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Title: TU-AB-202-10: How Effective Are Current Atlas Selection Methods for Atlas-Based Auto-Contouring in Radiotherapy Planning?

Abstract

Purpose: To investigate the effectiveness of atlas selection methods for improving atlas-based auto-contouring in radiotherapy planning. Methods: 275 H&N clinically delineated cases were employed as an atlas database from which atlases would be selected. A further 40 previously contoured cases were used as test patients against which atlas selection could be performed and evaluated. 26 variations of selection methods proposed in the literature and used in commercial systems were investigated. Atlas selection methods comprised either global or local image similarity measures, computed after rigid or deformable registration, combined with direct atlas search or with an intermediate template image. Workflow Box (Mirada-Medical, Oxford, UK) was used for all auto-contouring. Results on brain, brainstem, parotids and spinal cord were compared to random selection, a fixed set of 10 “good” atlases, and optimal selection by an “oracle” with knowledge of the ground truth. The Dice score and the average ranking with respect to the “oracle” were employed to assess the performance of the top 10 atlases selected by each method. Results: The fixed set of “good” atlases outperformed all of the atlas-patient image similarity-based selection methods (mean Dice 0.715 c.f. 0.603 to 0.677). In general, methods based on exhaustive comparison of local similaritymore » measures showed better average Dice scores (0.658 to 0.677) compared to the use of either template image (0.655 to 0.672) or global similarity measures (0.603 to 0.666). The performance of image-based selection methods was found to be only slightly better than a random (0.645). Dice scores given relate to the left parotid, but similar results patterns were observed for all organs. Conclusion: Intuitively, atlas selection based on the patient CT is expected to improve auto-contouring performance. However, it was found that published approaches performed marginally better than random and use of a fixed set of representative atlases showed favourable performance. This research was funded via InnovateUK Grant 600277 as part of Eurostars Grant E!9297. DP,BS,MG,TK are employees of Mirada Medical Ltd.« less

Authors:
; ; ;  [1]; ; ; ;  [2]
  1. Mirada Medical Limited, Science and Medical Technology, Oxford (United Kingdom)
  2. Maastricht University Medical Centre, Department of Radiation Oncology MAASTRO - GROW School for Oncology Developmental Biology, Maastricht (Netherlands)
Publication Date:
OSTI Identifier:
22653960
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; GROUND TRUTH MEASUREMENTS; IMAGES; PERFORMANCE; PERSONNEL; PLANNING; RADIOTHERAPY; RANDOMNESS; SPINAL CORD

