1
|
Westley R, Casey F, Mitchell A, Alexander S, Nill S, Murray J, Ratnakumaran R, Pathmanathan A, Oelfke U, Dunlop A, Tree AC. Stereotactic Body Radiotherapy (SBRT) to Localised Prostate Cancer in the Era of MRI-Guided Adaptive Radiotherapy: Doses Delivered in the HERMES Trial Comparing Two- and Five-Fraction Treatments. Cancers (Basel) 2024; 16:2073. [PMID: 38893193 PMCID: PMC11171331 DOI: 10.3390/cancers16112073] [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: 04/28/2024] [Revised: 05/19/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
HERMES is a phase II trial of MRI-guided daily-adaptive radiotherapy (MRIgART) randomising men with localised prostate cancer to either 2-fractions of SBRT with a boost to the tumour or 5-fraction SBRT. In the context of this highly innovative regime the dose delivered must be carefully considered. The first ten patients recruited to HERMES were analysed in order to establish the dose received by the targets and organs at risk (OARS) in the context of intrafraction motion. A regression analysis was performed to measure how the volume of air within the rectum might further impact rectal dose secondary to the electron return effect (ERE). One hundred percent of CTV target objectives were achieved on the MRI taken prior to beam-on-time. The post-delivery MRI showed that high-dose CTV coverage was achieved in 90% of sub-fractions (each fraction is delivered in two sub-fractions) in the 2-fraction cohort and in 88% of fractions the 5-fraction cohort. Rectal D1 cm3 was the most exceeded constraint; three patients exceeded the D1 cm3 < 20.8 Gy in the 2-fraction cohort and one patient exceeded the D1 cm3 < 36 Gy in the 5-fraction cohort. The volume of rectal gas within 1 cm of the prostate was directly proportional to the increase in rectal D1 cm3, with a strong (R = 0.69) and very strong (R = 0.90) correlation in the 2-fraction and 5-fraction cohort respectively. Dose delivery specified in HERMES is feasible, although for some patients delivered doses to both target and OARs may vary from those planned.
Collapse
Affiliation(s)
- Rosalyne Westley
- The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
- Radiotherapy and Imaging Division, Institute of Cancer Research, London SM2 5NG, UK
| | - Francis Casey
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
| | - Adam Mitchell
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
| | - Sophie Alexander
- The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
- Radiotherapy and Imaging Division, Institute of Cancer Research, London SM2 5NG, UK
| | - Simeon Nill
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
| | - Julia Murray
- The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
- Radiotherapy and Imaging Division, Institute of Cancer Research, London SM2 5NG, UK
| | - Ragu Ratnakumaran
- The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
- Radiotherapy and Imaging Division, Institute of Cancer Research, London SM2 5NG, UK
| | - Angela Pathmanathan
- The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
- Radiotherapy and Imaging Division, Institute of Cancer Research, London SM2 5NG, UK
| | - Uwe Oelfke
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
| | - Alex Dunlop
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
| | - Alison C. Tree
- The Royal Marsden NHS Foundation Trust, London SM2 5PT, UK
- Radiotherapy and Imaging Division, Institute of Cancer Research, London SM2 5NG, UK
| |
Collapse
|
2
|
van den Dobbelsteen M, Hackett SL, van Asselen B, Oolbekkink S, Raaymakers BW, de Boer JC. Treatment planning evaluation and experimental validation of the magnetic resonance-based intrafraction drift correction. Phys Imaging Radiat Oncol 2024; 30:100580. [PMID: 38707627 PMCID: PMC11068926 DOI: 10.1016/j.phro.2024.100580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/17/2024] [Accepted: 04/18/2024] [Indexed: 05/07/2024] Open
Abstract
Background and purpose MRI-guided online adaptive treatments can account for interfractional variations, however intrafraction motion reduces treatment accuracy. Intrafraction plan adaptation methods, such as the Intrafraction Drift Correction (IDC) or sub-fractionation, are needed. IDC uses real-time automatic monitoring of the tumor position to initiate plan adaptations by repositioning segments. IDC is a fast adaptation method that occurs only when necessary and this method could enable margin reduction. This research provides a treatment planning evaluation and experimental validation of the IDC. Materials and methods An in silico treatment planning evaluation was performed for 13 prostate patients mid-treatment without and with intrafraction plan adaptation (IDC and sub-fractionation). The adaptation methods were evaluated using dose volume histogram (DVH) metrics. To experimentally verify IDC a treatment was mimicked whereby a motion phantom containing an EBT3 film moved mid-treatment, followed by repositioning of segments. In addition, the delivered treatment was irradiated on a diode array phantom for plan quality assurance purposes. Results The planning study showed benefits for using intrafraction adaptation methods relative to no adaptation, where the IDC and sub-fractionation showed consistently improved target coverage with median target coverages of 100.0%. The experimental results verified the IDC with high minimum gamma passing rates of 99.1% and small mean dose deviations of maximum 0.3%. Conclusion The straightforward and fast IDC technique showed DVH metrics consistent with the sub-fractionation method using segment weight re-optimization for prostate patients. The dosimetric and geometric accuracy was shown for a full IDC workflow using film and diode array dosimetry.
