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Hobson MA, Hu Y, Caldwell B, Cohen GN, Glide-Hurst C, Huang L, Jackson PD, Jang S, Langner U, Lee HJ, Levesque IR, Narayanan S, Park JC, Steffen J, Wu QJ, Zhou Y. AAPM Task Group 334: A guidance document to using radiotherapy immobilization devices and accessories in an MR environment. Med Phys 2024; 51:3822-3849. [PMID: 38648857 DOI: 10.1002/mp.17061] [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: 07/10/2023] [Revised: 11/13/2023] [Accepted: 03/28/2024] [Indexed: 04/25/2024] Open
Abstract
Use of magnetic resonance (MR) imaging in radiation therapy has increased substantially in recent years as more radiotherapy centers are having MR simulators installed, requesting more time on clinical diagnostic MR systems, or even treating with combination MR linear accelerator (MR-linac) systems. With this increased use, to ensure the most accurate integration of images into radiotherapy (RT), RT immobilization devices and accessories must be able to be used safely in the MR environment and produce minimal perturbations. The determination of the safety profile and considerations often falls to the medical physicist or other support staff members who at a minimum should be a Level 2 personnel as per the ACR. The purpose of this guidance document will be to help guide the user in making determinations on MR Safety labeling (i.e., MR Safe, Conditional, or Unsafe) including standard testing, and verification of image quality, when using RT immobilization devices and accessories in an MR environment.
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Affiliation(s)
- Maritza A Hobson
- Department of Radiation Oncology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Yanle Hu
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, Arizona, USA
| | - Barrett Caldwell
- School of Industrial Engineering, Purdue University, West Lafayette, Indiana, USA
- School of Aeronautics and Astronautics, Purdue University, West Lafayette, Indiana, USA
| | - Gil'ad N Cohen
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
| | - Carri Glide-Hurst
- Department of Human Oncology, University of Wisconsin--Madison, Madison, Wisconsin, USA
- Department of Medical Physics, University of Wisconsin--Madison, Madison, Wisconsin, USA
| | - Long Huang
- Department of Radiation Oncology, University of Utah, Salt Lake City, Utah, USA
| | - Paul D Jackson
- Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan, USA
| | - Sunyoung Jang
- Department of Radiation Oncology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Ulrich Langner
- Department of Radiation Oncology, Rhode Island Hospital, Providence, Rhode Island, USA
| | - Hannah J Lee
- Corewell Health William Beaumont University Hospital, Royal Oak, Michigan, USA
| | - Ives R Levesque
- Gerald Bronfman Department of Oncology and Medical Physics Unit, McGill University, Montreal, QC, Canada
- Department of Medical Physics, McGill University Health Centre, Cedars Cancer Centre, Montreal, QC, Canada
| | - Sreeram Narayanan
- Department of Radiation Oncology, Virginia Mason Cancer Institute, Seattle, Washington, USA
| | - Justin C Park
- Division of Medical Physics, Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA
| | | | - Q Jackie Wu
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - Yong Zhou
- Department of Radiology Services, Corewell Health, Grand Rapids, Michigan, USA
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Aleong AM, Berlin A, Borg J, Helou J, Beiki-Ardakani A, Rink A, Raman S, Chung P, Weersink RA. Rapid multi-catheter segmentation for magnetic resonance image-guided catheter-based interventions. Med Phys 2024. [PMID: 38713919 DOI: 10.1002/mp.17117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 04/02/2024] [Accepted: 04/18/2024] [Indexed: 05/09/2024] Open
Abstract
BACKGROUND Magnetic resonance imaging (MRI) is the gold standard for delineating cancerous lesions in soft tissue. Catheter-based interventions require the accurate placement of multiple long, flexible catheters at the target site. The manual segmentation of catheters in MR images is a challenging and time-consuming task. There is a need for automated catheter segmentation to improve the efficiency of MR-guided procedures. PURPOSE To develop and assess a machine learning algorithm for the detection of multiple catheters in magnetic resonance images used during catheter-based interventions. METHODS In this work, a 3D U-Net was trained to retrospectively segment catheters in scans acquired during clinical MR-guided high dose rate (HDR) prostate brachytherapy cases. To assess confidence in segmentation, multiple AI models were trained. On clinical test cases, average segmentation results were used to plan the brachytherapy delivery. Dosimetric parameters were compared to the original clinical plan. Data was obtained from 35 patients who underwent HDR prostate brachytherapy for focal disease with a total of 214 image volumes. 185 image volumes from 30 patients were used for training using a five-fold cross validation split to divide the data for training and validation. To generate confidence measures of segmentation accuracy, five trained models were generated. The remaining five patients (29 volumes) were used to test the performance of the trained model by comparison to manual segmentations of three independent observers and assessment of dosimetric impact on the final clinical brachytherapy plans. RESULTS The network successfully identified 95% of catheters in the test set at a rate of 0.89 s per volume. The multi-model method identified the small number of cases where AI segmentation of individual catheters was poor, flagging the need for user input. AI-based segmentation performed as well as segmentations by independent observers. Plan dosimetry using AI-segmented catheters was comparable to the original plan. CONCLUSION The vast majority of catheters were accurately identified by AI segmentation, with minimal impact on plan outcomes. The use of multiple AI models provided confidence in the segmentation accuracy and identified catheter segmentations that required further manual assessment. Real-time AI catheter segmentation can be used during MR-guided insertions to assess deflections and for rapid planning of prostate brachytherapy.
