open access

Vol 23, No 2 (2018)
Original research articles
Published online: 2018-03-01
Submitted: 2017-05-15
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Interfractional diaphragm changes during breath-holding in stereotactic body radiotherapy for liver cancer

Daisuke Kawahara, Shuichi Ozawa, Takeo Nakashima, Shintaro Tsuda, Yusuke Ochi, Takuro Okumura, Hirokazu Masuda, Kazunari Hioki, Tathsuhiko Suzuki, Yoshimi Ohno, Tomoki Kimura, Yuji Murakami, Yasushi Nagata
DOI: 10.1016/j.rpor.2018.01.007
·
Rep Pract Oncol Radiother 2018;23(2):84-90.

open access

Vol 23, No 2 (2018)
Original research articles
Published online: 2018-03-01
Submitted: 2017-05-15

Abstract

Aim and background

IGRT based on bone matching may produce a large target positioning error in terms of the reproducibility of expiration breath-holding on SBRT for liver cancer. We evaluated the intrafractional and interfractional errors using the diaphragm position at the end of expiration by utilising Abches and analysed the factor of the interfractional error.

Materials and methods

Intrafractional and interfractional errors were measured using a couple of frontal kV images, planning computed tomography (pCT) and daily cone-beam computed tomography (CBCT). Moreover, max–min diaphragm position within daily CBCT image sets with respect to pCT and the maximum value of diaphragm position difference between CBCT and pCT were calculated.

Results

The mean[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]SD (standard deviation) of the intra-fraction diaphragm position variation in the frontal kV images was 1.0[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]0.7[[ce:hsp sp="0.25"/]]mm in the C-C direction. The inter-fractional diaphragm changes were 0.4[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]4.6[[ce:hsp sp="0.25"/]]mm in the C-C direction, 1.4[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]2.2[[ce:hsp sp="0.25"/]]mm in the A-P direction, and −0.6[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]1.8[[ce:hsp sp="0.25"/]]mm in the L-R direction. There were no significant differences between the maximum value of the max–min diaphragm position within daily CBCT image sets with respect to pCT and the maximum value of diaphragm position difference between CBCT and pCT.

Conclusions

Residual intrafractional variability of diaphragm position is minimal, but large interfractional diaphragm changes were observed. There was a small effect in the patient condition difference between pCT and CBCT. The impact of the difference in daily breath-holds on the interfractional diaphragm position was large or the difference in daily breath-holding heavily influenced the interfractional diaphragm change.

Abstract

Aim and background

IGRT based on bone matching may produce a large target positioning error in terms of the reproducibility of expiration breath-holding on SBRT for liver cancer. We evaluated the intrafractional and interfractional errors using the diaphragm position at the end of expiration by utilising Abches and analysed the factor of the interfractional error.

Materials and methods

Intrafractional and interfractional errors were measured using a couple of frontal kV images, planning computed tomography (pCT) and daily cone-beam computed tomography (CBCT). Moreover, max–min diaphragm position within daily CBCT image sets with respect to pCT and the maximum value of diaphragm position difference between CBCT and pCT were calculated.

Results

The mean[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]SD (standard deviation) of the intra-fraction diaphragm position variation in the frontal kV images was 1.0[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]0.7[[ce:hsp sp="0.25"/]]mm in the C-C direction. The inter-fractional diaphragm changes were 0.4[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]4.6[[ce:hsp sp="0.25"/]]mm in the C-C direction, 1.4[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]2.2[[ce:hsp sp="0.25"/]]mm in the A-P direction, and −0.6[[ce:hsp sp="0.25"/]]±[[ce:hsp sp="0.25"/]]1.8[[ce:hsp sp="0.25"/]]mm in the L-R direction. There were no significant differences between the maximum value of the max–min diaphragm position within daily CBCT image sets with respect to pCT and the maximum value of diaphragm position difference between CBCT and pCT.

Conclusions

Residual intrafractional variability of diaphragm position is minimal, but large interfractional diaphragm changes were observed. There was a small effect in the patient condition difference between pCT and CBCT. The impact of the difference in daily breath-holds on the interfractional diaphragm position was large or the difference in daily breath-holding heavily influenced the interfractional diaphragm change.

Get Citation

Keywords

Interfractional diaphragm changes; SBRT; IGRT; Breath-hold

About this article
Title

Interfractional diaphragm changes during breath-holding in stereotactic body radiotherapy for liver cancer

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 23, No 2 (2018)

Pages

84-90

Published online

2018-03-01

DOI

10.1016/j.rpor.2018.01.007

Bibliographic record

Rep Pract Oncol Radiother 2018;23(2):84-90.

Keywords

Interfractional diaphragm changes
SBRT
IGRT
Breath-hold

Authors

Daisuke Kawahara
Shuichi Ozawa
Takeo Nakashima
Shintaro Tsuda
Yusuke Ochi
Takuro Okumura
Hirokazu Masuda
Kazunari Hioki
Tathsuhiko Suzuki
Yoshimi Ohno
Tomoki Kimura
Yuji Murakami
Yasushi Nagata

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