Hoegele, Wolfgang and Loeschel, Rainer and Dobler, Barbara and Koelbl, Oliver and Beard, Clair and Zygmanski, Piotr (2013) Stochastic triangulation for prostate positioning during radiotherapy using short CBCT arcs. RADIOTHERAPY AND ONCOLOGY, 106 (2). pp. 241-249. ISSN 0167-8140,
Full text not available from this repository. (Request a copy)Abstract
Background and purpose: Fast and reliable tumor localization is an important part of today's radiotherapy utilizing new delivery techniques. This proof-of-principle study demonstrates the use of a method called herein 'stochastic triangulation' for this purpose. Stochastic triangulation uses very short imaging arcs and a few projections. Materials and methods: A stochastic Maximum A Posteriori (MAP) estimator is proposed based on an uncertainty-driven model of the acquisition geometry and inter-/intra-fractional deformable anatomy. The application of this method was designed to use the available linac-mounted cone-beam computed tomography (CBCT) and/or electronic portal imaging devices (EPID) for the patient setup based on short imaging arcs. For the proof-of-principle clinical demonstration, the MAP estimator was applied to 5 CBCT scans of a prostate cancer patient with 2 implanted gold markers. Estimation was performed for several (18) very short imaging arcs of 5 degrees with 10 projections resulting in 90 estimations. Results: Short-arc stochastic triangulation led to residual radial errors compared to manual inspection with a mean value of 1.4 mm and a standard deviation of 0.9 mm (median 1.2 mm, maximum 3.8 mm) averaged over imaging directions all around the patient. Furthermore, abrupt intra-fractional motion of up to 10 mm resulted in radial errors with a mean value of 1.8 mm and a standard deviation of 1.1 mm (median 1.5 mm, maximum 5.6 mm). Slow periodic intra-fractional motions in the range of 12 mm resulted in radial errors with a mean value of 1.8 mm and a standard deviation of 1.1 mm (median 1.6 mm, maximum 4.7 mm). Conclusion: Based on this study, the proposed stochastic method is fast, robust and can be used-for inter- as well as intra-fractional target localization using current CBCT units. (C) 2013 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 106 (2013) 241-249
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | INTRAFRACTION MOTION; RADIATION-THERAPY; SUPINE POSITIONS; FIDUCIAL MARKERS; PRONE; LOCALIZATION; TRACKING; CANCER; IRRADIATION; ACCURACY; Patient positioning; Setup error; Maximum A Posteriori estimation; Short arc; Stochastic triangulation |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Strahlentherapie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 24 Apr 2020 08:02 |
| Last Modified: | 24 Apr 2020 08:02 |
| URI: | https://pred.uni-regensburg.de/id/eprint/17168 |
Actions (login required)
 |
View Item |
