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Title: SU-F-I-19: MRI Positive Contrast Visualization of Prostate Brachytherapy Seeds Using An Integrated Laplacian-Based Phase Processing

Abstract

Purpose: To propose a new method that provides a positive contrast visualization of the prostate brachytherapy seeds using the phase information from MR images. Additionally, the feasibility of using the processed phase information to distinguish seeds from calcifications is explored. Methods: A gel phantom was constructed using 2% agar dissolved in 1 L of distilled water. Contrast agents were added to adjust the relaxation times. Four iodine-125 (Eckert & Ziegler SML86999) dummy seeds were placed at different orientations with respect to the main magnetic field (B0). Calcifications were obtained from a sheep femur cortical bone due to its close similarity to human bone tissue composition. Five samples of calcifications were shaped into different dimensions with lengths ranging between 1.2 – 6.1 mm.MR imaging was performed on a 3T Philips Achieva using an 8-channel head coil. Eight images were acquired at eight echo-times using a multi-gradient echo sequence. Spatial resolution was 0.7 × 0.7 × 2 mm, TR/TE/dTE = 20.0/2.3/2.3 ms and BW = 541 Hz/pixel. Complex images were acquired and fed into a two-step processing pipeline: the first includes phase unwrapping and background phase removal using Laplacian operator (Wei et al. 2013). The second step applies a specific phase maskmore » on the resulting tissue phase from the first step to provide the desired positive contrast of the seeds and to, potentially, differentiate them from the calcifications. Results: The phase-processing was performed in less than 30 seconds. The proposed method has successfully resulted in a positive contrast of the brachytherapy seeds. Additionally, the final processed phase image showed difference between the appearance of seeds and calcifications. However, the shape of the seeds was slightly distorted compared to the original dimensions. Conclusion: It is feasible to provide a positive contrast of the seeds from MR images using Laplacian operator-based phase processing.« less

Authors:
;  [1];  [2]; ;  [2];  [1]
  1. Sunnybrook Research Institute, Toronto, ON (Canada)
  2. Sunnybrook Health Sciences Center, Toronto, ON (Canada)
Publication Date:
OSTI Identifier:
22626789
Resource Type:
Journal Article
Journal Name:
Medical Physics
Additional Journal Information:
Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; AGAR; BIOMEDICAL RADIOGRAPHY; BONE TISSUES; BRACHYTHERAPY; CONTRAST MEDIA; FEMUR; IMAGES; IODINE 125; LAPLACIAN; NMR IMAGING; PHANTOMS; PROSTATE; RADIATION SOURCE IMPLANTS; SPATIAL RESOLUTION

Citation Formats

Soliman, A, Safigholi, H, Sunnybrook Health Sciences Center, Toronto, ON, Nosrati, R, Ryerson University, Toronto, ON, Owrangi, A, Morton, G, University of Toronto, Toronto, ON, Song, W, Sunnybrook Health Sciences Center, Toronto, ON, Ryerson University, Toronto, ON, and University of Toronto, Toronto, ON. SU-F-I-19: MRI Positive Contrast Visualization of Prostate Brachytherapy Seeds Using An Integrated Laplacian-Based Phase Processing. United States: N. p., 2016. Web. doi:10.1118/1.4955847.
Soliman, A, Safigholi, H, Sunnybrook Health Sciences Center, Toronto, ON, Nosrati, R, Ryerson University, Toronto, ON, Owrangi, A, Morton, G, University of Toronto, Toronto, ON, Song, W, Sunnybrook Health Sciences Center, Toronto, ON, Ryerson University, Toronto, ON, & University of Toronto, Toronto, ON. SU-F-I-19: MRI Positive Contrast Visualization of Prostate Brachytherapy Seeds Using An Integrated Laplacian-Based Phase Processing. United States. doi:10.1118/1.4955847.
Soliman, A, Safigholi, H, Sunnybrook Health Sciences Center, Toronto, ON, Nosrati, R, Ryerson University, Toronto, ON, Owrangi, A, Morton, G, University of Toronto, Toronto, ON, Song, W, Sunnybrook Health Sciences Center, Toronto, ON, Ryerson University, Toronto, ON, and University of Toronto, Toronto, ON. Wed . "SU-F-I-19: MRI Positive Contrast Visualization of Prostate Brachytherapy Seeds Using An Integrated Laplacian-Based Phase Processing". United States. doi:10.1118/1.4955847.
@article{osti_22626789,
title = {SU-F-I-19: MRI Positive Contrast Visualization of Prostate Brachytherapy Seeds Using An Integrated Laplacian-Based Phase Processing},
author = {Soliman, A and Safigholi, H and Sunnybrook Health Sciences Center, Toronto, ON and Nosrati, R and Ryerson University, Toronto, ON and Owrangi, A and Morton, G and University of Toronto, Toronto, ON and Song, W and Sunnybrook Health Sciences Center, Toronto, ON and Ryerson University, Toronto, ON and University of Toronto, Toronto, ON},
abstractNote = {Purpose: To propose a new method that provides a positive contrast visualization of the prostate brachytherapy seeds using the phase information from MR images. Additionally, the feasibility of using the processed phase information to distinguish seeds from calcifications is explored. Methods: A gel phantom was constructed using 2% agar dissolved in 1 L of distilled water. Contrast agents were added to adjust the relaxation times. Four iodine-125 (Eckert & Ziegler SML86999) dummy seeds were placed at different orientations with respect to the main magnetic field (B0). Calcifications were obtained from a sheep femur cortical bone due to its close similarity to human bone tissue composition. Five samples of calcifications were shaped into different dimensions with lengths ranging between 1.2 – 6.1 mm.MR imaging was performed on a 3T Philips Achieva using an 8-channel head coil. Eight images were acquired at eight echo-times using a multi-gradient echo sequence. Spatial resolution was 0.7 × 0.7 × 2 mm, TR/TE/dTE = 20.0/2.3/2.3 ms and BW = 541 Hz/pixel. Complex images were acquired and fed into a two-step processing pipeline: the first includes phase unwrapping and background phase removal using Laplacian operator (Wei et al. 2013). The second step applies a specific phase mask on the resulting tissue phase from the first step to provide the desired positive contrast of the seeds and to, potentially, differentiate them from the calcifications. Results: The phase-processing was performed in less than 30 seconds. The proposed method has successfully resulted in a positive contrast of the brachytherapy seeds. Additionally, the final processed phase image showed difference between the appearance of seeds and calcifications. However, the shape of the seeds was slightly distorted compared to the original dimensions. Conclusion: It is feasible to provide a positive contrast of the seeds from MR images using Laplacian operator-based phase processing.},
doi = {10.1118/1.4955847},
journal = {Medical Physics},
issn = {0094-2405},
number = 6,
volume = 43,
place = {United States},
year = {2016},
month = {6}
}