open access

Vol 25, No 5 (2020)
Original research articles
Published online: 2020-09-01
Submitted: 2019-12-11
Get Citation

Dosimetric impact of baseline drift in volumetric modulated arc therapy with breath holding

Shunsuke Ono, Yoshihiro Ueda, Shoki Inui, Masaru Isono, Shingo Ohira, Seiya Murata, Masayoshi Miyazaki, Teruki Teshima
DOI: 10.1016/j.rpor.2020.06.004
·
Rep Pract Oncol Radiother 2020;25(5):703-708.

open access

Vol 25, No 5 (2020)
Original research articles
Published online: 2020-09-01
Submitted: 2019-12-11

Abstract

Background

We investigated the change of dose distributions in volumetric modulated arc therapy (VMAT) under baseline drift (BD) during breath holding.

Materials and methods

Ten VMAT plans recalculated to a static field at a gantry angle of 0° were prepared for measurement with a 2D array device and five original VMAT plans were prepared for measurement with gafchromic films. These measurement approaches were driven by a waveform reproducing breath holding with BD. We considered breath holding times of 15 and 10 s, and BD at four speeds; specifically, BD0 (0 mm/s), BD0.2 (0.2 mm/s), BD0.3 (0.3 mm/s), and BD0.4 (0.4 mm/s). The BD was periodically reproduced from the isocenter along the craniocaudal direction and the shift during breath holding (ShiftBH) ranged 0–6 mm.

The dose distribution of BD0.2, BD0.3 and BD0.4 were compared to that of BD0 using gamma analysis with the criterion of 2%/2 mm.

Results

The mean pass rates of each ShiftBH were 99.8% and 98.9% at 0 mm, 96.8% and 99.4% at 2 mm, 94.9% and 98.6% at 3 mm, 91.5% and 98.4% at 4 mm, 70.8% and 94.1% at 4.5 mm, and 55.0% and 83.6% at 6 mm for the array and film measurements, respectively.

Conclusion

We found significant differences in ShiftBH above 4 mm (ρ < 0.05). Hence, it is recommended that breath holding time should be shortened for patients to preserve the reproducibility of dose distributions.

Abstract

Background

We investigated the change of dose distributions in volumetric modulated arc therapy (VMAT) under baseline drift (BD) during breath holding.

Materials and methods

Ten VMAT plans recalculated to a static field at a gantry angle of 0° were prepared for measurement with a 2D array device and five original VMAT plans were prepared for measurement with gafchromic films. These measurement approaches were driven by a waveform reproducing breath holding with BD. We considered breath holding times of 15 and 10 s, and BD at four speeds; specifically, BD0 (0 mm/s), BD0.2 (0.2 mm/s), BD0.3 (0.3 mm/s), and BD0.4 (0.4 mm/s). The BD was periodically reproduced from the isocenter along the craniocaudal direction and the shift during breath holding (ShiftBH) ranged 0–6 mm.

The dose distribution of BD0.2, BD0.3 and BD0.4 were compared to that of BD0 using gamma analysis with the criterion of 2%/2 mm.

Results

The mean pass rates of each ShiftBH were 99.8% and 98.9% at 0 mm, 96.8% and 99.4% at 2 mm, 94.9% and 98.6% at 3 mm, 91.5% and 98.4% at 4 mm, 70.8% and 94.1% at 4.5 mm, and 55.0% and 83.6% at 6 mm for the array and film measurements, respectively.

Conclusion

We found significant differences in ShiftBH above 4 mm (ρ < 0.05). Hence, it is recommended that breath holding time should be shortened for patients to preserve the reproducibility of dose distributions.

Get Citation

Keywords

Breath holding; Volumetric modulated arc therapy; Baseline drift; Dosimetry; Pancreatic cancer

About this article
Title

Dosimetric impact of baseline drift in volumetric modulated arc therapy with breath holding

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 25, No 5 (2020)

Pages

703-708

Published online

2020-09-01

DOI

10.1016/j.rpor.2020.06.004

Bibliographic record

Rep Pract Oncol Radiother 2020;25(5):703-708.

Keywords

Breath holding
Volumetric modulated arc therapy
Baseline drift
Dosimetry
Pancreatic cancer

Authors

Shunsuke Ono
Yoshihiro Ueda
Shoki Inui
Masaru Isono
Shingo Ohira
Seiya Murata
Masayoshi Miyazaki
Teruki Teshima

Important: This website uses cookies. More >>

The cookies allow us to identify your computer and find out details about your last visit. They remembering whether you've visited the site before, so that you remain logged in - or to help us work out how many new website visitors we get each month. Most internet browsers accept cookies automatically, but you can change the settings of your browser to erase cookies or prevent automatic acceptance if you prefer.

By "Via Medica sp. z o.o." sp.k., ul. Świętokrzyska 73, 80–180 Gdańsk, Poland
tel.:+48 58 320 94 94, fax:+48 58 320 94 60, e-mail: journals@viamedica.pl