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Zakeri A, Hokmabadi A, Nix MG, Gooya A, Wijesinghe I, Taylor ZA. 4D-Precise: Learning-based 3D motion estimation and high temporal resolution 4DCT reconstruction from treatment 2D+t X-ray projections. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 250:108158. [PMID: 38604010 DOI: 10.1016/j.cmpb.2024.108158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/23/2024] [Accepted: 03/29/2024] [Indexed: 04/13/2024]
Abstract
BACKGROUND AND OBJECTIVE In radiotherapy treatment planning, respiration-induced motion introduces uncertainty that, if not appropriately considered, could result in dose delivery problems. 4D cone-beam computed tomography (4D-CBCT) has been developed to provide imaging guidance by reconstructing a pseudo-motion sequence of CBCT volumes through binning projection data into breathing phases. However, it suffers from artefacts and erroneously characterizes the averaged breathing motion. Furthermore, conventional 4D-CBCT can only be generated post-hoc using the full sequence of kV projections after the treatment is complete, limiting its utility. Hence, our purpose is to develop a deep-learning motion model for estimating 3D+t CT images from treatment kV projection series. METHODS We propose an end-to-end learning-based 3D motion modelling and 4DCT reconstruction model named 4D-Precise, abbreviated from Probabilistic reconstruction of image sequences from CBCT kV projections. The model estimates voxel-wise motion fields and simultaneously reconstructs a 3DCT volume at any arbitrary time point of the input projections by transforming a reference CT volume. Developing a Torch-DRR module, it enables end-to-end training by computing Digitally Reconstructed Radiographs (DRRs) in PyTorch. During training, DRRs with matching projection angles to the input kVs are automatically extracted from reconstructed volumes and their structural dissimilarity to inputs is penalised. We introduced a novel loss function to regulate spatio-temporal motion field variations across the CT scan, leveraging planning 4DCT for prior motion distribution estimation. RESULTS The model is trained patient-specifically using three kV scan series, each including over 1200 angular/temporal projections, and tested on three other scan series. Imaging data from five patients are analysed here. Also, the model is validated on a simulated paired 4DCT-DRR dataset created using the Surrogate Parametrised Respiratory Motion Modelling (SuPReMo). The results demonstrate that the reconstructed volumes by 4D-Precise closely resemble the ground-truth volumes in terms of Dice, volume similarity, mean contour distance, and Hausdorff distance, whereas 4D-Precise achieves smoother deformations and fewer negative Jacobian determinants compared to SuPReMo. CONCLUSIONS Unlike conventional 4DCT reconstruction techniques that ignore breath inter-cycle motion variations, the proposed model computes both intra-cycle and inter-cycle motions. It represents motion over an extended timeframe, covering several minutes of kV scan series.
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Affiliation(s)
- Arezoo Zakeri
- Centre for Computational Imaging and Simulation Technologies in Biomedicine, School of Computing, University of Leeds, Leeds, UK.
| | - Alireza Hokmabadi
- Department of Infection, Immunity & Cardio Disease, University of Sheffield, Sheffield, UK
| | - Michael G Nix
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, UK
| | - Ali Gooya
- School of Computing Science, University of Glasgow, Glasgow, UK; Alan Turing Institute, London, UK
| | - Isuru Wijesinghe
- Centre for Computational Imaging and Simulation Technologies in Biomedicine, School of Mechanical Engineering, University of Leeds, Leeds, UK
| | - Zeike A Taylor
- Centre for Computational Imaging and Simulation Technologies in Biomedicine, School of Mechanical Engineering, University of Leeds, Leeds, UK.
