Technical Note: Accurate replication of soft and bone tissues with 3D printing.

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Materials Science

Background:

• Patient-specific phantoms are crucial for medical imaging research and development.
• Accurate replication of tissue properties, particularly Hounsfield Units (HU), is essential for realistic simulations.
• Existing 3D printing methods often struggle to replicate the complex density variations found in human anatomy.

Purpose of the Study:

• To fabricate a patient-specific skull phantom using a novel filament extrusion rate method.
• To accurately replicate soft and bone tissues in terms of Hounsfield Units (HU) and texture.
• To validate the efficacy of the new method compared to standard 3D printing techniques.

Main Methods:

• Developed an in-house software to process patient Computed Tomography (CT) data for voxel-by-voxel replication.
• Utilized polylactic acid (PLA) for soft tissues and a PLA-stone mixture for bone tissues.
• Employed a new filament extrusion rate technique to achieve variable density and HU replication.

Main Results:

• The fabricated phantom closely matched the patient's anatomy.
• Achieved similar Hounsfield Unit (HU) ranges for both soft and bone tissues without air gaps.
• Replicated bone tissues reached maximum measured HU values of approximately 900.
• Demonstrated significant improvement in bone tissue HU replication compared to standard methods.

Conclusions:

• The filament extrusion rate method enables accurate replication of soft and bone tissue HU.
• This technique offers a significant advancement for creating realistic, custom-made medical phantoms.
• Future research could explore high-density materials for advanced applications in diagnostic imaging and radiotherapy.