Essers M, Mesch L, Beugeling M, Dekker J, de Kruijf W. Setup and intra-fractional motion measurements using surface scanning in head and neck cancer radiotherapy- A feasibility study.
Phys Imaging Radiat Oncol 2024;
29:100563. [PMID:
38444887 PMCID:
PMC10912619 DOI:
10.1016/j.phro.2024.100563]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/30/2023] [Accepted: 02/15/2024] [Indexed: 03/07/2024] Open
Abstract
Background and purpose
Surface-guided radiotherapy (SGRT) is applied to improve patient set-up and to monitor intra-fraction motion. Head and neck cancer (H&N) patients are usually fixated using 5-point thermoplastic masks, that are experienced as uncomfortable or even stressful. Therefore, the feasibility of irradiating H&N patients without a mask by using SGRT was examined.
Material and methods
Nineteen H&N patients were included in a simulation study. Once a week, before the standard treatment, a maskless treatment was simulated, using SGRT for setup and intrafraction motion monitoring. Initial patient setup accuracy and intrafraction motion was determined using ConeBeam CT (CBCT) images as well as SGRT before and after the (simulated) treatment. The clinical target volume to planning target volume (CTV-PTV) margin for intrafraction motion was calculated. Using patient questionnaires, the patient-friendliness H&N irradiation with and without mask was determined.
Results
Maskless setup with SGRT and CBCT was as accurate as with a mask. SGRT showed that intrafraction motion was gradual during the treatment. The CTV-PTV margin correcting for intrafraction motion was 1.7 mm for maskless treatment without interventions, and 1.2 mm if corrected for motions > 2 mm. For 19 % of fractions, the intrafraction motion, as detected by both SGRT and CBCT, was larger than 2 mm in at least one direction. Sixteen patients preferred maskless treatment, while 3 worried they would move too much.
Conclusions
Using SGRT and a standard head rest resulted in a patient-friendly treatment with accurate patient setup and acceptably small intrafraction motion for H&N patients.
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