3D-printed Magnetic Resonance (MR)-based gynecological phantom for image-guided brachytherapy training

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Gynecological Oncology

Background:

• Clinical training for gynecological brachytherapy requires realistic anatomical models.
• Existing training phantoms may lack sufficient fidelity for advanced simulation.

Purpose of the Study:

• To develop a step-by-step method for constructing a life-sized gynecological phantom using patient-specific MRI data.
• To evaluate the ability of the phantom to produce convincing ultrasound images comparable to patient scans.

Main Methods:

• Patient-specific MRI data was used to segment organs-at-risk.
• A 3D-printed positive mold and polyvinyl chloride (PVC) plastisol were used for phantom construction.
• Varying ratios of plastic softener/hardener and microbead densities were employed to simulate tissue acoustic properties.
• A multireader, multicase equivalence study was conducted to assess image classification accuracy (patient vs. phantom).
• Readers evaluated ultrasound videos for interstitial needle insertion accuracy.
• Computed Tomography (CT) and Magnetic Resonance (MR) imaging were performed on the phantom.

Main Results:

• Readers achieved a 53.3% ± 6.2% accuracy in classifying patient and phantom scans.
• Interstitial needle insertion was identified with 100% accuracy in transabdominal ultrasound views and 78% in transrectal views.
• The phantom demonstrated safety for CT and MR imaging.

Conclusions:

• A reproducible manufacturing process for a life-sized, multi-modality imaging-compatible gynecological phantom has been established.
• This phantom serves as a valuable tool for simulating clinical scenarios in image-guided brachytherapy.
• The phantom's ability to generate realistic ultrasound images supports its use in simulation-based medical education.