Additively manufactured test phantoms for mimicking soft tissue radiation attenuation in CBCT using Polyjet...

Area of Science:

• Medical Imaging
• Additive Manufacturing
• Materials Science

Background:

• Cone Beam Computed Tomography (CBCT) requires specialized imaging phantoms for accurate calibration and testing.
• Existing phantoms can be expensive and may not fully replicate the diverse radiation attenuation properties of human soft tissues.

Purpose of the Study:

• To develop and validate a cost-effective method for creating CBCT imaging phantoms.
• To utilize modified Polyjet additive manufacturing to achieve a single material that mimics a range of human soft-tissue radiation attenuation.
• To enable customized imaging phantom development.

Main Methods:

• Designed cubic lattice test phantoms with varying air:material ratios (0-70%) using 3-Matic software.
• Printed phantoms using Polyjet technology with Vero PureWhite, VeroClear, and TangoPlus materials.
• Analyzed CT values, performed non-contact profile measurements, and conducted microCT-based volumetric analysis.

Main Results:

• Printed phantoms achieved a grey value spectrum (-757 to +286 HU) equivalent to human soft tissues.
• Dimensional accuracy reached 99.07% via non-contact profile measurement.
• Volumetric accuracy ranged from 84.80% to 94.91% using microCT analysis.
• The cost for 24 test phantoms was only 83.00 Euro.

Conclusions:

• Additive manufacturing, through macrostructure manipulation, effectively modifies material radiographic visibility in CBCT.
• This technique allows for the creation of customized imaging phantoms with 1 mm³ resolution.
• The developed method offers a cost-effective solution for producing versatile CBCT phantoms.