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Vanhanen A, Poulsen P, Kapanen M. Dosimetric effect of intrafraction motion and different localization strategies in prostate SBRT. Phys Med 2020; 75:58-68. [PMID: 32540647 DOI: 10.1016/j.ejmp.2020.06.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 05/04/2020] [Accepted: 06/06/2020] [Indexed: 01/02/2023] Open
Abstract
The aim of this study was to evaluate the dosimetric effect of continuous motion monitoring based localization (Calypso, Varian Medical Systems), gating and intrafraction motion correction in prostate SBRT. Delivered doses were modelled by reconstructing motion inclusive dose distributions for different localization strategies. Actually delivered dose (strategy A) utilized initial Calypso localization, CBCT and additional pre-treatment motion correction by kV-imaging and Calypso, and gating during the irradiation. The effect of gating was investigated by simulating non-gated treatments (strategy B). Additionally, non-gated and single image-guided (CBCT) localization was simulated (strategy C). A total of 308 fractions from 22 patients were reconstructed. The dosimetric effect was evaluated by comparing motion inclusive target and risk organ dose-volume parameters to planned values. Motion induced dose deficits were seen mainly in PTV and CTV to PTV margin regions, whereas CTV dose deficits were small in all strategies: mean ± SD difference in CTVD99% was -0.3 ± 0.4%, -0.4 ± 0.6% and -0.7 ± 1.2% in strategies A, B and C, respectively. Largest dose deficits were seen in individual fractions for strategy C (maximum dose reductions were -29.0% and -7.1% for PTVD95% and CTVD99%, respectively). The benefit of gating was minor, if additional motion correction was applied immediately prior to irradiation. Continuous motion monitoring based localization and motion correction ensured the target coverage and minimized the OAR exposure for every fraction and is recommended to use in prostate SBRT. The study is part of clinical trial NCT02319239.
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Affiliation(s)
- A Vanhanen
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, POB-2000, 33521 Tampere, Finland; Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, POB-2000, 33521 Tampere, Finland.
| | - P Poulsen
- Department of Oncology and Danish Center for Particle Therapy, Aarhus University Hospital, Palle Juul-Jensens Boulevard 25, Entrance B3, 8200 Aarhus N, Denmark
| | - M Kapanen
- Department of Oncology, Unit of Radiotherapy, Tampere University Hospital, POB-2000, 33521 Tampere, Finland; Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, POB-2000, 33521 Tampere, Finland
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Choi YJ, Kim TW, Kim S, Choung H, Lee MJ, Kim N, Khwarg SI, Yu YS. Effects on Periocular Tissues after Proton Beam Radiation Therapy for Intraocular Tumors. J Korean Med Sci 2018; 33:e120. [PMID: 29651818 PMCID: PMC5897156 DOI: 10.3346/jkms.2018.33.e120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/20/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND To present our experience on orbital and periorbital tissue changes after proton beam radiation therapy (PBRT) in patients with intraocular tumors, apart from treatment outcomes and disease control. METHODS Medical records of 6 patients with intraocular tumors who had been treated with PBRT and referred to oculoplasty clinics of two medical centers (Seoul National University Hospital and Seoul Metropolitan Government-Seoul National University Boramae Medical Center) from October 2007 to September 2014 were retrospectively reviewed. The types of adverse effects associated with PBRT, their management, and progression were analyzed. In anophthalmic patients who eventually underwent enucleation after PBRT due to disease progression, orbital volume (OV) was assessed from magnetic resonance (MR) images using the Pinnacle3 program. RESULTS Among the six patients with PBRT history, three had uveal melanoma, and three children had retinoblastoma. Two eyes were treated with PBRT only, while the other four eyes ultimately underwent enucleation. Two eyes with PBRT only suffered from radiation dermatitis and intractable epiphora due to canaliculitis or punctal obstruction. All four anophthalmic patients showed severe enophthalmic features with periorbital hollowness. OV analysis showed that the difference between both orbits was less than 0.1 cm before enucleation, but increased to more than 2 cm³ after enucleation. CONCLUSION PBRT for intraocular tumors can induce various orbital and periorbital tissue changes. More specifically, when enucleation is performed after PBRT due to disease progression, significant enophthalmos and OV decrease can develop and can cause poor facial cosmesis as treatment sequelae.