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Affiliation(s)
- Amanda M Aleong
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Alejandro Berlin
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Jette Borg
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Joelle Helou
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Akbar Beiki-Ardakani
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Alexandra Rink
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Srinivas Raman
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Peter Chung
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Robert A Weersink
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Department of Radiation Medicine, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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Portocarrero-Bonifaz A, Syed S, Kassel M, McKenzie GW, Shah VM, Forry BM, Gaskins JT, Sowards KT, Avula TB, Masters A, Silva SR. Dosimetric and toxicity comparison between Syed-Neblett and Fletcher-Suit-Delclos Tandem and Ovoid applicators in high dose rate cervix cancer brachytherapy. Brachytherapy 2024:S1538-4721(24)00045-X. [PMID: 38643046 DOI: 10.1016/j.brachy.2024.03.003] [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: 12/20/2023] [Revised: 02/21/2024] [Accepted: 03/06/2024] [Indexed: 04/22/2024]
Abstract
PURPOSE To compare patient and tumor characteristics, dosimetry, and toxicities between interstitial Syed-Neblett and intracavitary Fletcher-Suit-Delclos Tandem and Ovoid (T&O) applicators in high dose rate (HDR) cervical cancer brachytherapy. METHODS A retrospective analysis was performed for cervical cancer patients treated with 3D-based HDR brachytherapy from 2011 to 2023 at a single institution. Dosimetric parameters for high-risk clinical target volume and organs at risk were obtained. Toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 5.0. RESULTS A total of 115 and 58 patients underwent Syed and T&O brachytherapy, respectively. Patients treated with Syed brachytherapy were more likely to have larger tumors and FIGO stage III or IV disease. The median D2cc values to the bladder, small bowel, and sigmoid colon were significantly lower for Syed brachytherapy. Patients treated with Syed brachytherapy were significantly more likely to be free of acute gastrointestinal (44% vs. 21%, p = 0.003), genitourinary (58% vs. 36%, p = 0.01), and vaginal toxicities (60% vs. 33%, p = 0.001) within 6 months following treatment compared to patients treated with T&O applicators. In contrast, Syed brachytherapy patients were more likely to experience late gastrointestinal (68% vs. 49%, p = 0.082), genitourinary (51% vs. 35%, p = 0.196), and vaginal toxicities (70% vs. 57%, p = 0.264). CONCLUSIONS Syed-Neblett and T&O applicators are suitable for HDR brachytherapy for cervical cancer in distinct patient populations. Acute toxicities are more prevalent with T&O applicators, while patients treated with Syed-Neblett applicators are more likely to develop late toxicities.
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Affiliation(s)
- Andres Portocarrero-Bonifaz
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY; Physics Department, Pontificia Universidad Catolica del Peru, Lima, Peru.
