Assessment of commercially available deformable image registration (DIR) software for CT-MRI registration in breast radiotherapy patients

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1 Assessment of commercially available deformable image registration (DIR) software for CT-MRI registration in breast radiotherapy patients Poster No.: R-0019 Congress: 2014 CSM Type: Scientific Exhibit Authors: L. Holloway, R. Speight, R. Stensmyr, J. Foo, E. M. Pogson, G. Liney, J. Sykes, D. Thwaites ; WOLLONGONG/AU, LEEDS/GB, WESTMEAD/AU, PENRITH/AU, SYDNEY/AU Keywords: Breast, CT, MR, Radiation therapy / Oncology, Image registration DOI: /ranzcr2014/R-0019 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply RANZCR/AIR/ACPSEM's endorsement, sponsorship or recommendation of the third party, information, product or service. RANZCR/AIR/ ACPSEM is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold RANZCR/AIR/ACPSEM harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies,.ppt slideshows,.doc documents and any other multimedia files are not available in the pdf version of presentations. Page 1 of 7

2 Aim Radiotherapy plays an important role in breast cancer therapy with treatments typically planned on supine-ct images. MRI allows more accurate tissue definition and its role in radiotherapy planning is increasing [1]. Prone-MRI is normally acquired utilising dedicated coils for improved image quality. This study assessed if commercial DIR software can co-register CT-MRI acquired in different geometries to allow MRI to be utilised. Methods and materials Ten patients had CT and T1-w or T2-w weighted MRI acquired supine and prone at Liverpool Hospital. Mirada RTx-1.2; Velocity AI-3.0.1; and MIM DIR software packages were tested. To evaluate algorithms, DIR was performed between the 3 image sets shown in figure 1. Images for this section: Fig. 1 Page 2 of 7

3 Results All DIR software performed similarly. The lack of dedicated CT-MRI registration algorithm in MIM made registrations time consuming and user dependent as many points had to be locked. DIR was more successful using T1-w MRI, even though T2-w had less artefacts and appeared to have more detail within the breast tissue, see figure 2. Sub 5mm accuracy was achieved with all systems tested for prone-mri to prone-ct DIR for 6 out of 10 patients, examples shown in figure 3. DIR accuracy for prone to supine was poor (>10mm) for all systems. Algorithms attempt to register external, lung and chest wall at the expense of breast tissue detail and often misalign the nipple. Results had unrealistic deformations, examples shown in figure 4. Accuracy was reduced further for DIR between supine-ct and prone-mr even when registering in a small ROI, all 3 packages produced clinically unusable results. Figure 5 shows examples; Velocity shows unrealistic deformations within the lung; MIM gave bad results after spending ~2hrs locking points; Mirada limits the amount of deformation so does not match the patient surface. Images for this section: Fig. 2 Page 3 of 7

4 Fig. 3: Registrations between prone-mri and prone-ct. Top = registration, bottom = deformations applied. MIM results top = prone-ct, bottom = prone-mri deformed onto prone-ct Fig. 4: Registrations between supine-ct and prone-ct. Top = registration, bottom = deformations applied. MIM results top = supine-ct, bottom = prone-ct deformed onto supine-ct Page 4 of 7

5 Fig. 5: Registrations between supine-mri and prone-ct. Top = registration, bottom = deformations applied. MIM results top = prone-ct, bottom = supine-mri deformed onto prone-ct Page 5 of 7

6 Conclusion Commercial software is capable of DIR between CT and MRI in a similar geometry with registration accuracy being better with T1-w MRI than T2-w. Registering CT-CT, MRI-MRI or CT-MRI between prone and supine position is beyond the capabilities of the software tested. For such registrations there is a need for intelligent algorithms including prior knowledge e.g. effect of gravity. Personal information Richard Speight's time was funded by a Cancer Research UK Leeds Centre award (C37059/A11941). The authors would also like to thank Cancer Australia and The National Breast Cancer Foundation (Project ). Images for this section: Fig. 6 Fig. 7 Page 6 of 7

7 References 1 Australian and New Zealand Clinical Trials Registry: National Health and Medical Research Council (Australia); Identifier ACTRN TROG 12.02; 2013 March 4. Available from TrialReview.aspx?id= Page 7 of 7