Bladder dose–surface maps and urinary toxicity: Robustness with respect to motion in assessing local dose effects

Palorini, F.; Botti, A.; Carillo, V.; Gianolini, Stefano; Improta, Ilaria; Iotti, Cinzia; Rancati, T.; Cozzarini, C.; Fiorino, Claudio

doi:10.1016/j.ejmp.2016.03.006

Cited by 23 publications

(27 citation statements)

References 28 publications

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“…For example, bladder size or volume could be considered as fixed parameters that may determine changes in volume and directions of geometric variations. (Rios et al, 2016) and (Palorini et al, 2016a) reported, in line with Fig. 7, that bladders with large volumes exhibited geometric variations in the superior-ventral region and…”

Section: A C C E P T E D Msupporting

confidence: 82%

“…The bladder is particular for presenting the largest inter-fraction shape variations during treatment, caused by continuous volume changes (Roeske et al, 1995;Turner et al, 1997). These shape variations introduce geometric uncertainties that render assessment of the actual dose delivered to the bladder during treatment difficult, thereby leading to dose uncertainties that limit the possibility of modeling dose-volume response for late genitourinary (GU) toxicity (Fiorino et al, 2009;Thor et al, 2013b;Nassef et al, 2016;Palorini et al, 2016a;Landoni et al, 2016). The Quantitative Analysis of Normal Tissue Effects in the Clinic (QUAN-TEC) project has stated that a similar dose-response to that of late gastrointestinal (GI) toxicity is far from being established.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

See 1 more Smart Citation

Population model of bladder motion and deformation based on dominant eigenmodes and mixed-effects models in prostate cancer radiotherapy

Ríos

Crevoisier

Ospina

et al. 2017

Medical Image Analysis

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In radiotherapy for prostate cancer irradiation of neighboring organs at risk may lead to undesirable side-effects. Given this setting, the bladder presents the largest inter-fraction shape variations hampering the computation of the actual delivered dose vs. planned dose. This paper proposes a population model, based on longitudinal data, able to estimate the probability of bladder presence during treatment, using only the planning computed tomography (CT) scan as input information. As in previously-proposed principal component analysis (PCA) population-based models, we have used the data to obtain the dominant eigenmodes that describe bladder geometric variations between fractions. However, we have used a longitudinal analysis along each mode in order to properly characterize patient's variance from the total population variance. We have proposed is a mixed-effects (ME) model in order to separate intra- and inter-patient variability, in an effort to control confounding cohort effects. Other than using PCA, bladder shapes are represented by using spherical harmonics (SPHARM) that additionally enables data compression without information lost. Based on training data from repeated CT scans, the ME model was thus implemented following dimensionality reduction by means of SPHARM and PCA. We have evaluated the model in a leave-one-out cross validation framework on the training data but also using independent data. Probability maps (PMs) were thus generated with several draws from the learnt model as predicted regions where the bladder will likely move and deform. These PMs were compared with the actual regions using metrics based on mutual information distance and misestimated voxels. The prediction was also compared with two previous population PCA-based models. The proposed model was able to reduce the uncertainties in the estimation of the probable region of bladder motion and deformation. This model can thus be used for tailoring radiotherapy treatments.

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Section: A C C E P T E D Msupporting

confidence: 82%

Section: Accepted Manuscriptmentioning

confidence: 99%

Population model of bladder motion and deformation based on dominant eigenmodes and mixed-effects models in prostate cancer radiotherapy

Ríos

Crevoisier

Ospina

et al. 2017

Medical Image Analysis

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“…Changes in doses to the clinical target volume (CTV) and OAR resulting from patient movement have been recently reported for the proton and x‐ray fields . Warren et al reported that the change in the D 98% of the CTV was <5% in most cases of volume‐modulated arc radiotherapy for esophageal cancer when the patient shifted ±5 mm in the LR and AP directions and ±7 mm in the SI direction.…”

Section: Discussionmentioning

confidence: 99%

Impact of treatment planning using a structure block function on the target and organ doses related to patient movement in cervical esophageal cancer: A phantom study

