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Nill S. TH-AB-BRB-05: Using a Research Real-Time Control Interface to Go Beyond Dynamic MLC Tracking. Med Phys 2016. [DOI: 10.1118/1.4958051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fast M, Kamerling C, Crijns S, Menten M, Nill S, Raaymakers B, Oelfke U. TH-AB-202-03: A Novel Tool for Computing Deliverable Doses in Dynamic MLC Tracking Treatments. Med Phys 2016. [DOI: 10.1118/1.4958067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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53
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Tsang H, Kamerling C, Nill S, Oelfke U. OC-0380: Moving away from binary definition of PTVs: a novel probabilistic approach to PTV definition. Radiother Oncol 2016. [DOI: 10.1016/s0167-8140(16)31629-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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54
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Fast MF, Kamerling CP, Ziegenhein P, Menten MJ, Bedford JL, Nill S, Oelfke U. Assessment of MLC tracking performance during hypofractionated prostate radiotherapy using real-time dose reconstruction. Phys Med Biol 2016; 61:1546-62. [PMID: 26816273 PMCID: PMC5390952 DOI: 10.1088/0031-9155/61/4/1546] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/25/2015] [Accepted: 12/16/2015] [Indexed: 11/16/2022]
Abstract
By adapting to the actual patient anatomy during treatment, tracked multi-leaf collimator (MLC) treatment deliveries offer an opportunity for margin reduction and healthy tissue sparing. This is assumed to be especially relevant for hypofractionated protocols in which intrafractional motion does not easily average out. In order to confidently deliver tracked treatments with potentially reduced margins, it is necessary to monitor not only the patient anatomy but also the actually delivered dose during irradiation. In this study, we present a novel real-time online dose reconstruction tool which calculates actually delivered dose based on pre-calculated dose influence data in less than 10 ms at a rate of 25 Hz. Using this tool we investigate the impact of clinical target volume (CTV) to planning target volume (PTV) margins on CTV coverage and organ-at-risk dose. On our research linear accelerator, a set of four different CTV-to-PTV margins were tested for three patient cases subject to four different motion conditions. Based on this data, we can conclude that tracking eliminates dose cold spots which can occur in the CTV during conventional deliveries even for the smallest CTV-to-PTV margin of 1 mm. Changes of organ-at-risk dose do occur frequently during MLC tracking and are not negligible in some cases. Intrafractional dose reconstruction is expected to become an important element in any attempt of re-planning the treatment plan during the delivery based on the observed anatomy of the day.
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Tsang H, Kamerling CP, Nill S, Oelfke U. TH-AB-BRB-12: A Novel 2D Expansion Technique Based On Beam Geometry for Generating Margins. Med Phys 2015. [DOI: 10.1118/1.4926143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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56
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Kamerling CP, Fast MF, Ziegenhein P, Menten MJ, Nill S, Oelfke U. TH-AB-303-06: Real-Time 4D Dose Reconstruction for Tracked Dynamic MLC Deliveries in the Presence of Respiratory Motion. Med Phys 2015. [DOI: 10.1118/1.4926161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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57
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Wisotzky E, Fast MF, Oelfke U, Nill S. Automated marker tracking using noisy X-ray images degraded by the treatment beam. Z Med Phys 2015; 25:123-34. [PMID: 25280891 DOI: 10.1016/j.zemedi.2014.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 08/01/2014] [Accepted: 08/15/2014] [Indexed: 12/25/2022]
Abstract
This study demonstrates the feasibility of automated marker tracking for the real-time detection of intrafractional target motion using noisy kilovoltage (kV) X-ray images degraded by the megavoltage (MV) treatment beam. The authors previously introduced the in-line imaging geometry, in which the flat-panel detector (FPD) is mounted directly underneath the treatment head of the linear accelerator. They found that the 121 kVp image quality was severely compromised by the 6 MV beam passing through the FPD at the same time. Specific MV-induced artefacts present a considerable challenge for automated marker detection algorithms. For this study, the authors developed a new imaging geometry by re-positioning the FPD and the X-ray tube. This improved the contrast-to-noise-ratio between 40% and 72% at the 1.2 mAs/image exposure setting. The increase in image quality clearly facilitates the quick and stable detection of motion with the aid of a template matching algorithm. The setup was tested with an anthropomorphic lung phantom (including an artificial lung tumour). In the tumour one or three Calypso beacons were embedded to achieve better contrast during MV radiation. For a single beacon, image acquisition and automated marker detection typically took around 76 ± 6 ms. The success rate was found to be highly dependent on imaging dose and gantry angle. To eliminate possible false detections, the authors implemented a training phase prior to treatment beam irradiation and also introduced speed limits for motion between subsequent images.
