Dosimetry verification of three-dimensional printed polylactic acid template-guided precision 125 I seed implantation for lung cancer using a desktop three-dimensional printer

Recent progress in radioactive seed implantation brachytherapy of non-small cell lung cancer: a narrative review

Background and Objective

Brachytherapy, a new form of radiation therapy, has been used to treat lung cancer and consists of two main forms of treatment: endobronchial brachytherapy and radioactive seed implantation brachytherapy (RSI-BT), the latter of which is used to treat non-small cell lung cancer (NSCLC). The use of RSI-BT in the treatment of NSCLC at our centre has yielded some positive results.

Methods

To more fully consider the context of this application, we conducted a search of PubMed from 2018 to March 5, 2023. The search included a combination of the MeSH terms: "brachytherapy" and "lung neoplasm".

Key Content and Findings

The majority of NSCLC patients who received RSI-BT achieved positive benefits. Most patients had a progression-free survival (PFS) of between 12 and 18 months. Additionally, radioactive particle stent implantation as a specific RSI-BT has shown therapeutic potential in the treatment of malignant airway obstruction. With the application of new technologies, RSI-BT will become more precise, efficient and inexpensive.

Conclusions

This review demonstrates that RSI-BT can be therapeutic in the treatment of both early and advanced NSCLC with manageable complications. There have also been reports on the combination of RSI-BT with other therapies, but more research is needed on the combination of RSI-BT with them.

3D printing in brachytherapy: A systematic review of gynecological applications

PURPOSE

To provide a systematic review of the applications of 3D printing in gynecological brachytherapy.

METHODS

Peer-reviewed articles relating to additive manufacturing (3D printing) from the 34 million plus biomedical citations in National Center for Biotechnology Information (NCBI/PubMed), and 53 million records in Web of Science (Clarivate) were queried for 3D printing applications. The results were narrowed sequentially to, (1) all literature in 3D printing with final publications prior to July 2022 (in English, and excluding books, proceedings, and reviews), and then to applications in, (2) radiotherapy, (3) brachytherapy, (4) gynecological brachytherapy. Brachytherapy applications were reviewed and grouped by disease site, with gynecological applications additionally grouped by study type, methodology, delivery modality, and device type.

RESULTS

From 47,541 3D printing citations, 96 publications met the inclusion criteria for brachytherapy, with gynecological clinical applications compromising the highest percentage (32%), followed by skin and surface (19%), and head and neck (9%). The distribution of delivery modalities was 58% for HDR (Ir-192), 35% for LDR (I-125), and 7% for other modalities. In gynecological brachytherapy, studies included design of patient specific applicators and templates, novel applicator designs, applicator additions, quality assurance and dosimetry devices, anthropomorphic gynecological applicators, and in-human clinical trials. Plots of year-to-year growth demonstrate a rapid nonlinear trend since 2014 due to the improving accessibility of low-cost 3D printers. Based on these publications, considerations for clinical use are provided.

CONCLUSIONS

3D printing has emerged as an important clinical technology enabling customized applicator and template designs, representing a major advancement in the methodology for implantation and delivery in gynecological brachytherapy.

A new technique for trans-perirectal iodine-125 seed implantation in prostatic cancer guided by CT and 3D printed template: Two case reports

Low-dose-rate prostate brachytherapy with permanent iodine-125 is an important curative treatment for low-risk prostate cancer, and it has been demonstrated that brachytherapy with permanent seeds is an effective treatment. However, differences in prostate volume, spatial location, and gland deformation between images obtained in the pre-planning phase and those obtained during the implantation procedure affect accurate delivery of the pre-planned dose. Furthermore, the complicated procedure could be a burden to elderly patients, for example, the risks associated with general anesthesia. In addition, ultrasound images are not as clear as computed tomography (CT) images with regard to identifying the location of seeds. Therefore, a new method for guidance during the procedure is urgently needed. Here, we have described a new method for precise trans-perirectal insertion of radioactive iodine-125 seeds in patients with prostate cancer under the guidance of CT and a 3D-printed template. These are some of the advantages of this technique over the standard procedure for seed implantation in the prostate: It requires only local anesthesia, the pre-planning phase can be completed before the procedure, and the operation time is considerably shorter. This report describes trans-pararectal iodine-125 seed brachytherapy for prostate cancer under local anesthesia and the guidance of a 3D printed template in two elderly patients. The dose parameters determined in the preoperative planning phase were verified postoperatively and found to be consistent. Further, the procedure was completely successfully with no major complications in both cases, and the patients’ prostate-specific antigen levels were normal at the most recent follow-up conducted 50 months after the procedure. Therefore, this technique seems promising for prostate cancer brachytherapy, and its application needs to be researched and extended further in the future.

Dosimetry verification of three-dimensional printed polylactic acid template-guided precision 125 I seed implantation for lung cancer using a desktop three-dimensional printer

Introduction

The purpose of this study was to verify the effectiveness of polylactic acid (PLA) template puncture route planning by comparing preoperative and postoperative dosimetry using computerized tomography (CT)‐guided implantation of ¹²⁵I radioactive seeds.

Methods

A total of 28 patients who underwent ¹²⁵I seed implantation between January 2018 and June 2019 were selected for the statistical study of seed dosimetry. All patients received preoperative treatment planning system (TPS) planning, of which 13 patients in the experimental 3D template group underwent intraoperative puncture and implantation using the PLA template planning route. The other 15 patients in the traditional control group underwent intraoperative puncture and implantation using CT images for guidance. By calculating the dose‐volume histogram, preoperative and postoperative D90 values and postoperative V90 values were compared between the two groups.

Results

The mean D90 values in the template group before and after surgery were 136.06 ± 7.10 and 134.72 ± 7.85 Gy, respectively. There was no statistically significant difference. The preoperative and postoperative mean D90 values in the traditional group were 132.97 ± 8.04 and 126.06 ± 9.19 Gy, respectively, which were statistically significantly different. The mean postoperative V90 values in the template and traditional groups were 93.80 ± 1.34% and 88.42 ± 6.55 %, respectively, showing a statistically significant difference.

Conclusions

The preoperative TPS plan for the experimental group guided by the PLA template was almost the same as that for the final guided particle implantation. The dose parameters in the experimental group were also better than those in the traditional group, making the use of the presented PLA template more efficient for clinical applications.