3D-printed applicators for high dose rate brachytherapy: Dosimetric assessment at different infill percentage.
OBJECTIVE
Dosimetric assessment of high dose rate (HDR) brachytherapy applicators, printed in 3D with acrylonitrile butadiene styrene (ABS) at different infill percentage.


METHODS
A low-cost, desktop, 3D printer (Hamlet 3DX100, Hamlet, Dublin, IE) was used for manufacturing simple HDR applicators, reproducing typical geometries in brachytherapy: cylindrical (common in vaginal treatment) and flat configurations (generally used to treat superficial lesions). Printer accuracy was investigated through physical measurements. The dosimetric consequences of varying the applicator's density by tuning the printing infill percentage were analysed experimentally by measuring depth dose profiles and superficial dose distribution with Gafchromic EBT3 films (International Specialty Products, Wayne, NJ). Dose distributions were compared to those obtained with a commercial superficial applicator.


RESULTS
Measured printing accuracy was within 0.5mm. Dose attenuation was not sensitive to the density of the material. Surface dose distribution comparison of the 3D printed flat applicators with respect to the commercial superficial applicator showed an overall passing rate greater than 94% for gamma analysis with 3% dose difference criteria, 3mm distance-to-agreement criteria and 10% dose threshold.


CONCLUSIONS
Low-cost 3D printers are a promising solution for the customization of the HDR brachytherapy applicators. However, further assessment of 3D printing techniques and regulatory materials approval are required for clinical application.
Department of Radiation Oncology, European Institute of Oncology, Milan, Italy. Electronic address: rosalinda.ricotti@ieo.it.
Rosalinda
R
Ricotti
Department of Radiation Oncology, European Institute of Oncology, Milan, Italy.
Andrea
A
Vavassori
Unit of Medical Physics, European Institute of Oncology, Milan, Italy.
Alessia
A
Bazani
Department of Radiation Oncology, European Institute of Oncology, Milan, Italy.
Delia
D
Ciardo
Unit of Medical Physics, European Institute of Oncology, Milan, Italy.
Floriana
F
Pansini
Department of Radiation Oncology, European Institute of Oncology, Milan, Italy; Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy.
Ruggero
R
Spoto
Tecniche di radiologia medica, per immagini e radioterapia, University of Milan, Milan, Italy.
Vittorio
V
Sammarco
Unit of Medical Physics, European Institute of Oncology, Milan, Italy.
Federica
F
Cattani
Dipartimento di Elettronica Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy; Bioengineering Unit, Centro Nazionale di Adroterapia Oncologica, Pavia, Italy.
Guido
G
Baroni
Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy; Scientific Directorate, European Institute of Oncology, Milan, Italy.
Roberto
R
Orecchia
Department of Radiation Oncology, European Institute of Oncology, Milan, Italy; Department of Oncology and Hemato-oncology, University of Milan, Milan, Italy.
Barbara Alicja
BA
Jereczek-Fossa
D065638:Absorption, Radiation; D001918:Brachytherapy; D005373:Film Dosimetry / Q000295:instrumentation*; D066330:Printing, Three-Dimensional; D011829:Radiation Dosage; D011879:Radiotherapy Dosage
3D printing; Applicator; Brachytherapy; Dosimetry; Infill percentage; Low-cost 3D printer