Title |
Evaluating organ delineation, dose calculation and daily localization in an open-MRI simulation workflow for prostate cancer patients
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Published in |
Radiation Oncology, February 2015
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DOI | 10.1186/s13014-014-0309-0 |
Pubmed ID | |
Authors |
Anthony Doemer, Indrin J Chetty, Carri Glide-Hurst, Teamour Nurushev, David Hearshen, Milan Pantelic, Melanie Traughber, Joshua Kim, Kenneth Levin, Mohamed A Elshaikh, Eleanor Walker, Benjamin Movsas |
Abstract |
This study describes initial testing and evaluation of a vertical-field open Magnetic Resonance Imaging (MRI) scanner for the purpose of simulation in radiation therapy for prostate cancer. We have evaluated the clinical workflow of using open MRI as a sole modality for simulation and planning. Relevant results related to MRI alignment (vs. CT) reference dataset with Cone-Beam CT (CBCT) for daily localization are presented. Ten patients participated in an IRB approved study utilizing MRI along with CT simulation with the intent of evaluating the MRI-simulation process. Differences in prostate gland volume, seminal vesicles, and penile bulb were assessed with MRI and compared to CT. To evaluate dose calculation accuracy, bulk-density-assignments were mapped onto respective MRI datasets and treated IMRT plans were re-calculated. For image localization purposes, 400 CBCTs were re-evaluated with MRI as the reference dataset and daily shifts compared against CBCT-to-CT registration. Planning margins based on MRI/CBCT shifts were computed using the van Herk formalism. Significant organ contour differences were noted between MRI and CT. Prostate volumes were on average 39.7% (p = 0.002) larger on CT than MRI. No significant difference was found in seminal vesicle volumes (p = 0.454). Penile bulb volumes were 61.1% higher on CT, without statistical significance (p = 0.074). MRI-based dose calculations with assigned bulk densities produced agreement within 1% with heterogeneity corrected CT calculations. The differences in shift positions for the cohort between CBCT-to-CT registration and CBCT-to-MRI registration are -0.15 ± 0.25 cm (anterior-posterior), 0.05 ± 0.19 cm (superior-inferior), and -0.01 ± 0.14 cm (left-right). This study confirms the potential of using an open-field MRI scanner as primary imaging modality for prostate cancer treatment planning simulation, dose calculations and daily image localization. |
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Country | Count | As % |
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United Kingdom | 2 | 50% |
United States | 1 | 25% |
Guatemala | 1 | 25% |
Demographic breakdown
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Science communicators (journalists, bloggers, editors) | 1 | 25% |
Scientists | 1 | 25% |
Mendeley readers
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Unknown | 82 | 99% |
Demographic breakdown
Readers by professional status | Count | As % |
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Student > Master | 19 | 23% |
Unspecified | 10 | 12% |
Student > Bachelor | 8 | 10% |
Other | 7 | 8% |
Student > Ph. D. Student | 7 | 8% |
Other | 16 | 19% |
Unknown | 16 | 19% |
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Unspecified | 10 | 12% |
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Computer Science | 3 | 4% |
Other | 11 | 13% |
Unknown | 21 | 25% |