External-beam radiotherapy followed by high dose rate (HDR) brachytherapy is the standard-of-care for treating gynecologic cancers. The enhanced soft-tissue contrast provided by magnetic resonance imaging (MRI) makes it a valuable imaging modality for diagnosing and treating these cancers. However, in contrast to computed tomography (CT) imaging, the appearance of the brachytherapy catheters, through which radiation sources are inserted to reach the cancerous tissue later on, is often variable across images. This paper reports, for the first time, a new deep-learning-based method for fully automatic segmentation of multiple closely spaced brachytherapy catheters in intraoperative MRI. Represented in the data are 50 gynecologic cancer patients treated by MRI-guided HDR brachytherapy. For each patient, a single intraoperative MRI was used. 826 catheters in the images were manually segmented by an expert radiation physicist who is also a trained radiation oncologist. The number of catheters in a patient ranged between 10 and 35. A deep 3D convolutional neural network (CNN) model was developed and trained. In order to make the learning process more robust, the network was trained 5 times, each time using a different combination of shown patients. Finally, each test case was processed by the five networks and the final segmentation was generated by voting on the obtained five candidate segmentations. 4-fold validation was executed and all the patients were segmented. An average distance error of 2.0 ± 3.4 mm was achieved. False positive and false negative catheters were 6.7% and 1.5% respectively. Average Dice score was equal to 0.60 ± 0.17. The algorithm is available for use in the open source software platform 3D Slicer allowing for wide scale testing and research discussion. In conclusion, to the best of our knowledge, fully automatic segmentation of multiple closely spaced catheters from intraoperative MR images was achieved for the first time in gynecological brachytherapy.

Objective: This study aimed to compare the dose difference in ¹²⁵ I seed implantation between three-dimensional (3D) print template-guided operation and traditional implantation. Materials and Methods: This study retrospectively analyzed 27 patients who underwent ¹²⁵I seed implantation from August 2015 to December 2015 in Hebei General Hospital. Of these, 13 underwent seed implantation guided by a 3D print template, named the template group, and 14 underwent traditional implantation, named the traditional group. All patients underwent computed tomography (CT) scan. Then, 3D templates were printed in the template group. The implantation was guided by CT and 3D templates. The patients in the traditional group underwent implantation with free hands guided by CT scan. Postplan was performed after the operation. The dose-volume histogram, D90, and V90 were calculated. The D90 values pre- and post-operation were compared in each group. The postoperation V90 values of the two groups were also compared. Results: The mean D90 values pre- and post-operation in the template group were (87.09 ± 33.63) Gy and (85.31 ± 34.40) Gy, respectively, with no statistically significant difference. The mean D90 values pre- and post-operation in the traditional group were (86.04 ± 29.93) Gy and (74.96 ± 46.10) Gy, respectively, with a statistically significant difference. The mean V90 values postoperation in the template and traditional groups were (92.76% ± 1.89%) and (84.59% ± 7.56%), respectively, with a statistically significant difference. Conclusions: The postplan and preplan dose parameters of 3D print template-guided seed implantation were nearly consistent. The dose parameters of template group superior to the traditional group. The seeds can be implanted accurately with 3D print template.

The objective of the study is to test whether three-dimensional (3D)-printed template can be used reproducibly for guiding malignant tumors brachytherapy and study the dosimetric consistency and adequacy between pre- and post-plan. Between January and December 2016 in our hospital, a total of 14 patients underwent 3D-printed template-guided brachytherapy. All the patients were fixed into position using a vacuum cushion before undertaking a computed tomography (CT) scan. After the preplan was designed, the templates were printed. The tumors were punctured through predesigned needle holes. Following this, another CT scan was used to confirm the locations of needles, and then the 125 I radioactive seeds were implanted into the tumor according to the preplan. Postplan was performed after the operation. Data of the D90 (minimum absorbed dose of 90% target volume), V90 (90% prescription dose coverage volume percentage of target volume), V100, V150, and seed number pre- and post-operation were collected and compared. The mean D90, V90, V100, V150, and seed number preoperation were 94.96 ± 16.43 Gy, 94.64% ± 1.43%, 91.21% ± 1.59%, 65.01% ± 5.78%, and 46.67 ± 21.87, respectively. The mean D90, V90, V100, V150, and seed number postoperation were 91.97 ± 17.54 Gy, 93.35% ± 2.45%, 89.35% ± 3.21%, 63.40% ± 6.36%, and 46.60 ± 22.85, respectively. No significant difference between pre- and post-operation was observed across the data (P >0.05). For immobilized malignant tumors, 3D-printed template can be used reproducibly. The dose parameters in preplan can be achieved easily and satisfactorily by 3D-printed template guided brachytherapy, and it may become an easily reproducible standardized procedure in the future.