| | - Salman Syed
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Maxwell Kassel
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Grant W McKenzie
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Vishwa M Shah
- Department of Gynecologic Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Bryce M Forry
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Jeremy T Gaskins
- Department of Bioinformatics & Biostatistics, University of Louisville School of Public Health and Information Sciences, Louisville, KY
| | - Keith T Sowards
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Thulasi Babitha Avula
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Adrianna Masters
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
| | - Scott R Silva
- Department of Radiation Oncology, Brown Cancer Center, University of Louisville School of Medicine, Louisville, KY
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Poulin E, Lacroix F, Archambault L, Jutras JD. Commissioning and implementing a Quality Assurance program for dedicated radiation oncology MRI scanners. J Appl Clin Med Phys 2024; 25:e14185. [PMID: 38332556 DOI: 10.1002/acm2.14185] [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: 01/20/2023] [Revised: 09/20/2023] [Accepted: 10/05/2023] [Indexed: 02/10/2024] Open
Abstract
PURPOSE ACR and AAPM task group's guidelines addressing commissioning for dedicated MR simulators were recently published. The goal of the current paper is to present the authors' 2-year experience regarding the commissioning and introduction of a QA program based on these guidelines and an associated automated workflow. METHODS All mandatory commissioning tests suggested by AAPM report 284 were performed and results are reported for two MRI scanners (MAGNETOM Sola and Aera). Visual inspection, vendor clinical or service platform, third-party software, or in-house python-based code were used. Automated QA and data analysis was performed via vendor, in-house or third-party software. QATrack+ was used for QA data logging and storage. 3D geometric distortion, B0 inhomogeneity, EPI, and parallel imaging performance were evaluated. RESULTS Contrasting with AAPM report 284 recommendations, homogeneity and RF tests were performed monthly. The QA program allowed us to detect major failures over time (shimming, gradient calibration and RF interference). Automated QA, data analysis, and logging allowed fast ACR analysis daily and monthly QA to be performed in 3 h. On the Sola, the average distortion is 1 mm for imaging radii of 250 mm or less. For radii of up to 200 mm, the maximum, average (standard deviation) distortion is 1.2 and 0.4 mm (0.3 mm). Aera values are roughly double the Sola for radii up to 200 mm. EPI geometric distortion, ghosting ratio, and long-term stability were found to be under the maximum recommended values. Parallel imaging SNR ratio was stable and close to the theoretical value (ideal g-factor). No major failures were detected during commissioning. CONCLUSION An automated workflow and enhanced QA program allowed to automatically track machine and environmental changes over time and to detect periodic failures and errors that might otherwise have gone unnoticed. The Sola is more geometrically accurate, with a more homogenous B0 field than the Aera.
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Affiliation(s)
- Eric Poulin
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada
- Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec-Université Laval, Québec, Canada
| | - Frederic Lacroix
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada
- Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec-Université Laval, Québec, Canada
| | - Louis Archambault
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada
- Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec-Université Laval, Québec, Canada
| | - Jean-David Jutras
- Département de physique, de génie physique et d'optique et Centre de recherche sur le cancer de l'Université Laval, Université Laval, Québec, Canada
- Département de radio-oncologie et Axe Oncologie du Centre de recherche du CHU de Québec, CHU de Québec-Université Laval, Québec, Canada
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Gomez-Sarmiento IN, Tho D, Dürrbeck C, de Jager W, Laurendeau D, Beaulieu L. Accuracy of an electromagnetic tracking enabled afterloader based on the automated registration with CT phantom images. Med Phys 2024; 51:799-808. [PMID: 38127342 DOI: 10.1002/mp.16903] [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: 08/06/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Electromagnetic tracking (EMT) has been researched for brachytherapy applications, showing a great potential for automating implant reconstruction, and overcoming image-based limitations such as contrast and spatial resolution. One of the challenges of this technology is that it does not intrinsically share the same reference frame as the patient's medical imaging. PURPOSE To present a novel phantom that can be used for a comprehensive quality assurance (QA) program of brachytherapy EMT systems and use this phantom to validate a novel applicator-based registration method of EMT and image reference frames for gynecological (GYN) interstitial brachytherapy. MATERIALS AND METHODS Eleven 6F-catheters (20 cm long), one 6F round tip catheter (29.4 cm long) and a tandem and ring gynecological applicator (Elekta, CT/MR 60°, 40 mm long tandem, 30 mm diameter ring) were placed in a rigid custom-made phantom (Elekta Brachytherapy, Veenendaal, The Netherlands) to reconstruct their geometry using a five-degree of freedom EMT sensor attached to an afterloader's check cable. All EMT reconstructions were done in three different environments: disturbance free (no metal nearby), computed tomography (CT)-on-rails brachytherapy suite and magnetic resonance imaging (MRI) brachytherapy suite. Implants were placed parallel to a magnetic field generatorand were reconstructed using two different