Clinical Development and Evaluation of Megavoltage Topogram for Fast Patient Alignment on Helical Tomotherapy

• DOI: 10.1016/j.adro.2020.05.014
• Publication Date: 2020-06-17T16:01:16Z
• Authors: X. Sharon Qi; Fang-I. Chu; Zhe Zhang; Robert K. Chin; Ann Raldow; Amar U. Kishan; Percy Lee; Albert Chang; Anusha Kalbasi; Mitchell Kamrava; Michael L. Steinberg; Daniel A. Low
• Keywords: Tomotherapy

To develop and evaluate a fast patient localization tool using megavoltage (MV)-topogram on helical tomotherapy.Eighty-one MV-topogram pairs for 18 pelvis patients undergoing radiation were acquired weekly under an institutional review board-approved clinical trial. The imaging protocol requires 2 orthogonal acquisitions at static gantry angles of 0 degrees 90 programed scan length. A MATLAB based in-house software was developed to reconstruct the MV-topograms offline. Reference images (digitally reconstructed topograms, digitally topograms) generated planning computed tomography tomotherapy geometry. alignment determined by registering topogram bony landmark commercial MIM software. daily shifts in 3 translational directions from compared with (MVCT) shifts. Linear-regression two one-sided tests equivalence performed investigate relation between techniques. Seventy-eight 19 head neck included validate finding.The magnitudes differences (MVCT - MV-topogram) (and standard deviations) -0.3 ± 2.1, -0.8 2.4, 1.6 1.7 mm 0.6 1.2, 0.8 4.2, 2.6 neck; linear-regression coefficients techniques 1.18, 1.10, 0.94, 0.86, 0.63, 0.38 lateral, longitudinal, vertical neck, respectively. acquisition time pair up 12.7 times less than MVCT scans (coarse mode) while covering longer longitudinal length.MV-topograms showed equivalent performance significantly H&N patients. can be used as alternative or complimentary landmark-based tomotherapy.