Characterizing 3D printing in the fabrication of variable density phantoms for quality assurance of radiotherapy.
OBJECTIVE
To present characterization, process flow, and applications of 3D fabricated low density phantoms for radiotherapy quality assurance (QA).


METHODS
A Rostock 3D printer using polystyrene was employed to print slabs of varying relative electron densities (0.18-0.75). A CT scan was used to calibrate infill-to-density and characterize uniformity of the print. Two printed low relative density rods (0.18, 0.52) were benchmarked against a commercial CT-electron-density phantom. Density scaling of Anisotropic Analytical Algorithm (AAA) was tested with EBT3 film for a 0.57 slab. Gamma criterion of 3% and 3 mm was used for analysis.


RESULTS
3D printed slabs demonstrated uniformity for densities 0.4-0.75. The printed 0.52 rod had close agreement with the commercial phantom. Dosimetric comparison for 0.57 density slab showed >95% agreement between calculation and measurements.


CONCLUSIONS
3D printing allows fabrication of variable density phantoms for QA needs of a small clinic.
Department of Physics Astronomy and Oncology, University of Calgary, Calgary, Alberta T2N 4N2, Canada.
Joseph
J
Madamesila
Department of Physics Astronomy and Oncology, University of Calgary, Calgary, Alberta T2N 4N2, Canada.
Philip
P
McGeachy
Department of Physics Astronomy and Oncology, University of Calgary, Calgary, Alberta T2N 4N2, Canada.
J Eduardo
JE
Villarreal Barajas
Department of Physics Astronomy and Oncology, University of Calgary, Calgary, Alberta T2N 4N2, Canada. Electronic address: rfkhan@ucalgary.ca.
Rao
R
Khan
D000465:Algorithms; D016880:Anisotropy; D002138:Calibration; D004583:Electrons; D004867:Equipment Design; D005373:Film Dosimetry / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D019047:Phantoms, Imaging; D011137:Polystyrenes / Q000737:chemistry; D066330:Printing, Three-Dimensional; D011785:Quality Assurance, Health Care / Q000592:standards; D011786:Quality Control; D011874:Radiometry; D011878:Radiotherapy / Q000379:methods / Q000592:standards*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods / Q000592:standards*
D011137:Polystyrenes
3D printing; Desktop phantom fabrication; Dose calculation algorithm; Experimental verification