Dosimetric comparison of automatically propagated prostate contours with manually drawn contours in MRI-guided radiotherapy: A step towards a contouring free workflow?
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Authors
Sritharan, K
Dunlop, A
Mohajer, J
Adair-Smith, G
Barnes, H
Brand, D
Greenlay, E
Hijab, A
Oelfke, U
Pathmanathan, A
Mitchell, A
Murray, J
Nill, S
Parker, C
Sundahl, N
Tree, AC
Dunlop, A
Mohajer, J
Adair-Smith, G
Barnes, H
Brand, D
Greenlay, E
Hijab, A
Oelfke, U
Pathmanathan, A
Mitchell, A
Murray, J
Nill, S
Parker, C
Sundahl, N
Tree, AC
Document Type
Journal Article
Date
2022-11-01
Date Accepted
2022-08-04
Abstract
BACKGROUND: The prostate demonstrates inter- and intra- fractional changes and thus adaptive radiotherapy would be required to ensure optimal coverage. Daily adaptive radiotherapy for MRI-guided radiotherapy can be both time and resource intensive when structure delineation is completed manually. Contours can be auto-generated on the MR-Linac via a deformable image registration (DIR) based mapping process from the reference image. This study evaluates the performance of automatically generated target structure contours against manually delineated contours by radiation oncologists for prostate radiotherapy on the Elekta Unity MR-Linac. METHODS: Plans were generated from prostate contours propagated by DIR and rigid image registration (RIR) for forty fractions from ten patients. A two-dose level SIB (simultaneous integrated boost) IMRT plan is used to treat localised prostate cancer; 6000 cGy to the prostate and 4860 cGy to the seminal vesicles. The dose coverage of the PTV 6000 and PTV 4860 created from the manually drawn target structures was evaluated with each plan. If the dose objectives were met, the plan was considered successful in covering the gold standard (clinician-delineated) volume. RESULTS: The mandatory PTV 6000 dose objective (D98% > 5580 cGy) was met in 81 % of DIR plans and 45 % of RIR plans. The SV were mapped by DIR only and for all the plans, the PTV 4860 dose objective met the optimal target (D98% > 4617 cGy). The plans created by RIR led to under-coverage of the clinician-delineated prostate, predominantly at the apex or the bladder-prostate interface. CONCLUSION: Plans created from DIR propagation of prostate contours outperform those created from RIR propagation. In approximately 1 in 5 DIR plans, dosimetric coverage of the gold standard PTV was not clinically acceptable. Thus, at our institution, we use a combination of DIR propagation of contours alongside manual editing of contours where deemed necessary for online treatments.
Citation
Clinical and Translational Radiation Oncology, 2022, 37 pp. 25 - 32
Source Title
Clinical and Translational Radiation Oncology
Publisher
ELSEVIER IRELAND LTD
ISSN
2405-6308
eISSN
2405-6308
2405-6308
2405-6308
Collections
Research Team
Uro-oncology Trials
Stereotactic Radiother
Radiother Phys Modelling
Stereotactic Radiother
Radiother Phys Modelling