Objective: To investigate the efficacy of ¹²⁵I seed brachytherapy for non-central pelvic recurrence of cervical cancer after external beam radiotherapy, and to analyze the clinical influential factors. Methods: Between June 2015 and April 2022, 32 patients with 41 lesions were treated with ¹²⁵I seed brachytherapy. The seeds were implanted under the guidance of CT and/or 3D-printed template images at a median dose of 100 Gy (range, 80–120 Gy), and the local control rate (LCR) and survival rates were calculated. We used multivariate logistic regression to identify prognosis predictors, and receiver operating characteristic (ROC) curve analysis to determine the optimal cut-off values. Results: The median follow-up was 48.52 months (range, 4–86 months), and the 6-, 12-, and 24-month LCR was 88.0%, 63.2%, and 42.1%, respectively. The 1- and 2-year survival rates were 36% and 33%, respectively, and the median survival time was 13.26 months. No significant adverse events occurred. Multivariate regression analysis showed that tumor diameter, tumor stage, and LCR were independent factors influencing survival. ROC curve analysis showed that the area under the curve for tumor diameter and D90 were 0.765 and 0.542, respectively, with cut-off values of 5.3 cm and 108.5 Gy. Conclusions: The present findings indicate that ¹²⁵I seed brachytherapy is feasible for treating non-central pelvic recurrence of cervical cancer after external beam radiotherapy. Further, tumor diameter < 5.3 cm and immediate postoperative D90 > 108.5 Gy were associated with better efficacy.

Background: The treatment of local–regional recurrent breast cancer (BC) after external beam radiotherapy is challenging. We aim to evaluate the effectiveness and safety of computed tomography (CT)–guided percutaneous iodine-125 brachytherapy for local recurrent BC.Methods: We retrospectively analyzed 15 patients with local recurrent BC treated with CT-guided interstitial implantation of iodine-125 seeds. Regular contrast-enhanced CT was conducted to evaluate the tumor response. Follow-up survival, quality of life, and adverse events were analyzed.Results: Among the 15 patients, five were elderly patients (older than 80 years) and six were complicated with chronic underlying diseases. The median number of ¹²⁵I seeds implantation was 33 (range: 20–130) with median dose 90 (D90, the minimum dose covering 90% of the target volume) of 108 Gy (range: 60–120 Gy). There was no significant difference in D90, V100 (the volume of the target receiving 100% of the prescription dose), and V150 (the volume of the target receiving 150% of the prescription dose) before and after operation (p > 0.05). The median follow-up was 14 months (range: 6–18 months). Six months after operation, the ORR was 66.7% (10/15) and the LCR was 93.3% (14/15). The 6- and 12-month survival rates were 100 and 41.6%, respectively, and the median survival time was 12.5 months. PS score decreased from 1.53 ± 0.81 to 0.53 ± 0.49. The pain score decreased from 2.87 ± 1.67 before operation to 1.07 ± 1.18 after operation, and the differences were statistically significant (p< 0.05). No severe complications occurred.Conclusions: CT-guided iodine-125 brachytherapy provided a safe and effective choice for recurrent BC with significant local therapeutic effects and minor complications, especially for elderly patients with chronic underlying disease and those who were not eligible for surgical resection and had failed to benefit from systemic therapy.

Solitary fibrous tumor (SFT) is a rare spindle cell tumor, benign or low-grade malignant, with an extremely low possibility of occurrence of malignant solitary fibrous tumor (MSFT). Surgery is an effective way for treating SFT, but it is often difficult to resect completely due to a large size, with a high recurrence rate and mortality rate after operation. Additionally, SFT is relatively resistant to chemotherapy, and there is a lack of effective systemic drug treatment. These lead to certain difficulties in the treatment of SFT. We report a case of a rare MSFT in the pelvic cavity. With a history of recurrence after two surgeries, this patient underwent surgical removal combined with ¹²⁵I seed implantation at our hospital in the context that the tumor could not be completely removed because it was large and adhered to surrounding tissues; after up to 43 months of progression-free survival (PFS), the patient underwent ¹²⁵I seed implantation alone, and achieved a complete remission, with a PFS up to 35 months. ¹²⁵I seed implantation can be a safe and effective treatment option for unresectable MSFT as well as a potential solution to repeated local recurrence.