Towards adaptive radiotherapy for head and neck patients: validation of an in-house deformable registration algorithm

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

Veiga, C.^1 ; McClelland, J.^1 ; Moinuddin, S.^2 ; Ricketts, K.^1 ; Modat, M.^1 ; Ourselin, S.^1 ; D'Souza, D.^3 ; Royle, G.^1

Department of Medical Physics and Bioengineering, University College London, London, United Kingdom^1

Department of Radiotherapy, University College London Hospital, London, United Kingdom^2

Radiotherapy Physics Group, University College London Hospital, London, United Kingdom^3

关键词: Adaptive radiotherapy;    Deformable image registration;    Deformable registration;    Head and neck;    Open source implementation;    Parameter setting;    Similarity coefficients;    Vertebral body;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012083/pdf
DOI  :  10.1088/1742-6596/489/1/012083

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

The purpose of this work is to validate an in-house deformable image registration (DIR) algorithm for adaptive radiotherapy for head and neck patients. We aim to use the registrations to estimate the dose of the day and assess the need to replan. NiftyReg is an open-source implementation of the B-splines deformable registration algorithm, developed in our institution. We registered a planning CT to a CBCT acquired midway through treatment for 5 HN patients that required replanning. We investigated 16 different parameter settings that previously showed promising results. To assess the registrations, structures delineated in the CT were warped and compared with contours manually drawn by the same clinical expert on the CBCT. This structure set contained vertebral bodies and soft tissue. Dice similarity coefficient (DSC), overlap index (OI), centroid position and distance between structures' surfaces were calculated for every registration, and a set of parameters that produces good results for all datasets was found. We achieve a median value of 0.845 in DSC, 0.889 in OI, error smaller than 2 mm in centroid position and over 90% of the warped surface pixels are distanced less than 2 mm of the manually drawn ones. By using appropriate DIR parameters, we are able to register the planning geometry (pCT) to the daily geometry (CBCT).