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Trumpour T, du Toit C, van Gaalen A, Park CKS, Rodgers JR, Mendez LC, Surry K, Fenster A. Three-dimensional trans-rectal and trans-abdominal ultrasound image fusion for the guidance of gynecologic brachytherapy procedures: a proof of concept study. Sci Rep 2024; 14:18459. [PMID: 39117682 PMCID: PMC11310523 DOI: 10.1038/s41598-024-69211-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 08/01/2024] [Indexed: 08/10/2024] Open
Abstract
High dose-rate brachytherapy is a treatment technique for gynecologic cancers where intracavitary applicators are placed within the patient's pelvic cavity. To ensure accurate radiation delivery, localization of the applicator at the time of insertion is vital. This study proposes a novel method for acquiring, registering, and fusing three-dimensional (3D) trans-abdominal and 3D trans-rectal ultrasound (US) images for visualization of the pelvic anatomy and applicators during gynecologic brachytherapy. The workflow was validated using custom multi-modal pelvic phantoms and demonstrated during two patient procedures. Experiments were performed for three types of intracavitary applicators: ring-and-tandem, ring-and-tandem with interstitial needles, and tandem-and-ovoids. Fused 3D US images were registered to magnetic resonance (MR) and computed tomography (CT) images for validation. The target registration error (TRE) and fiducial localization error (FLE) were calculated to quantify the accuracy of our fusion technique. For both phantom and patient images, TRE and FLE across all modality registrations (3D US versus MR or CT) resulted in mean ± standard deviation of 4.01 ± 1.01 mm and 0.43 ± 0.24 mm, respectively. This work indicates proof of concept for conducting further clinical studies leveraging 3D US imaging as an accurate, accessible alternative to advanced modalities for localizing brachytherapy applicators.
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Affiliation(s)
- Tiana Trumpour
- Department of Medical Biophysics, Western University, London, Canada.
- Robarts Research Institute, London, Canada.
| | | | - Alissa van Gaalen
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
| | - Claire K S Park
- Brigham and Women's Hospital and Dana-Farber Cancer Institute, Department of Radiation Oncology, Harvard Medical School, Boston, USA
| | - Jessica R Rodgers
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Canada
| | | | - Kathleen Surry
- Department of Medical Biophysics, Western University, London, Canada
- Verspeeten Family Cancer Centre, London, Canada
- Department of Oncology, Western University, London, Canada
| | - Aaron Fenster
- Department of Medical Biophysics, Western University, London, Canada
- Robarts Research Institute, London, Canada
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Van Elburg D, Meyer T, Martell K, Quirk S, Banerjee R, Phan T, Fenster A, Roumeliotis M. Clinical implementation of 3D transvaginal ultrasound for intraoperative guidance of needle implant in template interstitial gynecologic high-dose-rate brachytherapy. Brachytherapy 2023; 22:790-799. [PMID: 37722991 DOI: 10.1016/j.brachy.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 09/20/2023]
Abstract
PURPOSE To demonstrate novel clinical implementation of a 3D transvaginal ultrasound (3DTVUS) system for intraoperative needle insertion guidance in perineal template interstitial gynecologic high-dose-rate brachytherapy and assess its impact on implant quality. METHODS AND MATERIALS Interstitial implants began with preimplant 3DTVUS to visualize the tumor and anatomy, with intermittent 3DTVUS to assess the implant and guide needle adjustment. Analysis includes visualization of the implant relative to anatomy, identification of cases where 3DTVUS is beneficial, dosimetry, and a survey distributed to 3DTVUS clinicians. RESULTS Seven patients treated between November 2021 and October 2022 were included in this study. Twenty needles were inserted under 3DTVUS guidance. The tumor and vaginal wall were well-differentiated in four and all seven patients, respectively. Patients with tumours below the superior aspect of the vagina are suited for 3DTVUS. Four radiation oncologists responded to the survey. There was general agreement that 3DTVUS improves implant and anatomy visualization and is preferred over standard 2D ultrasound guidance techniques. CONCLUSIONS Based on qualitative feedback from primary users and a small preliminary patient cohort, 3DTVUS imaging improves tumor and vaginal wall visualization during gynecologic perineal template interstitial needle implant and is a powerful tool for implant assessment in an intraoperative setting.
