Zhang, Ying;
Alshaikhi, Jailan;
Amos, Richard A;
Tan, Wenyong;
Anaya, Virginia Marin;
Pang, Yaru;
Royle, Gary;
(2022)
Pre-treatment analysis of non-rigid variations can assist robust IMPT plan selection for head and neck patients.
Medical Physics
, 49
(12)
pp. 7683-7693.
10.1002/mp.15971.
Preview |
Text
Royle_Medical Physics - 2022 - Zhang.pdf Download (740kB) | Preview |
Abstract
PURPOSE: To incorporate small non-rigid variations of head and neck patients into the robust evaluation of IMPT for the selection of robust treatment plans. METHODS: A cohort of 20 nasopharynx cancer patients with weekly kVCT and 15 oropharynx cancer patients with weekly cone beam CT (CBCT) were retrospectively included. Anatomical variations between week 0/week 1 of treatment were acquired using deformable image registration (DIR) for all 35 patients and then applied to the planning CT of four patients who have kVCT scanned each week to simulate potential small non-rigid variations (sNRVs). The robust evaluations were conducted on intensity-modulated proton therapy (IMPT) plans with: 1) different number of beam fields from 3-field to 5-field. 2) different beam angles. The robust evaluation before treatment including the sNRVs and setup uncertainty, referred to as sNRV+R evaluation was compared with the conventional evaluation (without sNRVs) in terms of robustness consistency with the gold standard evaluation based on weekly CT. RESULTS: Among four patients (490 scenarios), we observed a maximum difference in the sNRV+R evaluation to the nominal dose of: 9.37% dose degradation on D95 of CTVs, increase in mean dose (Dmean ) of parotid 11.87 Gy, increase in max dose (Dmax ) of brainstem 20.82 Gy. In contrast, in conventional evaluation, we observed a maximum difference to the nominal dose of: 7.58% dose degradation on D95 of the CTVs, increase in parotid Dmean by 4.88 Gy, increase in brainstem Dmax by 13.5 Gy. In the measurement of the robustness ranking consistency with the gold standard evaluation, the sNRV+R evaluation was better or equal to the conventional evaluation in 77% of cases, particularly, better on spinal cord, parotid glands and low-risk CTV. CONCLUSION: This study demonstrated the additional dose discrepancy that sNRVs can make. The inclusion of sNRVs can be beneficial to robust evaluation, providing information on clinical uncertainties additional to the conventional rigid isocenter shift. This article is protected by copyright. All rights reserved.
| Type: | Article |
|---|---|
| Title: | Pre-treatment analysis of non-rigid variations can assist robust IMPT plan selection for head and neck patients |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/mp.15971 |
| Publisher version: | https://doi.org/10.1002/mp.15971 |
| Language: | English |
| Additional information: | This is an open access article under the terms of theCreative Commons AttributionLicense,which permits use,distribution and reproduction in any medium,providedthe original work is properly cited.© 2022 The Authors.Medical Physicspublished by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine. |
| Keywords: | anatomical uncertainty, head and neck cancer, intensity-modulated proton therapy, robust evaluation |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10155734 |
Archive Staff Only
 |
View Item |
