A dosimetric evaluation of VMAT for the treatment of non‐small cell lung cancer

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

The purpose of this study was to demonstrate the dosimetric potential of volumetric‐modulated arc therapy (VMAT) for the treatment of patients with medically inoperable stage I/II non‐small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT). Fourteen patients treated with 3D CRT with varying tumor locations, tumor sizes, and dose fractionation schemes were chosen for study. The prescription doses were 48 Gy in 4 fractions, 52.5 Gy in 5 fractions, 57.5 Gy in 5 fractions, and 60 Gy in 3 fractions for 2, 5, 1, and 6 patients, respectively. VMAT treatment plans with a mix of two to three full and partial noncoplanar arcs with 5°–25° separations were retrospectively generated using Eclipse version 10.0. The 3D CRT and VMAT plans were then evaluated by comparing their target dose, critical structure dose, high dose spillage, and low dose spillage as defined according to RTOG 0813 and RTOG 0236 protocols. In the most dosimetrically improved case, VMAT was able to decrease the dose from 17.35 Gy to 1.54 Gy to the heart. The $D_{2 cm}$ decreased in 11 of 14 cases when using VMAT. The three that worsened were still within the acceptance criteria. Of the 14 3D CRT plans, seven had a $D_{2 cm}$ minor deviation, while only one of the 14 VMAT plans had a $D_{2 cm}$ minor deviation. The $R_{50 %}$ improved in 13 of the 14 VMAT cases. The one case that worsened was still within the acceptance criteria of the RTOG protocol. Of the 14 3D CRT plans, seven had an $R_{50 %}$ deviation. Only one of the 14 VMAT plans had an $R_{50 %}$ deviation, but it was still improved compared to the 3D CRT plan. In this cohort of patients, no evident dosimetric compromises resulted from planning SBRT treatments with VMAT relative to the 3D CRT treatment plans actually used in their treatment.

PACS numbers: 87.50.‐a, 87.53.‐j, 87.55.‐x, 87.55.D‐, 87.55.dk, 87.55.de

Related collections

Most cited references 15

Record: found
Abstract: found
Article: not found

Radiation dose-volume effects in the lung.

Lawrence Marks, Soren M. Bentzen, Joseph O. Deasy … (2010)

The three-dimensional dose, volume, and outcome data for lung are reviewed in detail. The rate of symptomatic pneumonitis is related to many dosimetric parameters, and there are no evident threshold "tolerance dose-volume" levels. There are strong volume and fractionation effects. Copyright 2010 Elsevier Inc. All rights reserved.

0 comments Cited 276 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Volumetric modulated arc therapy: IMRT in a single gantry arc.

Karl-Otto Bischoff (2007)

In this work a novel plan optimization platform is presented where treatment is delivered efficiently and accurately in a single dynamically modulated arc. Improvements in patient care achieved through image-guided positioning and plan adaptation have resulted in an increase in overall treatment times. Intensity-modulated radiation therapy (IMRT) has also increased treatment time by requiring a larger number of beam directions, increased monitor units (MU), and, in the case of tomotherapy, a slice-by-slice delivery. In order to maintain a similar level of patient throughput it will be necessary to increase the efficiency of treatment delivery. The solution proposed here is a novel aperture-based algorithm for treatment plan optimization where dose is delivered during a single gantry arc of up to 360 deg. The technique is similar to tomotherapy in that a full 360 deg of beam directions are available for optimization but is fundamentally different in that the entire dose volume is delivered in a single source rotation. The new technique is referred to as volumetric modulated arc therapy (VMAT). Multileaf collimator (MLC) leaf motion and number of MU per degree of gantry rotation is restricted during the optimization so that gantry rotation speed, leaf translation speed, and dose rate maxima do not excessively limit the delivery efficiency. During planning, investigators model continuous gantry motion by a coarse sampling of static gantry positions and fluence maps or MLC aperture shapes. The technique presented here is unique in that gantry and MLC position sampling is progressively increased throughout the optimization. Using the full gantry range will theoretically provide increased flexibility in generating highly conformal treatment plans. In practice, the additional flexibility is somewhat negated by the additional constraints placed on the amount of MLC leaf motion between gantry samples. A series of studies are performed that characterize the relationship between gantry and MLC sampling, dose modeling accuracy, and optimization time. Results show that gantry angle and MLC sample spacing as low as 1 deg and 0.5 cm, respectively, is desirable for accurate dose modeling. It is also shown that reducing the sample spacing dramatically reduces the ability of the optimization to arrive at a solution. The competing benefits of having small and large sample spacing are mutually realized using the progressive sampling technique described here. Preliminary results show that plans generated with VMAT optimization exhibit dose distributions equivalent or superior to static gantry IMRT. Timing studies have shown that the VMAT technique is well suited for on-line verification and adaptation with delivery times that are reduced to approximately 1.5-3 min for a 200 cGy fraction.

