Dataset Information

Intrafractional 6D head movement increases with time of mask fixation during stereotactic intracranial RT-sessions.

ABSTRACT:

Background

The present study investigates the intrafractional accuracy of a frameless thermoplastic mask used for head immobilization during stereotactic radiotherapy. Non-invasive masks cannot completely prohibit head movements. Previous studies attempted to estimate the magnitude of intrafractional inaccuracy by means of pre- and postfractional measurements only. However, this might not be sufficient to accurately map also intrafractional head movements.

Materials and methods

Intrafractional deviation of mask-fixed head positions was measured in five patients during a total of 94 fractions by means of close-meshed repeated ExacTrac measurements (every 1.4 min) conducted during the entire treatment session. A median of six (range: 4 to 11) measurements were recorded per fraction, delivering a dataset of 453 measurements.

Results

Random errors (SD) for the x, y and z axes were 0.27 mm, 0.29 mm and 0.29 mm, respectively. Median 3D deviation was 0.29 mm. Of all 3D intrafractional motions, 5.5 and 0.4% exceeded 1 mm and 2 mm, respectively. A moderate correlation between treatment duration and mean 3D displacement was determined (r_s = 0.45). Mean 3D deviation increased from 0.21 mm (SD = 0.26 mm) in the first 2 min to a maximum of 0.53 mm (SD = 0.31 mm) after 10 min of treatment time.

Conclusion

Pre- and post-treatment measurement is not sufficient to adequately determine the range of intrafractional head motion. Thermoplastic masks provide both reliable interfractional and intrafractional immobilization for image-guided stereotactic hypofractionated radiotherapy. Greater positioning accuracy may be obtained by reducing treatment duration (< 6 min) and applying intrafractional correction.

Trial registration

Clinicaltrials.gov, NCT03896555, Registered 01 April 2019 - retrospectively registered.

SUBMITTER: Mangesius J

PROVIDER: S-EPMC6921566 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Intrafractional 6D head movement increases with time of mask fixation during stereotactic intracranial RT-sessions.

Mangesius Julian J Seppi Thomas T Weigel Rocco R Arnold Christoph Reinhold CR Vasiljevic Danijela D Goebel Georg G Lukas Peter P Ganswindt Ute U Nevinny-Stickel Meinhard M

Radiation oncology (London, England) 20191218 1

<h4>Background</h4>The present study investigates the intrafractional accuracy of a frameless thermoplastic mask used for head immobilization during stereotactic radiotherapy. Non-invasive masks cannot completely prohibit head movements. Previous studies attempted to estimate the magnitude of intrafractional inaccuracy by means of pre- and postfractional measurements only. However, this might not be sufficient to accurately map also intrafractional head movements.<h4>Materials and methods</h4>In ...[more]

PMID: 31852497

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Project description:PurposeTo determine the 3-dimensional (3D) intrafractional motion of head and neck squamous cell carcinoma (HNSCC).Methods and materialsDynamic contrast-enhanced magnetic resonance images from 56 patients with HNSCC in the treatment position were analyzed. Dynamic contrast-enhanced magnetic resonance imaging consisted of 3D images acquired every 2.9 seconds for 4 minutes 50 seconds. Intrafractional tumor motion was studied in the 3 minutes 43 seconds of images obtained after initial contrast enhancement. To assess tumor motion, rigid registration (translations only) was performed using a region of interest (ROI) mask around the tumor. The results were compared with bulk body motion from registration to all voxels. Motion was split into systematic motion and random motion. Correlations between the tumor site and random motion were tested. The within-subject coefficient of variation was determined from 8 patients with repeated baseline measures. Random motion was also assessed at the end of the first week (38 patients) and second week (25 patients) of radiation therapy to investigate trends of motion.ResultsTumors showed irregular occasional rapid motion (eg, swallowing or coughing), periodic intermediate motion (respiration), and slower systematic drifts throughout treatment. For 95% of the patients, displacements due to systematic and random motion were <1.4 mm and <2.1 mm, respectively, 95% of the time. The motion without an ROI mask was significantly (P<.0001, Wilcoxon signed rank test) less than the motion with an ROI mask, indicating that tumors can move independently from the bony anatomy. Tumor motion was significantly (P=.005, Mann-Whitney U test) larger in the hypopharynx and larynx than in the oropharynx. The within-subject coefficient of variation for random motion was 0.33. The average random tumor motion did not increase notably during the first 2 weeks of treatment.ConclusionsThe 3D intrafractional tumor motion of HNSCC is small, with systematic motion <1.4 mm and random motion <2.1 mm 95% of the time.

