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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Oncol. | doi: 10.3389/fonc.2019.00826

A multi-center prospective study for implementation of an MRI-only prostate treatment planning workflow

 Peter B. Greer1, 2*, Jarad Martin1, 2, Mark Sidhom3, Perry Hunter1, Peter Pichler1, Jae H. Choi2, Leah Best4,  Jo Smart1, Tony Young3, Michael Jameson3, 5, 6, Tess Afinidad3, Chris Wratten1, 2, James Denham1, 2, Lois Holloway3, 5, 6, Swetha Sridharan1, Robba Rai3, 5, 6, Gary Liney3, 5, 6, Parnesh Raniga7 and  Jason Dowling7
  • 1Calvary Mater Newcastle Hospital, Australia
  • 2University of Newcastle, Australia
  • 3Sydney South West Area Health Service, Australia
  • 4Hunter New England Health, Australia
  • 5University of New South Wales, Australia
  • 6Ingham Institute of Applied Medical Research, Australia
  • 7Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia

Purpose:
This project investigates the feasibility of implementation of MRI-only prostate planning in a prospective multi-center study.
Method and /Materials:
A two-phase implementation model was utilized where centers performed retrospective analysis of MRI-only plans for 5 patients followed by prospective MRI-only planning for subsequent patients. Feasibility was assessed if at least 23/25 patients recruited to phase 2 received MRI-only treatment workflow. Whole-pelvic MRI scans (T2 weighted, isotropic 1.6 mm voxel 3D sequence) were converted to pseudo-CT using an established atlas-based method. Dose plans were generated using MRI contoured anatomy with pseudo-CT for dose calculation. A conventional CT scan was acquired subsequent to MRI-only plan approval for quality assurance purposes (QA-CT). 3D Gamma evaluation was performed between pseudo-CT calculated plan dose and recalculation on QA-CT. Criteria was 2%,2 mm criteria with 20% low dose threshold. Gold fiducial marker positions for image guidance were compared between pseudo-CT and QA-CT scan prior to treatment.
Results:
All twenty-five patients recruited to phase 2 were treated using the MRI-only workflow. Isocenter dose differences between pseudo-CT and QA-CT were -0.04  0.93% (mean SD). 3D Gamma dose comparison pass-rates were 99.7%  0.5% with mean gamma 0.22  0.07. Results were similar for the two centers using two different scanners. All gamma comparisons exceeded the 90% pass-rate tolerance with a minimum gamma pass-rate of 98.0%. In all cases the gold fiducial markers were correctly identified on MRI and the distances of all seeds to centroid were within the tolerance of 1.0 mm of the distances on QA-CT (0.07 0.41 mm), with a root-mean-square difference of 0.42 mm.
Conclusion:
The results support the hypothesis that an MRI-only prostate workflow can be implemented safely and accurately with appropriate quality assurance methods.

Keywords: MRI-only, MRI-alone, synthetic CT, pseudo CT, Prostate

Received: 31 May 2019; Accepted: 12 Aug 2019.

Copyright: © 2019 Greer, Martin, Sidhom, Hunter, Pichler, Choi, Best, Smart, Young, Jameson, Afinidad, Wratten, Denham, Holloway, Sridharan, Rai, Liney, Raniga and Dowling. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Prof. Peter B. Greer, Calvary Mater Newcastle Hospital, Newcastle, Australia, peter.greer@newcastle.edu.au