Clinical use, challenges, and barriers to implementation of deformable image registration in radiotherapy - the need for guidance and QA tools.

Mohammad Hussein,Adeyemi Akintonde,Jamie Mcclelland,Richard Speight,Catharine H Clark

doi:10.1259/bjr.20210001

Abstract

Objective:The aim of this study was to evaluate the current status of the clinical use of deformable image registration (DIR) in radiotherapy and to gain an understanding of the challenges faced by centres in clinical implementation of DIR, including commissioning and quality assurance (QA), and to determine the barriers faced. The goal was to inform whether additional guidance and QA tools were needed.Methods:A survey focussed on clinical use, metrics used, how centres would like to use DIR in the future and challenges faced, was designed and sent to 71 radiotherapy centres in the UK. Data were gathered specifically on which centres we using DIR clinically, which applications were being used, what commissioning and QA tests were performed, and what barriers were preventing the integration of DIR into the clinical workflow. Centres that did not use DIR clinically were encouraged to fill in the survey and were asked if they have any future plans and in what timescale.Results:51 out of 71 (70%) radiotherapy centres responded. 47 centres reported access to a commercial software that could perform DIR. 20 centres already used DIR clinically, and 22 centres had plans to implement an application of DIR within 3 years of the survey. The most common clinical application of DIR was to propagate contours from one scan to another (19 centres). In each of the applications, the types of commissioning and QA tests performed varied depending on the type of application and between centres. Some of the key barriers were determining when a DIR was satisfactory including which metrics to use, and lack of resources.Conclusion:The survey results highlighted that there is a need for additional guidelines, training, better tools for commissioning DIR software and for the QA of registration results, which should include developing or recommending which quantitative metrics to use.Advances in knowledge:This survey has given a useful picture of the clinical use and lack of use of DIR in UK radiotherapy centres. The survey provided useful insight into how centres commission and QA DIR applications, especially the variability among centres. It was also possible to highlight key barriers to implementation and determine factors that may help overcome this which include the need for additional guidance specific to different applications, better tools and metrics.

Highlights

Deformable image registration (DIR) is the process of non-rigidly aligning one image to another, into a common spatial coordinate frame, in order to account for anatomical differences between the two images.[1]
The use of DIR has become more common in radiotherapy, in particular for adaptive radiotherapy,[2,3] where treatment is adapted to account for anatomical changes in between treatment fractions
Data were gathered from UK centres, on which centres were using DIR clinically, which applications were being used, what commissioning and quality assurance (QA) tests were performed, and what barriers were preventing the integration of DIR into the clinical workflow

Summary

Introduction

Deformable image registration (DIR) is the process of non-rigidly aligning one image to another, into a common spatial coordinate frame, in order to account for anatomical differences between the two images.[1]. Multimodal pre-treatment images are often used during planning to combine information from different imaging modality to aid in the delineation of tumour volumes or organs at risks (OARs).[4,5] Another application is contour propagation, here the planning contours are propagated to repeat CT images acquired during treatment, thereby saving delineation time.[6,7,8] Treatment adaptation methods such as the “dose of the day” are another application, which are based on creating a deformed CT from the planning CT and cone beam CT (CBCT). Dose accumulation is another potential application where DIR could be used, here quantification of the dose absorbed over the course of treatment fractions is estimated by warping the dose to a common reference anatomy.[13,14] This approach could be used to estimate the discrepancies between the planned and the delivered dose

Methods

Results

Discussion

Conclusion