Collapse
Affiliation(s)
- Madelon van den Dobbelsteen
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Sara L. Hackett
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bram van Asselen
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Stijn Oolbekkink
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bas W. Raaymakers
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Johannes C.J. de Boer
- Department of Radiotherapy, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| |
Collapse
|
3
|
Akdag O, Borman PTS, Mandija S, Woodhead PL, Uijtewaal P, Raaymakers BW, Fast MF. Experimental demonstration of real-time cardiac physiology-based radiotherapy gating for improved cardiac radioablation on an MR-linac. Med Phys 2024; 51:2354-2366. [PMID: 38477841 DOI: 10.1002/mp.17024] [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: 09/28/2023] [Revised: 02/09/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Cardiac radioablation is a noninvasive stereotactic body radiation therapy (SBRT) technique to treat patients with refractory ventricular tachycardia (VT) by delivering a single high-dose fraction to the VT isthmus. Cardiorespiratory motion induces position uncertainties resulting in decreased dose conformality. Electocardiograms (ECG) are typically used during cardiac MRI (CMR) to acquire images in a predefined cardiac phase, thus mitigating cardiac motion during image acquisition. PURPOSE We demonstrate real-time cardiac physiology-based radiotherapy beam gating within a preset cardiac phase on an MR-linac. METHODS MR images were acquired in healthy volunteers (n = 5, mean age = 29.6 years, mean heart-rate (HR) = 56.2 bpm) on the 1.5 T Unity MR-linac (Elekta AB, Stockholm, Sweden) after obtaining written informed consent. The images were acquired using a single-slice balance steady-state free precession (bSSFP) sequence in the coronal or sagittal plane (TR/TE = 3/1.48 ms, flip angle = 48∘ $^{\circ }$ , SENSE = 1.5,field-of-view = 400 × 207 $\text{field-of-view} = {400}\times {207}$ mm 2 ${\text{mm}}^{2}$ , voxel size =3 × 3 × 15 $3\times 3\times 15$ mm 3 ${\rm mm}^{3}$ , partial Fourier factor = 0.65, frame rate = 13.3 Hz). In parallel, a 4-lead ECG-signal was acquired using MR-compatible equipment. The feasibility of ECG-based beam gating was demonstrated with a prototype gating workflow using a Quasar MRI4D motion phantom (IBA Quasar, London, ON, Canada), which was deployed in the bore of the MR-linac. Two volunteer-derived combined ECG-motion traces (n = 2, mean age = 26 years, mean HR = 57.4 bpm, peak-to-peak amplitude = 14.7 mm) were programmed into the phantom to mimic dose delivery on a cardiac target in breath-hold. Clinical ECG-equipment was connected to the phantom for ECG-voltage-streaming in real-time using research software. Treatment beam gating was performed in the quiescent phase (end-diastole). System latencies were compensated by delay time correction. A previously developed MRI-based gating workflow was used as a benchmark in this study. A 15-beam intensity-modulated radiotherapy (IMRT) plan (1 × 6.25 ${1}\times {6.25}$ Gy) was delivered for different motion scenarios onto radiochromic films. Next, cardiac motion was then estimated at the basal anterolateral myocardial wall via normalized cross-correlation-based template matching. The estimated motion signal was temporally aligned with the ECG-signal, which were then used for position- and ECG-based gating simulations in the cranial-caudal (CC), anterior-posterior (AP), and right-left (RL) directions. The effect of gating was investigated by analyzing the differences in residual motion at 30, 50, and 70% treatment beam duty cycles. RESULTS ECG-based (MRI-based) beam gating was performed with effective duty cycles of 60.5% (68.8%) and 47.7% (50.4%) with residual motion reductions of 62.5% (44.7%) and 43.9% (59.3%). Local gamma analyses (1%/1 mm) returned pass rates of 97.6% (94.1%) and 90.5% (98.3%) for gated scenarios, which exceed the pass rates of 70.3% and 82.0% for nongated scenarios, respectively. In average, the gating simulations returned maximum residual motion reductions of 88%, 74%, and 81% at 30%, 50%, and 70% duty cycles, respectively, in favor of MRI-based gating. CONCLUSIONS Real-time ECG-based beam gating is a feasible alternative to MRI-based gating, resulting in improved dose delivery in terms of highγ -pass $\gamma {\text{-pass}}$ rates, decreased dose deposition outside the PTV and residual motion reduction, while by-passing cardiac MRI challenges.
