Publication 1/8

Potential benefits of crawl position for prone radiation therapy in breast cancer.

Boute B, De Neve W, Speleers B, Van Greveling A, Monten C, Van Hoof T, Van de Velde J, Paelinck L, De Gersem W, Vercauteren T, Detand J, Veldeman L.

J Appl Clin Med Phys. 2017 Jul;18(4):200-205. doi: 10.1002/acm2.12118. Epub 2017 Jun 26.



Purpose: To investigate crawl position with the arm at the treated side alongside the body and at the opposite side above the head for prone treatment in patients requiring breast and regional lymph node irradiation.

Methods: Patient support devices for crawl position were built for CT simulation and treatment. An asymmetric fork design resulted from an iterative process of prototype construction and testing. The fork's large horn supports the hemi-thorax, shoulder, and elevated arm at the nontreated side and the head. The short, narrow horn supports the arm at the treated side. Between both horns, the treated breast and its regional lymph nodes are exposed. Endpoints were pain, comfort, set-up precision, beam access to the breast and lymph nodes, and plan dose metrics. Pain and comfort were tested by volunteers (n = 9); set-up precision, beam access, and plan dose metrics were tested by means of a patient study (n = 10). The AIO™ (Orfit, Wijnegem, Belgium) prone breastboard (AIO™) was used as a reference regarding comfort and set-up precision.

Results: Pain at the sternum, the ipsilateral shoulder, upper arm, and neck was lower in crawl position than with bilateral arm elevation on AIO™. Comfort and set-up precision were better on the crawl prototype than on AIO™. In crawl position, beam directions in the coronal and near-sagittal planes have access to the breast or regional lymph nodes without traversing device components. Plan comparison between supine and crawl positions showed better dose homogeneity for the breast and lymph node targets and dose reductions to all organs at risk for crawl position.

Conclusions: Radiation therapy for breast and regional lymph nodes in crawl position is feasible. Good comfort and set-up precision were demonstrated. Planning results support the hypothesis that breast and regional lymph nodes can be treated in crawl position with less dose to organs at risk and equal or better dose distribution in the target volumes than in supine position. The crawl technique is a candidate methodology for further investigation for patients requiring breast and regional lymph node irradiation.

Publication 2/8

The relation between patient discomfort and uncompensated forces of a patient support device for breast and regional lymph node radiotherapy.

Boute B, Veldeman L, Speleers B, Van Greveling A, Van Hoof T, Van de Velde J, Vercauteren T, De Neve W, Detand J.

Appl Ergon. 2018 Oct;72:48-57. doi: 10.1016/j.apergo.2018.05.002. Epub 2018 May 12


Although many authors stated that a user-centred design approach in medical device development has added values, the most common research approach within healthcare is evidence-based medicine, which tend to focus on functional data rather than patient wellbeing and comfort. End user comfort is well addressed in literature for commercial products such as seats and hand tools but no data was found for medical devices.

A commercial patient support device for breast radiotherapy was analysed and a relation was found between discomfort and uncompensated internal body forces. Derived from CT-images, simplified patient free-body diagrams were analysed and pain and comfort evaluated. Subsequently, a new patient position was established and prototypes were developed. Patient comfort- and prototype optimization was done through iterative prototyping. With this approach, we were able to compensate all internal body forces and establish a force neutral patient free-body diagram. This resulted in comfortable patient positioning and favourable medical results.

Publication 3/8

Whole breast and regional nodal irradiation in prone versus supine position in left sided breast cancer.

Deseyne P, Speleers B, De Neve W, Boute B, Paelinck L, Van Hoof T, Van de Velde J, Van Greveling A, Monten C, Post G, Depypere H, Veldeman L.

Radiat Oncol. 2017 May 26;12(1):89. doi: 10.1186/s13014-017-0828-6


Background: Prone whole breast irradiation (WBI) leads to reduced heart and lung doses in breast cancer patients receiving adjuvant radiotherapy. In this feasibility trial, we investigated the prone position for whole breast + lymph node irradiation (WB + LNI).

Methods: A new support device was developed for optimal target coverage, on which patients are positioned in a position resembling a phase from the crawl swimming technique (prone crawl position). Five left sided breast cancer patients were included and simulated in supine and prone position. For each patient, a treatment plan was made in prone and supine position for WB + LNI to the whole axilla and the unoperated part of the axilla. Patients served as their own controls for comparing dosimetry of target volumes and organs at risk (OAR) in prone versus in supine position.

