Comparison of whole-field simultaneous integrated boost VMAT and IMRT in the treatment of nasopharyngeal cancer

Jin, Xiance; Jin, Yi; Zhou, Yanfang; Yan, Huawei; Han, Ce; Xie, Conghua

doi:10.1016/j.meddos.2013.05.004

Cited by 33 publications

(32 citation statements)

References 18 publications

(23 reference statements)

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“…The average delivery time of CDR-VMAT was longer than VDR-VMAT (7.01 ± 0.43 min vs. 4.75 ± 0.07 min), but it was still much shorter than that of IMRT (11.01 ± 0.43 min) as reported in our previous study [6]. All the CDR-VMAT plans were delivered smoothly and accurately in this study with an average percent γpassing rate of 95.75% ± 2.57%.…”

Section: Discussionsupporting

confidence: 69%

“…VDR-VMAT both with single arc and dual arc has been widely investigated in the treatment of various tumor sites with superior or equivalent dose distribution and reduced delivery time and MUs [5,6,18]. However, the VDR-VMAT capability is not available for the low- or intermediate-end linacs without upgrade in institutions especially in the underdeveloped countries and regions.…”

Section: Discussionmentioning

confidence: 99%

“…VDR-VMAT objective settings were employed in the optimization for all plans as shown in Table 1. The optimization parameters of VDR-VMAT have been reported in our previous study and are summarized briefly here [6]. Leaf motion constraints of 0.46 cm/deg and a final arc spacing of 4 degree were employed.…”

Section: Methodsmentioning

confidence: 99%

“…VMAT plans with shorter delivery time, fewer MU, and superior or equivalent plan quality compared to conventional step-and-shoot IMRT have been reported for prostate cancer and NPC [5,6]. However, to use the VMAT approach, the hardware and software systems of the radiation treatment planning system (TPS), as well as the linear accelerator (linac), must be upgraded.…”

Section: Introductionmentioning

confidence: 99%

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Feasibility of constant dose rate VMAT in the treatment of nasopharyngeal cancer patients

Shang²,

Xie

et al. 2014

Radiat Oncol

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PurposeTo investigate the feasibility of constant dose rate volumetric modulated arc therapy (CDR-VMAT) in the treatment of nasopharyngeal cancer (NPC) patients and to introduce rotational arc radiotherapy for linacs incapable of dose rate variation.Materials and methodsTwelve NPC patients with various stages treated previously using variable dose rate (VDR) VMAT were enrolled in this study. CDR-VMAT, VDR-VMAT and mutlicriteria optimization (MCO) VMAT plans were generated for each patient on RayStation treatment planning system with identical objective functions and the dosimetric differences among these three planning schemes were evaluated and compared. Non dosimetric parameters of optimization time, delivery time and delivery accuracy were also evaluated.ResultsThe planning target volume of clinical target volume (PTV-CTV) coverage of CDR-VMAT was a bit inferior to those of VDR- and MCO-VMAT. The V93 (p = 0.01) and V95 (percent volume covered by isodose line) (p = 0.04) for CDR-VMAT, VDR-VMAT and MCO-VMAT were 98.74% ± 0.31%, 99.76% ± 0.16%, 99.38% ± 0.43%, and 98.40% ± 0.48%, 99.53% ± 0.28%, 99.07% ± 0.52%, respectively. However, the CDR-VMAT showed a better dose homogeneity index (HI) (p = 0.01) in PTV-CTV. No significant difference in other target coverage parameters was observed. There was no significant difference in OAR sparing among these three planning schemes except for a higher maximum dose (Dmax) on the brainstem for CDR-VMAT. The brainstem Dmax of CDR-VMAT, VDR-VMAT and MCO-VMAT were 54.26 ± 3.21 Gy, 52.19 ± 1.65 Gy, and 52.79 ± 4.77 Gy, respectively. The average delivery time (p < 0.01) and the average percent γ passing rates (p = 0.02) of CDR-VMAT, VDR-VMAT and MCO-VMAT were 7.01 ± 0.43 min, 4.75 ± 0.07 min, 4.01 ± 0.28 min, and 95.75% ± 2.57%, 97.65% ± 1.45%, 97.36% ± 2.45%, respectively.ConclusionCDR-VMAT offers an additional option of rotational arc radiotherapy for linacs incapable of dose rate variation with a lower initial cost. Its plan quality was acceptable but should be thoroughly checked compared with VDR-VMAT and MCO-VMAT in the treatment of NPC.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Feasibility of constant dose rate VMAT in the treatment of nasopharyngeal cancer patients