Collapse
Affiliation(s)
- Osman Akdag
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Pim T S Borman
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Stefano Mandija
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
- Computational Imaging Group for MR Diagnostics and Therapy, Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter L Woodhead
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
- Elekta AB, Stockholm, Sweden
| | - Prescilla Uijtewaal
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bas W Raaymakers
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martin F Fast
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
4
|
Winter JD, Reddy V, Li W, Craig T, Raman S. Impact of technological advances in treatment planning, image guidance, and treatment delivery on target margin design for prostate cancer radiotherapy: an updated review. Br J Radiol 2024; 97:31-40. [PMID: 38263844 PMCID: PMC11027310 DOI: 10.1093/bjr/tqad041] [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: 05/07/2023] [Revised: 08/22/2023] [Accepted: 11/21/2023] [Indexed: 01/25/2024] Open
Abstract
Recent innovations in image guidance, treatment delivery, and adaptive radiotherapy (RT) have created a new paradigm for planning target volume (PTV) margin design for patients with prostate cancer. We performed a review of the recent literature on PTV margin selection and design for intact prostate RT, excluding post-operative RT, brachytherapy, and proton therapy. Our review describes the increased focus on prostate and seminal vesicles as heterogenous deforming structures with further emergence of intra-prostatic GTV boost and concurrent pelvic lymph node treatment. To capture recent innovations, we highlight the evolution in cone beam CT guidance, and increasing use of MRI for improved target delineation and image registration and supporting online adaptive RT. Moreover, we summarize new and evolving image-guidance treatment platforms as well as recent reports of novel immobilization strategies and motion tracking. Our report also captures recent implementations of artificial intelligence to support image guidance and adaptive RT. To characterize the clinical impact of PTV margin changes via model-based risk estimates and clinical trials, we highlight recent high impact reports. Our report focusses on topics in the context of PTV margins but also showcase studies attempting to move beyond the PTV margin recipes with robust optimization and probabilistic planning approaches. Although guidelines exist for target margins conventional using CT-based image guidance, further validation is required to understand the optimal margins for online adaptation either alone or combined with real-time motion compensation to minimize systematic and random uncertainties in the treatment of patients with prostate cancer.
