Toward adaptive radiotherapy for head and neck patients: Uncertainties in dose warping due to the choice of deformable registration algorithm

Veiga, Catarina; Lourenço, Ana; Mouinuddin, Syed; Herk, Marcel van; Modat, Marc; Ourselin, Sébastien; Royle, G.; McClelland, Jamie R.

doi:10.1118/1.4905050

Cited by 81 publications

(76 citation statements)

References 52 publications

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“…It has been shown that DIR error is specific to the algorithm used27, 28 and image quality 22. In this study, only one commercial algorithm was used to evaluate the utility of applying DIR to CBCT studies using an unmodified commercial product.…”

Section: Discussionmentioning

confidence: 99%

“…Typical plan adaptation strategies revolve around re‐planning on the CBCT study using DIR to propagate contours and evaluate dose 30, 31, 32. Two publications by Veiga et al have evaluated the process of using DIR to CBCT studies for determining daily dose23 and accumulated dose with different DIR algorithms,28 but in both cases dose computations are needed for each fraction. In this study, DIR of the daily CBCT study is proposed to evaluate anatomical changes without a re‐scan of the patient or dose calculation using a commercial DIR algorithm.…”

Section: Discussionmentioning

confidence: 99%

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Online daily assessment of dose change in head and neck radiotherapy without dose‐recalculation

Vickress

Battista

Barnett

et al. 2018

J Applied Clin Med Phys

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BackgroundHead and neck cancers are commonly treated with radiation therapy, but due to possible volume changes, plan adaptation may be required during the course of treatment. Currently, plan adaptations consume significant clinical resources. Existing methods to evaluate the need for plan adaptation requires deformable image registration (DIR) to a new CT simulation or daily cone beam CT (CBCT) images and the recalculation of the dose distribution. In this study, we explore a tool to assist the decision for plan adaptation using a CBCT without re‐computation of dose, allowing for rapid online assessment.MethodsThis study involved 18 head and neck cancer patients treated with CBCT image guidance who had their treatment plan modified based on a new CT simulation (ReCT). Dose changes were estimated using different methods and compared to the current gold standard of using DIR between the planning CT scan (PCT) and ReCT with recomputed dose. The first and second methods used DIR between the PCT and daily CBCT with the planned dose or recalculated dose from the ReCT respectively, with the dose transferred to the CBCT using rigid registration. The necessity of plan adaptation was assessed by the change in dose to 95% of the planning target volume (D95) and mean dose to the parotids.ResultsThe treatment plans were adapted clinically for all 18 patients but only 7 actually needed an adaptation yielding 11 unnecessary adaptations. Applying a method using the daily CBCT with the planned dose distribution would have yielded only four unnecessary adaptations and no missed adaptations: a significant improvement from that done clinically.ConclusionUsing the DIR between the planning CT and daily CBCT can flag cases for plan adaptation before every fraction while not requiring a new re‐planning CT scan and dose recalculation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Online daily assessment of dose change in head and neck radiotherapy without dose‐recalculation

Vickress

Battista

Barnett

et al. 2018

J Applied Clin Med Phys

View full text Add to dashboard Cite

show abstract

“…To use the deformable image registration to deform the dose distribution back to the planning CT, a voxel‐by‐voxel accuracy of the deformable image registration would be required 19. On CBCT, which suffers from poor soft tissue contrast and image artifacts, the target volumes as well as the organs at risk (OARs) are not well visible.…”

Section: Methodsmentioning

confidence: 99%

Dosimetric effects of anatomical changes during fractionated photon radiation therapy in pancreatic cancer patients

Horst

Houweling

Tienhoven

et al. 2017

J Applied Clin Med Phys

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Pancreatic tumors show large interfractional position variation. In addition, changes in gastrointestinal gas volumes and body contour take place over the course of radiation therapy. We aimed to quantify the effect of these anatomical changes on target dose coverage, for the clinically used fiducial marker‐based patient position verification and, for comparison, also for simulated bony anatomy‐based position verification. Nine consecutive patients were included in this retrospective study. To enable fraction dose calculations on cone‐beam CT (CBCT), the planning CT was deformably registered to each CBCT (13–15 per patient); gas volumes visible on CBCT were copied to the deformed CT. Fraction doses were calculated for the clinically used 10 MV VMAT treatment plan (with for the planning target volume (PTV): D98% = 95%), according to fiducial marker‐based and bony anatomy‐based image registrations. Dose distributions were rigidly summed to yield the accumulated dose. To evaluate target dose coverage, we defined an iCTV +5 mm volume, i.e., the internal clinical target volume (iCTV) expanded with a 5 mm margin to account for remaining uncertainties including delineation uncertainties. We analyzed D98%, Dmean, and D2% for iCTV +5 mm and PTV (i.e., iCTV plus 10 mm margin). We found that for fiducial marker‐based registration, differences between fraction doses and planned dose were minimal. For bony anatomy‐based registration, fraction doses differed considerably, resulting in large differences between planned and accumulated dose for some patients, up to a decrease in D98% of the iCTV +5 mm from 95.9% to 85.8%. Our study shows that fractionated photon irradiation of pancreatic tumors is robust against variations in body contour and gastrointestinal gas, with dose coverage only mildly affected. However, as a result of interfractional tumor position variations, target dose coverage can severely decline when using bony anatomy for patient position verification. Therefore, the use of intratumoral fiducial marker‐based daily position verification is essential in pancreatic cancer patients.

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“…All these approaches have been extensively used for DIR validation, and guidelines on their application in the framework of contour propagation have recently been published in the AAPM report 132 . It is important to underline that the geometric accuracy of the propagated contours of anatomical regions does not necessarily mean that their interior is correctly handled, depending on the physical proprieties of the applied DVF . Hence, some groups proposed methods based on inverse consistency metrics or related to the Jacobian of the deformation fields to assure the plausibility of the physical characteristic of DVFs for clinical implementation of dose warping.…”

Section: Introductionmentioning

confidence: 99%

Performance of commercially available deformable image registration platforms for contour propagation using patient‐based computational phantoms: A multi‐institutional study

Loi¹,

Fusella

Lanzi

et al. 2018

Medical Physics

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Toward adaptive radiotherapy for head and neck patients: Uncertainties in dose warping due to the choice of deformable registration algorithm

Abstract: The authors evaluated several DIR algorithms for CT-to-CBCT registrations. In spite of all methods resulting in comparable geometrical matching, the choice of DIR implementation leads to uncertainties in dose warped, particularly in regions of high gradient and/or poor imaging quality.

Cited by 81 publications

References 52 publications

Online daily assessment of dose change in head and neck radiotherapy without dose‐recalculation

Online daily assessment of dose change in head and neck radiotherapy without dose‐recalculation

Dosimetric effects of anatomical changes during fractionated photon radiation therapy in pancreatic cancer patients

Performance of commercially available deformable image registration platforms for contour propagation using patient‐based computational phantoms: A multi‐institutional study

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