Results: Target volume coverage differed only slightly between prone and supine position. Doses were significantly reduced (P < 0.05) in prone position for ipsilateral lung (Dmean, D2, V5, V10, V20, V30), contralateral lung (Dmean, D2), contralateral breast (Dmean, D2 and for total axillary WB + LNI also V5), thyroid (Dmean, D2, V5, V10, V20, V30), oesophagus (Dmean and for partial axillary WB + LNI also D2 and V5), skin (D2 and for partial axillary WB + LNI V105 and V107). There were no significant differences for heart and humeral head doses.

Conclusions: Prone crawl position in WB + LNI allows for good breast and nodal target coverage with better sparing of ipsilateral lung, thyroid, contralateral breast, contralateral lung and oesophagus when compared to supine position. There is no difference in heart and humeral head doses.


Publication 4/8

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

Deseyne P, Speleers B, De Neve W, Boute B, Paelinck L, Vakaet V, Van Hulle H, Schoepen M, Stouthandel M, Van Greveling A, Post G, Detand J, Monten C, Depypere H, Veldeman L.

Sci Rep. 2020 Oct 2;10(1):16376. doi: 10.1038/s41598-020-72702-3.


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.

Publication 5/8

Comparison of supine or prone crawl photon or proton breast and regional lymph node radiation therapy including the internal mammary chain.

Speleers BA, Belosi FM, De Gersem WR, Deseyne PR, Paelinck LM, Bolsi A, Lomax AJ, Boute BG, Van Greveling AE, Monten CM, Van de Velde JJ, Vercauteren TH, Veldeman L, Weber DC, De Neve WC.

Sci Rep. 2019 Mar 18;9(1):4755. doi: 10.1038/s41598-019-41283-1.


We report on a dosimetrical study comparing supine (S) and prone-crawl (P) position for radiotherapy of whole breast (WB) and loco-regional lymph node regions, including the internal mammary chain (LN_IM). Six left sided breast cancer patients were CT-simulated in S and P positions and four patients only in P position. Treatment plans were made using non-coplanar volumetric modulated arc photon therapy (VMAT) or pencil beam scanning intensity modulated proton therapy (IMPT). Dose prescription was 15*2.67 Gy(GyRBE). The average mean heart doses for S or P VMAT were 5.6 or 4.3 Gy, respectively (p = 0.16) and 1.02 or 1.08 GyRBE, respectively for IMPT (p = 0.8; p < 0.001 for IMPT versus VMAT). The average mean lung doses for S or P VMAT were 5.91 or 2.90 Gy, respectively (p = 0.002) and 1.56 or 1.09 GyRBE, respectively for IMPT (p = 0.016). In high-risk patients, average (range) thirty-year mortality rates from radiotherapy-related cardiac injury and lung cancer were estimated at 6.8(5.4-9.4)% or 3.8(2.8-5.1)% for S or P VMAT (p < 0.001), respectively, and 1.6(1.1-2.0)% or 1.2(0.8-1.6)% for S or P IMPT (p = 0.25), respectively. Radiation-related mortality risk could outweigh the ~8% disease-specific survival benefit of WB + LN_IM radiotherapy for S VMAT but not P VMAT. IMPT carries the lowest radiation-related mortality risks.

Publication 6/8

Effects of deep inspiration breath hold on prone photon or proton irradiation of breast and regional lymph nodes.

Speleers B, Schoepen M, Belosi F, Vakaet V, De Neve W, Deseyne P, Paelinck L, Vercauteren T, Parkes MJ, Lomax T, Van Greveling A, Bolsi A, Weber DC, Veldeman L, De Gersem W.

