TY - JOUR
T1 - Estimation of internal organ motion-induced variance in radiation dose in non-gated radiotherapy
AU - Zhou, Sumin
AU - Zhu, Xiaofeng
AU - Zhang, Mutian
AU - Zheng, Dandan
AU - Lei, Yu
AU - Li, Sicong
AU - Bennion, Nathan
AU - Verma, Vivek
AU - Zhen, Weining
AU - Enke, Charles Arthur
N1 - Publisher Copyright:
© 2016 Institute of Physics and Engineering in Medicine.
PY - 2016/11/2
Y1 - 2016/11/2
N2 - In the delivery of non-gated radiotherapy (RT), owing to intra-fraction organ motion, a certain degree of RT dose uncertainty is present. Herein, we propose a novel mathematical algorithm to estimate the mean and variance of RT dose that is delivered without gating. These parameters are specific to individual internal organ motion, dependent on individual treatment plans, and relevant to the RT delivery process. This algorithm uses images from a patient's 4D simulation study to model the actual patient internal organ motion during RT delivery. All necessary dose rate calculations are performed in fixed patient internal organ motion states. The analytical and deterministic formulae of mean and variance in dose from non-gated RT were derived directly via statistical averaging of the calculated dose rate over possible random internal organ motion initial phases, and did not require constructing relevant histograms. All results are expressed in dose rate Fourier transform coefficients for computational efficiency. Exact solutions are provided to simplified, yet still clinically relevant, cases. Results from a volumetric-modulated arc therapy (VMAT) patient case are also presented. The results obtained from our mathematical algorithm can aid clinical decisions by providing information regarding both mean and variance of radiation dose to non-gated patients prior to RT delivery.
AB - In the delivery of non-gated radiotherapy (RT), owing to intra-fraction organ motion, a certain degree of RT dose uncertainty is present. Herein, we propose a novel mathematical algorithm to estimate the mean and variance of RT dose that is delivered without gating. These parameters are specific to individual internal organ motion, dependent on individual treatment plans, and relevant to the RT delivery process. This algorithm uses images from a patient's 4D simulation study to model the actual patient internal organ motion during RT delivery. All necessary dose rate calculations are performed in fixed patient internal organ motion states. The analytical and deterministic formulae of mean and variance in dose from non-gated RT were derived directly via statistical averaging of the calculated dose rate over possible random internal organ motion initial phases, and did not require constructing relevant histograms. All results are expressed in dose rate Fourier transform coefficients for computational efficiency. Exact solutions are provided to simplified, yet still clinically relevant, cases. Results from a volumetric-modulated arc therapy (VMAT) patient case are also presented. The results obtained from our mathematical algorithm can aid clinical decisions by providing information regarding both mean and variance of radiation dose to non-gated patients prior to RT delivery.
KW - 4D CT
KW - Fourier transformation
KW - dose variance
KW - interplay effect
KW - intra-fraction organ motion
KW - non-gated radiotherapy
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U2 - 10.1088/0031-9155/61/23/8157
DO - 10.1088/0031-9155/61/23/8157
M3 - Article
C2 - 27804926
AN - SCOPUS:84994904723
SN - 0031-9155
VL - 61
SP - 8157
EP - 8179
JO - Physics in medicine and biology
JF - Physics in medicine and biology
IS - 23
ER -