On Voxel-by-voxel Accumulated Dose for Prostate Radiation Therapy using Deformable Image Registration

Yu, Jialu; Hardcastle, Nicholas; Jeong, Ki-Hun; Bender, Edward T.; Ritter, Mark A.

doi:10.7785/tcrt.2012.500397

Cited by 10 publications

(16 citation statements)

References 34 publications

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“…Automated techniques using deformable image registration (DIR) and automated segmentation of contours or contour propagation, followed by automated replanning, can make ART more feasible for use across all body sites and cancer types. These automated techniques, especially DIR and auto segmentation, require volumetric imaging with sufficient image quality to produce correct results 3‐6 …”

Section: Introductionmentioning

confidence: 99%

Recommendations of megavoltage computed tomography settings for the implementation of adaptive radiotherapy on helical tomotherapy units

Velten

Boyd

Jeong

et al. 2020

J Applied Clin Med Phys

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Megavoltage computed tomography (MVCT) image quality metrics were evaluated on an Accuray Radixact unit to recommend scan settings for the implementation of a consistent adaptive radiotherapy program. Megavoltage computed tomography image quality was evaluated and compared to a kilovoltage CT (kVCT) simulator using a commercial cone beam computed tomography image quality phantom. Megavoltage computed tomographies were acquired on the Accuray Radixact using fine, normal, and coarse pitches, with all available reconstruction slice thicknesses, each of which were reconstructed using standard and iterative reconstruction (IR). Image quality metrics (IQM) were evaluated using DoseLab: automatically and manually calculated spatial resolution, subject contrast, and contrast‐to‐noise ratio (CNR). Scanning time was 15.6 s/cm for fine, 8.1 s/cm for normal, and 5.6 s/cm for coarse pitch. Automatically evaluated spatial resolutions ranged from 0.39, 0.41, to 0.42 lp/mm for standard reconstruction and from 0.24, 0.21, to 0.18 lp/mm for soft‐tissue IR, respectively, with general IR yielding values in between these. Spatial resolution for kVCT was measured to be at least 0.42 lp/mm. Contrast was consistent across MVCT settings with 8.1 ± 0.2%, while kVCT contrast was 10.27 ± 0.05%. CNR was calculated to be 3.3 ± 0.4 for standard reconstruction, 7.4 ± 0.4 for general IR, and 12.0 ± 1.9 for soft‐tissue IR. It was found that increasing reconstruction slice thickness for a given pitch does not improve IQMs. Based on the consistency of contrast metrics across pitch values and the only slightly reduced spatial resolution using normal compared to fine pitch, we recommend the use of normal pitch with 2 mm slice thickness to maximize image quality for ART while limiting scanning time. Only for sites for which improved CNR is required and reduced spatial resolution is acceptable, soft‐tissue IR is recommended.

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Section: Introductionmentioning

confidence: 99%

Recommendations of megavoltage computed tomography settings for the implementation of adaptive radiotherapy on helical tomotherapy units

Velten

Boyd

Jeong

et al. 2020

J Applied Clin Med Phys

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“…10,11 Moreover, previous studies have primarily compared the different methods of generating the multiple PTVs for the POD strategy 10,15,19 or between 2 adaptive strategies. 23 Because deformable image registration (DIR) enables the accumulation of delivered dose to the target and the normal tissue onto a reference image by tracking the corresponding voxels between multiple image datasets, [25][26][27] it was applied in the present study to conduct a dosimetric comparison of 3 adaptive strategies against a standard population marginbased PTV in assessing their efficacy in reducing the irradiated volume for locoregional radiotherapy for bladder cancer.…”

Section: Introductionmentioning

confidence: 99%

Comparison of 3 image-guided adaptive strategies for bladder locoregional radiotherapy

et al. 2019

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The objective of this study was to compare the dosimetric differences of a population-based planning target volume (PTV) approach and 3 proposed adaptive strategies: plan of the day (POD), patient-specific PTV (PS-PTV), and daily reoptimization (ReOpt). Bladder patients (n = 10) were planned and treated to 46 Gy in 23 fractions with a full bladder in supine position by the standard strategy using a population-based PTV. For each patient, the adaptive strategy was executed retrospectively as follows: (1) POD-multiple distributions of various PTV sizes were generated, and the appropriate distribution based on the bladder of the day was selected for each fraction; (2) PS-PTV-population-based PTV was used for the first 5 fractions and a new PTV derived using information from these fractions was used to deliver the remaining 18 fractions; and (3) ReOpt-distribution was reoptimized for each fraction based on the bladder of the day. Daily dose was computed on all cone beam computed tomographies (CBCTs) and deformed back to the planning computed tomography (CT) for dose summation afterward. V, the volume receiving an accumulated delivered dose of 43.7 Gy (95% prescription dose), was measured for comparison. Mean V (cm) values were 1410 (standard deviation [SD]: 227), 1212 (SD: 186), 1236 (SD: 199), and 1101 (SD: 180) for standard, POD, PS-PTV, and ReOpt, respectively. All adaptive strategies significantly reduced the irradiated volume, with ReOpt demonstrating the greatest reduction compared with the standard (- 25%), followed by PS-PTV (- 16%) and POD (- 12%). The difference in the magnitude of reduction between ReOpt and the other 2 strategies reached statistical significance (p = 0.0006). ReOpt is the best adaptive strategy at reducing the irradiated volume because of its frequent adaptation based on the daily geometry of the bladder. The need to adapt only once renders PS-PTV to be the best alternative adaptive strategy.

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“…accumulation of doses during EBRT and/or BT and, in the case of re-irradiation, in a large number of tumor localizations. In prostate cancer, OAR deformations mean that differences between the planning and cumulated dose have been quantified [99,100]. The mean dose difference is reportedly 7 Gy for the bladder and 2 Gy for the rectum [99].…”

Section: Dir In Art For Dose Accumulation Justification and Principlementioning

confidence: 99%

“…The mean dose difference is reportedly 7 Gy for the bladder and 2 Gy for the rectum [99]. The use of DIR has also allowed the decrease in rectal dose when using a rectal balloon to be quantified (70% of patients showed a decrease of more than 5% in the normal tissue complication probability, NTCP) [100]. Moreover, DIR can be used to accumulate the rectal dose of EBRT and high-dose-rate (HDR) BT [101].…”

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

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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.

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On Voxel-by-voxel Accumulated Dose for Prostate Radiation Therapy using Deformable Image Registration

Cited by 10 publications

References 34 publications

Recommendations of megavoltage computed tomography settings for the implementation of adaptive radiotherapy on helical tomotherapy units

Recommendations of megavoltage computed tomography settings for the implementation of adaptive radiotherapy on helical tomotherapy units

Comparison of 3 image-guided adaptive strategies for bladder locoregional radiotherapy

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

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