Feasibility of 3D-printed phantoms for quantifying Bragg peak degeneration due to tissue heterogeneity in lung proton therapy

Feasibility of 3D-printed phantoms for quantifying Bragg peak degeneration due to tissue heterogeneity in lung proton therapy

Moret, Thijs (TU Delft Mechanical, Maritime and Materials Engineering)

Schaart, Dennis (mentor)

Delft University of Technology

2019-08-27

In the field of radiation oncology, proton therapy is a relatively new technique. It shows a great advantage over conventional radiation therapy in the depth-dose relation, which results in the possibility to deliver dose far more concentrated at a specific depth. This in turn has the potential to spare the healthy tissue surrounding a tumour from receiving a very high dose. However, this depth-dose relation has the downside that it is very sensitive to small uncertainties in geometry and tissue composition, which are present in heterogeneous tissues such as lung tissue.
Because of this sensitivity, it is essential that the dose delivery can be verified properly for these heterogeneous tissues, which requires highly accurate quality assurance. To improve this quality assurance, highly anthropomorphic phantoms could offer a solution. The currently commercially available phantoms however lack the high level of detail necessary, as these are produced using casting techniques. Thus a new production technique should be considered to create phantoms of greater heterogeneity and at a higher level of detail. A possible solution to this problem is to apply additive manufacturing, since this manufacturing technique can supposedly address both these issues.
An important issue with the application of additive manufacturing is the lack of knowledge on the accuracy of 3D-printers. Next to the unknown accuracy, there are other challenges concerning additive manufacturing, such as the layered creation of objects and the material that is to be printed over an air cavity and the support structures this is associated with.
The goal of this research is to explore the possibility to apply additive manufacturing in the creation of a phantom with a high level of detail and heterogeneity and the effect of the heterogeneous object on the quality of the Bragg peak. More specifically, simulations are performed on porous materials to quantify the degeneration of the Bragg peak. Also, a literature study on additive manufacturing will be performed, combined with the use of commercially available tabletop 3D-printers. Together, the capacity of the printer to create a high level of heterogeneity and the simulations performed on these heterogeneous structures, should give an indication on the feasibility to create a 3D-printed phantom for lung proton therapy.

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Student theses

master thesis

© 2019 Thijs Moret