Generic method for automatic bladder segmentation on cone beam CT using a patient‐specific bladder shape model

Schoot, A.J.A.J. Van de; Schooneveldt, G.; Wognum, S.; Hoogeman, M.; Chai, Xiaodong; Stalpers, Lukas J.A.; Rasch, Coen R. N.; Bel, Arjan

doi:10.1118/1.4865762

Cited by 17 publications

(11 citation statements)

References 54 publications

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“…Previously conducted research on cervical cancer ART focused either on the quantification of inter-and intrafraction anatomical changes [11], the optimization of various adaptive strategies [9,10,21], tools to guide or automate adaptive workflows [12,13] or the clinical implementation [7]. However, the actual benefit of ART in terms of delivered dose while taking into account day-to-day anatomical variations is essential to further improve current adaptive strategies.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, several adaptive strategies in cervical cancer were investigated to anticipate on anatomical changes during the course of RT [9,10]. Next to the description of a clinically implemented adaptive strategy [7], most studies reported on tools to support or automate adaptive workflows [9,[11][12][13]. However, actual dosimetric improvements of ART compared with previously applied non-adaptive approaches in terms of target coverage and organ at risk (OAR) sparing are still unknown.…”

Section: Introductionmentioning

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: Introductionmentioning

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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“…CBCT-based plan selection is more challenging due to limited soft-tissue contrast, resulting in an additional observer variation. To minimize the effect of this variation, plan selection based on automatic organ segmentation could be applied [23]. However, disturbed CBCT quality could hinder automatic organ segmentation and still requires manual selection.…”

Section: Discussionmentioning

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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“…When bladder volume is not controlled through a urinary catheter, treatment parameters as power, phase and amplitude have to be adjusted during treatment to ensure a homogeneous temperature rise in the bladder. Since a change in bladder filling may also cause significant changes to the neighbouring anatomy [49,50] this is also relevant for adjacent hyperthermia treatment sites such as the cervix [21,43].…”

Section: Quality Controlmentioning

confidence: 99%

Thermal dosimetry for bladder hyperthermia treatment. An overview

Schooneveldt

Bakker

Balidemaj

et al. 2016

International Journal of Hyperthermia

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The urinary bladder is a fluid-filled organ. This makes, on the one hand, the internal surface of the bladder wall relatively easy to heat and ensures in most cases a relatively homogeneous temperature distribution; on the other hand the variable volume, organ motion, and moving fluid cause artefacts for most non-invasive thermometry methods, and require additional efforts in planning accurate thermal treatment of bladder cancer. We give an overview of the thermometry methods currently used and investigated for hyperthermia treatments of bladder cancer, and discuss their advantages and disadvantages within the context of the specific disease (muscle-invasive or non-muscle-invasive bladder cancer) and the heating technique used. The role of treatment simulation to determine the thermal dose delivered is also discussed. Generally speaking, invasive measurement methods are more accurate than non-invasive methods, but provide more limited spatial information; therefore, a combination of both is desirable, preferably supplemented by simulations. Current efforts at research and clinical centres continue to improve non-invasive thermometry methods and the reliability of treatment planning and control software. Due to the challenges in measuring temperature across the non-stationary bladder wall and surrounding tissues, more research is needed to increase our knowledge about the penetration depth and typical heating pattern of the various hyperthermia devices, in order to further improve treatments. The ability to better determine the delivered thermal dose will enable clinicians to investigate the optimal treatment parameters, and consequentially, to give better controlled, thus even more reliable and effective, thermal treatments.

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Generic method for automatic bladder segmentation on cone beam CT using a patient‐specific bladder shape model

Cited by 17 publications

References 54 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

Thermal dosimetry for bladder hyperthermia treatment. An overview

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