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Fast M, Kamerling C, Ziegenhein P, Bedford J, Nill S, Oelfke U. TH-AB-303-10: Influence of Margins and Prostate Rotations On Tracked Dynamic MLC Deliveries. Med Phys 2015. [DOI: 10.1118/1.4926165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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59
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Fast M, Nill S, Menten M, Bedford J, Oelfke U. PO-0928: Dosimetric consequences of dynamic MLC tracking with an FFF beam for off-axis targets. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40920-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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60
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Vestergaard A, Hafeez S, Muren L, Nill S, Høyer M, Hansen V, Grønborg C, Pedersen E, Petersen J, Huddart R, Olfke U. OC-0403: The potential of MRI-guided online adaptive radiotherapy of urinary bladder cancer. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40399-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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61
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Bedford J, Fast M, Nill S, Ahmed M, McDonald F, Nordmark Hansen V, Oelfke U. PO-0919: Impact of system latency on 4D SABR lung plans delivered using MLC tracking. Radiother Oncol 2015. [DOI: 10.1016/s0167-8140(15)40911-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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62
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Franz AM, Schmitt D, Seitel A, Chatrasingh M, Echner G, Oelfke U, Nill S, Birkfellner W, Maier-Hein L. Standardized accuracy assessment of the calypso wireless transponder tracking system. Phys Med Biol 2014; 59:6797-810. [PMID: 25332308 DOI: 10.1088/0031-9155/59/22/6797] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Electromagnetic (EM) tracking allows localization of small EM sensors in a magnetic field of known geometry without line-of-sight. However, this technique requires a cable connection to the tracked object. A wireless alternative based on magnetic fields, referred to as transponder tracking, has been proposed by several authors. Although most of the transponder tracking systems are still in an early stage of development and not ready for clinical use yet, Varian Medical Systems Inc. (Palo Alto, California, USA) presented the Calypso system for tumor tracking in radiation therapy which includes transponder technology. But it has not been used for computer-assisted interventions (CAI) in general or been assessed for accuracy in a standardized manner, so far. In this study, we apply a standardized assessment protocol presented by Hummel et al (2005 Med. Phys. 32 2371-9) to the Calypso system for the first time. The results show that transponder tracking with the Calypso system provides a precision and accuracy below 1 mm in ideal clinical environments, which is comparable with other EM tracking systems. Similar to other systems the tracking accuracy was affected by metallic distortion, which led to errors of up to 3.2 mm. The potential of the wireless transponder tracking technology for use in many future CAI applications can be regarded as extremely high.
