| 1. |
- Aitken, Candice L., et al.
(författare)
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Tumor localization and image registration of F-18FDG coincidence detection scans with computed tomographic scans
- 2002
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Ingår i: Clinical Nuclear Medicine. - : Ovid Technologies (Wolters Kluwer Health). - 0363-9762 .- 1536-0229. ; 27:4, s. 275-282
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aim of this study was to determine the feasibility of registering routine clinical F-18 fluorodeoxyglucose (FDG) coincidence detection (CD) scans with computed tomographic (CT) scans for radiation treatment planning and case management. Methods: F-18 FDG CD and chest CT scans, performed in 10 randomly selected patients with confirmed or possible adenocarcinoma of the lung, were evaluated. The quality of the matches was verified by comparisons of the center-to-center distance between a region of interest (ROI) manually drawn on the CT slice and warped onto the CD slice with an ROI drawn manually directly on the CD slice. In addition, the overlap between the two ROIs was calculated. Results: All 10 F-18 FDG CD and CT scans were registered with good superimposition of soft tissue density on increased radionuclide activity. The center-to-center distance between the ROIs ranged from 0.29 mm to 8.08 mm, with an average center-to-center distance of 3.89 mm 2.42 mm (0.69 pixels +/- 0.34 pixels). The ROI overlap ranged from 77% to 99%, with an average of 90% +/- 5.6%. Conclusions: Although the use of F-18 FDG CD shows great promise for the identification of tumors, it shares the same drawbacks as those associated with radiolabeled monoclonal antibody SPECT and ligand-based positron emission tomographic scans in that anatomic markers are limited. This study shows that image registration is feasible and may improve the clinical relevance of CD images.
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| 2. |
- Crafoord, Joakim, et al.
(författare)
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Comparison of two landmark based image registration methods for use with a body atlas
- 2000
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Ingår i: Physica medica (Testo stampato). - 1120-1797 .- 1724-191X. ; 16:2, s. 75-82
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Tidskriftsartikel (refereegranskat)abstract
- We describe preliminary work registering abdominal MRI images from three healthy male volunteers. Anatomically selected 3D homologous point pairs (landmarks), from which eigenvalues were generated to form the basis for a 3D non-affine polynomial transformation, were placed on axial slices alone and on axial, coronal and sagittal slices. Registration accuracy was judged visually by comparing superimposed 3D isosurfaces from the reference, untransformed, and transformed volume data and by comparing merged 2D slices projected fi om the transformed and reference volume data superimposed with 2D isolines. The squared sum of intensity differences between the transformed/untransformed and the reference volume was significant at the 0.05 (p >0.05) confidence level. The correlation coefficient improved by an average of 38% and the cross correlation between pixel values improved by an average of 22%. In each trial, the standard deviation of the landmarks after transformation was within one voxel and the standard error of the mean was not significantly different from zero at the 0.05 confidence level. Abdominal isosurface volume differences (between individuals) changed from an average of 14.5% before registration to 2.9% after registration. This experiment shows that it is possible to choose landmarks such that abdominal data from different subject volumes can be mapped to a common reference, and thus that it is possible to use this combined volume both to form an atlas and to warp abdominal data from an atlas to a patient volume.
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| 3. |
- Dewyngaert, J. Keith, et al.
(författare)
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Procedure for unmasking localization information from ProstaScint scans for prostate radiation therapy treatment planning
- 2004
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 60:2, s. 654-662
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To demonstrate a method to extract the meaningful biologic information from In-111-radiolabeled capromab pendetide (ProstaScint) SPECT scans for use in radiation therapy treatment planning by removing that component of the In-111 SPECT images associated with normal structures. Methods and Materials: We examined 20 of more than 80 patients who underwent simultaneous Tc-99m/In-111 SPECT scans, which were subsequently registered to the corresponding CT/MRI scans. A thresholding algorithm was used to identify Tc-99m uptake associated with blood vessels and CT electron density associated with bone marrow. Corresponding voxels were removed from the In-111 image set. Results: No single threshold value was found to be associated with the Tc-99m uptake that corresponded to the blood vessels. Intensity values were normalized to a global maximum and, as such, were dependent upon the quantity of Tc-99m pooled in the bladder. The reduced ProstaScint volume sets were segmented by use of a thresholding feature of the planning system and superimposed on the CT/MRI scans. Conclusions: ProstaScint images are now closer to becoming a biologically and therapeutically useful and accurate image set. After known sources of normal intensity are stripped away, the remaining areas that demonstrate uptake may be segmented and superimposed on the treatment-planning CT/MRI volume.
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| 4. |
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| 5. |
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| 6. |
- Lee, Benjamin Y., et al.