acquisition methods: step-and-record and continuous motion. In all cases, the acquisition is performed at a rate of approximately 40 Hz. A CT scan of the phantom inside a water cube was obtained. In the treatment planning system (TPS), all catheters in the CT images were manually reconstructed and the applicator reconstruction was achieved by manually placing its solid 3D model, found in the applicator library of the TPS. The Iterative Closest Point and the Coherent Point Drift algorithms were used, initialized with four known points, to register both EMT and CT scan reference frames using corresponding points from the EMT and CT based reconstructions of the phantom, following three approaches: one gynecological applicator, four interstitial catheters inside four calibration plates having an S-shaped path, and four 5 mm diameter ceramic marbles found in each of the four calibration plates. Once registered, the registration error (perpendicular distance) was computed. RESULTS The absolute median deviation from the expected value for EMT measurements in the disturbance free environment, CT-on-rails brachytherapy suite, and MRI-brachytherapy suite are 0.41, 0.23, and 0.31 mm, respectively, while for the CT scan it is 0.18 mm. These values significantly lie below the sensor's expected accuracy of 0.70 mm (p < 0.001), suggesting that the environment did not have a significant impact on the measurements, given that care is taken in the immediate surroundings. In all three environments, the two acquisitions and three registration approaches have mean and median registration errors that lie at or below 1 mm, which is lower than the clinical acceptable threshold of 2 mm. CONCLUSIONS The novel phantom allowed to successfully evaluate the accuracy of EMT-based reconstructions of catheters and a GYN tandem and ring applicator in different clinical environments. A registration method based only on the applicator geometry, reconstructed withan EMT sensor and the TPS solid applicator library, was validated and shows clinically acceptable accuracy, comparable to CT-based reconstruction but within a few minutes. Since the applicator is also visible in MRI, this method could potentially be used in clinics in an EMT-MR interstitial GYN brachytherapy workflow.
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Affiliation(s)
- Isaac Neri Gomez-Sarmiento
- Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer, Université Laval, Québec, Québec, Canada
- Service de physique médicale et de radioprotection, Centre Intégré de Cancérologie, CHU de Québec - Université Laval et Centre de recherche du CHU de Québec, Québec, Québec, Canada
| | - Daline Tho
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Christopher Dürrbeck
- Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
- Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany
| | - Wim de Jager
- Elekta Brachytherapy, Veenendaal, The Netherlands
| | - Denis Laurendeau
- Département de génie électrique et de génie informatique, Faculté de sciences et de génie, Université Laval, Québec, Québec, Canada
| | - Luc Beaulieu
- Département de physique, de génie physique et d'optique, et Centre de recherche sur le cancer, Université Laval, Québec, Québec, Canada
- Service de physique médicale et de radioprotection, Centre Intégré de Cancérologie, CHU de Québec - Université Laval et Centre de recherche du CHU de Québec, Québec, Québec, Canada
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Massock W, Kim Y, Dresner MA, Sun W, Caster J, Adams Q, Jespersen J, St-Aubin J. MRI-Guided High-Dose-Rate Gynecologic Brachytherapy Using an MR-Linac as an MR Simulator: A Single Institutional Experience. Pract Radiat Oncol 2024; 14:70-79. [PMID: 37652344 DOI: 10.1016/j.prro.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/07/2023] [Accepted: 08/19/2023] [Indexed: 09/02/2023]
Abstract
PURPOSE The goal of this study was to commission the use of a magnetic resonance linear accelerator (MR-linac; Unity) for imaging of gynecologic high-dose-rate (HDR) brachytherapy. This included optimizing imaging protocols and workflow development. METHODS AND MATERIALS T1-weighted and T2-weighted HDR imaging protocols were optimized on the Unity for HDR gynecologic imaging and treatment planning. Phantom measurements using these protocols were performed to determine geometric distortion and to assess reconstruction accuracy of the applicator compared with the ground truth computed tomography image. A treatment plan was created within the treatment planning system that was then delivered to a phantom. New workflows were developed which were tested with a full dry run with a healthy volunteer including patient transfer, anesthesia considerations, and data transfer. Validation of the workflow was completed on 1 patient who received imaging on both the Unity magnetic resonance imaging (MRI) and on a dedicated 3 Tesla MRI simulator. RESULTS Imaging analysis results were favorable with MR-linac images with a maximum distortion of 0.96 mm and a 1.36-mm over a 350-mm diameter spherical volume on the T1- and T2-weighted images, respectively, and the maximum effect of the applicator was 0.36 ppm of the main magnetic field. Reconstruction uncertainties of the Venezia applicator's tandem and 2 lunar-ovoids on the MR-linac images were within the 2-mm tolerance of the International Commission on Radiation Units and Measurements Report 89. Treatment planning and delivery was performed on the MR-HDR quality assurance phantom without issue. Dry run and healthy volunteer imaging showed adequate performance of both vital monitoring and HDR equipment. For the patient for which both the Unity MRI and 3 Tesla images were acquired, 95.78% and 95.80% of the high risk clinical target volume received 100% of the dose, respectively. Both plans were considered clinically acceptable. CONCLUSIONS Unity MR-linac images were successfully used in gynecologic HDR brachytherapy treatment planning, and a usable workflow was established.
