Abstract
PURPOSE
A pointwise encoding time reduction with radial acquisition (PETRA) sequence was optimized
to detect empty catheters in interstitial (HDR) brachytherapy with clinically acceptable
spatial accuracy for the first time. Image quality and catheter detectability were
assessed in phantoms, and the feasibility of PETRA's clinical implementation was assessed
on a gynecological cancer patient.
METHODS AND RESULTS
Empty catheters embedded in a gelatin phantom displayed positive signal on PETRA and
more accurate cross-sections than on clinically employed T2-weighted sequences, differing
by 0.4 mm on average from their nominal 2 mm diameter. PETRA presented minimal susceptibility
differences and a symmetric metal artifact, contrary to the clinical sequences. The
PETRA-CT catheter tip position differences assessed by a treatment planning system
(TPS) were < 1 mm. PETRA also detected an interstitial template with empty catheters
penetrating a poultry phantom and fused very well with CT. Interstitial catheter positional
difference between PETRA and CT images was < 1 mm on average, increasing with distance
from isocenter. All interstitial catheters and the employed interstitial template
were detected on PETRA images of an endometrial adenocarcinoma patient. Empty needles
were traceable using a TPS, with higher spatial resolution and more favorable contrast
than on T2-weighted images used for contouring. A treatment plan could be produced
by combining information from PETRA for catheter detection and from T2-weighted images
for tumor and organs delineation.
CONCLUSIONS
PETRA detected successfully and accurately interstitial catheters in phantoms. Its
first clinical implementation shows a potential for MR-only treatment planning in
interstitial HDR brachytherapy.
Keywords
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References
- Recommendations from Gynecological (GYN) GEC-ESTRO Working Group (4): basic principles and parameters for MR imaging within the frame of image based adaptive cervix cancer brachytherapy.Radiother Oncol J Eur Soc Ther Radiol Oncol. 2012; 103: 113-122
- Air kerma and absorbed dose standards for reference dosimetry in brachytherapy.Br J Radiol. 2014; 87: 10
- Review of strategies for MRI based reconstruction of endocavitary and interstitial applicators in brachytherapy of cervical cancer.Reports Pract Oncol Radiother [Internet]. 2018; 23: 547-561https://doi.org/10.1016/j.rpor.2018.06.005
- Task group 284 report: magnetic resonance imaging simulation in radiotherapy: considerations for clinical implementation, optimization, and quality assurance.Med Phys. 2021; 48: e652-e657
- Code of practice for brachytherapy physics: report of the AAPM radiation therapy committee task group no. 56.Med Phys. 1997; 24: 1557-1598
- Potential applications of the quantitative susceptibility mapping (QSM) in MR-guided radiation therapy.Phys Med Biol [Internet]. 2019; 64: ab2623https://doi.org/10.1088/1361-6560/ab2623
- Clinical utility and value contribution of an MRI-positive line marker for image-guided brachytherapy in gynecologic malignancies.Brachytherapy. 2020; 19: 305-315
- Three-dimensional ultrashort echo time imaging of solid polymers on a 3-tesla whole-body MRI scanner.Invest Radiol. 2008; 43: 802-808
- Clinical ultrashort echo time imaging of bone and other connective tissues.NMR Biomed. 2006; 19: 765-780
- Applicator visualization using ultrashort echo time MRI for high-dose-rate endorectal brachytherapy.Brachytherapy [Internet]. 2020; 19: 618-623https://doi.org/10.1016/j.brachy.2020.06.010
- MRI with zero echo time: hard versus sweep pulse excitation.Magn Reson Med. 2011; 66: 379-389
- Ultrashort echo time imaging using pointwise encoding time reduction with radial acquisition (PETRA).Magn Reson Med. 2012; 67: 510-518
- Ultrashort echo (UTE) versus pointwise encoding time reduction with radial acquisition (PETRA) sequences at 3 Tesla for knee meniscus: a comparative study.Magn Reson Imaging. 2016; 34: 75-80
- Biopsy Needle Susceptibility Artifacts in Magnetic Resonance Imaging.Magn Reson Med. 1996; 36: 646-651
- MRI visualization of applicators for skin HDR brachytherapy.in: AAPM virtual conference. 2020 ([Internet]Available at:)
- Review of clinical brachytherapy uncertainties: analysis guidelines of GEC-ESTRO and the AAPM.Radiother Oncol. 2014; 110: 199-212
- Buzurovic I. Feasibility of MR-only high-dose-rate (HDR) surface brachytherapy for clinical application.Med Phys. 2021; 48: 7313-7322
Article Info
Publication History
Published online: March 22, 2022
Accepted:
January 15,
2022
Received in revised form:
December 15,
2021
Received:
September 25,
2021
Footnotes
Disclosures: The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article. This work was funded by the Taiclet MR-Program in Radiation Oncology awards 2020.
Identification
Copyright
© 2022 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.
