Deformable image registration to assist clinical decision for radiotherapy treatment adaptation for head and neck cancer patients

Vasiliki Iliadou; Theodore L Economopoulos; Pantelis Karaiskos; Vasileios Kouloulias; Kalliopi Platoni; George K Matsopoulos

doi:10.1088/2057-1976/ac14d1

Deformable image registration to assist clinical decision for radiotherapy treatment adaptation for head and neck cancer patients

Biomed Phys Eng Express. 2021 Jul 30;7(5). doi: 10.1088/2057-1976/ac14d1.

Authors

Vasiliki Iliadou¹, Theodore L Economopoulos¹, Pantelis Karaiskos², Vasileios Kouloulias³, Kalliopi Platoni³, George K Matsopoulos¹

Affiliations

¹ School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece.
² Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
³ 2nd Department of Radiology, Radiotherapy Unit, ATTIKON University Hospital, Athens, Greece.

PMID: 34265756
DOI: 10.1088/2057-1976/ac14d1

Abstract

Head and neck (H&N) cancer patients often present anatomical and geometrical changes in tumors and organs at risk (OARs) during radiotherapy treatment. These changes may result in the need to adapt the existing treatment planning, using an expert's subjective opinion, for offline adaptive radiotherapy and a new treatment planning before each treatment, for online adaptive radiotherapy. In the present study, a fast methodology is proposed to assist in planning adaptation clinical decision using tumor and parotid glands percentage volume changes during treatment. The proposed approach was applied to 40 Η&Ν cases, with one planning Computed Tomography (pCT) image and CBCT scans for 6 weeks of treatment per case. Deformable registration was used for each patient's pCT image alignment to its weekly CBCT. The calculated transformations were used to align each patient's anatomical structures to the weekly anatomy. Clinical target volume (CTV) and parotid gland volume percentage changes were calculated in each case. The accuracy of the achieved image alignment was validated qualitatively and quantitatively. Furthermore, statistical analysis was performed to test if there is a statistically significant correlation between CTV and parotid glands volume percentage changes. Average MDA for CTV and parotid glands between corresponding structures defined by an expert in CBCTs and automatically calculated through registration was 1.4 ± 0.1 mm and 1.5 ± 0.1 mm, respectively. The mean registration time of the first CBCT image registration for 40 cases was lower than 3.4 min. Five patients show more than 20% tumor volume change. Six patients show more than 30% parotid glands volume change. Ten out of 40 patients proposed for planning adaptation. All the statistical tests performed showed no correlation between CTV/parotid glands percentage volume changes. The aim to assist in clinical decision making on a fast and automatic way was achieved using the proposed methodology, thereby reducing workload in clinical practice.

Keywords: DIR; H&N; deformable registration; optimized DIR parameters; treatment planning adaptation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cone-Beam Computed Tomography
Head and Neck Neoplasms* / diagnostic imaging
Head and Neck Neoplasms* / radiotherapy
Humans
Organs at Risk / diagnostic imaging
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Intensity-Modulated*