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Affiliation(s)
- Youn Joo Choi
- Department of Ophthalmology, Hallym University Kangdong Sacred Heart Hospital, Seoul, Korea
| | - Tae Wan Kim
- Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul, Korea
| | - Suzy Kim
- Department of Radiation Oncology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
| | - Hokyung Choung
- Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul, Korea.
| | - Min Joung Lee
- Department of Ophthalmology, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Namju Kim
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul, Korea
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Sang In Khwarg
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul, Korea
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
| | - Young Suk Yu
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul, Korea
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
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Ravkilde T, Keall PJ, Grau C, Høyer M, Poulsen PR. Fast motion-including dose error reconstruction for VMAT with and without MLC tracking. Phys Med Biol 2014; 59:7279-96. [DOI: 10.1088/0031-9155/59/23/7279] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Feygelman V, Stambaugh C, Zhang G, Hunt D, Opp D, Wolf TK, Nelms BE. Motion as a perturbation: measurement-guided dose estimates to moving patient voxels during modulated arc deliveries. Med Phys 2013; 40:021708. [PMID: 23387731 DOI: 10.1118/1.4773887] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To present a framework for measurement-guided VMAT dose reconstruction to moving patient voxels from a known motion kernel and the static phantom data, and to validate this perturbation-based approach with the proof-of-principle experiments. METHODS As described previously, the VMAT 3D dose to a static patient can be estimated by applying a phantom measurement-guided perturbation to the treatment planning system (TPS)-calculated dose grid. The fraction dose to any voxel in the presence of motion, assuming the motion kernel is known, can be derived in a similar fashion by applying a measurement-guided motion perturbation. The dose to the diodes in a helical phantom is recorded at 50 ms intervals and is transformed into a series of time-resolved high-density volumetric dose grids. A moving voxel is propagated through this 4D dose space and the fraction dose to that voxel in the phantom is accumulated. The ratio of this motion-perturbed, reconstructed dose to the TPS dose in the phantom serves as a perturbation factor, applied to the TPS fraction dose to the similarly situated voxel in the patient. This approach was validated by the ion chamber and film measurements on four phantoms of different shape and structure: homogeneous and inhomogeneous cylinders, a homogeneous cube, and an anthropomorphic thoracic phantom. A 2D motion stage was used to simulate the motion. The stage position was synchronized with the beam start time with the respiratory gating simulator. The motion patterns were designed such that the motion speed was in the upper range of the expected tumor motion (1-1.4 cm∕s) and the range exceeded the normally observed limits (up to 5.7 cm). The conformal arc plans for X or Y motion (in the IEC 61217 coordinate system) consisted of manually created narrow (3 cm) rectangular strips moving in-phase (tracking) or phase-shifted by 90° (crossing) with respect to the phantom motion. The XY motion was tested with the computer-derived VMAT MLC sequences. For all phantoms and plans, time-resolved (10 Hz) ion chamber dose was collected. In addition, coronal (XY) films were exposed in the cube phantom to a VMAT beam with two different starting phases, and compared to the reconstructed motion-perturbed dose planes. RESULTS For the X or Y motions with the moving strip and geometrical phantoms, the maximum difference between perturbation-reconstructed and ion chamber doses did not exceed 1.9%, and the average for any motion pattern∕starting phase did not exceed 1.3%. For the VMAT plans on the cubic and thoracic phantoms, one point exhibited a 3.5% error, while the remaining five were all within 1.1%. Across all the measurements (N = 22), the average disagreement was 0.5 ± 1.3% (1 SD). The films exhibited γ(3%∕3 mm) passing rates ≥90%. CONCLUSIONS The dose to an arbitrary moving voxel in a patient can be estimated with acceptable accuracy for a VMAT delivery, by performing a single QA measurement with a cylindrical phantom and applying two consecutive perturbations to the TPS-calculated patient dose. The first one accounts for the differences between the planned and delivered static doses, while the second one corrects for the motion.
