Quantification and reduction of uncertainties for online adaptive particle therapy

Project leaders:

Dr. Lena Nenoff1,2 Lena.Nenoff(at)oncoray.de

Dr. Friderike Longarino3,4 f.longarino(at)dkfz-heidelberg.de

1OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden

2Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology-OncoRay, Dresden

3Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Research Center (DKFZ)

4Department of Radiation Oncology and Heidelberg Ion Beam Therapy Center (HIT), Heidelberg University Hospital

Funded since: mid of 2024 for 3 years

Project rationale:

Anatomical changes during treatment can complicate delivering the planned dose, which may increase side effects or decrease local tumor control. Treatment outcomes may be improved by taking such changes into account during treatment with online adapted radiotherapy. This is even more important in particle therapy, where anatomical changes have a much larger impact on the resulting dose distortion. Although several institutions are working towards a clinical implementation, online adaptive particle therapy (OAPT) is not yet widely applied. In both HIRO and OncoRay, such OAPT workflows are being developed. However, the dosimetric impact of uncertainties of the OAPT workflow remains unknown, and there is currently no method to calculate it. Yet the assessment of the overall uncertainty influences the decision to adapt or not.

The research project aims to cooperatively develop and implement general methods for quantifying dose calculation and accumulation uncertainties in OAPT for:

  • assessing the uncertainty of the total delivered dose,
  • identifying the most uncertain steps in OAPT pipelines, and
  • developing methods to mitigate the effects of these uncertainties.

The jointly developed methods to quantify the uncertainties of each workflow step and combine them to calculate the total uncertainty of the delivered dose will be applied to both workflows and respective clinical applications (Figure 1). The most uncertain steps will thereby be identified, and the uncertainties will be reduced to improve OAPT workflows in both institutions.

Figure 1: Use cases and synergies in the joint NCRO project. At HIRO, the focus is on the abdomen; the intended workflow includes a shuttle-based system combined with an off-room MRI, and uses deformable image registration (DIR) to propagate structures and generate a synthetic CT for dose optimization. At OncoRay, the focus is on the lung, with an in-room CT for imaging and dose calculation, and DIR and deep learning for structure generation. Both institutions intend to use DIR for dose accumulation.

Operating Partners Oncoray

Operating Partners HIRO

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