New Possibilities for Volumetric-modulated Arc Therapy Using the Agility™ 160-leaf Multileaf Collimator

Overview

Journal Strahlenther Onkol

Specialties Oncology
Radiology

Date 2014 Jul 26

PMID 25060175

Citations 6

Authors

Nadine Blumer

Christian Scherf

Janett Kohn

Eugen Kara

Britta Loutfi-Krauss

Detlef Imhoff

Claus Rodel

Ulla Ramm

Jorg Licher

Affiliations

Soon will be listed here.

Abstract

Purpose: This study compares the quality of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans optimized for an Elekta Agility(TM) (Elekta, Stockholm, Sweden) multileaf collimator (MLC; leaf width 5 mm) and an Elekta MLCi2 (leaf width 10 mm) for complex target volumes (anal, AC; head and neck, H&N and prostate cancer, PC).

Patients And Methods: For plan comparisons, 15 patients who had been treated with IMRT or VMAT using the MLCi2 were selected. For each patient, a retrospective treatment plan using the MLCi2 for the technique not applied was created, as were treatment plans for both techniques using the Agility(TM) MLC. Dose-volume histograms (DHVs) for planning target volumes (PTVs) and organs at risk (OARs) were compared. Further parameters relating to dose conformity, dose homogeneity and mean dose (Dmean) to the PTV, compliance with the intended OAR dose criteria and overall dose to normal tissue were analyzed. Verification measurements were performed and optimization and treatment times were compared.

Results: Compared to the MLCi2 plans, the Agility(TM) IMRT and VMAT plans show better or equivalent results in terms of PTV dose conformity and homogeneity. Compliance with the intended OAR dose criteria does not differ according to technique or MLC type. Slight differences are shown for dose distributions in OARs and normal tissue. Verification measurements show that all plans fulfill the acceptance criteria of a minimum of 95 % matched dose points for the 3 %/3 mm γ criterion. Optimization times for the VMAT plans increase compared to the IMRT plans, whereas treatment times decrease.

Conclusion: With the MLCi2, treatment of complex target volumes with VMAT was only possible with compromises in terms of target coverage. Using the Agility(TM) MLC, even complex target volumes can be treated with VMAT without compromising target coverage or resulting in higher exposure of OARs or normal tissue.

Citing Articles

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Dosimetric evaluation study of IMRT and VMAT techniques for prostate cancer based on different multileaf collimator designs.

Fathy M, Hassan B, El-Gebaly R, Mokhtar M Radiat Environ Biophys. 2022; 62(1):97-106.

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Challenges in modeling the Agility multileaf collimator in treatment planning systems and current needs for improvement.

Hernandez V, Angerud A, Bogaert E, Hussein M, Lemire M, Garcia-Miguel J Med Phys. 2022; 49(12):7404-7416.

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Effect of dental metal artifact conversion volume on dose distribution in head-and-neck volumetric-modulated arc therapy.

Kitagawa K, Ikushima H, Sasaki M, Furutani S, Kawanaka T, Kubo A J Appl Clin Med Phys. 2020; 21(12):253-262.

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Monte Carlo Modeling of the Agility MLC for IMRT and VMAT Calculations.

Ohira S, Takegawa H, Miyazaki M, Koizumi M, Teshima T In Vivo. 2020; 34(5):2371-2380.

PMID: 32871762 PMC: 7652464. DOI: 10.21873/invivo.12050.

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