China: 3D Printing to Assist in Workflow for Seed Implantation Therapy for Prostate Cancer

Medical scientists from several different universities and hospitals in China continue in the fight against cancer, along with working to create better and more comfortable treatment plans for patients in the early stages of prostate cancer. With their findings outlined in the recently published ‘Expert consensus on computed tomography-assisted three-dimensional-printed coplanar template guidance for interstitial permanent radioactive ¹²⁵I seed implantation therapy,’ the research team outlines the need for better procedures in workflow.

With interstitial permanent radioactive seed implantation, cancer patients can receive large, localized doses for treating tumors. The doses affect the tumors but very little of the surrounding healthy tissue. Today, most seeds are implanted in the patient with the assistance of ultrasound guidance or computed tomography.

This type of procedure is meant to be ‘minimally invasive’ and patients are expected to have a very short recovery period after implantation of the seeds; however, CT-guided ‘puncturing’ procedures for seed implantation is ‘very complicated and time-consuming,’ state the authors, and technicians must be well-trained over a long period of time:

“At present, seed implantation brachytherapy in China is a restricted technology, which requires strict training to obtain a license. The relevant state administrative departments carry out supervision. In 2009, the Ministry of Health released the Technical Management Standards for Radioactive Seed Implantation Brachytherapy for the first time. In 2017, the National Health and Family Planning Commission released the Technical Management Standards for Radioactive Seed Implantation Brachytherapy (2017 edition), further amending and standardizing the institutional, personnel, and technical conditions and requirements for carrying out seed implantation,” reported the researchers.

“It was emphasized that physicians should receive systematic training for at least 3 months, participate in seed implantation therapy for at least 30 cases under the guidance of superior physicians, and participate in the entire management process of patients, including preoperative diagnosis, preoperative planning, implantation modality, postoperative dose verification, perioperative management, and follow-up. Only after passing the examination could they go on duty.”

Radioactive seed implantation is recommended by a wide variety of organizations related to cancer research around the world, to include:

• The American Cancer Society
• The Urology Society
• The Clinical Oncology Society
• The Radiation Oncology Society
• The Brachytherapy Society

“Seed implantation techniques for prostate carcinomas are well-established and quality assurance is controlled by transperineal ultrasound-guidance combined with planar template assistance to achieve a precise three-dimensional (3D) distribution of seeds in the prostate and ensuring seed implantation treatment is strictly followed up as per preplanning,” state the researchers.

The circuit diagram of computed tomography-assisted three-dimensional-printed coplanar templates guidance for seed implantation

The authors were motivated to perform this particular research because while there are templates for transrectal implantation, so far there has been no established workflow to implant seeds anywhere else in the human body—meaning that surgical pre-planning can be much more challenging, especially due to issues like movement of organs, patient’s changing position, and even interference from bone. In using 3D-PCT-guided seed implantation, assisted by CT processes, implantation is ‘suitable’ for salvage treatment of recurrent and metastatic solid tumors.

Standard workflows for CT-assisted 3D-PCT-guided seed implantation include:

• Patient position fixation
• CT-simulated positioning
• Pre-planning design
• 3D-PCT image production
• Stabilization by 3D-PCT
• Needle puncture for seed implantation
• Implantation of ¹²⁵I seeds
• Post-plan evaluation

“The key to successful seed implantation is strict quality assurance in all steps,” concluded the researchers.

“Despite current data supporting ¹²⁵I seed implantation for some solid carcinomas, there is a need for prospectively-randomized multicenter clinical trials to gather strong evidence for using ¹²⁵I seed implantation in other solid carcinomas.”

3D printing continues to be connected with cancer treatments, from the combination of technologies like robotic surgery and 3D printing, to 3D printed phantoms for better cancer treatment, the creation of microfluidic devices, and more.

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Detailed requirements and workflow

Characteristics of computed tomography-assisted three-dimensional-printed coplanar templates-guided seed implantation in different organs