eprintid: 1543969 rev_number: 38 eprint_status: archive userid: 608 dir: disk0/01/54/39/69 datestamp: 2017-03-05 05:09:51 lastmod: 2021-09-26 23:00:57 status_changed: 2019-10-07 13:06:11 type: article metadata_visibility: show creators_name: Guerreiro, F creators_name: Burgos, N creators_name: Dunlop, A creators_name: Wong, K creators_name: Petkar, I creators_name: Nutting, C creators_name: Harrington, K creators_name: Bhide, S creators_name: Newbold, K creators_name: Dearnaley, D creators_name: deSouza, NM creators_name: Morgan, VA creators_name: McClelland, J creators_name: Nill, S creators_name: Cardoso, MJ creators_name: Ourselin, S creators_name: Oelfke, U creators_name: Knopf, AC title: Evaluation of a multi-atlas CT synthesis approach for MRI-only radiotherapy treatment planning ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F42 keywords: MRI-only radiotherapy workflow, Multi-atlas approach, Synthetic CT note: © 2017 The Author. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). abstract: BACKGROUND AND PURPOSE: Computed tomography (CT) imaging is the current gold standard for radiotherapy treatment planning (RTP). The establishment of a magnetic resonance imaging (MRI) only RTP workflow requires the generation of a synthetic CT (sCT) for dose calculation. This study evaluates the feasibility of using a multi-atlas sCT synthesis approach (sCTa) for head and neck and prostate patients. MATERIAL AND METHODS: The multi-atlas method was based on pairs of non-rigidly aligned MR and CT images. The sCTa was obtained by registering the MRI atlases to the patient's MRI and by fusing the mapped atlases according to morphological similarity to the patient. For comparison, a bulk density assignment approach (sCTbda) was also evaluated. The sCTbda was obtained by assigning density values to MRI tissue classes (air, bone and soft-tissue). After evaluating the synthesis accuracy of the sCTs (mean absolute error), sCT-based delineations were geometrically compared to the CT-based delineations. Clinical plans were re-calculated on both sCTs and a dose-volume histogram and a gamma analysis was performed using the CT dose as ground truth. RESULTS: Results showed that both sCTs were suitable to perform clinical dose calculations with mean dose differences less than 1% for both the planning target volume and the organs at risk. However, only the sCTa provided an accurate and automatic delineation of bone. CONCLUSIONS: Combining MR delineations with our multi-atlas CT synthesis method could enable MRI-only treatment planning and thus improve the dosimetric and geometric accuracy of the treatment, and reduce the number of imaging procedures. date: 2017-03 date_type: published official_url: http://dx.doi.org/10.1016/j.ejmp.2017.02.017 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1212049 doi: 10.1016/j.ejmp.2017.02.017 pii: S1120-1797(17)30045-5 lyricists_name: Burgos, Ninon lyricists_name: Cardoso, Manuel lyricists_name: McClelland, James lyricists_name: Ourselin, Sebastien lyricists_id: BURGO78 lyricists_id: MJMCA47 lyricists_id: JRMCC68 lyricists_id: SOURS59 full_text_status: public publication: Physica Medica volume: 35 pagerange: 7-17 event_location: Italy issn: 1724-191X citation: Guerreiro, F; Burgos, N; Dunlop, A; Wong, K; Petkar, I; Nutting, C; Harrington, K; ... Knopf, AC; + view all <#> Guerreiro, F; Burgos, N; Dunlop, A; Wong, K; Petkar, I; Nutting, C; Harrington, K; Bhide, S; Newbold, K; Dearnaley, D; deSouza, NM; Morgan, VA; McClelland, J; Nill, S; Cardoso, MJ; Ourselin, S; Oelfke, U; Knopf, AC; - view fewer <#> (2017) Evaluation of a multi-atlas CT synthesis approach for MRI-only radiotherapy treatment planning. Physica Medica , 35 pp. 7-17. 10.1016/j.ejmp.2017.02.017 <https://doi.org/10.1016/j.ejmp.2017.02.017>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1543969/7/Burgos%20VoR%201-s2.0-S1120179717300455-main.pdf