Evaluation of a new method for calculation of cumulative doses in the rectum wall using repeat ct scans

Kvinnsland, Yngve; Muren, L.P.; Dahl, Olav

doi:10.1080/02841860410031381

Cited by 6 publications

(5 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the ordering (ranking) of OR sub-volume elements according to dose is approximately the same in all fractions, DVH summation will resemble DIR-based dose accumulation. Similar observations may be expected in ORs such as rectum (in prostate, bladder and cervix cancer) (Kvinnsland et al 2004) and parotid glands (in head and neck cancer), since the location of the hot and cold regions are expected to be stable during RT. However, the discrepancy between DIR-based dose accumulation and DVH summation will be larger for very deformable organs which may completely change location in relation to the treatment field, e.g.…”

Section: Discussionsupporting

confidence: 72%

“…The bladder DVH parameters from the initial treatment plan and DVH parameters based on DVH summation were compared to the corresponding parameters derived using DIR-based dose accumulation. DVH summation was performed by crude addition across the plans recalculated on the repeat CT scans (the so-called histogram method investigated by Kvinnsland et al (2004)). For a given patient, each of the DVHs from the repeat CTs was weighted with a factor, F, given by the ratio between the total number of fractions (39) and the number of available CTs for treatment simulation (8 or 9).…”

Section: Dvh Analysismentioning

confidence: 99%

See 1 more Smart Citation

Bladder dose accumulation based on a biomechanical deformable image registration algorithm in volumetric modulated arc therapy for prostate cancer

et al. 2012

View full text Add to dashboard Cite

Variations in bladder position, shape and volume cause uncertainties in the doses delivered to this organ during a course of radiotherapy for pelvic tumors. The purpose of this study was to evaluate the potential of dose accumulation based on repeat imaging and deformable image registration (DIR) to improve the accuracy of bladder dose assessment. For each of nine prostate cancer patients, the initial treatment plan was re-calculated on eight to nine repeat computed tomography (CT) scans. The planned bladder dose-volume histogram (DVH) parameters were compared to corresponding parameters derived from DIR-based accumulations as well as DVH summation based on dose re-calculations. It was found that the deviations between the DIR-based accumulations and the planned treatment were substantial and ranged (-0.5-2.3) Gy and (-9.4-13.5) Gy for D(2%) and D(mean), respectively, whereas the deviations between DIR-based accumulations and DVH summation were small and well within 1 Gy. For the investigated treatment scenario, DIR-based bladder dose accumulation did not result in substantial improvement of dose estimation as compared to the straightforward DVH summation. Large variations were found in individual patients between the doses from the initial treatment plan and the accumulated bladder doses. Hence, the use of repeat imaging has a potential for improved accuracy in treatment dose reporting.

show abstract

Section: Discussionsupporting

confidence: 72%

Section: Dvh Analysismentioning

confidence: 99%

Bladder dose accumulation based on a biomechanical deformable image registration algorithm in volumetric modulated arc therapy for prostate cancer

et al. 2012

View full text Add to dashboard Cite

show abstract

“…However, the availability of large-scale patient-specific accumulated/delivered dose distributions along with corresponding follow-up data is still limited. Several investigators have described organ shape variations on a population basis using the information from multiple CT images to simulate organ motion [1,11–13]. Overall, these studies have shown that the doses from simulated motion can often better reflect the actual dose delivered to the organ than the dose distribution from the pCT.…”

mentioning

confidence: 99%

Statistical simulations to estimate motion-inclusive dose-volume histograms for prediction of rectal morbidity following radiotherapy