Sci Rep. 2021 Mar 16;11(1):6085. doi: 10.1038/s41598-021-85401-4 Abstract


We report on a comparative dosimetrical study between deep inspiration breath hold (DIBH) and shallow breathing (SB) in prone crawl position for photon and proton radiotherapy of whole breast (WB) and locoregional lymph node regions, including the internal mammary chain (LN_MI). We investigate the dosimetrical effects of DIBH in prone crawl position on organs-at-risk for both photon and proton plans. For each modality, we further estimate the effects of lung and heart doses on the mortality risks of different risk profiles of patients. Thirty-one patients with invasive carcinoma of the left breast and pathologically confirmed positive lymph node status were included in this study. DIBH significantly decreased dose to heart for photon and proton radiotherapy. DIBH also decreased lung doses for photons, while increased lung doses were observed using protons because the retracting heart is displaced by low-density lung tissue. For other organs-at-risk, DIBH resulted in significant dose reductions using photons while minor differences in dose deposition between DIBH and SB were observed using protons. In patients with high risks for cardiac and lung cancer mortality, average thirty-year mortality rates from radiotherapy-related cardiac injury and lung cancer were estimated at 3.12% (photon DIBH), 4.03% (photon SB), 1.80% (proton DIBH) and 1.66% (proton SB). The radiation-related mortality risk could not outweigh the ~ 8% disease-specific survival benefit of WB + LN_MI radiotherapy in any of the assessed treatments.


Publication 7/8

Reproducibility of repeated breathhold and impact of breathhold failure in whole breast and regional nodal irradiation in prone crawl position.

Deseyne P, Speleers B, Paelinck L, De Gersem W, De Neve W, Schoepen M, Van Greveling A, Van Hulle H, Vakaet V, Post G, Monten C, Depypere H, Veldeman L.

Sci Rep. 2022 Feb 3;12(1):1887. doi: 10.1038/s41598-022-05957-7


In whole breast and regional nodal irradiation (WB + RNI), breathhold increases organ at risk (OAR) sparing. WB + RNI is usually performed in supine position, because positioning materials obstruct beam paths in prone position. Recent advancements allow prone WB + RNI (pWB + RNI) with increased sparing of OARs compared to supine WB + RNI. We evaluate positional and dosimetrical impact of repeated breathhold (RBH) and failure to breathhold (FTBH) in pWB + RNI. Twenty left-sided breast cancer patients were scanned twice in breathhold (baseline and RBH) and once free breathing (i.e. FTBH). Positional impact was evaluated using overlap index (OI) and Dice similarity coefficient (DSC). Dosimetrical impact was assessed by beam transposition from the baseline plan. Mean OI and DSC ranges were 0.01-0.98 and 0.01-0.92 for FTBH, and 0.73-1 and 0.69-1 for RBH. Dosimetric impact of RBH was negligible. FTBH significantly decreased minimal dose to CTV WBI, level II and the internal mammary nodes, with adequate mean doses. FTBH significantly increased heart, LAD, left lung and esophagus dose. OI and DSC for RBH and FTBH show reproducible large ROI positions. Small ROIs show poor overlap. FTBH maintained adequate target coverage but increased heart, LAD, ipsilateral lung and esophagus dose. RBH is a robust technique in pWB + RNI. ( NCT05179161, registered 05/01/2022).

Publication 8/8

Delineation guidelines for the lymphatic target volumes in 'prone crawl' radiotherapy treatment position for breast cancer patients.

Stouthandel MEJ, Kayser F, Vakaet V, Khoury R, Deseyne P, Monten C, Schoepen M, Remouchamps V, De Caluwé A, Janoray G, De Neve W, Mazy S, Veldeman L, Van Hoof T.

Sci Rep. 2021 Nov 18;11(1):22529. doi: 10.1038/s41598-021-01841-y



Our recently developed prone crawl position (PCP) for radiotherapy of breast cancer patients with lymphatic involvement showed promising preliminary data and it is being optimized for clinical use. An important aspect in this process is making new, position specific delineation guidelines to ensure delineation (for treatment planning) is uniform across different centers. The existing ESTRO and PROCAB guidelines for supine position (SP) were adapted for PCP. Nine volunteers were MRI scanned in both SP and PCP. Lymph node regions were delineated in SP using the existing ESTRO and PROCAB guidelines and were then translated to PCP, based on the observed changes in reference structure position. Nine PCP patient CT scans were used to verify if the new reference structures were consistently identified and easily applicable on different patient CT scans. Based on these data, a team of specialists in anatomy, CT- and MRI radiology and radiation oncology postulated the final guidelines. By taking the ESTRO and PROCAB guidelines for SP into account and by using a relatively big number of datasets, these new PCP specific guidelines incorporate anatomical variability between patients. The guidelines are easily and consistently applicable, even for people with limited previous experience with delineations in PCP.