Collapse
Affiliation(s)
- Jeff D Winter
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Varun Reddy
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Winnie Li
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Tim Craig
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Srinivas Raman
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
| |
Collapse
|
5
|
Snyder J, Smith B, Aubin JS, Shepard A, Hyer D. Simulating an intra-fraction adaptive workflow to enable PTV margin reduction in MRIgART volumetric modulated arc therapy for prostate SBRT. Front Oncol 2024; 13:1325105. [PMID: 38260830 PMCID: PMC10800949 DOI: 10.3389/fonc.2023.1325105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/18/2023] [Indexed: 01/24/2024] Open
Abstract
Purpose This study simulates a novel prostate SBRT intra-fraction re-optimization workflow in MRIgART to account for prostate intra-fraction motion and evaluates the dosimetric benefit of reducing PTV margins. Materials and methods VMAT prostate SBRT treatment plans were created for 10 patients using two different PTV margins, one with a 5 mm margin except 3 mm posteriorly (standard) and another using uniform 2 mm margins (reduced). All plans were prescribed to 36.25 Gy in 5 fractions and adapted onto each daily MRI dataset. An intra-fraction adaptive workflow was simulated for the reduced margin group by synchronizing the radiation delivery with target position from cine MRI imaging. Intra-fraction delivered dose was reconstructed and prostate DVH metrics were evaluated under three conditions for the reduced margin plans: Without motion compensation (no-adapt), with a single adapt prior to treatment (ATP), and lastly for intra-fraction re-optimization during delivery (intra). Bladder and rectum DVH metrics were compared between the standard and reduced margin plans. Results As expected, rectum V18 Gy was reduced by 4.4 ± 3.9%, D1cc was reduced by 12.2 ± 6.8% (3.4 ± 2.3 Gy), while bladder reductions were 7.8 ± 5.6% for V18 Gy, and 9.6 ± 7.3% (3.4 ± 2.5 Gy) for D1cc for the reduced margin reference plans compared to the standard PTV margin. For the intrafraction replanning approach, average intra-fraction optimization times were 40.0 ± 2.9 seconds, less than the time to deliver one of the four VMAT arcs (104.4 ± 9.3 seconds) used for treatment delivery. When accounting for intra-fraction motion, prostate V36.25 Gy was on average 96.5 ± 4.0%, 99.1 ± 1.3%, and 99.6 ± 0.4 for the non-adapt, ATP, and intra-adapt groups, respectively. The minimum dose received by the prostate was less than 95% of the prescription dose in 84%, 36%, and 10% of fractions, for the non-adapt, ATP, and intra-adapt groups, respectively. Conclusions Intra-fraction re-optimization improves prostate coverage, specifically the minimum dose to the prostate, and enables PTV margin reduction and subsequent OAR sparing. Fast re-optimizations enable uninterrupted treatment delivery.
Collapse
Affiliation(s)
- Jeffrey Snyder
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
| | | | | | | | | |
Collapse
|
6
|
Abstract
Magnetic resonance imaging-guided radiation therapy (MRIgRT) has improved soft tissue contrast over computed tomography (CT) based image-guided RT. Superior visualization of the target and surrounding radiosensitive structures has the potential to improve oncological outcomes partly due to safer dose-escalation and adaptive planning. In this review, we highlight the workflow of adaptive MRIgRT planning, which includes simulation imaging, daily MRI, identifying isocenter shifts, contouring, plan optimization, quality control, and delivery. Increased utilization of MRIgRT will depend on addressing technical limitations of this technology, while addressing treatment efficacy, cost-effectiveness, and workflow training.
Collapse
Affiliation(s)
- Cecil M Benitez
- Department of Radiation Oncology, UCLA Medical Center, Los Angeles, CA
| | - Michael D Chuong
- Department of Radiation Oncology, Miami Cancer Institute, Baptist Health South Florida; Miami, FL
| | - Luise A Künzel
- National Center for Tumor Diseases (NCT), Dresden; German Cancer Research Center (DKFZ), Heidelberg; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden; Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Dresden, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.; OncoRay-National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden Rossendorf, Dresden, Germany
| | - Daniela Thorwarth
- Department of Radiation Oncology, Section for Biomedical Physics, University of Tübingen, Tübingen, Germany..
| |
Collapse
|
7
|
Oolbekkink S, van Asselen B, Woodings SJ, Wolthaus JWH, de Vries JHW, van Appeldoorn AA, Feijoo M, van den Dobbelsteen M, Raaymakers BW. Influence of magnetic field on a novel scintillation dosimeter in a 1.5 T MR-linac. J Appl Clin Med Phys 2024; 25:e14180. [PMID: 38011008 PMCID: PMC10795437 DOI: 10.1002/acm2.14180] [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: 06/30/2023] [Revised: 08/23/2023] [Accepted: 09/18/2023] [Indexed: 11/29/2023] Open
Abstract
For commissioning and quality assurance for adaptive workflows on the MR-linac, a dosimeter which can measure time-resolved dose during MR image acquisition is desired. The Blue Physics model 10 scintillation dosimeter is potentially an ideal detector for such measurements. However, some detectors can be influenced by the magnetic field of the MR-linac. To assess the calibration methods and magnetic field dependency of the Blue Physics scintillator in the 1.5 T MR-linac. Several calibration methods were assessed for robustness. Detector characteristics and the influence of the calibration methods were assessed based on dose reproducibility, dose linearity, dose rate dependency, relative output factor (ROF), percentage depth dose profile, axial rotation and the radial detector orientation with respect to the magnetic field. The potential application of time-resolved dynamic dose measurements during MRI acquisition was assessed. A variation of calibration factors was observed for different calibration methods. Dose reproducibility, dose linearity and dose rate stability were all found to be within tolerance and were not significantly affected by different calibration methods. Measurements with the detector showed good correspondence with reference chambers. The ROF and radial orientation dependence measurements were influenced by the calibration method used. Axial detector dependence was assessed and relative readout differences of up to 2.5% were observed. A maximum readout difference of 10.8% was obtained when rotating the detector with respect to the magnetic field. Importantly, measurements with and without MR image acquisition were consistent for both static and dynamic situations. The Blue Physics scintillation detector is suitable for relative dosimetry in the 1.5 T MR-linac when measurements are within or close to calibration conditions.
