Inter- and intra-observer variability in contouring of the prostate gland on planning computed tomography and cone beam computed tomography

Choi, Hyung Rim; Kim, Young Seok; Lee, Se Hyung; Lee, Yu-Sun; Park, Geumju; Jung, Jae Hyung; Cho, Byoung Chul; Park, Sung Ho; Ahn, Hanjong; Kim, Choung‐Soo; Yi, Seong Yoon; Ahn, Seung Do

doi:10.3109/0284186x.2011.562916

Cited by 36 publications

(38 citation statements)

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“…For the HR case, whilst most observers segmented a structure larger than that automatically segmented, one particularly generous observer’s segmented structure (observer J in Table 2) eclipses the others substantially, dominating results. The principal region for disagreement for CTV was at the prostatic apex, a well-recognised location for observer-disagreement when using CT imaging [7,9,10], where most observers included more inferior slices to that from the automatic segmentation. During the RADAR trial, an ‘audit’ of CTV outlining was undertaken where definition of the prostatic apex proved highly variable, with many contributing clinicians extending prostate definition far more inferiorly than considered acceptable by RADAR investigators [13].…”

Section: Discussionmentioning

confidence: 99%

“…Issues associated with prostate definition on CT have been well documented, especially at prostatic base and apex [7-10]. The question is posed therefore if automatic segmentation techniques could be utilised to homogenise definition of the prostate and associated anatomy across the population of participants contributing to a multicentre clinical trial, with the potential to enhance the translatability of outcomes analyses [11].…”

Section: Introductionmentioning

confidence: 99%

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Automatic segmentation of male pelvic anatomy on computed tomography images: a comparison with multiple observers in the context of a multicentre clinical trial

2013

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BackgroundThis study investigates the variation in segmentation of several pelvic anatomical structures on computed tomography (CT) between multiple observers and a commercial automatic segmentation method, in the context of quality assurance and evaluation during a multicentre clinical trial.MethodsCT scans of two prostate cancer patients (‘benchmarking cases’), one high risk (HR) and one intermediate risk (IR), were sent to multiple radiotherapy centres for segmentation of prostate, rectum and bladder structures according to the TROG 03.04 “RADAR” trial protocol definitions. The same structures were automatically segmented using iPlan software for the same two patients, allowing structures defined by automatic segmentation to be quantitatively compared with those defined by multiple observers. A sample of twenty trial patient datasets were also used to automatically generate anatomical structures for quantitative comparison with structures defined by individual observers for the same datasets.ResultsThere was considerable agreement amongst all observers and automatic segmentation of the benchmarking cases for bladder (mean spatial variations < 0.4 cm across the majority of image slices). Although there was some variation in interpretation of the superior-inferior (cranio-caudal) extent of rectum, human-observer contours were typically within a mean 0.6 cm of automatically-defined contours. Prostate structures were more consistent for the HR case than the IR case with all human observers segmenting a prostate with considerably more volume (mean +113.3%) than that automatically segmented. Similar results were seen across the twenty sample datasets, with disagreement between iPlan and observers dominant at the prostatic apex and superior part of the rectum, which is consistent with observations made during quality assurance reviews during the trial.ConclusionsThis study has demonstrated quantitative analysis for comparison of multi-observer segmentation studies. For automatic segmentation algorithms based on image-registration as in iPlan, it is apparent that agreement between observer and automatic segmentation will be a function of patient-specific image characteristics, particularly for anatomy with poor contrast definition. For this reason, it is suggested that automatic registration based on transformation of a single reference dataset adds a significant systematic bias to the resulting volumes and their use in the context of a multicentre trial should be carefully considered.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Automatic segmentation of male pelvic anatomy on computed tomography images: a comparison with multiple observers in the context of a multicentre clinical trial

2013

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“…Details regarding the planning CT and CBCT acquisition have been previously described. 11 Briefly, the planning CT simulation was performed with the patient in the supine position and using an intravenous contrast agent. A knee-immobilization device was used, either with or without ankle immobilization (Knee-Lok and Foot-Lok positioned, CIVCO, Coralville, IA, USA).…”

Section: Methodsmentioning

confidence: 99%

Analysis of prostate bed motion using an endorectal balloon and cone beam computed tomography during postprostatectomy radiotherapy

Joo¹,

Kim²,

Kim³

et al. 2016

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BackgroundThe authors conducted this prospective study to analyze the amount of interfractional prostate bed motion (PBM) and quantify its components with the use of an endorectal balloon (ERB).MethodsA total of 1,348 cone beam computed tomography images from 46 patients who underwent postprostatectomy radiotherapy were analyzed. For the pilot image, electronic portal imaging, guided by skin marks was performed to ensure proper positioning and inflation of the ERB. Then, for bone matching, manual or automatic registration of the planning and each cone beam computed tomography was performed, based on the bony anatomy of the pelvis. Shifts (bony misalignment [BM]) in three directions were recorded at each treatment session. For prostate bed matching, manual matching was conducted based on the anterior rectal wall and the shift (PBM) was recorded. Total setup error was defined as the shift from the skin mark to the prostate bed matching, based on anterior rectal wall stretched by the ERB. PBM was defined as the difference between the total setup error and BM.ResultsSystematic errors for the total setup error were 1.0, 1.3, and 1.0 mm in the right–left, anterior–posterior, and superior–inferior directions, with random errors of 1.9, 2.4, and 1.9 mm, respectively. Systematic errors were 1.6, 1.6, and 0.3 mm for BM and 0.8, 1.1, and 0.9 mm for PBM, with random errors of 2.4, 2.5, and 1.1 mm for BM and 1.8, 2.2, and 1.9 mm for PBM.ConclusionThe BM was the main component of the total setup error, suggesting that interfractional PBM was well controlled by the ERB device. Planning target volume margins of <5 mm were needed to include 95% of the interfractional variations when using an ERB.

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“…There were 31 studies which evaluated the effect of imaging on IOV, but they varied in methodology (Table 3). Some studies compared volume delineation on Volume delineation in radiation oncology two separate imaging modalities including two different CT scans, 41,42 CT vs MRI [43][44][45][46][47][48][49] , CT vs cone-beam CT [50][51][52] and MRI scans using different sequences. 53,54 Other studies compared standard imaging with the use of additional registered data sets such as specialised CT 55 , MRI [56][57][58] and PET.…”

Section: The Effect Of Additional Imaging Interventions On Iov In Volmentioning

confidence: 99%

A review of interventions to reduce inter‐observer variability in volume delineation in radiation oncology

et al. 2016

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Inter- and intra-observer variability in contouring of the prostate gland on planning computed tomography and cone beam computed tomography

Abstract: & Seung Do Ahn (2011) Inter-and intra-observer variability in contouring of the prostate gland on planning computed tomography and cone beam computed tomography, Acta Oncologica, 50:4, 539-546,

Cited by 36 publications

References 25 publications

Automatic segmentation of male pelvic anatomy on computed tomography images: a comparison with multiple observers in the context of a multicentre clinical trial

Automatic segmentation of male pelvic anatomy on computed tomography images: a comparison with multiple observers in the context of a multicentre clinical trial

Analysis of prostate bed motion using an endorectal balloon and cone beam computed tomography during postprostatectomy radiotherapy

A review of interventions to reduce inter‐observer variability in volume delineation in radiation oncology

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