A symmetric nonrigid registration method to handle large organ deformations in cervical cancer patients

Bondar, L. N.; Hoogeman, M.; Osorio, Eliana Vásquez; Heijmen, B.

doi:10.1118/1.3443436

Cited by 66 publications

(92 citation statements)

References 37 publications

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“…Despite the reported DIR accuracy for anatomical borders, the limited soft-tissue contrast in CBCT imaging prevents accurate correspondences within structures. Specific structure-based algorithms are developed to overcome this limitation [17]; however, the accuracy of such algorithms for dose accumulation is unknown and first need to be derived in an independent study. Also, a prospective evaluation of ART based on a large number of patient is required to determine the actual benefit of ART in terms of tumor control and toxicity.…”

Section: Discussionmentioning

confidence: 99%

“…After bony registration of both planning CTs, corresponding primary CTVs (pCTVs) which encompassed the GTV, cervix, corpus-uterus and upper part of the vagina were registered using a structure-based deformable image registration (DIR) algorithm [17]. The patient-specific full-range primary internal target volume (pITV) was divided in pITV subranges by scaling the deformation vectors (Supplementary Figure A1).…”

Section: Target and Oar Definitionmentioning

confidence: 99%

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Dosimetric advantages of a clinical daily adaptive plan selection strategy compared with a non-adaptive strategy in cervical cancer radiation therapy

et al. 2017

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Background: Radiation therapy (RT) using a daily plan selection adaptive strategy can be applied to account for interfraction organ motion while limiting organ at risk dose. The aim of this study was to quantify the dosimetric consequences of daily plan selection compared with non-adaptive RT in cervical cancer. Material and methods: Ten consecutive patients who received pelvic irradiation, planning CTs (full and empty bladder), weekly post-fraction CTs and pre-fraction CBCTs were included. Non-adaptive plans were generated based on the PTV defined using the full bladder planning CT. For the adaptive strategy, multiple PTVs were created based on both planning CTs by ITVs of the primary CTVs (i.e., GTV, cervix, corpus-uterus and upper part of the vagina) and corresponding library plans were generated. Daily CBCTs were rigidly aligned to the full bladder planning CT for plan selection. For daily plan recalculation, selected CTs based on initial similarity were deformably registered to CBCTs. Differences in daily target coverage (D 98% > 95%) and in V 0.5Gy , V 1.5Gy , V 2Gy , D 50% and D 2% for rectum, bladder and bowel were assessed. Results: Non-adaptive RT showed inadequate primary CTV coverage in 17% of the daily fractions. Plan selection compensated for anatomical changes and improved primary CTV coverage significantly (p < 0.01) to 98%. Compared with non-adaptive RT, plan selection decreased the fraction dose to rectum and bowel indicated by significant (p < 0.01) improvements for daily V 0.5Gy , V 1.5Gy , V 2Gy , D 50% and D 2% . However, daily plan selection significantly increased the bladder V 1.5Gy , V 2Gy , D 50% and D 2% . Conclusions: In cervical cancer RT, a non-adaptive strategy led to inadequate target coverage for individual patients. Daily plan selection corrected for day-to-day anatomical variations and resulted in adequate target coverage in all fractions. The dose to bowel and rectum was decreased significantly when applying adaptive RT.

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Section: Discussionmentioning

confidence: 99%

Section: Target and Oar Definitionmentioning

confidence: 99%

Dosimetric advantages of a clinical daily adaptive plan selection strategy compared with a non-adaptive strategy in cervical cancer radiation therapy

et al. 2017

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“…After bony registration of both planning CTs, the pCTV on the full bladder planning CT was registered to the pCTV on the empty bladder planning CT using a structure-based deformable image registration algorithm [15]. The obtained deformation vectors after registration represented the connection between corresponding points on both structures.…”