Collapse
Affiliation(s)
- Stijn Oolbekkink
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Bram van Asselen
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Simon J. Woodings
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | | | | | | | | | | | - Bas W. Raaymakers
- Department of RadiotherapyUniversity Medical Center UtrechtUtrechtThe Netherlands
| |
Collapse
|
8
|
Hyer DE, Caster J, Smith B, St-Aubin J, Snyder J, Shepard A, Zhang H, Mullan S, Geoghegan T, George B, Byrne J, Smith M, Buatti JM, Sonka M. A Technique to Enable Efficient Adaptive Radiation Therapy: Automated Contouring of Prostate and Adjacent Organs. Adv Radiat Oncol 2024; 9:101336. [PMID: 38260219 PMCID: PMC10801646 DOI: 10.1016/j.adro.2023.101336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 07/31/2023] [Indexed: 01/24/2024] Open
Abstract
Purpose The purpose of this work was to investigate the use of a segmentation approach that could potentially improve the speed and reproducibility of contouring during magnetic resonance-guided adaptive radiation therapy. Methods and Materials The segmentation algorithm was based on a hybrid deep neural network and graph optimization approach that also allows rapid user intervention (Deep layered optimal graph image segmentation of multiple objects and surfaces [LOGISMOS] + just enough interaction [JEI]). A total of 115 magnetic resonance-data sets were used for training and quantitative assessment. Expert segmentations were used as the independent standard for the prostate, seminal vesicles, bladder, rectum, and femoral heads for all 115 data sets. In addition, 3 independent radiation oncologists contoured the prostate, seminal vesicles, and rectum for a subset of patients such that the interobserver variability could be quantified. Consensus contours were then generated from these independent contours using a simultaneous truth and performance level estimation approach, and the deviation of Deep LOGISMOS + JEI contours to the consensus contours was evaluated and compared with the interobserver variability. Results The absolute accuracy of Deep LOGISMOS + JEI generated contours was evaluated using median absolute surface-to-surface distance which ranged from a minimum of 0.20 mm for the bladder to a maximum of 0.93 mm for the prostate compared with the independent standard across all data sets. The median relative surface-to-surface distance was less than 0.17 mm for all organs, indicating that the Deep LOGISMOS + JEI algorithm did not exhibit a systematic under- or oversegmentation. Interobserver variability testing yielded a mean absolute surface-to-surface distance of 0.93, 1.04, and 0.81 mm for the prostate, seminal vesicles, and rectum, respectively. In comparison, the deviation of Deep LOGISMOS + JEI from consensus simultaneous truth and performance level estimation contours was 0.57, 0.64, and 0.55 mm for the same organs. On average, the Deep LOGISMOS algorithm took less than 26 seconds for contour segmentation. Conclusions Deep LOGISMOS + JEI segmentation efficiently generated clinically acceptable prostate and normal tissue contours, potentially limiting the need for time intensive manual contouring with each fraction.
Collapse
Affiliation(s)
- Daniel E. Hyer
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Joseph Caster
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Blake Smith
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Joel St-Aubin
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Jeffrey Snyder
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Andrew Shepard
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Honghai Zhang
- Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa
| | - Sean Mullan
- Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa
| | - Theodore Geoghegan
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Benjamin George
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - James Byrne
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Mark Smith
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - John M. Buatti
- Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Milan Sonka
- Iowa Institute for Biomedical Imaging, University of Iowa, Iowa City, Iowa
| |
Collapse
|
9
|
Fast MF, Cao M, Parikh P, Sonke JJ. Intrafraction Motion Management With MR-Guided Radiation Therapy. Semin Radiat Oncol 2024; 34:92-106. [PMID: 38105098 DOI: 10.1016/j.semradonc.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
High quality radiation therapy requires highly accurate and precise dose delivery. MR-guided radiotherapy (MRgRT), integrating an MRI scanner with a linear accelerator, offers excellent quality images in the treatment room without subjecting patient to ionizing radiation. MRgRT therefore provides a powerful tool for intrafraction motion management. This paper summarizes different sources of intrafraction motion for different disease sites and describes the MR imaging techniques available to visualize and quantify intrafraction motion. It provides an overview of MR guided motion management strategies and of the current technical capabilities of the commercially available MRgRT systems. It describes how these motion management capabilities are currently being used in clinical studies, protocols and provides a future outlook.
