Evaluation of deformed image-based dose calculations for adaptive radiotherapy of nasopharyngeal carcinoma

Poon, Miranda; Holborn, Catherine; Cheng, K.F.; Fung, W.W.K.; Chiu, G.

doi:10.1016/j.meddos.2017.06.001

Cited by 4 publications

(2 citation statements)

References 22 publications

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“…However, direct use of CBCT in dose calculation is limited by inferior image quality and thus inaccurate Hounsfield units (HU) . Methods to mitigate or resolve this issue include image correction and image deformation . The former has shown promises, yet dose calculation inaccuracy still varies by up to 5% in phantom and patient studies of various sites .…”

Section: Introductionmentioning

confidence: 99%

“Dose of the day” based on cone beam computed tomography and deformable image registration for lung cancer radiotherapy

Yuan

Rong

Benedict

et al. 2019

J Applied Clin Med Phys

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Purpose: Adaptive radiotherapy (ART) has potential to reduce toxicity and facilitate safe dose escalation. Dose calculations with the planning CT deformed to cone beam CT (CBCT) have shown promise for estimating the "dose of the day". The purpose of this study is to investigate the "dose of the day" calculation accuracy based on CBCT and deformable image registration (DIR) for lung cancer radiotherapy.Methods: A total of 12 lung cancer patients were identified, for which daily CBCT imaging was performed for treatment positioning. A re-planning CT (rCT) was acquired after 20 Gy for all patients. A virtual CT (vCT) was created by deforming initial planning CT (pCT) to the simulated CBCT that was generated from deforming CBCT to rCT acquired on the same day. Treatment beams from the initial plan were copied to the vCT and rCT for dose calculation. Dosimetric agreement between vCT-based and rCT-based accumulated doses was evaluated using the Bland-Altman analysis.Results: Mean differences in dose-volume metrics between vCT and rCT were smaller than 1.5%, and most discrepancies fell within the range of ± 5% for the target volume, lung, esophagus, and heart. For spinal cord D max , a large mean difference of −5.55% was observed, which was largely attributed to very limited CBCT image quality (e.g., truncation artifacts). Conclusion:This study demonstrated a reasonable agreement in dose-volume metrics between dose accumulation based on vCT and rCT, with the exception for cases with poor CBCT image quality. These findings suggest potential utility of vCT for providing a reasonable estimate of the "dose of the day", and thus facilitating the process of ART for lung cancer. K E Y W O R D S adaptive radiotherapy, CBCT, dose of the day, virtual CT

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Section: Introductionmentioning

confidence: 99%

“Dose of the day” based on cone beam computed tomography and deformable image registration for lung cancer radiotherapy

Yuan

Rong

Benedict

et al. 2019

J Applied Clin Med Phys

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“…Daily dose accumulation based on DIR of scan-CT with the kV plan-CT maybe a novel strategy. 19 Poon et al 20 proposed an efficient tool to registrar CBCT with planning CT by DIR to stimulate the actual accumulated dose distributions. The greatest percentage difference in observed dose parameters of target was less than 5%.…”

Section: Discussionmentioning

confidence: 99%

Accumulated Dose Deviation of Rotational and Residual Setup Errors on Nasopharyngeal Carcinoma Using MIM Treated by Helical Tomotherapy

Yao

et al. 2023

Technol Cancer Res Treat

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Background To analyze the relationship between the rotational and residual setup errors and the dose deviation on nasopharyngeal carcinoma (NPC) treated by helical tomotherapy (HT). Methods From 25 July 2017 to 20 August 2019, 16 treated NPC patients were enrolled in the study. These patients were scanned with full target range megavoltage computed tomography (MVCT) every other day. Adaptive radiotherapy function application software MIM7.1.3 were used to accumulate the actual dose. The dose deviation with the initial plan dose of the patients’ target and organs at risk (OAR) were compared, and the correlation between the dose change and the setup errors (rotational setup errors and neck residual setup error) was analyzed. Results Translational setup errors increased farther away from the head. Statistically significant difference among 3 groups was achieved in the directions of left-right ( P < .001) and anteroposterior ( P < .001) by analysis of variance test. Compared with the initial plan dose, the actual accumulated dose of the target area decreased with the actual exposure dose of the OAR increased. However, most of the dosimetric parameters differed by less than 5%. No correlation was found between dose deviation values and the translational setup errors of target. However, sagittal rotational setup errors (pitch) had a positive relationship ( P < .05) with the avearge dose of PTVnd (L) ( r = 0.885), PTVnd(R) ( r = 0.547) PTV1( r = 0.633) and PTV2( r = 0.584). Transverse rotational setup errors (roll) had a positive relationship ( P < .05) with the avearge dose of PTVnd(R) ( r = 0.593), PTV1( r = 0.505) and PTV2( r = 0.662). Conclusions Dose deviation between the actual accumulated and initial plan is not negligible, but most indicators difference is less than 5%, NPC patients treated by HT with MVCT correction setup errors every other day did not need adaptive radiotherapy model unless got rapid tumor shrinkage or weight loss. Moreover, to minimize the dose deviation, more attention should be paid to the reduction of pitch, roll, and residual error of cervical vertebrae during body positioning.

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A rationale for cone beam CT with extended longitudinal field-of-view in image guided adaptive radiotherapy

et al. 2019

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Evaluation of deformed image-based dose calculations for adaptive radiotherapy of nasopharyngeal carcinoma

Cited by 4 publications

References 22 publications

“Dose of the day” based on cone beam computed tomography and deformable image registration for lung cancer radiotherapy

“Dose of the day” based on cone beam computed tomography and deformable image registration for lung cancer radiotherapy

Accumulated Dose Deviation of Rotational and Residual Setup Errors on Nasopharyngeal Carcinoma Using MIM Treated by Helical Tomotherapy

A rationale for cone beam CT with extended longitudinal field-of-view in image guided adaptive radiotherapy

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