Evaluation of dosimetric uncertainty caused by MR geometric distortion in MRI-based liver SBRT treatment planning.
Abstract
PURPOSE:MRI-based treatment planning is a promising technique for liver stereotactic-body
radiation therapy (SBRT) treatment planning to improve target volume delineation and
reduce radiation dose to normal tissues. MR geometric distortion, however, is a source
of potential error in MRI-based treatment planning. The aim of this study is to investigate
dosimetric uncertainties caused by MRI geometric distortion in MRI-based treatment
planning for liver SBRT. MATERIALS AND METHODS:The study was conducted using computer
simulations. 3D MR geometric distortion was simulated using measured data in the literature.
Planning MR images with distortions were generated by integrating the simulated 3D
MR geometric distortion onto planning CT images. MRI-based treatment plans were then
generated on the planning MR images with two dose calculation methods: (1) using original
CT numbers; and (2) using organ-specific assigned CT numbers. Dosimetric uncertainties
of various dose-volume-histogram parameters were determined as their differences between
the simulated MRI-based plans and the original clinical CT-based plans for five liver
SBRT cases. RESULTS:The average simulated distortion for the five liver SBRT cases
was 2.77 mm. In the case of using original CT numbers for dose calculation, the average
dose uncertainties for target volumes and critical structures were <0.5 Gy, and the
average target volume percentage at prescription dose uncertainties was 0.97%. In
the case of using assigned CT numbers, the average dose uncertainties for target volumes
and critical structures were <1.0 Gy, and the average target volume percentage at
prescription dose uncertainties was 2.02%. CONCLUSIONS:Dosimetric uncertainties caused
by MR geometric distortion in MRI-based liver SBRT treatment planning was generally
small (<1 Gy) when the distortion is 3 mm.
Type
Journal articleSubject
HumansLiver Neoplasms
Magnetic Resonance Imaging
Radiosurgery
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted
Uncertainty
Phantoms, Imaging
Image Processing, Computer-Assisted
Radiotherapy, Intensity-Modulated
Organs at Risk
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https://hdl.handle.net/10161/19371Published Version (Please cite this version)
10.1002/acm2.12520Publication Info
Han, Silu; Yin, Fang-Fang; & Cai, Jing (2019). Evaluation of dosimetric uncertainty caused by MR geometric distortion in MRI-based
liver SBRT treatment planning. Journal of applied clinical medical physics, 20(2). pp. 43-50. 10.1002/acm2.12520. Retrieved from https://hdl.handle.net/10161/19371.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Jing Cai
Adjunct Associate Professor in the Radiation Oncology
Image-guided Radiation Therapy (IGRT), Magnetic Resonance Imaging (MRI), Tumor Motion
Management, Four-Dimensional Radiation Therapy (4DRT), Stereotatic-Body Radiation
Therapy (SBRT), Brachytherapy, Treatment Planning, Lung Cancer, Liver Cancer, Cervical
Cancer.
Fang-Fang Yin
Gustavo S. Montana Distinguished Professor of Radiation Oncology
Stereotactic radiosurgery, Stereotactic body radiation therapy, treatment planning
optimization, knowledge guided radiation therapy, intensity-modulated radiation therapy,
image-guided radiation therapy, oncological imaging and informatics
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