A phantom assessment of achievable contouring concordance across multiple treatment planning systems

Pogson, Elise M; Begg, Jarrad; Jameson, Michael; Dempsey, Claire; Latty, Drew; Batumalai, Vikneswary; Lim, Andrew Kean Seng; Kandasamy, Kankean; Metcalfe, Peter E; Holloway, Lois

doi:10.1016/j.radonc.2015.09.022

Cited by 9 publications

(12 citation statements)

References 28 publications

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“…The interobserver variation we found (median 95% Hausdorff of 4.3–5.1 mm) appears similar to those in [14] , where a maximum interobserver variation was found of 4.6 mm for MR based prostate delineation. Pogson et al [15] showed that interobserver variation in contouring increases with decreasing resolution, which is not what we found, however this study was CT based and considered delineation of inserts in a phantom, where no additional uncertainties are present. Since there was also no significant difference in volume between the different sequences, we conclude that all scans are in principle suitable for delineation of the prostate.…”

Section: Discussioncontrasting

confidence: 88%

The impact of image acquisition time on registration, delineation and image quality for magnetic resonance guided radiotherapy of prostate cancer patients

Nowee

Pelt

Walraven

et al. 2021

Physics and Imaging in Radiation Oncology

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Background and Purpose Magnetic resonance (MR) guided radiotherapy utilizes MR images for (online) plan adaptation and image guidance. The aim of this study was to investigate the impact of variation in MR acquisition time and scan resolution on image quality, interobserver variation in contouring and interobserver variation in registration. Materials and Methods Nine patients with prostate cancer were included. Four T2-weighted 3D turbo spin echo (T2w 3D TSE) sequences were acquired with different acquisition times and resolutions. Two radiologists assessed image quality, conspicuity of the capsule, peripheral zone and central gland architecture and motion artefacts on a 5 point scale. Images were delineated by two radiation oncologists and interobserver variation was assessed by the 95% Hausdorff distance. Seven observers registered the MR images on the planning CT. Registrations were compared on systematic offset and interobserver variation. Results Acquisition times ranged between 1.3 and 6.3 min. Overall image quality and capsule definition were significantly worse for the MR sequence with an acquisition time of 1.3 min compared to the other sequences. Median 95% Hausdorff distance showed no significant differences in interobserver variation of contouring. Systematic offset and interobserver variation in registration were small (<1 mm) and of no clinical significance. Conclusions Our results can be used to effectively shorten overall fraction time for online adaptive MR guided radiotherapy by optimising the imaging sequence used for registration. From the sequences studied, a sequence of 3.1 min with anisotropic voxels of 1.2 × 1.2 × 2.4 mm 3 provided the shortest acquisition time without compromising image quality.

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Section: Discussioncontrasting

confidence: 88%

The impact of image acquisition time on registration, delineation and image quality for magnetic resonance guided radiotherapy of prostate cancer patients

Nowee

Pelt

Walraven

et al. 2021

Physics and Imaging in Radiation Oncology

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“…(Mathworks Incorporated, Natick USA) platform, with a subset of metrics verified in MILXview to agree to within 2 significant figures, similarly to other reported values [26]. Generalized kappa (κ) statistics determine inter-observer delineation agreement which occurs by chance alone.…”

Section: Discussionmentioning

confidence: 60%

“…It has been well established that the main contouring discrepancies are at the medial and lateral edges of the WB CTV in supine imaging [31,32], however in prone datasets, geometrically these areas are reduced. Both intraobserver delineation variations [33] and differences due to planning system and data transfer [26] are much smaller than inter-observer variation and thus expected to have minimal impact on these WB results.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions

Pogson

Delaney

Ahern

et al. 2016

International Journal of Radiation Oncology*Biology*Physics

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Purpose/Objective(s): MRI provides no ionizing radiation dose (allowing inter and intra fraction imaging), improved soft tissue contrast and potentially improved conformity in delineation than CT. This study aimed to determine if T2 weighted magnetic resonance imaging improves seroma cavity (SC) and Whole Breast (WB) inter-observer conformity for radiotherapy purposes compared with the gold standard of CT, both in the prone and supine positions. Results: Imaging modality did not affect inter-observer variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than Supine CTVs (on both MRI and CT). SC volumes were larger on CT than MRI. SC volumes proved to be comparable in inter-observer conformity in both modalities (VOI of 0.57±0.03 for CT supine, 0.52±0.04 for MR supine, 0.56±0.03 for CT prone and 0.55±0.04 for MR prone) however after registering modalities together the inter-modality variation (DSC of 0.41±0.05 for supine and 0.38±0.04 for prone) was larger than the inter-observer variability for SC despite the location typically remaining constant.Conclusions: MRI inter-observer variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Whilst the CVS and inter-observer concordance M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 was not significantly higher for MRI than CT, the SCs were smaller on MRI, potentially due to clearer SC definition, especially on T2-weighted MR images.

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“…However by itself this is not enough. Imaging acquisition and reconstruction protocols should be specified in the methodology as these are known to affect volume delineation [144,145]. This particularly applies to the use of additional (non-CT) imaging datasets, usually not acquired within a radiation oncology department and susceptible to inter-scanner differences.…”

Section: Sample Size Detailsmentioning

confidence: 99%

“…In addition, results may vary according to the radiotherapy planning system used [147]. Pogson et al performed a phantom study on multiple planning systems and showed that concordance between them for delineated volumes can be very good, but is reduced with lower image resolution [144]. Single platform solutions are available although these have largely been used for training purposes [148].…”

Section: Metricsmentioning

confidence: 99%

Uncertainties in volume delineation in radiation oncology: A systematic review and recommendations for future studies

Vinod

Jameson

Min

et al. 2016

Radiotherapy and Oncology

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A phantom assessment of achievable contouring concordance across multiple treatment planning systems

Cited by 9 publications

References 28 publications

The impact of image acquisition time on registration, delineation and image quality for magnetic resonance guided radiotherapy of prostate cancer patients

The impact of image acquisition time on registration, delineation and image quality for magnetic resonance guided radiotherapy of prostate cancer patients

Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions

Uncertainties in volume delineation in radiation oncology: A systematic review and recommendations for future studies

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