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Deformable and rigid registration of MRI and microPET images for photodynamic therapy of cancer in mice
Author(s) -
Fei Baowei,
Wang Hesheng,
Muzic Raymond F.,
Flask Chris,
Wilson David L.,
Duerk Jeffrey L.,
Feyes Denise K.,
Oleinick Nancy L.
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2163831
Subject(s) - image registration , magnetic resonance imaging , positron emission tomography , centroid , nuclear medicine , artificial intelligence , computer science , medicine , computer vision , radiology , image (mathematics)
We are investigating imaging techniques to study the tumor response to photodynamic therapy (PDT). Positron emission tomography (PET) can provide physiological and functional information. High‐resolution magnetic resonance imaging (MRI) can provide anatomical and morphological changes. Image registration can combine MRI and PET images for improved tumor monitoring. In this study, we acquired high‐resolution MRI and microPET F18 ‐fluorodeoxyglucose (FDG) images from C3H mice with RIF‐1 tumors that were treated with Pc 4‐based PDT. We developed two registration methods for this application. For registration of the whole mouse body, we used an automatic three‐dimensional, normalized mutual information algorithm. For tumor registration, we developed a finite element model (FEM)‐based deformable registration scheme. To assess the quality of whole body registration, we performed slice‐by‐slice review of both image volumes; manually segmented feature organs, such as the left and right kidneys and the bladder, in each slice; and computed the distance between corresponding centroids. Over 40 volume registration experiments were performed with MRI and microPET images. The distance between corresponding centroids of organs was 1.5 ± 0.4 mm which is about 2 pixels of microPET images. The mean volume overlap ratios for tumors were 94.7% and 86.3% for the deformable and rigid registration methods, respectively. Registration of high‐resolution MRI and microPET images combines anatomical and functional information of the tumors and provides a useful tool for evaluating photodynamic therapy.