Citation Formats

Peressutti, D, Schipaanboord, B, Kadir, T, Gooding, M, Soest, J van, Lustberg, T, Elmpt, W van, and Dekker, A. TU-AB-202-10: How Effective Are Current Atlas Selection Methods for Atlas-Based Auto-Contouring in Radiotherapy Planning?. United States: N. p., 2016. Web. doi:10.1118/1.4957432.
Peressutti, D, Schipaanboord, B, Kadir, T, Gooding, M, Soest, J van, Lustberg, T, Elmpt, W van, & Dekker, A. TU-AB-202-10: How Effective Are Current Atlas Selection Methods for Atlas-Based Auto-Contouring in Radiotherapy Planning?. United States. doi:10.1118/1.4957432.
Peressutti, D, Schipaanboord, B, Kadir, T, Gooding, M, Soest, J van, Lustberg, T, Elmpt, W van, and Dekker, A. 2016. "TU-AB-202-10: How Effective Are Current Atlas Selection Methods for Atlas-Based Auto-Contouring in Radiotherapy Planning?". United States. doi:10.1118/1.4957432.
@article{osti_22653960,
title = {TU-AB-202-10: How Effective Are Current Atlas Selection Methods for Atlas-Based Auto-Contouring in Radiotherapy Planning?},
author = {Peressutti, D and Schipaanboord, B and Kadir, T and Gooding, M and Soest, J van and Lustberg, T and Elmpt, W van and Dekker, A},
abstractNote = {Purpose: To investigate the effectiveness of atlas selection methods for improving atlas-based auto-contouring in radiotherapy planning. Methods: 275 H&N clinically delineated cases were employed as an atlas database from which atlases would be selected. A further 40 previously contoured cases were used as test patients against which atlas selection could be performed and evaluated. 26 variations of selection methods proposed in the literature and used in commercial systems were investigated. Atlas selection methods comprised either global or local image similarity measures, computed after rigid or deformable registration, combined with direct atlas search or with an intermediate template image. Workflow Box (Mirada-Medical, Oxford, UK) was used for all auto-contouring. Results on brain, brainstem, parotids and spinal cord were compared to random selection, a fixed set of 10 “good” atlases, and optimal selection by an “oracle” with knowledge of the ground truth. The Dice score and the average ranking with respect to the “oracle” were employed to assess the performance of the top 10 atlases selected by each method. Results: The fixed set of “good” atlases outperformed all of the atlas-patient image similarity-based selection methods (mean Dice 0.715 c.f. 0.603 to 0.677). In general, methods based on exhaustive comparison of local similarity measures showed better average Dice scores (0.658 to 0.677) compared to the use of either template image (0.655 to 0.672) or global similarity measures (0.603 to 0.666). The performance of image-based selection methods was found to be only slightly better than a random (0.645). Dice scores given relate to the left parotid, but similar results patterns were observed for all organs. Conclusion: Intuitively, atlas selection based on the patient CT is expected to improve auto-contouring performance. However, it was found that published approaches performed marginally better than random and use of a fixed set of representative atlases showed favourable performance. This research was funded via InnovateUK Grant 600277 as part of Eurostars Grant E!9297. DP,BS,MG,TK are employees of Mirada Medical Ltd.},
doi = {10.1118/1.4957432},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = 2016,
month = 6
}
  • Purpose: To develop a high-resolution target volume atlas with intensity-modulated radiotherapy (IMRT) planning guidelines for the conformal treatment of anal cancer. Methods and Materials: A draft contouring atlas and planning guidelines for anal cancer IMRT were prepared at the Australasian Gastrointestinal Trials Group (AGITG) annual meeting in September 2010. An expert panel of radiation oncologists contoured an anal cancer case to generate discussion on recommendations regarding target definition for gross disease, elective nodal volumes, and organs at risk (OARs). Clinical target volume (CTV) and planning target volume (PTV) margins, dose fractionation, and other IMRT-specific issues were also addressed. A steeringmore » committee produced the final consensus guidelines. Results: Detailed contouring and planning guidelines and a high-resolution atlas are provided. Gross tumor and elective target volumes are described and pictorially depicted. All elective regions should be routinely contoured for all disease stages, with the possible exception of the inguinal and high pelvic nodes for select, early-stage T1N0. A 20-mm CTV margin for the primary, 10- to 20-mm CTV margin for involved nodes and a 7-mm CTV margin for the elective pelvic nodal groups are recommended, while respecting anatomical boundaries. A 5- to 10-mm PTV margin is suggested. When using a simultaneous integrated boost technique, a dose of 54 Gy in 30 fractions to gross disease and 45 Gy to elective nodes with chemotherapy is appropriate. Guidelines are provided for OAR delineation. Conclusion: These consensus planning guidelines and high-resolution atlas complement the existing Radiation Therapy Oncology Group (RTOG) elective nodal ano-rectal atlas and provide additional anatomic, clinical, and technical instructions to guide radiation oncologists in the planning and delivery of IMRT for anal cancer.« less
  • Purpose: To analyze the variation of sketching the parotid for patients with nasopharyngeal carcinoma who underwent radiotherapy based on computed tomography (CT) and magnetic resonance(MR) images. Methods: 41 nasopharyngeal cancer patients were randomly selected. Each patient underwent MR and CT scanning. The Gross Tumor Volume and Organs at risk were contoured on both contrasted CT and T1-MR images. For each patient, one radiotherapist sketched the parotid on CT and MR images for 10 times, and 10 different radiotherapists were asked to sketching the parotid on CT and MR images only one time. The inter- and intra-observers volumes and outline variationsmore » were compared. Results: The volumes of parotid contoured by inter-observer on CT and MR images were 34.6±12.1cm{sup 3}(left),34.3±9.0cm{sup 3}(right) and 24.6±7.6cm{sup 3}(L),23.2±8.1cm{sup 3}(R); In the same way, for intra-observer on CT and MR images the volumes were 28.2±7.6cm{sup 3}(L),29.4±9.4cm{sup 3}(R) and 24.4±7.6cm{sup 3}(L),22.5±7.4cm{sup 3}(R), respectively. The variable ratios of volume on MR images were 4.7±0.7%(L),5.0±0.6%(R) for inter-observer and 2.3±0.4%(L),2.1±0.7%(R) for intra-observer. Similarly, The inter- and intra-observer ratios for contouring on CT images reached 18.0±4.8%(L),17.4±4.6%(R) and 6.3±1.5%(L),6.8±1.5%(R), respectively. Conclusion: Contouring the parotids on MR images was more accurate and reproducible than that on CT images.« less
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