Prospective matched study on comparison of volumetric-modulated arc therapy and intensity-modulated radiotherapy for nasopharyngeal carcinoma: dosimetry, delivery efficiency and outcomes

The aim of this study was to evaluate the dosimetric variations of static intensity-modulated radiotherapy (sIMRT), dynamic intensity-modulated radiotherapy (dIMRT) and volumetric modulated arc therapy (VMAT) for thoracic esophageal cancer (EC). Ten patients with pathologically-confirmed EC were randomly selected. The Monaco 5.11 treatment planning system was used to design six radiotherapy plans, namely sIMRT with 5 fixedfields (S5) and 7 fixed-fields (S7), dIMRT with 5 fixed-fields (D5) and 7 fixed-fields (D7) and VMAT plan with single arc (VMAT1) and double arc (VMAT2), respectively. The dosimetric parameters were compared among six different plans. The dose to target volumes met the clinical prescription requirements in all six plans. The D5 plan had the lowest dose exposed to the whole lungs, except for V5, which was only 1.7% higher than that in the D7 plan. The low dose to lungs (V5 and V10) in VMAT plans (VMAT1 and VMAT2) were higher than in IMRT plans, but the statistical differences were significant (P < 0.05) only in comparison with dynamic IMRT plans (D5 and D7). The V20 and V30 of lungs in VMAT2 plan were also higher than that in other plans, but the statistical differences were significant (P < 0.05) only in comparison with D5 plan. The doses delivered to the spinal cord and heart showed no statistical significance (P > 0.05). The monitor units (MUs) and treatment time (TT) significantly increased with the increasing number of fields in the same kind of fixed-fields IMRT plans (S5 vs. S7; D5 vs. D7). The MUs in VMAT plans, especially in VMAT2, increased significantly (P < 0.05) when compared with sIMRT and 5-fields dIMRT plans, respectively. VMAT1 plan had the shortest TT and the highest delivery efficiency. For thoracic esophageal cancer, the D5 plan can shorten the TT and improve the delivery efficiency while meeting the dosimetric requirements and sparing the lungs. VMAT can significantly reduce the TT, but at the expense of increasing the dose to lower-dose regions of lungs, which means VMAT plan may not shows obvious dose advantage for thoracic esophageal cancer.

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877P Comparison of dosimetric benefits in nasopharyngeal carcinoma patients among intensity-modulated radiotherapy, volumetric-modulated arc therapy and tomotherapy

Annals of Oncology ◽

10.1016/j.annonc.2021.08.1287 ◽

2021 ◽

Vol 32 ◽

pp. S793

Author(s):

W. Xiong ◽

X. Guoqiang ◽

Q. Wang ◽

T. Xu ◽

R. Cao ◽

...

Keyword(s):

Nasopharyngeal Carcinoma ◽

Volumetric Modulated Arc Therapy ◽

Intensity Modulated Radiotherapy ◽

Intensity Modulated ◽

Arc Therapy

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Volumetric Modulated Arc Radiotherapy for Early Stage Non-Small-Cell Lung Carcinoma: Is It Better Than the Conventional Static Beam Intensity Modulated Radiotherapy?

Journal of Radiotherapy ◽

10.1155/2014/164165 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5

Author(s):

Vincent Wing Cheung Wu ◽

Man In Pun ◽

Cho Pan Lam ◽

To Wing Mok ◽

Wah Wai Mok

Keyword(s):

Early Stage ◽

Small Cell Lung Carcinoma ◽

Volumetric Modulated Arc Therapy ◽

Intensity Modulated Radiotherapy ◽

Small Cell ◽

Small Cell Lung ◽

Cell Lung Carcinoma ◽

Intensity Modulated ◽

Significant Difference ◽

Arc Therapy

This study compared the performance of volumetric modulated arc therapy (VMAT) techniques: single arc volumetric modulated arc therapy (SA-VMAT) and double arc volumetric modulated arc therapy (DA-VMAT) with the static beam conventional intensity modulated radiotherapy (C-IMRT) for non-small-cell lung carcinoma (NSCLC). Twelve stage I and II NSCLC patients were recruited and their planning CT with contoured planning target volume (PTV) and organs at risk (OARs) was used for planning. Using the same dose constraints and planning objectives, the C-IMRT, SA-VMAT, and DA-VMAT plans were optimized. C-IMRT consisted of 7 static beams, while SA-VMAT and DA-VMAT plans consisted of one and two full gantry rotations, respectively. No significant difference was found among the three techniques in target homogeneity and conformity. Mean lung dose in C-IMRT plan was significantly lower than that in DA-VMAT plan P=0.04. The ability of OAR sparing was similar among the three techniques, with no significant difference in V20, V10, or V5 of normal lungs, spinal cord, and heart. Less MUs were required in SA-VMAT and DA-VMAT. Besides, SA-VMAT required the shortest beam on time among the three techniques. In treatment of early stage NSCLC, no significant dosimetric superiority was shown by the VMAT techniques over C-IMRT and DA-VMAT over SA-VMAT.

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