Johannes Müller1,2, Christian Neubert1,3, Cläre von Neubeck1,4,5, Michael Baumann1,2,5,6,7, Mechthild Krause1,2,4,6,7, Wolfgang Enghardt1,2,4,6,7, Rebecca Bütof1,6,7, Antje Dietrich1,4,5, Armin Lühr1,2,4. 1. a OncoRay - National Center for Radiation Research in Oncology , Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf , Dresden , Germany. 2. b Helmholtz-Zentrum Dresden - Rossendorf , Institute of Radiooncology - OncoRay , Dresden , Germany. 3. c Brandenburg University of Technology Cottbus-Senftenberg , Cottbus , Germany. 4. d German Cancer Consortium (DKTK), Partner Site Dresden , Dresden , Germany. 5. e German Cancer Research Center (DKFZ) , Heidelberg , Germany. 6. f National Center for Tumor Diseases (NCT), Partner Site Dresden , Dresden , Germany. 7. g Department of Radiotherapy and Radiation Oncology , Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden , Dresden , Germany.
Abstract
INTRODUCTION: As proton therapy becomes increasingly well established, there is a need for high-quality clinically relevant in vivo data to gain better insight into the radiobiological effects of proton irradiation on both healthy and tumor tissue. This requires the development of easily applicable setups that allow for efficient, fractionated, image-guided proton irradiation of small animals, the most widely used pre-clinical model. MATERIAL AND METHODS: Here, a method is proposed to perform dual-energy proton radiography for inline positioning verification and treatment planning. Dual-energy proton radiography exploits the differential enhancement of object features in two successively measured two-dimensional (2D) dose distributions at two different proton energies. The two raw images show structures that are dominated by energy absorption (absorption mode) or scattering (scattering mode) of protons in the object, respectively. Data post-processing allowed for the separation of both signal contributions in the respective images. The images were evaluated regarding recognizable object details and feasibility of rigid registration to acquired planar X-ray scans. RESULTS: Robust, automated rigid registration of proton radiography and planar X-ray images in scattering mode could be reliably achieved with the animal bedding unit used as registration landmark. Distinguishable external and internal features of the imaged mouse included the outer body contour, the skull with substructures, the lung, abdominal structures and the hind legs. Image analysis based on the combined information of both imaging modes allowed image enhancement and calculation of 2D water-equivalent path length (WEPL) maps of the object along the beam direction. DISCUSSION: Fractionated irradiation of exposed target volumes (e.g., subcutaneous tumor model or brain) can be realized with the suggested method being used for daily positioning and range determination. Robust registration of X-ray and proton radiography images allows for the irradiation of tumor entities that require conventional computed tomography (CT)-based planning, such as orthotopic lung or brain tumors, similar to conventional patient treatment.
INTRODUCTION: As proton therapy becomes increasingly well established, there is a need for high-quality clinically relevant in vivo data to gain better insight into the radiobiological effects of proton irradiation on both healthy and tumor tissue. This requires the development of easily applicable setups that allow for efficient, fractionated, image-guided proton irradiation of small animals, the most widely used pre-clinical model. MATERIAL AND METHODS: Here, a method is proposed to perform dual-energy proton radiography for inline positioning verification and treatment planning. Dual-energy proton radiography exploits the differential enhancement of object features in two successively measured two-dimensional (2D) dose distributions at two different proton energies. The two raw images show structures that are dominated by energy absorption (absorption mode) or scattering (scattering mode) of protons in the object, respectively. Data post-processing allowed for the separation of both signal contributions in the respective images. The images were evaluated regarding recognizable object details and feasibility of rigid registration to acquired planar X-ray scans. RESULTS: Robust, automated rigid registration of proton radiography and planar X-ray images in scattering mode could be reliably achieved with the animal bedding unit used as registration landmark. Distinguishable external and internal features of the imaged mouse included the outer body contour, the skull with substructures, the lung, abdominal structures and the hind legs. Image analysis based on the combined information of both imaging modes allowed image enhancement and calculation of 2D water-equivalent path length (WEPL) maps of the object along the beam direction. DISCUSSION: Fractionated irradiation of exposed target volumes (e.g., subcutaneous tumor model or brain) can be realized with the suggested method being used for daily positioning and range determination. Robust registration of X-ray and proton radiography images allows for the irradiation of tumor entities that require conventional computed tomography (CT)-based planning, such as orthotopic lung or brain tumors, similar to conventional patient treatment.
Authors: Elke Beyreuther; Michael Baumann; Wolfgang Enghardt; Stephan Helmbrecht; Leonhard Karsch; Mechthild Krause; Jörg Pawelke; Lena Schreiner; Michael Schürer; Cläre von Neubeck; Armin Lühr Journal: Int J Part Ther Date: 2018-09-21
Authors: Emília Rita Szabó; Michael Brand; Stefan Hans; Katalin Hideghéty; Leonhard Karsch; Elisabeth Lessmann; Jörg Pawelke; Michael Schürer; Elke Beyreuther Journal: PLoS One Date: 2018-11-08 Impact factor: 3.240