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Affiliation(s)
- Vladimir Feygelman
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL 33612, USA
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Poulsen PR, Schmidt ML, Keall P, Worm ES, Fledelius W, Hoffmann L. A method of dose reconstruction for moving targets compatible with dynamic treatments. Med Phys 2012; 39:6237-46. [PMID: 23039659 DOI: 10.1118/1.4754297] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop a method that allows a commercial treatment planning system (TPS) to perform accurate dose reconstruction for rigidly moving targets and to validate the method in phantom measurements for a range of treatments including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and dynamic multileaf collimator (DMLC) tracking. METHODS An in-house computer program was developed to manipulate Dicom treatment plans exported from a TPS (Eclipse, Varian Medical Systems) such that target motion during treatment delivery was incorporated into the plans. For each treatment, a motion including plan was generated by dividing the intratreatment target motion into 1 mm position bins and construct sub-beams that represented the parts of the treatment that were delivered, while the target was located within each position bin. For each sub-beam, the target shift was modeled by a corresponding isocenter shift. The motion incorporating Dicom plans were reimported into the TPS, where dose calculation resulted in motion including target dose distributions. For experimental validation of the dose reconstruction a thorax phantom with a moveable lung equivalent rod with a tumor insert of solid water was first CT scanned. The tumor insert was delineated as a gross tumor volume (GTV), and a planning target volume (PTV) was formed by adding margins. A conformal plan, two IMRT plans (step-and-shoot and sliding windows), and a VMAT plan were generated giving minimum target doses of 95% (GTV) and 67% (PTV) of the prescription dose (3 Gy). Two conformal fields with MLC leaves perpendicular and parallel to the tumor motion, respectively, were generated for DMLC tracking. All treatment plans were delivered to the thorax phantom without tumor motion and with a sinusoidal tumor motion. The two conformal fields were delivered with and without portal image guided DMLC tracking based on an embedded gold marker. The target dose distribution was measured with a radiochromic film in the moving rod and compared with the reconstructed doses using gamma tests. RESULTS Considerable interplay effects between machine motion and target motion were observed for the treatments without tracking. For nontracking experiments, the mean 2 mm∕2% gamma pass rate over all investigated scenarios was 99.6% between calculated and measured doses. For tracking experiments, the mean gamma pass rate was 99.4%. CONCLUSIONS A method for accurate dose reconstruction for moving targets with dynamic treatments was developed and experimentally validated in a variety of delivery scenarios. The method is suitable for integration into TPSs, e.g., for reconstruction of the dose delivered to moving tumors or calculation of target doses delivered with DMLC tracking.
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Affiliation(s)
- Per Rugaard Poulsen
- Department of Oncology, Aarhus University Hospital, Noorrebrogade 44, 8000 Aarhus C, Denmark.
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Adaptive radiation therapy for postprostatectomy patients using real-time electromagnetic target motion tracking during external beam radiation therapy. Int J Radiat Oncol Biol Phys 2012; 85:1038-44. [PMID: 23021439 DOI: 10.1016/j.ijrobp.2012.08.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/31/2012] [Accepted: 08/01/2012] [Indexed: 11/21/2022]
Abstract
PURPOSE Using real-time electromagnetic (EM) transponder tracking data recorded by the Calypso 4D Localization System, we report inter- and intrafractional target motion of the prostate bed, describe a strategy to evaluate treatment adequacy in postprostatectomy patients receiving intensity modulated radiation therapy (IMRT), and propose an adaptive workflow. METHODS AND MATERIALS Tracking data recorded by Calypso EM transponders was analyzed for postprostatectomy patients that underwent step-and-shoot IMRT. Rigid target motion parameters during beam delivery were calculated from recorded transponder positions in 16 patients with rigid transponder geometry. The delivered doses to the clinical target volume (CTV) were estimated from the planned dose matrix and the target motion for the first 3, 5, 10, and all fractions. Treatment adequacy was determined by comparing the delivered minimum dose (Dmin) with the planned Dmin to the CTV. Treatments were considered adequate if the delivered CTV Dmin is at least 95% of the planned CTV Dmin. RESULTS Translational target motion was minimal for all 16 patients (mean: 0.02 cm; range: -0.12 cm to 0.07 cm). Rotational motion was patient-specific, and maximum pitch, yaw, and roll were 12.2, 4.1, and 10.5°, respectively. We observed inadequate treatments in 5 patients. In these treatments, we observed greater target rotations along with large distances between the CTV centroid and transponder centroid. The treatment adequacy from the initial 10 fractions successfully predicted the overall adequacy in 4 of 5 inadequate treatments and 10 of 11 adequate treatments. CONCLUSION Target rotational motion could cause underdosage to partial volume of the postprostatectomy targets. Our adaptive treatment strategy is applicable to post-prostatectomy patients receiving IMRT to evaluate and improve radiation therapy delivery.
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