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A Novel Positive-Contrast Magnetic Resonance Imaging Line Marker for High-Dose-Rate (HDR) MRI-Assisted Radiosurgery
Li Wang1, Yao Ding2, Teresa L Bruno3
1Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Cancers
|May 25, 2024
Summary
A new MRI positive-contrast marker, C4:S, enhances visualization of HDR brachytherapy applicators. This breakthrough enables precise imaging for MRI-Assisted Radiosurgery (MARS), improving cancer treatment planning.
Area of Science:
- Medical Imaging
- Radiotherapy
- Materials Science
Background:
- High-dose-rate (HDR) MRI-Assisted Radiosurgery (MARS) requires accurate organ delineation and dose distribution.
- Current MRI techniques lack positive-contrast markers for clear applicator lumen and HDR source path visualization.
- This limitation hinders precise treatment planning in HDR MARS.
Purpose of the Study:
- To investigate a novel positive-contrast MRI line marker, C4:S, for HDR brachytherapy.
- To assess the visibility and contrast properties of C4:S on T1- and T2-weighted MRI sequences.
- To evaluate the potential of C4:S for MRI-guided HDR MARS planning.
Main Methods:
- Synthesized C4:S, a complex of C4 and saline, as a positive-contrast marker.
- Measured longitudinal (T1) and transverse (T2) relaxation times of C4:S at 1.5 T.
- Tested C4:S-filled HDPE tubing in a pelvis phantom for MRI visibility on T1- and T2-weighted sequences.
Main Results:
- C4:S demonstrated good T1- and T2-weighted contrast at room and body temperatures.
- Relaxivity measurements confirmed effective contrast properties (r2/r1 > 1).
- C4:S-filled HDPE tubing was clearly visualized as a positive line marker on both MRI sequences.
Conclusions:
- C4:S functions as an effective positive-contrast MRI line marker for HDR brachytherapy.
- The marker is visible on both T1- and T2-weighted MRI sequences, independent of orientation.
- C4:S holds promise for enabling MRI-guided HDR planning in MARS for various cancers.
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