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Affiliation(s)
- Whitney Massock
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Yusung Kim
- Department of Radiation Physics, MD Anderson Cancer Center, Houston, Texas
| | | | - Wenqing Sun
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Joseph Caster
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Quentin Adams
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Jill Jespersen
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
| | - Joel St-Aubin
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa.
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Kanani A, Fatemi-Ardakani A, Owrangi AM, Yazdi M, Baghbani H, Mosleh-Shirazi MA. Quantification of Artifacts and Image Distortions in 1.5 Tesla Magnetic Resonance Images of a Commercial Multi-Channel Vaginal Cylinder Brachytherapy Applicator Set. J Biomed Phys Eng 2023; 13:523-534. [PMID: 38148963 PMCID: PMC10749412 DOI: 10.31661/jbpe.v0i0.2309-1665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 10/08/2023] [Indexed: 12/28/2023]
Abstract
Background The BEBIG Portio multi-channel applicator provides better target dose coverage and sparing organs-at-risk compared to a single-channel cylinder. However, artifacts and distortions of Portio in magnetic resonance images (MRI) have not yet been reported. Objective We aimed to quantify the artifacts and distortions in its 1.5-Tesla MR images before clinical use. Material and Methods In this experimental study, we employed a gelatin-filled phantom to conduct our measurements. T2-weighted (T2W) images were examined for artifacts and distortions. Computed tomography (CT) images were used as a reference to assess image distortions. Artifact severity was measured by recording the full-width-at-half-maximum (FWHM) image pixel values at various positions along the length of the applicator/channels. CT and MRI-based applicator reconstruction accuracy were then compared, and signal-to-noise ratio (SNR) and contrast were also determined for the applicator images. Results The applicator distortion level for the Portio applicator was less than the image spatial resolution (0.5±0.5 pixels). The average FWHM for the tandem applicator images was 5.23±0.39 mm, while it was 3.21±0.37 mm for all channels (compared to their actual diameters of 5.0 mm and 3.0 mm, respectively). The average applicator reconstruction difference between CT and MR images was 0.75±0.30 mm overall source dwell positions. The image SNR and contrast were both acceptable. Conclusion These findings indicate that the Portio applicator has a satisfactory low level of artifacts and image distortions in 1.5-Tesla, T2W images. It may, therefore, be a promising option for MRI-guided multi-channel vaginal brachytherapy.
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Affiliation(s)
- Abolfazl Kanani
- Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Fatemi-Ardakani
- Department of Physics, Jackson State University (JSU), Jackson, Mississippi, USA
- SpinTecx, Jackson, Mississippi, USA
- Department of Radiation Oncology, Community Health Systems (CHS) Cancer Network, Jackson, Mississippi, USA
| | - Amir M Owrangi
- Department of Radiation Oncology, UT Southwestern Medical Center, 2280 Inwood Rd, EC2.242, Dallas, TX 75235, USA
| | - Mehran Yazdi
- Signal and Image Processing Lab (SIPL), School of Electrical and Computer Eng, Shiraz University, Shiraz, Iran
| | - Hadi Baghbani
- Department of Radiology, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Amin Mosleh-Shirazi
- Ionizing and Non-Ionizing Radiation Protection Research Center (INIRPRC), School of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
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8
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Fagerstrom JM. Practical experience commissioning MRI-compatible tandem and ring applicators for use with the Bravos HDR afterloader. J Appl Clin Med Phys 2023; 24:e14094. [PMID: 37469228 PMCID: PMC10647988 DOI: 10.1002/acm2.14094] [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: 03/21/2023] [Revised: 05/10/2023] [Accepted: 06/22/2023] [Indexed: 07/21/2023] Open
Abstract
Five complete MR-conditionally approved ring sets, including fifteen tandems, and two additional rings, were commissioned at an institution intending to use them in an MRI planning environment with a Bravos HDR brachytherapy remote afterloader. Channel length, radiograph, autoradiograph, ring offset, and treatment interrupt measurements were performed, and applicators were assessed in both CT and MRI. During commissioning, one ring was found to be defective and was returned to the manufacturer for a replacement. The eventual complete applicator suite (including the replacement ring) was found to follow the manufacturer-provided specifications, including those delineated in vendor-provided 3D virtual models and those defined within the manufacturer's instructions for use documentation. Based on this work, an offset correction of -0.4 cm will be used for all tested rings using the Bravos system's internal distal dwell position correction feature during treatment preparation. This study reiterated the requirement for careful commissioning of each applicator intended for clinical service considering the intended use and the planned clinical environment and work processes.
