PMID- 18501456 OWN - NLM STAT- MEDLINE DCOM- 20090210 LR - 20220408 IS - 0167-8140 (Print) IS - 0167-8140 (Linking) VI - 89 IP - 1 DP - 2008 Oct TI - Comparison of 12 deformable registration strategies in adaptive radiation therapy for the treatment of head and neck tumors. PG - 1-12 LID - 10.1016/j.radonc.2008.04.010 [doi] AB - BACKGROUND AND PURPOSE: Weight loss, tumor shrinkage, and tissue edema induce substantial modification of patient's anatomy during head and neck (HN) radiotherapy (RT) or chemo-radiotherapy. These modifications may impact on the dose distribution to both target volumes (TVs) and organs at risk (OARs). Adaptive radiotherapy (ART) where patients are re-imaged and re-planned several times during the treatment is a possible strategy to improve treatment delivery. It however requires the use of specific deformable registration (DR) algorithms that requires proper validation on a clinical material. MATERIALS AND METHODS: Twelve voxel-based DR strategies were compared with a dataset of 5 patients imaged with computed tomography (CT) before and once during RT (on average after a mean dose of 36.8Gy): level-set (LS), level-set implemented in multi-resolution (LS(MR)), Demons' algorithm implemented in multi-resolution (D(MR)), D(MR) followed by LS (D(MR)-LS), fast free-form deformable registration via calculus of variations (F3CV) and F3CV followed by LS (F3CV-LS). The use of an edge-preserving denoising filter called "local M-smoothers" applied to the registered images and combined to all the aforesaid strategies was also tested (fLS, fLS(MR), fD(MR), fD(MR)-LS, fF3CV, fF3CV-LS). All these strategies were compared to a rigid registration based on mutual information (MI, fMI). Chronological and anti-chronological registrations were also studied. The various DR strategies were evaluated using a volume-based criterion (i.e. Dice similarity index, DSI) and a voxel-intensity criterion (i.e. correlation coefficient, CC) on a total of 18 different manually contoured volumes. RESULTS: For the DSI analysis, the best three strategies were D(MR), fD(MR)-LS, and fD(MR), with the median values of 0.86, 0.85 and 0.85, respectively; corresponding inter-quartile range (IQR) reached 9.6%, 10% and 10.2%. For the CC analysis, the best three strategies were fD(MR)-LS, D(MR)-LS and D(MR) with the median values of 0.97, 0.96 and 0.94, respectively; corresponding IQR reached 11%, 9% and 15%. Concerning the time-sequence analysis, the anti-chronological registration (all deformable strategies pooled) showed a better median DSI value (0.84 vs 0.83, p<0.001) and IQR (11.2% vs 12.4%). For CC, the anti-chronological registration (all deformable strategies pooled) had a slightly lower median value (0.91 vs 0.912, p<0.001) but a better IQR (16.4% vs 21%). CONCLUSIONS: The use of fD(MR)-LS is a good registration strategy for HN-ART as it is the best compromise in terms of median and IQR for both DSI and CC. Even though less robust in terms of CC, D(MR) is a good alternative. None of the time-sequence appears superior. FAU - Castadot, Pierre AU - Castadot P AD - Department of Radiation Oncology, Universite catholique de Louvain, St-Luc University Hospital, Brussels, Belgium. FAU - Lee, John Aldo AU - Lee JA FAU - Parraga, Adriane AU - Parraga A FAU - Geets, Xavier AU - Geets X FAU - Macq, Benoit AU - Macq B FAU - Gregoire, Vincent AU - Gregoire V LA - eng PT - Comparative Study PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20080522 PL - Ireland TA - Radiother Oncol JT - Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology JID - 8407192 SB - IM MH - Algorithms MH - Head and Neck Neoplasms/diagnostic imaging/*radiotherapy MH - Humans MH - Outcome and Process Assessment, Health Care MH - Radiographic Image Interpretation, Computer-Assisted MH - Radiotherapy/*methods MH - Radiotherapy Dosage MH - Radiotherapy Planning, Computer-Assisted/*methods MH - Statistics, Nonparametric MH - Tomography, X-Ray Computed EDAT- 2008/05/27 09:00 MHDA- 2009/02/12 09:00 CRDT- 2008/05/27 09:00 PHST- 2008/02/19 00:00 [received] PHST- 2008/04/09 00:00 [revised] PHST- 2008/04/20 00:00 [accepted] PHST- 2008/05/27 09:00 [pubmed] PHST- 2009/02/12 09:00 [medline] PHST- 2008/05/27 09:00 [entrez] AID - S0167-8140(08)00230-2 [pii] AID - 10.1016/j.radonc.2008.04.010 [doi] PST - ppublish SO - Radiother Oncol. 2008 Oct;89(1):1-12. doi: 10.1016/j.radonc.2008.04.010. Epub 2008 May 22.