Development of a physical geometric phantom for deformable image registration credentialing of radiotherapy centers for a clinical trial

Noriyuki Kadoya, Siwaporn Sakulsingharoj, Tomas Kron, Adam Yao, Nicholas Hardcastle, Alanah Bergman, Hiroyuki Okamoto, Nobutaka Mukumoto, Yujiro Nakajima, Keiichi Jingu, Mitsuhiro Nakamura

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: This study aimed to develop a physical geometric phantom for the deformable image registration (DIR) credentialing of radiotherapy centers for a clinical trial and tested the feasibility of the proposed phantom at multiple domestic and international institutions. Methods and materials: The phantom reproduced tumor shrinkage, rectum shape change, and body shrinkage using several physical phantoms with custom inserts. We tested the feasibility of the proposed phantom using 5 DIR patterns at 17 domestic and 2 international institutions (21 datasets). Eight institutions used the MIM software (MIM Software Inc, Cleveland, OH); seven used Velocity (Varian Medical Systems, Palo Alto, CA), and six used RayStation (RaySearch Laboratories, Stockholm, Sweden). The DIR accuracy was evaluated using the Dice similarity coefficient (DSC) and Hausdorff distance (HD). Results: The mean and one standard deviation (SD) values (range) of DSC were 0.909 ± 0.088 (0.434–0.984) and 0.909 ± 0.048 (0.726–0.972) for tumor and rectum proxies, respectively. The mean and one SD values (range) of the HD value were 5.02 ± 3.32 (1.53–20.35) and 5.79 ± 3.47 (1.22–21.48) (mm) for the tumor and rectum proxies, respectively. In three patterns evaluating the DIR accuracy within the entire phantom, 61.9% of the data had more than a DSC of 0.8 in both tumor and rectum proxies. In two patterns evaluating the DIR accuracy by focusing on tumor and rectum proxies, all data had more than a DSC of 0.8 in both tumor and rectum proxies. Conclusions: The wide range of DIR performance highlights the importance of optimizing the DIR process. Thus, the proposed method has considerable potential as an evaluation tool for DIR credentialing and quality assurance.

Original languageEnglish
Pages (from-to)255-265
Number of pages11
JournalJournal of applied clinical medical physics
Volume22
Issue number7
DOIs
Publication statusPublished - 2021 Jul

Keywords

  • adaptive radiotherapy
  • credentialing
  • deformable image registration
  • physical phantom
  • quality assurance

ASJC Scopus subject areas

  • Radiation
  • Instrumentation
  • Radiology Nuclear Medicine and imaging

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