Tomographic Imaging with Carbon Ion Beams

Meyer, Sebastian; Magallanes, Lorena; Kopp, Benedikt; Tessonnier, Thomas; Landry, Guillaume; Dedes, George; Voss, Bernd; Jaekel, Oliver; Belka, Claus; Gianoli, Chiara and Parodi, Katia (2016): Tomographic Imaging with Carbon Ion Beams. 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD), Strasbourg, France, 29. Oktober - 6. November 2016. New York: IEEE.

Abstract

The sensitivity of ion therapy to inaccuracies in treatment planning and delivery procedures demands the development of imaging techniques capable of accurate assessment of the Relative (to water) ion Stopping Power (RSP). The investigated tomographic carbon ion CT (iCT) imaging setup consists of a prototype integration-mode detector working as range telescope using active scanning ion beam delivery. Extensive Monte Carlo simulations using the FLUKA code were performed and compared to experimental data. The influence of acquisition parameters was investigated to optimize the imaging dose. A dedicated post-processing method relying on the linear decomposition of the integrated signal was applied to solve ambiguities in the presence of material inhomogeneities due to the finite beam size. As comparison the performance of a single-particle list-mode detector was examined. For raw iCT images of a tissue-equivalent phantom, an average median error of 2.1% was observed, consistent with experimental data. An optimization of the acquisition parameters reduced the imaging dose exposure down to below 30 mGy without severe RSP accuracy degradation. The signal decomposition showed a considerable benefit reducing the average RSP error to around 1%, being comparable to the list-mode performance for C-12 ions. Similar observations were made for simulations using as patient model an X-ray CT of a head and neck patient case. This study quantitatively supports the benefit of carbon iCT for range verification, showing the performance of different detector modes for direct RSP assessment at acceptable dose levels.

• Item Type: Conference or Workshop Item (Speech)
• Keywords: Detectors; Ions; Carbon; Phantoms; Computed tomography; biological tissues; computerised tomography; dosimetry; image reconstruction; medical image processing; Monte Carlo methods; phantoms; radiation therapy; tomographic imaging; carbon ion beams; ion therapy; treatment planning; delivery procedures; prototype integration-mode detector; active scanning ion beam delivery; acquisition parameters; finite beam size; single-particle list-mode detector; raw iCT images; signal decomposition; direct RSP assessment; Monte Carlo simulations; post-processing method;dose exposure; relative ion stopping power; tomographic carbon ion CT imaging setup; linear decomposition; material inhomogeneities; tissue-equivalent phantom; head-and-neck patient case
• Faculties: Physics
• Subjects: 500 Science > 530 Physics; 600 Technology > 610 Medicine and health
• Place of Publication: New York
• Language: English