Project description:ObjectiveThe primary aim of this investigation is to assess the effectiveness of implementing an innovative immobilization approach, spec ically the utilization of personalized open-face masks in combination with styrofoam fixation, for head and neck cancers receiving radiotherapy. The study seeks to evaluate the influence of this method on improving patients' precision in positioning and their overall comfort during the treatment process, in addition to exploring its potential capacity to mitigate the occurrence of anxiety and depression in this patient population.MethodsA prospective, randomized controlled trial was undertaken to investigate the comparative efficacy of two immobilization approaches for the radiotherapy treatment of head and neck cancers. The experimental group was randomly assigned to receive fixation using personalized open-face masks with nose and mouth apertures, while the control group was immobilized using closed-face masks. Weekly cone-beam computed tomography (CBCT) scans were conducted pre-treatment to assess and record setup errors along three axes. Comparative analysis of setup errors and the planning target volume (PTV) margin between the two groups was performed. Furthermore, the patients' comfort levels and anxiety and depression status were evaluated using the modified Likert questionnaire and the Hospital Anxiety and Depression Scale (HADS).ResultsA total of 106 patients were enrolled in the study and randomly assigned to either the experimental group (n = 53) or the control group (n = 53). There were no statistically significant differences observed between the two groups in terms of age, sex, and disease type indicating comparability. Analysis of the setup errors along different directions showed no significant differences between the experimental and control groups in the X direction (0.90 ± 0.84 mm vs. 0.92 ± 0.85 mm, p = 0.825), Y direction (1.26 ± 0.98 mm vs. 1.37 ± 1.09 mm, p = 0.172), Z direction (1.18 ± 0.84 mm vs. 1.15 ± 0.98 mm, p = 0.651), and Rtn direction (0.65 ± 0.57 vs. 0.62 ± 0.55, p = 0.489). Evaluating the local setup errors in the experimental and control groups, there were no significant differences observed in the X direction (1.13 ± 1.15 mm vs. 1.01 ± 0.89 mm, p = 0.152) and Z direction (1.31 ± 0.88 mm vs. 1.26 ± 1.17 mm, p = 0.549). However, a significant difference was found in the Y direction (1.49 ± 1.19 mm vs. 1.80 ± 1.45 mm, p = 0.003). The Rtn direction also did not show a significant difference (0.90 ± 0.81 vs. 0.84 ± 0.73, p = 0.328). The PTV margin in the X, Y, and Z directions were determined as 2.20 mm, 3.12 mm, and 2.57 mm in the experimental group and 2.35 mm, 3.58 mm, and 2.86 mm in the control group, respectively. The personalized open-face mask patients reported higher levels of comfort compared to the perforated head, neck, and shoulder thermoplastic mask (31.32 ± 1.16 vs. 30.00 ± 1.49, p < 0.001). The prevalence rates of anxiety in the experimental and control groups were as follows: (18.8% vs. 12.5%, p = 0.399), (18.8% vs. 14.6%, p = 0.584), (23.4% vs. 25%, p = 0.856), and (23.4% vs. 33.3%, p = 0.283).ConclusionsIn head and neck cancer radiotherapy, we propose the idea of personalized open-face mask combined with styrofoam for the first time, which can improve patient comfort without sacrificing positioning accuracy, and has a tendency to relieve patients' tension and anxiety. It is worth promoting and using in clinical positioning.

Dataset Information

Intrafractional 6D head movement increases with time of mask fixation during stereotactic intracranial RT-sessions.

Background

Materials and methods

Results

Conclusion

Trial registration

Publications

Intrafractional 6D head movement increases with time of mask fixation during stereotactic intracranial RT-sessions.

Similar Datasets

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