Experimental verification of a 4D MLEM reconstruction algorithm used for in-beam PET measurements in particle therapy
- Resource Type
- Authors
- S. Helmbrecht; M. Priegnitz; Kristin Stützer; Katia Parodi; Christoph Bert; Wolfgang Enghardt; Fine Fiedler; Nami Saito
- Source
- Physics in Medicine and Biology
Physics in Medicine and Biology 58(2013), 5085-5111
Physics in Medicine and Biology; Vol 58
- Subject
- Rotation
Ion beam
Computer science
Movement
medicine.medical_treatment
4D in-beam PET
030218 nuclear medicine & medical imaging
Reduction (complexity)
03 medical and health sciences
Imaging, Three-Dimensional
0302 clinical medicine
medicine
Humans
Radiology, Nuclear Medicine and imaging
Computer vision
Irradiation
Particle therapy
Radiological and Ultrasound Technology
medicine.diagnostic_test
business.industry
Reconstruction algorithm
Radiation therapy
Positron emission tomography
Positron-Emission Tomography
030220 oncology & carcinogenesis
Artificial intelligence
ion beam therapy
intra-fractional target motion
business
Nuclear medicine
Algorithms
Beam (structure)
dose monitoring
Radiotherapy, Image-Guided
- Language
- ISSN
- 1361-6560
0031-9155
In-beam positron emission tomography (PET) has been proven to be a reliable technique in ion beam radiotherapy for the in situ and non-invasive evaluation of the correct dose deposition in static tumour entities. In the presence of intra-fractional target motion an appropriate time-resolved (four-dimensional, 4D) reconstruction algorithm has to be used to avoid reconstructed activity distributions suffering from motion-related blurring artefacts and to allow for a dedicated dose monitoring. Four-dimensional reconstruction algorithms from diagnostic PET imaging that can properly handle the typically low counting statistics of in-beam PET data have been adapted and optimized for the characteristics of the double-head PET scanner BASTEI installed at GSI Helmholtzzentrum Darmstadt, Germany (GSI). Systematic investigations with moving radioactive sources demonstrate the more effective reduction of motion artefacts by applying a 4D maximum likelihood expectation maximization (MLEM) algorithm instead of the retrospective co-registration of phasewise reconstructed quasi-static activity distributions. Further 4D MLEM results are presented from in-beam PET measurements of irradiated moving phantoms which verify the accessibility of relevant parameters for the dose monitoring of intra-fractionally moving targets. From in-beam PET listmode data sets acquired together with a motion surrogate signal, valuable images can be generated by the 4D MLEM reconstruction for different motion patterns and motion-compensated beam delivery techniques.