Shang²,

Xie

et al. 2014

Radiat Oncol

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“…Optimization pmeters and process have been reported in our previous study [17]. Briefly, the first arc rotates clockwise with a start angle of 181° and a stop angle of 180°, and the second arc rotates counterclockwise from 180° to 181°.…”

Section: Methodsmentioning

confidence: 99%

CBCT-based volumetric and dosimetric variation evaluation of volumetric modulated arc radiotherapy in the treatment of nasopharyngeal cancer patients

Jin

Shang³

et al. 2013

Radiat Oncol

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ObjectiveTo investigate the anatomic and dosimetric variations of volumetric modulated arc therapy (VMAT) in the treatment of nasopharyngeal cancer (NPC) patients based on weekly cone beam CT (CBCT).Materials and methodsTen NPC patients treated by VMAT with weekly CBCT for setup corrections were reviewed retrospectively. Deformed volumes of targets and organs at risk (OARs) in the CBCT were compared with those in the planning CT. Delivered doses were recalculated based on weekly CBCT and compared with the planned doses.ResultsNo significant volumetric changes on targets, brainstem, and spinal cord were observed. The average volumes of right and left parotid measured from the fifth CBCT were about 4.4 and 4.5 cm3 less than those from the first CBCT, respectively. There were no significant dose differences between average planned and delivered doses for targets, brainstem and spinal cord. For right parotid, the delivered mean dose was 10.5 cGy higher (p = 0.004) than the planned value per fraction, and the V26 and V32 increased by 7.5% (p = 0.002) and 7.4% (p = 0.01), respectively. For the left parotid, the D50 (dose to the 50% volume) was 8.8 cGy higher (p = 0.03) than the planned values per fraction, and the V26 increased by 8.8% (p = 0.002).ConclusionWeekly CBCTs were applied directly to study the continuous volume changes and resulting dosimetric variations of targets and OARs for NPC patients undergoing VMAT. Significant volumetric and dosimetric variations were observed for parotids. Replanning after 30 Gy will benefit the protection on parotids.

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Individual volume‐based 3D gamma indices for pretreatment VMAT QA

Jiang

Han

Zheng

et al. 2017

J Applied Clin Med Phys

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Although gamma analysis is still a widely accepted quantitative tool to analyze and report patient‐specific QA for intensity‐modulated radiotherapy (IMRT) and volumetric‐modulated arc therapy (VMAT), the correlation between the 2D percentage gamma passing rate (%GP), and the clinical dosimetric difference for IMRT and VMAT has been questioned. The purpose of this study was to investigate the feasibility of individual volume‐based 3D gamma indices for pretreatment VMAT QA. Percentage dosimetric errors (%DE) of dose‐volume histogram metrics (includes target volumes and organ at risks) between the treatment planning system and QA‐reconstructed dose distribution, %GPs for individual volume and global gamma indices, as well their correlations and sensitivities were investigated for one‐ and two‐arc VMAT plans. The %GPs of individual volumes had a higher percent of correlation with individual 15 %DE metrics compared with global %GPs. For two‐arc VMAT at 2%/2 mm, 3%/3 mm, and 4%/4 mm criteria, individual volume %GPs were correlated with 9, 12, and 9 out of 15 %DE metrics, while global %GPs were correlated with only 2 out of 15 %DE metrics, respectively. For one‐arc VMAT at 2%/2 mm, 3%/3 mm, and 4%/4 mm criteria, individual volume %GPs were correlated with 18, 16, and 13 out of 23 %DE metrics, and global %GPs were correlated with 19, 12, and 1 out 23 %DE metrics, respectively. The area under curves (AUC) of individual volume %GPs were higher than those of global %GPs for two‐arc VMAT plans, but with mixed results for one‐arc VMAT plans. In a conclusion, the idea of individual volume %GP was created and investigated to better serve for VMAT QA and individual volume‐based %GP had a higher percent of correlation with DVH 15 %DE metrics compared with global %GP for both one‐ and two‐arc VMAT plans.

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Comparison of whole-field simultaneous integrated boost VMAT and IMRT in the treatment of nasopharyngeal cancer

Cited by 33 publications

References 18 publications

Feasibility of constant dose rate VMAT in the treatment of nasopharyngeal cancer patients

Feasibility of constant dose rate VMAT in the treatment of nasopharyngeal cancer patients

CBCT-based volumetric and dosimetric variation evaluation of volumetric modulated arc radiotherapy in the treatment of nasopharyngeal cancer patients

Individual volume‐based 3D gamma indices for pretreatment VMAT QA

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