Collapse
Affiliation(s)
- Martin F Fast
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Minsong Cao
- Department of Radiation Oncology, University of California, Los Angeles, CA
| | - Parag Parikh
- Department of Radiation Oncology, Henry Ford Health - Cancer, Detroit, MI
| | - Jan-Jakob Sonke
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
| |
Collapse
|
10
|
Tanaka S, Kadoya N, Ishizawa M, Katsuta Y, Arai K, Takahashi H, Xiao Y, Takahashi N, Sato K, Takeda K, Jingu K. Evaluation of Unity 1.5 T MR-linac plan quality in patients with prostate cancer. J Appl Clin Med Phys 2023; 24:e14122. [PMID: 37559561 PMCID: PMC10691646 DOI: 10.1002/acm2.14122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/26/2023] [Accepted: 07/31/2023] [Indexed: 08/11/2023] Open
Abstract
The Unity magnetic resonance (MR) linear accelerator (MRL) with MR-guided adaptive radiotherapy (MRgART) is capable of online MRgART where images are acquired on the treatment day and the radiation treatment plan is immediately replanned and performed. We evaluated the MRgART plan quality and plan reproducibility of the Unity MRL in patients with prostate cancer. There were five low- or moderate-risk and five high-risk patients who received 36.25 Gy or 40 Gy, respectively in five fractions. All patients underwent simulation magnetic resonance imaging (MRI) and five online adaptive MRI. We created plans for 5, 7, 9, 16, and 20 beams and for 60, 100, and 150 segments. We evaluated the target and organ doses for different number of beams and segments, respectively. Variation in dose constraint between the simulation plan and online adaptive plan was measured for each patient to assess plan reproducibility. The plan quality improved with the increasing number of beams. However, the proportion of significantly improved dose constraints decreased as the number of beams increased. For some dose parameters, there were statistically significant differences between 60 and 100 segments, and 100 and 150 segments. The plan of five beams exhibited limited reproducibility. The number of segments had minimal impact on plan reproducibility, but 60 segments sometimes failed to meet dose constraints for online adaptive plan. The optimization and delivery time increased with the number of beams and segments. We do not recommend using five or fewer beams for a reproducible and high-quality plan in the Unity MRL. In addition, many number of segments and beams may help meet dose constraints during online adaptive plan. Treatment with the Unity MRL should be performed with the appropriate number of beams and segments to achieve a good balance among plan quality, delivery time, and optimization time.
