Treatment planning for tumors with residual motion in scanned ion beam therapy.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2012)
Available under Creative Commons Attribution Non-commercial No Derivatives, 2.5.
Download (16MB) | Preview
|Item Type:||Ph.D. Thesis|
|Title:||Treatment planning for tumors with residual motion in scanned ion beam therapy|
The treatment of mobile tumors with a scanned ion beam requires dedicated beam delivery and treatment planning techniques. Interference effects (interplay) between beam and tumor motion can lead to clinically unacceptable dose distributions. Motion mitigation techniques, such as beam gating or irradiation under abdominal compression, can effectively reduce tumor motion but typically do not fully compensate motion-induced dose inhomogeneities. Further mitigation therefore is desirable.
In this work, the dosimetric impact of optimized treatment plan parameters on dose heterogeneities caused by residual tumor motion was investigated. For this purpose, a 4D treatment planning system (4DTPS) for the treatment of moving tumors with a scanned ion beam was developed based on previous efforts at GSI Helmholtz Center for Heavy Ion research (GSI). The system was validated in dedicated experiments, reaching an accuracy of (-1 ± 4)% for the typical beam configuration. The new software enabled extensive experiments, simulations, and treatment planning studies for liver cancer patients. The results show that an enlarged beam spot size can considerably mitigate motion-induced dose inhomogeneities for treatments with respiratory gating and under abdominal compression. Moreover, the 4DTPS allowed 4D dose reconstructions of the first treatments of liver tumors with a scanned ion beam at the Heidelberg Ion-Beam Therapy Center (HIT), revealing a considerable degradation of the dose coverage in an exemplary case (V95=92.8%).
The 4DTPS is currently used as a basis for further research at GSI and by international collaborators. Results of this work have contributed to the world's first treatments of moving liver tumors with a scanned carbon ion beam at HIT.
|Place of Publication:||Darmstadt|
|Uncontrolled Keywords:||Medizinische Physik, Strahlentherapie|
|Classification DDC:||500 Naturwissenschaften und Mathematik > 530 Physik
500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin, Gesundheit
600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften
|Date Deposited:||15 Aug 2012 07:42|
|Last Modified:||07 Dec 2012 12:05|
|Referees:||Durante, Prof. Dr. Marco and Kraft, Prof. Dr. Gerhard|
|Refereed:||6 June 2012|