(författare)
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Unmasking true signal/tumor information from ProstaScint scans
- 2004
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Ingår i: MEDICAL IMAGING 2004: IMAGE PROCESSING, PTS 1-3. - : SPIE - International Society for Optical Engineering. - 0819452831 ; , s. 1980-1990
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Konferensbidrag (refereegranskat)abstract
- Purpose: Improve tumor localization in In-111 ProstaScint SPECT scans through improved reconstruction and identification/removal of non-specific blood pool volumes using simultaneously acquired Tc-99m tagged red blood cell (RBC) SPECT scans. Methods: We chose 30 patients with a history of prostate cancer who had undergone CT/MR and simultaneous Tc-99m RBC/In-111 ProstaScint SPECT scans due to rising PSA. To estimate the impact of reconstruction methods on anatomic definition and artifacts, SPECT volume data sets were reconstructed using ordered set-expectation maximization (OS-EM) with varying numbers of iterations and subsets, and these were compared against each other and against standard filtered back projection (FBP) reconstruction. Non-blood pool bladder activity in the Tc-99m scans was suppressed prior to subtraction from the In-111 scans by using an averaging algorithm within an ellipsoid volume encompassing the bladder. Outside the ellipsoid volume, Tc-99m voxel values were subtracted from the corresponding In-111 voxels after normalization of the data sets based on peak activity within the descending aorta. Results: OS-EM reconstruction using 3 iterations and 45 subsets showed improved representation of anatomy compared with FBP. Bladder suppression reduced artifacts in the prostate bed. The subtraction method reduced the blood pool signal, confirmed visually by superimposition with matched CT/MR scans. Conclusions: OS-EM reconstruction together with bladder suppression and subtraction of the blood pool may help improve the specificity of ProstaScint SPECT interpretation and increase its utility in radiation therapy treatment planning.
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| 8. |
- Mahmoud, Faaiza, et al.
(författare)
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Comparison of three methods for registration of abdominal/pelvic volume data sets from functional-anatomic scans
- 2000
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Ingår i: SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. ; , s. 1378-1386
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Konferensbidrag (refereegranskat)abstract
- The purpose of this work was to evaluate three volumetric registration methods in terms of technique, user-friendliness and time requirements. CT and SPECT data from 11 patients were interactively registered using: a 3D method involving only affine transformation; a mixed 3D - 2D non-affine (warping) method; and a 3D non-affine (warping) method. In the first method representative isosurfaces are generated from the anatomical images. Registration proceeds through translation, rotation, and scaling in all three space variables. Resulting isosurfaces are fused and quantitative measurements are possible. In the second method, the 3D volumes are rendered co-planar by performing an oblique projection. Corresponding landmark pairs are chosen on matching axial slice sets. A polynomial warp is then applied. This method has undergone extensive validation and was used to evaluate the results. The third method employs visualization tools. The data model allows images to be localized within two separate volumes. Landmarks are chosen on separate slices. Polynomial warping coefficients are generated and data points from one volume are moved to the corresponding new positions. The two landmark methods were the least time consuming (10 to 30 minutes from start to finish), but did demand a good knowledge of anatomy. The affine method was tedious and required a fair understanding of 3D geometry.
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| 9. |
- Noz, Marilyn E., et al.
(författare)
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A versatile functional-anatomic image fusion method for volume data sets
- 2001
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Ingår i: Journal of medical systems. - 0148-5598 .- 1573-689X. ; 25:5, s. 297-307
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Tidskriftsartikel (refereegranskat)abstract
- We describe and validate a volumetric three-dimensional registration method, and compare it to our previously validated two-dimensional/three-dimensional method. {CT/MRI} and {SPECT} data from 14 patients were interactively fused using a polynomial warping technique. Registration accuracy was confirmed visually and by a nonsignificant F value from multivariate analysis of the transformed landmarks, a significant difference of the squared sum of intensity differences between the transformed/untransformed and the reference volume both at the 0.05 (p {\textgreater} 0.05) confidence level and an average 31\% improvement of the correlation coefficient and cross correlation. For the two-dimensional/three-dimensional method, {ROI} center-to-center distance ranged from 1.42 to 11.32 mm (for liver) with an average of 6.13 mm +/- 3.09 mm. The average {ROI} overlap was 92.51\% with a 95\% confidence interval of 90.20-96.88\%. The new method is superior because it operates on the true three-dimensional volume. Both methods give good registration results, take 10 to 30 min, and require anatomic knowledge.
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| 10. |
- Noz, Marilyn E., et al.
(författare)
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Can the specificity of MRI breast imaging be improved by fusing 3D MRI volume data sets with FDG PET?
- 2004
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Ingår i: 2004 2ND IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING. - : IEEE. - 0780383885 ; , s. 1388-1391
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Konferensbidrag (refereegranskat)abstract
- MRI of the breast is an important tool for early detection of breast cancer in women at increased risk for tumor. MRI has a proven track record in identifying tissue abnormalities, but often lacks the ability to characterize this tissue abnormality as benign or malignant, i.e., for certain tissue abnormalities the specificity of MRI is very high, while for others it may be 50% or less. This inability of MRI to differentiate between certain types of tissue abnormalities has lead to our interest in exploring whether the fusion of MRI scans with metabolic imaging (PET) scans can be helpful. 18-FDG PET provides information about the metabolism of the tissue in the breast which in tumors is generally increased. This technique is widely used for detection of other forms of cancer, but has not yet been systematically applied to primary breast cancer, although it has been used to detect local recurrence.
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