Development of a phantom for the verification of stereotactic arrhythmic radioablation treatment deliveries

Abstract: Aim: Phantoms are used daily in the clinic for radiotherapy. As more realistic phantoms are requested, 3D printing could be used but the design of a realistic phantom is difficult. The purpose of this project was to design and 3D print an anthropomorphic phantom that could be used for verification of complex treatment such as stereotactic arrhythmic radioablation treatments without the use of patient data. Material and method:A phantom was designed and simulated in XCAT which generated virtual computed tomography (CT) images of the wanted phantom. Dif- ferent test cubes were printed to determine the different printing parameters to create a certain density. From XCAT data, tissues with different densities were delineated and gave the different components of the large phantom. A phantom was printed based on XCAT data using a thermoplastic material and a StoneFil composite for higher density components. Different infill percentages were used to create desired density in each component of the phantom. The phantom was sliced into 16 sagittal slices and printed separately with a RAISE3D printer. Quality assurance checks were done on the printed phantom in terms of geometric resolution and produced densities. Results:A linear correlation between infill percentage and HU values were obtained from test printing cubes. The evaluated geometric resolution in CloudCompare showed that 85% of the points in the phantom agreed with the design within 0.3 mm and the HU values disagreed with less than 1 %. Conclusion:Current results show that it is possible to design a phantom without the use of patient data. It is possible to create contrast inside with different infill percentage and with a good resolution. Different types of filament provide tissue- equivalent properties and could model different tissue of the human body. For further use it is possible to reprint a slice for dosimetric instruments to be placed inside. A phantom like this is clinically more realistic than currently existing and more cost effective than what is on the market.