et al. 2012

Self Cite

View full text Add to dashboard Cite

Background and purpose Internal organ motion over a course of radiotherapy (RT) leads to uncertainties in the actual delivered dose distributions. In studies predicting RT morbidity, the single estimate of the delivered dose provided by the treatment planning computed tomography (pCT) is typically assumed to be representative of the dose distribution throughout the course of RT. In this paper, a simple model for describing organ motion is introduced, and is associated to late rectal morbidity data, with the aim of improving morbidity prediction. Material and methods Organ motion was described by normally distributed translational motion, with its magnitude characterised by the standard deviation (SD) of this distribution. Simulations of both isotropic and anisotropic (anterior-posterior only) motion patterns were performed, as were random, systematic or combined random and systematic motion. The associations between late rectal morbidity and motion-inclusive delivered dose-volume histograms (dDVHs) were quantified using Spearman's rank correlation coefficient (Rs) in a series of 232 prostate cancer patients, and were compared to the associations obtained with the static/planned DVH (pDVH). Results For both isotropic and anisotropic motion, different associations with rectal morbidity were seen with the dDVHs relative to the pDVHs. The differences were most pronounced in the mid-dose region (40–60 Gy). The associations were dependent on the applied motion patterns, with the strongest association with morbidity obtained by applying random motion with an SD in the range 0.2–0.8 cm. Conclusion In this study we have introduced a simple model for describing organ motion occurring during RT. Differing and, for some cases, stronger dose-volume dependencies were found between the motion-inclusive dose distributions and rectal morbidity as compared to the associations with the planned dose distributions. This indicates that rectal organ motion during RT influences the efforts to model the risk of morbidity using planning distributions alone.

show abstract

“…dose over the fractions, either to report the delivered dose or to compare with the planning dose (dose monitoring), to trigger, for example, re-planning. Indeed, in EBRT, the dosevolume histograms (DVHs) cannot be simply aggregated when considering deformable structures [85][86][87][88][89]. Local anatomical variations must be accounted for in mapping the fraction doses to a CCS before summation.…”

Section: Dir In Art For Dose Accumulation Justification and Principlementioning

confidence: 99%

Deformable image registration for radiation therapy: principle, methods, applications and evaluation

et al. 2019

View full text Add to dashboard Cite

Background: Deformable image registration (DIR) is increasingly used in the field of radiation therapy (RT) to account for anatomical deformations. The aims of this paper are to describe the main applications of DIR in RT and discuss current DIR evaluation methods. Methods: Articles on DIR published from January 2000 to October 2018 were extracted from PubMed and Science Direct. Our search was restricted to articles that report data obtained from humans, were written in English, and address DIR methods for RT. A total of 207 articles were selected from among 2506 identified in the search process. Results: At planning, DIR is used for organ delineation using atlas-based segmentation, deformationbased planning target volume definition, functional planning and magnetic resonance imaging-based dose calculation. In image-guided RT, DIR is used for contour propagation and dose calculation on per-treatment imaging. DIR is also used to determine the accumulated dose from fraction to fraction in external beam RT and brachytherapy, both for dose reporting and adaptive RT. In the case of reirradiation, DIR can be used to estimate the cumulated dose of the two irradiations. Finally, DIR can be used to predict toxicity in voxel-wise population analysis. However, the evaluation of DIR remains an open issue, especially when dealing with complex cases such as the disappearance of matter. To quantify DIR uncertainties, most evaluation methods are limited to geometry-based metrics. Software companies have now integrated DIR tools into treatment planning systems for clinical use, such as contour propagation and fraction dose accumulation. Conclusions: DIR is increasingly important in RT applications, from planning to toxicity prediction. DIR is routinely used to reduce the workload of contour propagation. However, its use for complex dosimetric applications must be carefully evaluated by combining quantitative and qualitative analyses.

show abstract

Evaluation of a new method for calculation of cumulative doses in the rectum wall using repeat ct scans

Cited by 6 publications

References 20 publications

Bladder dose accumulation based on a biomechanical deformable image registration algorithm in volumetric modulated arc therapy for prostate cancer

Bladder dose accumulation based on a biomechanical deformable image registration algorithm in volumetric modulated arc therapy for prostate cancer

Statistical simulations to estimate motion-inclusive dose-volume histograms for prediction of rectal morbidity following radiotherapy

Deformable image registration for radiation therapy: principle, methods, applications and evaluation

Contact Info

Product

Resources

About