in group B. Conclusions:125 I brachytherapy was a feasible, safe, and effective treatment for locally recurrent NPC.125 I brachytherapy significantly reduced complications caused by re-irradiation and improved patients' quality of life.

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PurposeThis study aimed to compare the outcomes of 125I seed brachytherapy versus external beam radiation therapy (EBRT) for the palliation of painful bone metastases of lung cancer after one cycle of chemotherapy progression.Materials and methodsWe analyzed retrospectively 158 patients with painful bone metastases secondary to lung cancer after one cycle of chemotherapy progression treated between June 2013 and May 2016. Seventy-six patients with 96 lesions received 125I brachytherapy (Group A), whereas 82 patients with 98 metastases received EBRT (Group B). Pain intensity on Brief Pain Inventory, percentage of patients with pain severity, and quality of life were recorded prior to treatment (T0), 2, 4, 6, 8, 12, 16, 20, and 24 weeks (T2, T4, T6, T8, T12, T16, T20, and T24) after treatment during a 24-hour period. Cost-effectiveness and number of treatment appointments were also compared between groups.ResultsOne hundred and fifty-eight patients had been treated. Visual analog scale for worst pain in Group A was significantly lower than in Group B at T2, T4, T6, T16, T20, and T24. Group A was superior to group B concerning quality of life scores (T2, T4, T20, and T24), cost-effectiveness, and number of treatment appointments. No significant differences were observed for complications.ConclusionCompared with EBRT, 125I seed brachytherapy can be an alternative method for painful bone metastases from lung cancer after one cycle of chemotherapy progression.

PURPOSE: We aimed to evaluate the feasibility and clinical effectiveness of CT-guided 125I brachytherapy for distant oral and maxillofacial metastases. MATERIALS AND METHODS: We retrospectively analyzed 65 patients with 84 distant oral and maxillofacial metastases. Thirty-one patients with 38 lesions received 125I brachytherapy (group A) and 34 with 46 lesions received external beam radiotherapy (EBRT; group B). RESULTS: Median follow-up time was 16 months. The 3-, 6-, 12-, 18-, and 24-month local control rates for group A were 83.9%, 75.9%, 66.7%, 38.4%, and 25.0%, respectively; for group B they were 76.5%, 62.5%, 43.8%, 25.0%, and 0.0%, respectively (P < .05); the median local tumor progression-free survival times were 14 and 9 months, respectively. Group A had a better local tumor progression-free survival (LTPFS) relative to group B (P < .001; HR, 6.961 [95%CI, 2.109, 9.356]). Cox proportional hazards regression analysis indicated that 125I brachytherapy, tumor size, and primary pathological type were the independent factors affecting LTPFS. Additionally, 125I brachytherapy showed better performance in relieving patient clinical symptoms relative to EBRT (P < .05). Group A also had fewer complications than group B, especially regarding grade 3/4 complications according to Radiation Therapy Oncology Group grading criteria. Mean overall survival times in groups A and B were 17.1 and 14.8 months, respectively. CONCLUSION: CT-guided 125I brachytherapy is feasible and safe for distant oral and maxillofacial metastases; it achieved a better local control rate, longer LTPFS and fewer complications without compromising overall survival compared with EBRT.