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Affiliation(s)
- Jessica M. Fagerstrom
- Radiation OncologyUniversity of WashingtonSeattleWashingtonUSA
- Kaiser PermanenteSeattleWashingtonUSA
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9
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Oliver-Cañamás L, Vijande J, Candela-Juan C, Gimeno-Olmos J, Pujades-Claumarchirant MC, Rovira-Escutia JJ, Ballester F, Perez-Calatayud J. A User-Friendly System for Mailed Dosimetric Audits of 192Ir or 60Co HDR Brachytherapy Sources. Cancers (Basel) 2023; 15:cancers15092484. [PMID: 37173950 PMCID: PMC10177083 DOI: 10.3390/cancers15092484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
OBJECTIVES The main goal of this work is to design and characterize a user-friendly methodology to perform mailed dosimetric audits in high dose rate (HDR) brachytherapy for systems using either Iridium-192 (192Ir) or Cobalt-60 (60Co) sources. METHODS A solid phantom was designed and manufactured with four catheters and a central slot to place one dosimeter. Irradiations with an Elekta MicroSelectron V2 for 192Ir, and with a BEBIG Multisource for 60Co were performed for its characterization. For the dose measurements, nanoDots, a type of optically stimulated luminescent dosimeters (OSLDs), were characterized. Monte Carlo (MC) simulations were performed to evaluate the scatter conditions of the irradiation set-up and to study differences in the photon spectra of different 192Ir sources (Microselectron V2, Flexisource, BEBIG Ir2.A85-2 and Varisource VS2000) reaching the dosimeter in the irradiation set-up. RESULTS MC simulations indicate that the surface material on which the phantom is supported during the irradiations does not affect the absorbed dose in the nanoDot. Generally, differences below 5% were found in the photon spectra reaching the detector when comparing the Microselectron V2, the Flexisource and the BEBIG models. However, differences up to 20% are observed between the V2 and the Varisource VS2000 models. The calibration coefficients and the uncertainty in the dose measurement were evaluated. CONCLUSIONS The system described here is able to perform dosimetric audits in HDR brachytherapy for systems using either 192Ir or 60Co sources. No significant differences are observed between the photon spectra reaching the detector for the MicroSelectron V2, the Flexisource and the BEBIG 192Ir sources. For the Varisource VS2000, a higher uncertainty is considered in the dose measurement to allow for the nanoDot response.
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Affiliation(s)
- Laura Oliver-Cañamás
- Servei de Radiofísica i Protecció Radiològica, Consorci Hospitalari Provincial de Castelló (CHPC), 12002 Castelló de la Plana, Spain
| | - Javier Vijande
- Departamento de Física Atómica, Molecular y Nuclear, Universitat de Valencia (UV), 46100 Burjassot, Spain
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), 46026 València, Spain
- Instituto de Física Corpuscular, Instituto de Física Corpuscular-IFIC (UV-CSIC), 46100 Burjassot, Spain
| | | | - Jose Gimeno-Olmos
- Unitat de Radiofísica, Servei d'Oncologia Radioteràpica, Hospital Universitari i Politècnic La Fe, 46026 València, Spain
| | | | - Juan J Rovira-Escutia
- Servei de Radiofísica i Protecció Radiològica, Consorci Hospital General Universitari de València, 46014 València, Spain
| | - Facundo Ballester
- Departamento de Física Atómica, Molecular y Nuclear, Universitat de Valencia (UV), 46100 Burjassot, Spain
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), 46026 València, Spain
| | - Jose Perez-Calatayud
- Unidad Mixta de Investigación en Radiofísica e Instrumentación Nuclear en Medicina (IRIMED), Instituto de Investigación Sanitaria La Fe (IIS-La Fe), Universitat de Valencia (UV), 46026 València, Spain
- Unitat de Radiofísica, Servei d'Oncologia Radioteràpica, Hospital Universitari i Politècnic La Fe, 46026 València, Spain
- Hospital Clínica Benidorm, 03501 Benidorm, Spain
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