0 comments Cited 273 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Outcomes after stereotactic lung radiotherapy or wedge resection for stage I non-small-cell lung cancer.

L L Kestin, G Chmielewski, V S Mangona … (2010)

PURPOSE To compare outcomes between lung stereotactic radiotherapy (SBRT) and wedge resection for stage I non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS One hundred twenty-four patients with T1-2N0 NSCLC underwent wedge resection (n = 69) or image-guided lung SBRT (n = 58) from February 2003 through August 2008. All were ineligible for anatomic lobectomy; of those receiving SBRT, 95% were medically inoperable, with 5% refusing surgery. Mean forced expiratory volume in 1 second and diffusing capacity of lung for carbon monoxide were 1.39 L and 12.0 mL/min/mmHg for wedge versus 1.31 L and 10.14 mL/min/mmHg for SBRT (P = not significant). Mean Charlson comorbidity index and median age were 3 and 74 years for wedge versus 4 and 78 years for SBRT (P .16). SBRT reduced the risk of local recurrence (LR), 4% versus 20% for wedge (P = .07). Overall survival (OS) was higher with wedge but cause-specific survival (CSS) was identical. Results excluding synchronous primaries, nonbiopsied tumors, or pathologic T4 disease (wedge satellite lesion) showed reduced LR (5% v 24%, P = .05), RR (0% v 18%, P = .07), and LRR (5% v 29%, P = .03) with SBRT. There were no differences in DM, FFF, or CSS, but OS was higher with wedge. CONCLUSION Both lung SBRT and wedge resection are reasonable treatment options for stage I NSCLC patients ineligible for anatomic lobectomy. SBRT reduced LR, RR, and LRR. In this nonrandomized population of patients selected for surgery versus SBRT (medically inoperable) at physician discretion, OS was higher in surgical patients. SBRT and surgery, however, had identical CSS.

0 comments Cited 84 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Caitlin E. Merrow: Caitlin.Doring@roswellpark.org

Journal

Journal ID (nlm-ta): J Appl Clin Med Phys

Journal ID (iso-abbrev): J Appl Clin Med Phys

Journal ID (doi): 10.1002/(ISSN)1526-9914

Journal ID (publisher-id): ACM2

Title: Journal of Applied Clinical Medical Physics

Publisher: John Wiley and Sons Inc. (Hoboken )

ISSN (Electronic): 1526-9914

Publication date (Electronic): 01 September 2012

Publication date Collection: January 2013

Volume: 14

Issue: 1 ( doiID: 10.1002/acm2.2013.14.issue-1 )

Pages: 228-238

Affiliations

[ ¹ ] Department of Physiology and Biophysics State University of New York at Buffalo, SUNY at Buffalo, and Department of Radiation Medicine, Roswell Park Cancer Institute Buffalo NY USA

Author notes

[*] [* ]Corresponding author: Caitlin E. Merrow, Department of Radiation Medicine, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA; phone: 518‐727‐5243; email: Caitlin.Doring@ 123456roswellpark.org

Article

Publisher ID: ACM20228

DOI: 10.1120/jacmp.v14i1.4110

PMC ID: 5714051

PubMed ID: 23318374

SO-VID: b3aa45ff-59c1-457b-8744-11c21fae3ec1

License:

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

History

Date received : 06 July 2012

Date accepted : 29 August 2012

Page count

Figures: 4, Tables: 6, References: 20, Pages: 11, Words: 5417

Custom metadata

source-schema-version-number 2.0

component-id acm20228

cover-date January 2013

details-of-publishers-convertor Converter:WILEY_ML3GV2_TO_NLMPMC version:5.2.5 mode:remove_FC converted:16.11.2017

Keywords: volumetric‐modulated arc therapy (vmat),stereotactic body radiation therapy (sbrt),three‐dimensional conformal radiation therapy (3d crt),non‐small cell lung cancer (nsclc)

Data availability:

Keywords: volumetric‐modulated arc therapy (vmat), stereotactic body radiation therapy (sbrt), three‐dimensional conformal radiation therapy (3d crt), non‐small cell lung cancer (nsclc)

A dosimetric evaluation of VMAT for the treatment of non‐small cell lung cancer

Read this article at

Abstract

Related collections

International Journal of Applied Technology in Medical Sciences

Most cited references 15

Radiation dose-volume effects in the lung.

Volumetric modulated arc therapy: IMRT in a single gantry arc.

Outcomes after stereotactic lung radiotherapy or wedge resection for stage I non-small-cell lung cancer.

Author and article information

Contributors

Journal

Affiliations

Author notes

Article

History

Page count

Categories

Custom metadata

Comments

Comment on this article

Similar content 232

Cited by 11

Most referenced authors 427