Indirect evaluation of pretreatment imaging protocols and their clinical impact on patient dose delivery in radiotherapy
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ORIGINAL RESEARCH
Indirect evaluation of pretreatment imaging protocols and their clinical impact on patient dose delivery in radiotherapy Ravindra Shende 1 & Gourav Gupta 1 & S.J. Dhoble 2 & Ashutosh DasSharma 1 & Ganeshkumar Patel 3 Received: 7 July 2020 / Accepted: 15 November 2020 # The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature 2020
Abstract Objective Pretreatment imaging plays a crucial role in determining geometric positional uncertainty of the patient during radiotherapy. Our purpose is to investigate the effect of frequent pretreatment imaging protocol (scenario) on actual dose delivery in radiotherapy. This paper presents a critical analysis of frequent imaging protocol with respect to Idealized daily imaging protocol (IDIP). Methods and materials Retrospective patients of Ca-carcinoma cervix, Ca-buccal mucosa, Ca-tongue treated with intensitymodulated radiation therapy (IMRT) undergoing daily cone beam computed tomography (CBCT) imaging protocol was selected for this study. Every treated fraction of these patients was simulated considering its daily geometrical setup uncertainties occurred. Indirect evaluation of virtual treatment plans was conducted in the treatment planning system (TPS) for 3 days a week, 2 days a week, and 1 day a week frequency imaging protocols. Results obtained from these frequent imaging protocols were compared with IDIP. Result Deviation between predicted and delivered dose found increasing with decreasing frequency of imaging. Significant deviations were observed in all the estimated plan quality parameters for patients treated with frequent imaging protocols and IDIP. Deviations were found more in case of pelvis sites than head and neck sites. Conclusion This study plays a vital role in establishing optimum pretreatment imaging protocols in busy clinics. Three days a week imaging protocol is the best suit protocol found with minimal deviation and ample implementation feasibility. This study proposed an opinion pertaining to the revision of setup margin formula in order to accommodate variation due to imaging techniques and frequency of imaging attempted during radiotherapy. Keywords Imaging protocol . CBCT . Treatment planning system . IMRT
Introduction In the present time, intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) predominantly took over traditional conventional radiotherapy for
* Ravindra Shende [email protected] 1
Department of Radiation Oncology, Balco Medical Centre, Naya Raipur, Chhattisgarh, India
2
Department of Physics, R.T.M., Nagpur University, Nagpur, Maharashtra, India
3
Department of RTRM, Institute of Medical Science, BHU, Varanasi, Uttar Pradesh, India
curative therapy [1]. Both allow a greater degree of freedom and flexibility to deliver a high conformal dose to the planning target volume (PTV) and rapid dose fall adjacent to PTV. The ability of these techniques is to control the fluence. That helps in sharpen the dose fall-off at the PTV boundary [2].
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