Crawl positioning improves set-up precision and patient comfort in prone whole breast irradiation

Pieter Deseyne,Liv Veldeman,Herman Depypere,Leen Paelinck,Hans Van Hulle,Giselle Post,Vincent Vakaet,Bruno Speleers,Bert Boute,Michael Stouthandel,Annick Van Greveling,Wilfried De Neve,Chris Monten,Max Schoepen,Jan Detand

doi:10.1038/s41598-020-72702-3

Pieter Deseyne, Liv Veldeman + Show 13 more

Open Access

https://doi.org/10.1038/s41598-020-72702-3

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Journal: Scientific Reports	Publication Date: Oct 2, 2020
Citations: 11	License type: open-access

Affiliation: Ghent University, Ghent University Hospital

Abstract

Prone positioning for whole-breast irradiation (WBI) reduces dose to organs at risk, but reduces set-up speed, precision, and comfort. We aimed to improve these problems by placing patients in prone crawl position on a newly developed crawl couch (CrC). A group of 10 right-sided breast cancer patients requiring WBI were randomized in this cross-over trial, comparing the CrC to a standard prone breastboard (BB). Laterolateral (LL), craniocaudal (CC) and anterioposterior (AP) set-up errors were evaluated with cone beam CT. Comfort, preference and set-up time (SUT) were assessed. Forty left and right-sided breast cancer patients served as a validation group. For BB versus CrC, AP, LL and CC mean patient shifts were − 0.8 ± 2.8, 0.2 ± 11.7 and − 0.6 ± 4.4 versus − 0.2 ± 3.3, − 0.8 ± 2.5 and − 1.9 ± 5.7 mm. LL shift spread was reduced significantly. Nine out of 10 patients preferred the CrC. SUT did not differ significantly. The validation group had mean patient shifts of 1.7 ± 2.9 (AP), 0.2 ± 3.6 (LL) and − 0.2 ± 3.3 (CC) mm. Mean SUT in the validation group was 1 min longer (P < 0.05) than the comparative group. Median SUT was 3 min in all groups. The CrC improved precision and comfort compared to BB. Set-up errors compare favourably to other prone-WBI trials and rival supine positioning.

Highlights

Prone positioning for whole-breast irradiation (WBI) reduces dose to organs at risk, but reduces set-up speed, precision, and comfort
Σ, an estimator of the standard deviation (SD) of random error, is defined by the root mean square (RMS) of SD from the mean individual patient shift. We report these parameters and an estimated required planning target volume (PTV) margin using his formula, 2.5 +0.7σ to compare our results to historical results
There was no significant difference between mean shifts on the 2 support devices, but the SD was significantly smaller for the LL axis for the crawl couch compared to the standard breastboard (P < 0.001)

Summary

Introduction

Prone positioning for whole-breast irradiation (WBI) reduces dose to organs at risk, but reduces set-up speed, precision, and comfort. A group of 10 right-sided breast cancer patients requiring WBI were randomized in this cross-over trial, comparing the CrC to a standard prone breastboard (BB). In case of regional nodal irradiation (RNI), prone breastboards often obstruct optimal beam paths Their placement on top of the treatment couch hinders sagittal positioning of the laser on the target. We developed a support couch that addresses the problems of inaccuracy, discomfort and restricted beam access in classic prone breastboards. We named it the prone crawl breast couch (further called crawl couch), because patients take a position resembling a phase of Scientific Reports | (2020) 10:16376. There are no data available on set-up precision and comfort of the crawl couch

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