Evaluation of a 3D surface imaging system for deep inspiration breath-hold patient positioning and intra-fraction monitoring

Vincent C Hamming; Christa Visser; Estelle Batin; Leah N McDermott; Dianne M Busz; Stefan Both; Johannes A Langendijk; Nanna M Sijtsema

doi:10.1186/s13014-019-1329-6

Evaluation of a 3D surface imaging system for deep inspiration breath-hold patient positioning and intra-fraction monitoring

Radiat Oncol. 2019 Jul 11;14(1):125. doi: 10.1186/s13014-019-1329-6.

Authors

Vincent C Hamming¹, Christa Visser², Estelle Batin², Leah N McDermott³, Dianne M Busz², Stefan Both², Johannes A Langendijk², Nanna M Sijtsema²

Affiliations

¹ Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713, GZ, Groningen, The Netherlands. [email protected].
² Department of Radiation Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713, GZ, Groningen, The Netherlands.
³ Department of Radiation Oncology, Northwest Clinics, Alkmaar, The Netherlands.

Abstract

Purpose: To determine the accuracy of a surface guided radiotherapy (SGRT) system for positioning of breast cancer patients in breath-hold (BH) with respect to cone-beam computed tomography (CBCT). Secondly, to evaluate the thorax position stability during BHs with SGRT, when using an air-volume guidance system.

Methods and materials: Eighteen left-sided breast cancer patients were monitored with SGRT during CBCT and treatment, both in BH. CBCT scans were matched on the target volume and the patient surface. The setup error differences were evaluated, including with linear regression analysis. The intra-fraction variability and stability of the air-volume guided BHs were determined from SGRT measurements. The variability was determined from the maximum difference between the different BH levels within one treatment fraction. The stability was determined from the difference between the start and end position of each BH.

Results: SGRT data correlated well with CBCT data. The correlation was stronger for surface-to-CBCT (0.61) than target volume-to-CBCT (0.44) matches. Systematic and random setup error differences were ≤ 2 mm in all directions. The 95% limits of agreement (mean ± 2SD) were 0.1 ± 3.0, 0.6 ± 4.1 and 0.4 ± 3.4 mm in the three orthogonal directions, for the surface-to-CBCT matches. For air-volume guided BHs, the variability detected with SGRT was 2.2, 2.8 and 2.3 mm, and the stability - 1.0, 2.1 and 1.5 mm, in three orthogonal directions. Furthermore, the SGRT system could detect unexpected patient movement, undetectable by the air-volume BH system.

Conclusion: With SGRT, left-sided breast cancer patients can be positioned and monitored continuously to maintain position errors within 5 mm. Low intra-fraction variability and good stability can be achieved with the air-volume BH system, however, additional patient position information is available with SGRT, that cannot be detected with air-volume BH systems.

Keywords: Breast cancer; Cone-beam computed tomography; Deep inspiration breath-hold; Surface guided radiotherapy.

Publication types

Evaluation Study

MeSH terms

Brachytherapy / methods*
Breast Neoplasms / radiotherapy*
Breath Holding*
Cone-Beam Computed Tomography / methods*
Female
Humans
Image Processing, Computer-Assisted / methods
Imaging, Three-Dimensional / methods*
Patient Positioning*
Prognosis
Radiation Monitoring
Radiotherapy, Image-Guided / methods*