Prog Med Phys.  2017 Sep;28(3):106-110. 10.14316/pmp.2017.28.3.106.

Feasibility of Fabricating Variable Density Phantoms Using 3D Printing for Quality Assurance (QA) in Radiotherapy

• Oh SA
• Kim MJ
• Kang JS
• Hwang HS
• Kim YJ
• Kim SH
• Park JW
• Yea JW
• Kim SK

• KMID: 2393371
• DOI: http://doi.org/10.14316/pmp.2017.28.3.106

Abstract

The variable density phantom fabricated with varying the infill values of 3D printer to provide more accurate dose verification of radiation treatments. A total of 20 samples of rectangular shape were fabricated by using the Finebot™ (AnyWorks; Korea) Z420 model (width×length×height=50 mm×50 mm×10 mm) varying the infill value from 5% to 100%. The samples were scanned with 1-mm thickness using a Philips Big Bore Brilliance CT Scanner (Philips Medical, Eindhoven, Netherlands). The average Hounsfield Unit (HU) measured by the region of interest (ROI) on the transversal CT images. The average HU and the infill values of the 3D printer measured through the 2D area profile measurement method exhibited a strong linear relationship (adjusted R-square=0.99563) in which the average HU changed from −926.8 to 36.7, while the infill values varied from 5% to 100%. This study showed the feasibility fabricating variable density phantoms using the 3D printer with FDM (Fused Deposition Modeling)-type and PLA (Poly Lactic Acid) materials.

Keyword

Variable density phantom; 3D Printer; Infill value; Hounsfield unit

MeSH Terms

Methods
Printing, Three-Dimensional*
Radiotherapy*

Figure

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  Fig. 1. A total of 20 samples with dimensions (width×length×height=50 mm×50 mm×10 mm) were fabricated for infill values ranging from 5% to 100% by using FinebotTM (AnyWorks; Korea) Z420 3D printer model.

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  Fig. 2. (a) Photograph of samples with infill values from 5% to 100%, (b) Frontal image of samples with infill values from 5% to 100% obtained by CT scan.

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  Fig. 3. (a) HU was measured by using a two-dimensional area profile function at the center of the sample on a transversal image by CT scan. (b) Horizontal ROI Profile, vertical ROI Profile, pixel statistics, and ROI for the measured area of the sample with infill value of 5%.

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  Fig. 4. Correlation between infill value (%) and Hounsfield unit (HU) of the 3D printer.

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