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Affiliation(s)
- Devin Van Elburg
- Department of Physics & Astronomy, University of Calgary, Calgary AB, Canada; Medical Physics Department, Tom Baker Cancer Centre, Calgary AB, Canada.
| | - Tyler Meyer
- Department of Physics & Astronomy, University of Calgary, Calgary AB, Canada; Medical Physics Department, Tom Baker Cancer Centre, Calgary AB, Canada; Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary AB, Canada
| | - Kevin Martell
- Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary AB, Canada
| | - Sarah Quirk
- Department of Radiation Oncology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA
| | - Robyn Banerjee
- Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary AB, Canada
| | - Tien Phan
- Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary AB, Canada
| | - Aaron Fenster
- School of Biomedical Engineering, University of Western Ontario, London ON, Canada; Robarts Research Institute, University of Western Ontario, London ON, Canada
| | - Michael Roumeliotis
- Department of Radiation Oncology & Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD
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Van Elburg D, Roumeliotis M, Fenster A, Phan T, Meyer T. Technical Note: Commissioning of an ultrasound-compatible surrogate vaginal cylinder for transvaginal ultrasound-based gynecologic high-dose-rate brachytherapy. Med Phys 2022; 49:2203-2211. [PMID: 35199856 DOI: 10.1002/mp.15559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 01/19/2022] [Accepted: 02/12/2022] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To provide a comprehensive set of commissioning tests for clinical implementation of three-dimensional transvaginal ultrasound (3D TVUS) as a replacement of computed tomography (CT) for applicator reconstruction in gynecologic intracavitary high-dose-rate brachytherapy with a multi-channel vaginal cylinder. METHODS We introduce an ultrasound-compatible "surrogate" vaginal cylinder (SVC) for reconstruction of Elekta's CT-MR Multi Channel Applicator (MCVC) in 3D TVUS. The MCVC is digitized over the SVC in 3DUS using digital library model overlay. Consulting guidelines from various sources (CPQR, GEC-ESTRO, AAPM), we identify and describe three tests specific to commissioning the SVC: 1) verification of SVC outer dimensions, 2) source position accuracy of MCVC digitization over the SVC in 3D TVUS, and 3) MRI/US registration error. RESULTS The SVC outer dimensions (diameter and A-D marker locations) were well matched to the MCVC, however a 0.6 mm discrepancy in length between cylinder tips was observed. Source position accuracy was within 1 mm (tolerance recommended by CPQR) when reconstructing the MCVC in 3D TVUS. Dice similarity coefficients and target registration error for MRI/3D TVUS registration was similar to MRI/CT registration, which is the clinical standard. CONCLUSIONS These commissioning tests are performed using institutional equipment but provide the framework for any practitioners to repeat in their own setup, to demonstrate safe adoption of the 3D TVUS system for patient treatments. We demonstrate that MRI/US-based workflow achieves similar source position accuracy and image registration error as standard MRI/CT, which is consistent with standard tolerances. This is a critical step towards replacement of CT with US in gynecologic high-dose-rate brachytherapy treatments with the MCVC. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Devin Van Elburg
- Department of Physics & Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, T2N 4N2, Canada
| | - Michael Roumeliotis
- Department of Physics & Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, T2N 4N2, Canada.,Department of Oncology, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Aaron Fenster
- School of Biomedical Engineering, University of Western Ontario, London ON, N6A 3K7, Canada.,Robarts Research Institute, University of Western Ontario, London ON, N6A 5B7, Canada
| | - Tien Phan
- Department of Oncology, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Tyler Meyer
- Department of Physics & Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.,Medical Physics Department, Tom Baker Cancer Centre, Calgary, AB, T2N 4N2, Canada.,Department of Oncology, University of Calgary, Calgary, AB, T2N 1N4, Canada
