Optimal threshold of a control parameter for tomotherapy respiratory tracking: A phantom study.

Autor: Sano K; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan.; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Fujiwara M; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan.; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Okada W; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan.; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Tanooka M; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan.; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Takaki H; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan., Shibata M; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Nakamura K; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Sakai Y; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Suzuki H; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan.; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Takahashi K; Department of Biostatistics, Hyogo Medical University, Nishinomiya, Hyogo, Japan., Tanaka M; Department of Radiotherapy, Takarazuka City Hospital, Takarazuka, Hyogo, Japan., Yamakado K; Department of Radiology, Hyogo Medical University, Nishinomiya, Hyogo, Japan.
Jazyk: angličtina
Zdroj: Journal of applied clinical medical physics [J Appl Clin Med Phys] 2023 May; Vol. 24 (5), pp. e13901. Date of Electronic Publication: 2023 Jan 12.
DOI: 10.1002/acm2.13901
Abstrakt: Background: Radixact Synchrony ® , a real-time motion tracking and compensating modality, is used for helical tomotherapy. Control parameters are used for the accurate application of irradiation. Radixact Synchrony ® uses the potential difference, which is an index of the accuracy of the prediction model of target motion and is represented by a statistical prediction of the 3D distance error. Although there are several reports on Radixact Synchrony ® , few have reported the appropriate settings of the potential difference threshold.
Purpose: This study aims to determine the optimal threshold of the potential difference of Radixact Synchrony ® during respiratory tumor-motion-tracking irradiation.
Methods: The relationship among the dosimetric accuracy, motion tracking accuracy, and control parameter was evaluated using a moving platform, a phantom with a basic respiratory model (the fourth power of a sinusoidal wave), and several irregular respiratory model waveforms. The dosimetric accuracy was evaluated by gamma analysis (3%, 1 mm, 10% dose threshold). The tracking accuracy was measured by the distance error of the difference between the tracked and driven positions of the phantom. The largest potential difference for 95% of treatment time was evaluated, and its correlation with the gamma-pass ratio and distance error was investigated. The optimal threshold of the potential difference was determined by receiver operating characteristic (ROC) analysis.
Results: A linear correlation was identified between the potential difference and the gamma-pass ratio (R = -0.704). A linear correlation was also identified between the potential difference and distance error (R = 0.827). However, as the potential difference increased, it tended to underestimate the distance error. The ROC analysis revealed that the appropriate cutoff value of the potential difference was 3.05 mm.
Conclusion: The irradiation accuracy with motion tracking by Radixact Synchrony ® could be predicted from the potential difference, and the threshold of the potential difference should be set to ∼3 mm.
(© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)
Databáze: MEDLINE
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