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Wang, H.* ; Huang, Y.* ; Hu, Q.* ; Li, C.* ; Liu, H.* ; Wang, X.* ; Li, W.B. ; Ma, W.* ; Pu, Y.* ; Du, Y.* ; Wu, H.* ; Zhang, Y.*

A simulated dosimetric study of contribution to radiotherapy accuracy by fractional image guidance protocol of Halcyon system.

Front. Oncol. 10:543147 (2021)
Verlagsversion DOI
Open Access Gold
Creative Commons Lizenzvertrag
Purpose: Frequency of conventional kV-image guidance is sometimes sacrificed to reduce concomitant risk, leaving deviations of unguided fractions unknown. MV-imaging and treatment dose can be collectively optimized on Halcyon, where fractional MVCBCT provides complete anatomic records for course-wide dose reconstruction. By retrospective dose accumulation, this work simulated the impact of imaging frequency on patient treatment dose on the platform of Halcyon. Methods: Four hundred and sixteen MVCBCT image sets from 16 patients of various tumor sites treated with radiotherapy on Halcyon were retrospectively selected. After applying the image-guided couch shifts of the clinical records, deformable image registration was performed using Velocity software, to deform the planning CTs to the corresponding MVCBCTs, generating pseudo CTs representing the actual anatomies on the treatment day. Fractional treatment dose was reconstructed on pseudo CTs for accumulation, representing the actual patient dose (Ddaily). To simulate weekly image guidance, fractional dose was reconstructed and accumulated by incorporating 1 CBCT-guided corrections and 4 laser-guided setups of each week (Dweekly). Limited by partially imaged volumes and different organs-at-risk of various sites, only target dose-volume parameters were evaluated across all patients. Results: GTV_D98%, CTV_D98%, PTV_D90%, PTV_D95%, PGTV_D90%, and PGTV_D95% were evaluated, where Dx% means the minimal dose received by x% volume. Pairwise comparisons were made between plan dose and Ddaily, Ddaily and Dweekly respectively. PGTV_D95% of accumulated Dweekly were significantly lower than those of accumulated Ddaily by up to 32.90% of prescription dose, suggesting that weekly-guidance may result in unacceptable under dose to the target. The broad distribution of fractional differences between Ddaily and Dweekly suggested unreliable patient positioning based on aligning surface markers to laser beams, as a popular approach broadly used on conventional Linac systems. Slight target under-dose was observed on daily reconstructed results compared with planned dose, which provided quantitative data to guide clinical decisions such as the necessity of adaptive radiotherapy. Conclusion: Fractional image guided radiotherapy on Halcyon provides more reliable treatment accuracy than using sacrificed imaging frequency, which also provides complete anatomic records for deformable dose reconstruction supporting more informed clinical decisions.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Schlagwörter Halcyon ; Cone Beam Ct ; Deformable Image Registration ; Image Guided Radiotherapy ; Quality Assurance
ISSN (print) / ISBN 2234-943X
e-ISSN 2234-943X
Zeitschrift Frontiers in Oncology
Quellenangaben Band: 10, Heft: , Seiten: , Artikelnummer: 543147 Supplement: ,
Verlag Frontiers
Verlagsort Avenue Du Tribunal Federal 34, Lausanne, Ch-1015, Switzerland
Begutachtungsstatus Peer reviewed
Förderungen Varian Medical Systems
National Natural Science Foundation of China
Science Foundation of Peking University Cancer Hospital
Fundamental Research Funds for the Central Universities/Peking University Clinical Medicine Plus X -Young Scholars Project
UICC Technical Fellowship
Peking University Health Science Center Medical Education Research Funding Project
National Key R&D Program of China
Sichuan Science and Technology Program
Capital's Funds for Health Improvement and Research