Section: Library Of Structuresmentioning

confidence: 99%

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

et al. 2016

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Background Image-guided adaptive proton therapy (IGAPT) can potentially be applied to take into account interfraction motion while limiting organ at risk (OAR) dose in cervical cancer radiation therapy (RT). In this study, the potential dosimetric advantages of IGAPT compared with photonbased image-guided adaptive RT (IGART) were investigated. Material and methods For 13 cervical cancer patients, full and empty bladder planning computed tomography (CT) images and weekly CTs were acquired. Based on both primary clinical target volumes (pCTVs) [i.e. gross tumor volume (GTV), cervix, corpus-uterus and upper part of the vagina] on planning CTs, the pretreatment observed full range primary internal target volume (pITV) was interpolated to derive pITV subranges. Given corresponding ITVs (i.e. pITVs including lymph nodes), patient-specific photon and proton plan libraries were generated. Using all weekly CTs, IGART and IGAPT treatments were simulated by selecting library plans and recalculating the dose. For each recalculated IGART and IGAPT fraction, CTV (i.e. pCTV including lymph nodes) coverage was assessed and differences in fractionated substitutes of dose-volume histogram (DVH) parameters (V 15Gy , V 30Gy , V 45Gy , D mean , D 2cc ) for bladder, bowel and rectum were tested for significance (Wilcoxon signed-rank test). Also, differences in toxicity-related DVH parameters (rectum V 30Gy , bowel V 45Gy ) were approximated based on accumulated dose distributions. Results In 92% (96%) of all recalculated IGAPT (IGART) fractions adequate CTV coverage (V 95% 498%) was obtained. All dose parameters for bladder, bowel and rectum, except the fractionated substitute for rectum V 45Gy , were improved using IGAPT. Also, IGAPT reduced the mean dose to bowel, bladder and rectum significantly (p50.01). In addition, an average decrease of rectum V 30Gy and bowel V 45Gy indicated reductions in toxicity probabilities when using IGAPT. Conclusion This study demonstrates the feasibility of IGAPT in cervical cancer using a plan-library based plan-of-the-day approach. Compared to photon-based IGART, IGAPT maintains target coverage while significant dose reductions for the bladder, bowel and rectum can be achieved.

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“…Bondar et al [41] proposed to use a landmark guided thin spline based symmetric non-rigid registration to register organs of interest such as the bladder. Two variants of the registration algorithm were developed; symmetric and asymmetric.…”

Section: Ctmentioning

confidence: 99%

“…The regression based approach facilitated the selection of the most probable deformation of the cervix and the uterus depending on the bladder volume. A symmetric registration [41] between the predicted volume and the treatment day CT was finally performed for adaptive re-planning.…”

Section: Ctmentioning

confidence: 99%

A review of segmentation and deformable registration methods applied to adaptive cervical cancer radiation therapy treatment planning

Ghose

Holloway

Lim

et al. 2015

Artificial Intelligence in Medicine

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A c c e p t e d M a n u s c r i p t Highlights  This paper reviews the current state-of-the-art segmentation and deformable registration methods applied to cervical cancer adaptive radiation therapy planning. Strength and weaknesses of the registration and the segmentation methods are studied and analysed. Use of shape prior constraints can significantly reduce segmentation and registration errors.  Use of tissue specific classification of tumour may reduce tumour segmentation error. *Highlights (for review)Page 2 of 30 A c c e p t e d M a n u s c r i p t Abstract ObjectiveManual contouring and registration for radiotherapy treatment planning and online adaptation for cervical cancer radiation therapy in computed tomography (CT) and magnetic resonance images (MRI) is often necessary. However manual intervention is time consuming and may suffer from inter or intra rater variability. In recent years a number of computer-guided automatic or semi-automatic segmentation and registration methods have been proposed. Segmentation and registration in CT and MRI for this purpose is a challenging task due to soft tissue deformation, inter-patient shape and appearance variation and anatomical changes over the course of treatment. The objective of this work is to provide a state-of-the-art review of computer-aided methods developed for adaptive treatment planning and radiation therapy planning for cervical cancer radiation therapy. MethodsSegmentation and registration methods published with the goal of cervical cancer treatment planning and adaptation have been identified from the literature (PubMed and Google Scholar). A comprehensive description of each method is provided. Similarities and differences of these methods are highlighted and the strengths and weaknesses of these methods are discussed. A discussion about choice of an appropriate method for a given modality is provided. ResultsIn the reviewed papers a Dice similarity coefficient of around 0.85 along with mean absolute surface distance of 2-4 mm for the clinically treated volume were reported for transfer of contours from planning day to the treatment day. ConclusionsMost segmentation and non-rigid registration methods have been primarily designed for adaptive re-planning for the transfer of contours from planning day to the treatment day. The use of shape priors significantly improved segmen- 1Page 3 of 30 A c c e p t e d M a n u s c r i p t tation and registration accuracy compared to other models.

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A symmetric nonrigid registration method to handle large organ deformations in cervical cancer patients

Cited by 66 publications

References 37 publications

Dosimetric advantages of a clinical daily adaptive plan selection strategy compared with a non-adaptive strategy in cervical cancer radiation therapy

Dosimetric advantages of a clinical daily adaptive plan selection strategy compared with a non-adaptive strategy in cervical cancer radiation therapy

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

A review of segmentation and deformable registration methods applied to adaptive cervical cancer radiation therapy treatment planning

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