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Wikström, Kenneth
Publications (2 of 2) Show all publications
Wikström, K., Isacsson, U., Nilsson, K. & Ahnesjö, A. (2018). Reproducibility of heart and thoracic wall positionin repeated deep inspiration breath holds forradiotherapy of left-sided breast cancer patients. Acta Oncologica, 57(10), 1318-1324
Open this publication in new window or tab >>Reproducibility of heart and thoracic wall positionin repeated deep inspiration breath holds forradiotherapy of left-sided breast cancer patients
2018 (English)In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 57, no 10, p. 1318-1324Article in journal (Refereed) Published
Abstract [en]

Background: Deep inspiration breath hold (DIBH) for radiotherapy of left-sided breast cancer patientscan effectively move the heart away from the target and reduce the heart dose compared to treatmentsin free breathing. This study aims to investigate the positional reproducibility of heart edge(HE) and thoracic wall (TW) during repeated DIBHs.

Material and methods: At three occasions, 11 left-sided breast cancer patients were CT imaged during6 minutes of repeated DIBHs with 60 cine CT series. The series were evenly distributed over threebed positions and for each bed position, the heart edge associated maximum heart distance (MHD)and thoracic wall-associated maximum lung distance (MLD) from a reference line were retrospectivelyanalyzed. The high temporal resolution of the CT series enabled intrinsic heart movements to beresolved from breath hold variations. A body surface laser scanning system continuously extracted thethorax height and displayed it in a pair of goggles for patient feedback. To check for ‘fake-breathing’movements, e.g. that the patient lifts its back from the couch to reach DIBH, the couch-to-spine distancewas also measured in all CT series.

Results: The analysis was done for 1432 cine CTs captured during 292 breath holds. The DIBH movedthe heart on average 15mm in medial direction compared with free breathing. For the three bed positionsstudied, the mean value of the max range, across all patients, was between 11–13mm for theMHD and 4–8mm for the MLD. The MHD variation due to breath hold variation was twice as large asthe MHD variation due to intrinsic heart movement. The couch-to-spine distance varied less than3mm for all fractions, i.e., no fake-breathing was discovered.

Conclusions: The heart edge and thoracic wall reproducibility was high in relation to the medial heartdisplacement induced by the DIBH.

Keywords
Radiotherapy, Deep Inspiration Breath Hold, Breast Cancer
National Category
Cancer and Oncology
Identifiers
urn:nbn:se:uu:diva-358938 (URN)10.1080/0284186X.2018.1490027 (DOI)000448595500006 ()30074438 (PubMedID)
Available from: 2018-08-31 Created: 2018-08-31 Last updated: 2019-01-17Bibliographically approved
Wikström, K., Nilsson, K., Isacsson, U. & Ahnesjö, A. (2014). A comparison of patient position displacements from body surface laser scanning and cone beam CT bone registrations for radiotherapy of pelvic targets. Acta Oncologica, 53(2), 268-277
Open this publication in new window or tab >>A comparison of patient position displacements from body surface laser scanning and cone beam CT bone registrations for radiotherapy of pelvic targets
2014 (English)In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 53, no 2, p. 268-277Article in journal (Refereed) Published
Abstract [en]

Background and purpose

Optical surface detection has attractive features as a mean in radiotherapy for patient positioning tasks such as set-up, monitoring and gating. To aid in hitting radiotherapy targets the correlation between detected surface displacements and internal structure displacements is crucial. In this study, we compare set-up displacements derived from a body surface laser scanning (BSLS) system to displacements derived from bone registrations with a cone beam computed tomography (CBCT) system in order to quantify the accuracy and applicability of BSLS for fractionated treatments in the pelvic region.

Material and methods

Displacements from concurrent BSLS and CBCT registrations were compared for 40 patients treated in the pelvic region for a total of 170 set-ups. Surface data captured by BSLS at the first treatment fraction (BSLSref) was used as main reference for the BSLS system, while bony structures from the planning CT were used as a reference for the CBCT method. As comparison, the patient outline extracted from the planning CT was used as BSLS reference (CTref). The displacements detected by the CBCT system (skin-marks-only) was also used for comparison.

Results

The mean differences (+/- 1 SD) between the BSLS and CBCT displacements were -0.01 (+0.17) cm, 0.00 (+0.21) cm and 0.01 (+0.17) cm in the lateral, longitudinal and vertical directions, respectively. The median length of the difference was 0.26 cm (0.24-0.29 cm, 95% CI). The median of the difference between CBCT and BSLS displacements based on CTref was 0.37 cm (0.30-0.39 cm) and the median for skin-marks-only was 0.38 cm (0.34-0.42 cm).

Conclusions

The BSLS system is a good supplement to the CBCT system for accurate set-up for fractions when no CBCT is deemed necessary for pelvic targets. Inter-fractional skin movement in relation to bone was estimated to be 0.2 cm in the lateral (X), longitudinal (Y) and vertical direction (Z), respectively.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-217646 (URN)10.3109/0284186X.2013.802836 (DOI)000329522000014 ()
Available from: 2014-02-12 Created: 2014-02-04 Last updated: 2017-12-06
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