Shimizu

Sasaki

Ito

et al. 2019

J Applied Clin Med Phys

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Helical tomotherapy (HT) can restrict beamlets passing through the virtual contour on computed tomography (CT) image in dose optimization, reducing the dose to organs at risk (OARs). Beamlet restriction limits the incident beamlet angles; thus, the proper planning target volume (PTV) margin may differ from that of the standard treatment plan without beamlet restriction, depending on the patient's movement during dose delivery. Dose distribution changes resulting from patient movement have not been described for treatment plans with beamlet restriction. This study quantified changes in dose distribution to the target and OARs when beamlet restriction is applied to cervical esophageal cancer treatment plan using HT by systematically shifting a phantom. Treatment plans for cervical esophageal cancers with and without beamlet restriction modes [directional block (DB) and nonblock (NB), respectively] were designed for CT images of the RANDO phantom. The PTV margin for the DB mode was set to be the same as that for the NB mode (5 mm). The CT image was intentionally shifted by ±1, ±2, and ±3 voxels in the left–right, anterior–posterior, and superior–inferior directions, and the dose distribution was recalculated for each position using the fluence for the NB or DB mode. When the phantom shift was within the same PTV margin as the NB mode, changes in doses to the targets, lungs, heart, and spinal cord in the DB mode were small as those in the NB mode. In conclusion, the virtual contour shape used in this study would provide safe delivery even with patient movement within the same PTV margin as for the NB mode.

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“…Several published results (26,27,31,35,36,73) converged in the identification of the trigone dose as strongly associated with worsening of symptoms and an increased risk of severe acute and late injury. The exact mechanisms controlling the trigone are still unclear; however, as this muscle is actively involved in sphincter opening, it is realistic to claim that its damage might elicit frequency, urgency and/or incontinence symptoms.…”

Section: Are There Exceptionally Sensitive and Critical Substructuresmentioning

confidence: 93%

“…Some studies from the literature underlined the need to overcome the assumption that the urinary bladder is uniformly sensitive to radiation (26,27,31,35,36,73). As a matter of fact, the bladder comprises several substructures which may have distinct radiobiological behaviors and sensitivities, leading to different impacts on distinct urinary symptoms (see Fig.…”

Section: Are There Exceptionally Sensitive and Critical Substructuresmentioning

confidence: 99%

Understanding Urinary Toxicity after Radiotherapy for Prostate Cancer: First Steps Forward

Rancati

Palorini

Cozzarini

et al. 2017

Tumori

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Tumori 2017; 103(5): [395][396][397][398][399][400][401][402][403][404] REVIEW -BONADONNA LECTURE SERIES may be differently related to the absorbed dose. For example, rectal bleeding arises as a serial effect and is mainly related to the absorption of high doses in small rectal mucosa volumes, whilst fecal incontinence is related to intermediate doses absorbed by large rectal volumes.The development of reliable models of radiation-induced toxicities along with the available level of technology has determined an efficient improvement of the treatment plans, even in dose-escalated or hypofractionated regimens. This is particularly true for moderate and severe rectal toxicities, which had an incidence close to 20% in the 1990s while in the most recent publications they have fallen below 7%-10%.However, an analogous result has not yet been reached in urinary symptoms. This is mainly due to the difficulty in sparing the bladder, which is partially but unavoidably included in the target volume, as well as to the clear lack of knowledge concerning the predictors of urinary toxicity. The main reason for this deficiency is probably the difficulty in following for a sufficiently long time a large number of patients whose clinical and dosimetry data need to be individually and prospectively collected with proper evaluation of urinary symptoms. Some important symptoms (e.g., incontinence) may indeed continuously arise after radiation therapy and their incidence reaches a plateau only many years (typically 5-8) after treatment. The fulfilment of reliable models of radiation-induced urinary sequelae is therefore made particularly challenging by the complexity of symptoms, their evolution over time, and the strong dependence on the baseline situation.It is widely acknowledged that radiation-induced toxicity is a multifactorial problem, depending not only on the delivered

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Bladder dose–surface maps and urinary toxicity: Robustness with respect to motion in assessing local dose effects

Cited by 23 publications

References 28 publications

Population model of bladder motion and deformation based on dominant eigenmodes and mixed-effects models in prostate cancer radiotherapy

Population model of bladder motion and deformation based on dominant eigenmodes and mixed-effects models in prostate cancer radiotherapy

Impact of treatment planning using a structure block function on the target and organ doses related to patient movement in cervical esophageal cancer: A phantom study

Understanding Urinary Toxicity after Radiotherapy for Prostate Cancer: First Steps Forward

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