Collapse
Affiliation(s)
- Shohei Tanaka
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Noriyuki Kadoya
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Miyu Ishizawa
- Department of Radiological TechnologySchool of Health SciencesFaculty of MedicineTohoku UniversitySendaiJapan
| | - Yoshiyuki Katsuta
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Kazuhiro Arai
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Haruna Takahashi
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Yushan Xiao
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Noriyoshi Takahashi
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| | - Kiyokazu Sato
- Radiation TechnologyTohoku University HospitalSendaiJapan
| | - Ken Takeda
- Department of Radiological TechnologySchool of Health SciencesFaculty of MedicineTohoku UniversitySendaiJapan
| | - Keiichi Jingu
- Department of Radiation OncologyTohoku University Graduate School of MedicineSendaiJapan
| |
Collapse
|
11
|
Dassen MG, Janssen T, Kusters M, Pos F, Kerkmeijer LGW, van der Heide UA, van der Bijl E. Comparing adaptation strategies in MRI-guided online adaptive radiotherapy for prostate cancer: Implications for treatment margins. Radiother Oncol 2023; 186:109761. [PMID: 37348607 DOI: 10.1016/j.radonc.2023.109761] [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: 01/11/2023] [Revised: 05/26/2023] [Accepted: 06/15/2023] [Indexed: 06/24/2023]
Abstract
PURPOSE To quantify the difference in accuracy of adapt-to-position (ATP), adapt-to-rotation (ATR) and adapt-to-shape (ATS) workflows used in MRI-guided online adaptive radiotherapy for prostate carcinoma (PCa) by evaluating the margins required to accommodate intra-fraction motion of the clinical target volumes for prostate (CTVpros), prostate including seminal vesicles (CTVpros + sv) and gross tumor volume (GTV). MATERIALS AND METHODS Clinical delineations of the CTVpros, CTVpros + sv and GTV of 24 patients with intermediate- and high-risk PCa, treated using ATS on a 1.5 T MR-Linac, were used for analysis. Delineations were available pre- and during beam-on. To simulate ATP and ATR workflows, we automatically generated the structures associated with these workflows using rigid transformations from the planning-MRI to the daily online MRIs. Clinical GTVs were analyzed as ATR GTVs and only ATP GTVs were simulated. Planning target volumes (PTVs) were generated with isotropic margins ranging 0.0-5.0 mm. The volumetric overlap was calculated between these PTVs and their corresponding clinical delineation on the MRI acquired during beam-on and averaged over all treatment fractions. RESULTS The PTV margin required to cover > 95% of the CTVpros was equal (2.5 mm) for all workflows. For the CTVpros + sv, this margin increased to 5.0, 4.0 and 3.5 mm in the ATP, ATR and ATS workflow, respectively. GTV coverage improved from ATP to ATR for margins up to 4.0 mm. CONCLUSION ATP, ATR and ATS workflows ensure equal coverage of the CTVpros for the current clinical margins. For the CTVpros + sv, ATS showed optimal performance. GTV coverage improves by additional adaptations to prostate rotations.
Collapse
Affiliation(s)
- Mathijs G Dassen
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
| | - Tomas Janssen
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Martijn Kusters
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Floris Pos
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Linda G W Kerkmeijer
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Uulke A van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Erik van der Bijl
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, the Netherlands.
| |
Collapse
|
12
|
Snyder J, Smith B, St-Aubin J, Dunkerley D, Shepard A, Caster J, Hyer D. Intra-fraction motion of pelvic oligometastases and feasibility of PTV margin reduction using MRI guided adaptive radiotherapy. Front Oncol 2023; 13:1098593. [PMID: 37152034 PMCID: PMC10154517 DOI: 10.3389/fonc.2023.1098593] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/07/2023] [Indexed: 05/09/2023] Open
Abstract
Purpose This study assesses the impact of intra-fraction motion and PTV margin size on target coverage for patients undergoing radiation treatment of pelvic oligometastases. Dosimetric sparing of the bowel as a function of the PTV margin is also evaluated. Materials and methods Seven patients with pelvic oligometastases previously treated on our MR-linac (35 Gy in 5 fractions) were included in this study. Retrospective adaptive plans were created for each fraction on the daily MRI datasets using PTV margins of 5 mm, 3 mm, and 2 mm. Dosimetric constraint violations and GTV coverage were measured as a function of PTV margin size. The impact of intra-fraction motion on GTV coverage was assessed by tracking the GTV position on the cine MR images acquired during treatment delivery and creating an intra-fraction dose distribution for each IMRT beam. The intra-fraction dose was accumulated for each fraction to determine the total dose delivered to the target for each PTV size. Results All OAR constraints were achieved in 85.7%, 94.3%, and 100.0% of fractions when using 5 mm, 3 mm, and 2 mm PTV margins while scaling to 95% PTV coverage. Compared to plans with a 5 mm PTV margin, there was a 27.4 ± 12.3% (4.0 ± 2.2 Gy) and an 18.5 ± 7.3% (2.7 ± 1.4 Gy) reduction in the bowel D0.5cc dose for 2 mm and 3 mm PTV margins, respectively. The target dose (GTV V35 Gy) was on average 100.0 ± 0.1% (99.6 - 100%), 99.6 ± 1.0% (97.2 - 100%), and 99.0 ± 1.4% (95.0 - 100%), among all fractions for the 5 mm, 3 mm, and 2 mm PTV margins on the adaptive plans when accounting for intra-fraction motion, respectively. Conclusion A 2 mm PTV margin achieved a minimum of 95% GTV coverage while reducing the dose to the bowel for all patients.
Collapse
|