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Rodgers JR, Mendez LC, Hoover DA, Bax J, D'Souza D, Fenster A. Feasibility of fusing three-dimensional transabdominal and transrectal ultrasound images for comprehensive intraoperative visualization of gynecologic brachytherapy applicators. Med Phys 2021; 48:5611-5623. [PMID: 34415069 DOI: 10.1002/mp.15175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 07/28/2021] [Accepted: 08/01/2021] [Indexed: 11/09/2022] Open
Abstract
PURPOSE In this study, we propose combining three-dimensional (3D) transrectal ultrasound (TRUS) and 3D transabdominal ultrasound (TAUS) images of gynecologic brachytherapy applicators to leverage the advantages of each imaging perspective, providing a broader field-of-view and allowing previously obscured features to be recovered. The aim of this study was to evaluate the feasibility of fusing these 3D ultrasound (US) perspectives based on the applicator geometry in a phantom prior to clinical implementation. METHODS In proof-of-concept experiments, 3D US images of application-specific multimodality pelvic phantoms were acquired with tandem-and-ring and tandem-and-ovoids applicators using previously validated imaging systems. Two TRUS images were acquired at different insertion depths and manually fused based on the position of the ring/ovoids to broaden the TRUS field-of-view. The phantom design allowed "abdominal thickness" to be modified to represent different body habitus and TAUS images were acquired at three thicknesses for each applicator. The merged TRUS images were then combined with TAUS images by rigidly aligning applicator components and manually refining the registration using the positions of source channels and known tandem length, as well as the ring diameter for the tandem-and-ring applicator. Combined 3D US images were manually, rigidly registered to images from a second modality (magnetic resonance (MR) imaging for the tandem-and-ring applicator and X-ray computed tomography (CT) for the tandem-and-ovoids applicator (based on applicator compatibility)) to assess alignment. Four spherical fiducials were used to calculate target registration errors (TREs), providing a metric for validating registrations, where TREs were computed using root-mean-square distances to describe the alignment of manually identified corresponding fiducials. An analysis of variance (ANOVA) was used to identify statistically significant differences (p < 0.05) between the TREs for the three abdominal thicknesses for each applicator type. As an additional indicator of geometric accuracy, the bladder was segmented in the 3D US and corresponding MR/CT images, and volumetric differences and Dice similarity coefficients (DSCs) were calculated. RESULTS For both applicator types, the combination of 3D TRUS with 3D TAUS images allowed image information obscured by the shadowing artifacts under single imaging perspectives to be recovered. For the tandem-and-ring applicator, the mean ± one standard deviation (SD) TREs from the images with increasing thicknesses were 1.37 ± 1.35 mm, 1.84 ± 1.22 mm, and 1.60 ± 1.00 mm. Similarly, for the tandem-and-ovoids applicator, the mean ± SD TREs from the images with increasing thicknesses were 1.37 ± 0.35 mm, 1.95 ± 0.90 mm, and 1.61 ± 0.76 mm. No statistically significant difference was detected in the TREs for the three thicknesses for either applicator type. The mean volume differences for the bladder segmentations were 3.14% and 2.33% and mean DSCs were 87.8% and 87.7% for the tandem-and-ring and tandem-and-ovoids applicators, respectively. CONCLUSIONS In this proof-of-concept study, we demonstrated the feasibility of fusing 3D TRUS and 3D TAUS images based on the geometry of tandem-and-ring and tandem-and-ovoids applicators. This represents a step toward an accessible and low-cost 3D imaging method for gynecologic brachytherapy, with the potential to extend this approach to other intracavitary configurations and hybrid applicators.
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Affiliation(s)
- Jessica Robin Rodgers
- School of Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - Lucas C Mendez
- Department of Radiation Oncology, London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
| | - Douglas A Hoover
- Department of Medical Physics, London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
| | - Jeffrey Bax
- Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
| | - David D'Souza
- Department of Radiation Oncology, London Regional Cancer Program, London Health Sciences Centre, London, Ontario, Canada
| | - Aaron Fenster
- School of Biomedical Engineering, The University of Western Ontario, London, Ontario, Canada.,Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada
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