Intrafraction motion quantification and planning target volume margin determination of head-and-neck tumors using cine magnetic resonance imaging. (January 2019)

• Record Type: Journal Article
• Authors: Bruijnen, Tom; Stemkens, Bjorn; Terhaard, Chris H.J.; Lagendijk, Jan J.W.; Raaijmakers, Cornelis P.J.; Tijssen, Rob H.N.
• Is Part Of: Radiotherapy and oncology. Volume 130(2019)
• Page Start: 82
• Page End: 88
• Publication Date: 2019-01
• Subjects: Intrafraction motion -- Head-and-neck cancer -- MRI -- Radiotherapy -- Margins; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2018.09.015
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Intrafractional tumor motion was quantified in 84 patients using cine MRI. Mean maximum tumor motion was 2.4 mm in feet-head and 1.8 mm in anterior–posterior. Head-and-neck tumor motion varies considerably between patients. Laryngeal tumors show larger motion amplitudes than oropharyngeal tumors. Abstract: Purpose: To quantify intrafractional motion to determine population-based radiotherapy treatment margins for head-and-neck tumors. Methods: Cine MR imaging was performed in 100 patients with head-and-neck cancer on a 3T scanner in a radiotherapy treatment setup. MR images were analyzed using deformable image registration (optical flow algorithm) and changes in tumor contour position were used to calculate the tumor motion. The tumor motion was used together with patient setup errors (450 patients) to calculate population-based PTV margins. Results: Tumor motion was quantified in 84 patients (12/43/29 nasopharynx/oropharynx/larynx, 16 excluded). The mean maximum (95th percentile) tumor motion (swallowing excluded) was: 2.3 mm in superior, 2.4 mm in inferior, 1.8 mm in anterior and 1.7 mm in posterior direction. PTV margins were: 2.8 mm isotropic for nasopharyngeal tumors, 3.2 mm isotropic for oropharyngeal tumors and 4.3 mm in inferior–superior and 3.2 mm in anterior–posterior for laryngeal tumors, for our institution. Conclusions: Intrafractional head-and-neck tumor motion was quantified and population-based PTV margins were calculated. Although the average tumor motion was small (95th percentile motion <3.0 mm), tumor motion varied considerably between patients (0.1–12.0 mm). The intrafraction motion expanded the CTV-to-PTV with 1.7 mm for laryngeal tumors, 0.6 mm for oropharyngeal tumors and 0.2 mm for nasopharyngeal tumors.