open access

Vol 21, No 5 (2016)
Short communication
Published online: 2016-09-01
Submitted: 2015-12-30
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Comparison of set-up errors by breast size on wing board by portal imaging

Waseem Raza, Sushma Agarwal, Koilpillai Joseph Maria Das, Sellepolyam Kaliyaperumal Senthil Kumar, Punita Lal
DOI: 10.1016/j.rpor.2016.04.001
·
Rep Pract Oncol Radiother 2016;21(5):447-452.

open access

Vol 21, No 5 (2016)
Short communication
Published online: 2016-09-01
Submitted: 2015-12-30

Abstract

Aim

To quantify and compare setup errors between small and large breast patients undergoing intact breast radiotherapy.

Methods

20 patients were inducted. 10 small/moderate size breast in arm I and 10 large breast in arm II. Two orthogonal and one lateral tangent portal images (PIs) were obtained and analyzed for systematic (Σ) and random (σ) errors. Effect of no action level (NAL) was also evaluated retrospectively.

Results

142 PIs were analyzed. Σ(mm) was 3.2 versus 6.7 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.41) in the mediolateral (ML) direction, 2.1 versus 2.9 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.06) in the craniocaudal (CC) and 2.2 versus 3.6 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.08) in the anteroposterior (AP) direction in small and large breast, respectively. σ(mm) was 3.0, 3.3 and 3.3 for small breast and 4.1, 3.7 and 3.2 for large breast in the ML, CC and AP direction (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.07, 0.86, 0.37), respectively. 3 D Σ(mm) was 2.7 versus 4.2 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.01) and σ(mm) was 2.5 versus 3.2 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.14) in arm I and II, respectively. The standard deviation (SD) of variations (mm) in breast contour depicted by central lung distance (CLD) was 5.9 versus 7.4 (p[[ce:hsp sp="0.25"/]]<[[ce:hsp sp="0.25"/]]0.001), central flash distance (CFD) 6.6 versus 10.5 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.002), inferior central margin (ICM) 4 versus 4.9 (p[[ce:hsp sp="0.25"/]]<[[ce:hsp sp="0.25"/]]0.001) in arm I and II, respectively. NAL showed a significant reduction of systematic error in large breast in the mediolateral direction only.

Conclusion

Wing board can be used in a busy radiotherapy department for setting up breast patients with a margin of 1.1[[ce:hsp sp="0.25"/]]cm, 0.76[[ce:hsp sp="0.25"/]]cm and 0.71[[ce:hsp sp="0.25"/]]cm for small breasts and 1.96[[ce:hsp sp="0.25"/]]cm, 1.12[[ce:hsp sp="0.25"/]]cm and 0.98[[ce:hsp sp="0.25"/]]cm for large breast in the ML, AP and CC directions, respectively. The large PTV margin in the mediolateral direction in large breast can be reduced using NAL. Further research is needed to optimize positioning of large breasted women.

Abstract

Aim

To quantify and compare setup errors between small and large breast patients undergoing intact breast radiotherapy.

Methods

20 patients were inducted. 10 small/moderate size breast in arm I and 10 large breast in arm II. Two orthogonal and one lateral tangent portal images (PIs) were obtained and analyzed for systematic (Σ) and random (σ) errors. Effect of no action level (NAL) was also evaluated retrospectively.

Results

142 PIs were analyzed. Σ(mm) was 3.2 versus 6.7 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.41) in the mediolateral (ML) direction, 2.1 versus 2.9 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.06) in the craniocaudal (CC) and 2.2 versus 3.6 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.08) in the anteroposterior (AP) direction in small and large breast, respectively. σ(mm) was 3.0, 3.3 and 3.3 for small breast and 4.1, 3.7 and 3.2 for large breast in the ML, CC and AP direction (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.07, 0.86, 0.37), respectively. 3 D Σ(mm) was 2.7 versus 4.2 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.01) and σ(mm) was 2.5 versus 3.2 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.14) in arm I and II, respectively. The standard deviation (SD) of variations (mm) in breast contour depicted by central lung distance (CLD) was 5.9 versus 7.4 (p[[ce:hsp sp="0.25"/]]<[[ce:hsp sp="0.25"/]]0.001), central flash distance (CFD) 6.6 versus 10.5 (p[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.002), inferior central margin (ICM) 4 versus 4.9 (p[[ce:hsp sp="0.25"/]]<[[ce:hsp sp="0.25"/]]0.001) in arm I and II, respectively. NAL showed a significant reduction of systematic error in large breast in the mediolateral direction only.

Conclusion

Wing board can be used in a busy radiotherapy department for setting up breast patients with a margin of 1.1[[ce:hsp sp="0.25"/]]cm, 0.76[[ce:hsp sp="0.25"/]]cm and 0.71[[ce:hsp sp="0.25"/]]cm for small breasts and 1.96[[ce:hsp sp="0.25"/]]cm, 1.12[[ce:hsp sp="0.25"/]]cm and 0.98[[ce:hsp sp="0.25"/]]cm for large breast in the ML, AP and CC directions, respectively. The large PTV margin in the mediolateral direction in large breast can be reduced using NAL. Further research is needed to optimize positioning of large breasted women.

Get Citation

Keywords

Setup errors; Small and large breast; Wing board; NAL; Portal image

About this article
Title

Comparison of set-up errors by breast size on wing board by portal imaging

Journal

Reports of Practical Oncology and Radiotherapy

Issue

Vol 21, No 5 (2016)

Pages

447-452

Published online

2016-09-01

DOI

10.1016/j.rpor.2016.04.001

Bibliographic record

Rep Pract Oncol Radiother 2016;21(5):447-452.

Keywords

Setup errors
Small and large breast
Wing board
NAL
Portal image

Authors

Waseem Raza
Sushma Agarwal
Koilpillai Joseph Maria Das
Sellepolyam Kaliyaperumal Senthil Kumar
Punita Lal

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