Efficacy of Epid-Based In Vivo Dosimetry and Calibrated CBCT Images for a Timely Lung Cancer Replanning

Li, J.; Xin, Xie; Tang, Bin; Wang, P.; Kang, Shengwei; Liao, Xiaoxin; Piermattei, Alessia; Orlandini, L.C.

doi:10.1016/j.ijrobp.2018.07.1428

Cited by 1 publication

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“…Anatomical changes usually occur during treatment, and the planning CT will limit the accuracy of the EPID reconstruction dose. CBCT as online images acquired during treatment may be more suitable for the in vivo verification of anatomical changes if accurate CBCT dose calculations are available [31, 32].…”

Section: Discussionmentioning

confidence: 99%

Investigating the effectiveness of monitoring relevant variations during IMRT and VMAT treatments by EPID-based 3D in vivo verification performed using planning CTs

Zhu

Shi

et al. 2019

PLoS ONE

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Purpose The goal of this study was to investigate the effectiveness of monitoring relevant variations during treatments for electronic portal imaging device (EPID)-based 3D in vivo verification performed using planning CTs. Methods Experiments on two simple phantoms (uniform and nonuniform phantoms) and a thoracic phantom were analyzed in this study, and six relevant variations including the machine output, planning target volume (PTV) deformation, multileaf collimator (MLC) and Phantom shift (set-up errors), and gantry and couch angle shifts were evaluated. 3D gamma and dose-volume histogram (DVH) methods were used to evaluate the detection sensitivity of the EPID-based 3D in vivo dosimetry and the dose accuracy of the EPID reconstruction, respectively, as affected by the variations, and the results were validated by determining the consistency with TPS simulated results. Results The results of the simple phantoms showed that the gamma failure rates and DVH trend of EPID reconstructions were consistent with the results of TPS simulations for machine output and MLC shifts and inconsistent for phantom shift, gantry/couch angle shift and PTV deformation variations. The results of the thoracic phantom showed that CBCT-guided EPID reconstruction sensitively detected 3-mm Phantom shift in thoracic phantom and its gamma failure rates and DVH trend were consistent with the results of TPS simulations. Conclusion The variations, such as machine output and MLC shift, that are phantom unrelated and cause changes in the beam of the linear accelerator can be sensitively detected by EPID-based 3D in vivo dosimetry and do not affect the accuracy of the EPID reconstruction dose. Planning CT will limit the detection sensitivity and the accuracy of the reconstruction dose of the EPID-based 3D in vivo dosimetry for phantom-related variations (such as Phantom shift and gantry/couch angle shift). EPID reconstruction combined with IGRT technology is a more effective method to monitor phantom shift variations.

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Section: Discussionmentioning

confidence: 99%