A 3-D Printed Solution for Clinically-Relevant in Vitro HDR Brachytherapy
A Silvus*, T Mazur, S Goddu, A Cohen, A Heermann, J Zoberi, S Markovina, M Altman, Washington University School of Medicine, St. Louis, MO
Presentations
SU-H330-IePD-F7-6 (Sunday, 7/10/2022) 3:30 PM - 4:00 PM [Eastern Time (GMT-4)]
Exhibit Hall | Forum 7
Purpose: A 3D-printed solution for performing in vitro tissue culture studies using a clinical HDR brachytherapy afterloader was created to facilitate research advancing the field of brachytherapy. This platform was designed to allows investigation of radiobiological response in regions of maximum instantaneous dose rate to cells proximal to the 192Ir source (≥30-40 Gy/min) while being easily adaptable to other clinically relevant source-to-target(cell) distances as well as multi-modality studies.
Methods: The platform was designed and printed using a fused deposition modeling 3D printer (Ultimaker, Utrecht, Netherlands) with a polylactic acid filament. To assess the dosimetry of the platform, it was loaded with a 96-well tissue culture plate and CT-based treatment plans were created using BrachyVision and delivered with a Varisource iX HDR afterloader (both Varian Medical Systems, Palo Alto, CA). Dosimetry was evaluated immediately adjacent to the source underneath the 96-well plate using optically stimulated luminescent dosimeters (OSLDs, Landauer Inc., Glenwood IL). It was benchmarked against homogeneous water-based dose calculations (TG-43) and a commercial model-based dose calculation algorithm (MBDCA) accounting for heterogeneities (Acuros XB, Varian Medical Systems, Palo Alto, CA).
Results: Based on the treatment planning dose calculations, dosimetric variations in planes at the location of the cells were 1.5% and 1.6% for TG-43 and MBDCA calculations, respectively. Three independent OSLD measurements resulted in an average percent difference (+/- standard deviation) relative to TG-43 and MBDCA calculations of 10.7+/-3% and 10.3+/-4%, respectively. Average distances to agreement between measurement and calculated dose were 1.2+/-0.4 mm and 1.4+/-0.4 mm for TG-43 and MBDCA calculations, respectively.
Conclusion: The platform addresses some of the current limitations of research in brachytherapy by allowing for the delivery of uniform fields in regions of high dose rate while also being adaptable to other experimental setups. Dosimetric studies of this device indicate feasibility for in vitro HDR brachytherapy studies.
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