Low-density 3D-printed boluses with honeycomb infill in radiotherapy

Edyta Dąbrowska-Szewczyk; Anna Zawadzka; Piotr Kowalczyk; Rafał Podgórski; Gabriela Saworska; Maksymilian Głowacki; Paweł Kukołowicz; Beata Brzozowska

doi:10.1016/j.ejmp.2023.102600

Low-density 3D-printed boluses with honeycomb infill in radiotherapy

Phys Med. 2023 Jun:110:102600. doi: 10.1016/j.ejmp.2023.102600. Epub 2023 May 9.

Authors

Edyta Dąbrowska-Szewczyk¹, Anna Zawadzka², Piotr Kowalczyk³, Rafał Podgórski⁴, Gabriela Saworska⁵, Maksymilian Głowacki⁵, Paweł Kukołowicz², Beata Brzozowska⁶

Affiliations

¹ Biomedical Physics Division, Faculty of Physics, University of Warsaw, 5 L. Pasteur Street, 02-093 Warsaw, Poland; Medical Physics Department, The Maria Skłodowska-Curie National Research Institute of Oncology in Warsaw, 5 WK Roentgen Street, 02-781 Warsaw, Poland.
² Medical Physics Department, The Maria Skłodowska-Curie National Research Institute of Oncology in Warsaw, 5 WK Roentgen Street, 02-781 Warsaw, Poland.
³ Warsaw University of Technology, Faculty of Chemical and Process Engineering, Department of Biotechnology and Bioprocess Engineering, Waryńskiego 1, 00-645 Warsaw, Poland; Centre of Advanced Materials and Technologies CEZAMAT, Poleczki 19, 02-822 Warsaw, Poland.
⁴ Warsaw University of Technology, Faculty of Chemical and Process Engineering, Department of Biotechnology and Bioprocess Engineering, Waryńskiego 1, 00-645 Warsaw, Poland.
⁵ Biomedical Physics Division, Faculty of Physics, University of Warsaw, 5 L. Pasteur Street, 02-093 Warsaw, Poland.
⁶ Biomedical Physics Division, Faculty of Physics, University of Warsaw, 5 L. Pasteur Street, 02-093 Warsaw, Poland. Electronic address: Beata.Brzozowska@fuw.edu.pl.

PMID: 37167778
DOI: 10.1016/j.ejmp.2023.102600

Abstract

Purpose: Dosimetric characteristics of 3D-printed plates using different infill percentage and materials was the purpose of our study.

Methods: Test plates with 5%, 10%, 15% and 20% honeycomb structure infill were fabricated using TPU and PLA polymers. The Hounsfield unit distribution was determined using a Python script. Percentage Depth Dose (PDD) distribution in the build-up region was measured with the Markus plane-parallel ionization chamber for an open 10x10 cm² field of 6 MV. PDD was measured at a depth of 1 mm, 5 mm, 10 mm and 15 mm. Measurements were compared with Eclipse treatment planning system calculations using AAA and Acuros XB algorithms.

Results: The mean HU for CT scans of 3D-printed TPU plates increased with percentage infill increase from -739 HU for 5% to -399 HU for 20%. Differences between the average HU for TPU and PLA did not exceed 2% for all percentage infills. Even using a plate with the lowest infill PDD at 1 mm depth increase from 44.7% (without a plate) to 76.9% for TPU and 76.6% for PLA. Infill percentage did not affect the dose at depths greater than 5 mm. Differences between measurements and TPS calculations were less than 4.1% for both materials, regardless of the infill percentage and depth.

Conclusions: The use of 3D-printed light boluses increases the dose in the build-up region, which was shown based on the dosimetric measurements and TPS calculations.

Keywords: 3D printing; Build-up region; Percentage depth dose.

MeSH terms

Phantoms, Imaging
Polyesters
Printing, Three-Dimensional
Radiometry*
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted*

Substances

Polyesters