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Menten MJ, Fast MF, Nill S, Oelfke U. WE-E-18A-02: Enhancement of Lung Tumor Visibility by Dual-Energy X-Ray Imaging in An Anthropomorphic Chest Phantom Study. Med Phys 2014. [DOI: 10.1118/1.4889454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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64
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Murray J, McQuaid D, Dunlop A, Buettner F, Nill S, Hall E, Dearnaley D, Gulliford S. SU-E-J-14: A Novel Approach to Evaluate the Dosimetric Effect of Rectal Variation During Image Guided Prostate Radiotherapy. Med Phys 2014. [DOI: 10.1118/1.4888065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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65
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Altenstein G, Nill S, Schmitt D, Sterzing F, Oelfke U. PD-0095: Fast rotational IMRT with a 2d binary MLC (2D-bMLC): Dosimetric consequences of intrafraction prostate motion. Radiother Oncol 2014. [DOI: 10.1016/s0167-8140(15)30200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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66
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Altenstein G, Nill S, Sterzing F, Oelfke U. SU-C-108-01: Comparison of Fast Rotational IMRT with a 2d Binary Multileaf Collimator (2D-BMLC) with Helical Tomotherapy (HT). Med Phys 2013. [DOI: 10.1118/1.4813939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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67
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Schmitt D, Nill S, Roeder F, Herth F, Oelfke U. MO-F-WAB-12: Quantification of Intrafractional Tumor Motion in the Upper Lung Using An Electromagnetic Tumor Tracking System. Med Phys 2013. [DOI: 10.1118/1.4815301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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68
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Fast MF, Wisotzky E, Oelfke U, Nill S. TU-G-141-04: Phase-Selected 4d CBCT Acquisition Based On An Internal-External Motion Correlation Model. Med Phys 2013. [DOI: 10.1118/1.4815464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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69
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Wild E, Bangert M, Ulrich S, Nill S, Oelfke U. PO-0835: Ultra-fast arc therapy planning framework. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)33141-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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70
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Fast M, Oelfke U, Nill S. OC-0334: Actively triggered cone-beam CT acquisition based on electromagnetic respiratory motion tracking. Radiother Oncol 2013. [DOI: 10.1016/s0167-8140(15)32640-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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71
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Siggel M, Ziegenhein P, Nill S, Oelfke U. Boosting runtime-performance of photon pencil beam algorithms for radiotherapy treatment planning. Phys Med 2012; 28:273-80. [DOI: 10.1016/j.ejmp.2011.10.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 09/15/2011] [Accepted: 10/07/2011] [Indexed: 10/15/2022] Open
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72
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Altenstein G, Nill S, Heller J, Heid O, Oelfke U. A novel 2D binary collimator for IMRT dose delivery: dosimetric characterization using Monte Carlo simulations. Phys Med Biol 2012; 57:N345-64. [DOI: 10.1088/0031-9155/57/19/n345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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73
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Schmitt D, Nill S, Roeder F, Herfarth K, Oelfke U. SU-E-J-147: Dosimetric Consequences of Intrafraction Prostate Motion: Comparison Between Phantom Measurements and Three Different Calculation Methods. Med Phys 2012; 39:3686. [PMID: 28518909 DOI: 10.1118/1.4734984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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74
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Wisotzky E, Fast MF, Nill S, Oelfke U. SU-C-213CD-01: Automated Marker Tracking for Intra-Fractional Image Guidance in Radiotherapy. Med Phys 2012. [DOI: 10.1118/1.4734630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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75
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Fast M, Wisotzky E, Oelfke U, Nill S. PO-0856 SIMULTANEOUS USE OF AN ELECTROMAGNETIC TRACKING DEVICE AND A CONVENTIONAL FLAT-PANEL X-RAY IMAGER. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)71189-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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76
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Menten M, Guckenberger M, Herrmann C, Krauß A, Nill S, Oelfke U, Wilbert J. OC-0025 COMPARISON OF A MLC AND A HEXAPOD TRACKING SYSTEM FOR ORGAN MOTION COMPENSATION DURING RADIOTHERAPY. Radiother Oncol 2012. [DOI: 10.1016/s0167-8140(12)70364-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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77
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Fast MF, Koenig T, Oelfke U, Nill S. Performance characteristics of a novel megavoltage cone-beam-computed tomography device. Phys Med Biol 2012; 57:N15-24. [DOI: 10.1088/0031-9155/57/3/n15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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78
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Zabel-du Bois A, Nill S, Ulrich S, Oelfke U, Rhein B, Haering P, Milker-Zabel S, Schwahofer A. Dosimetric integration of daily mega-voltage cone-beam CT for image-guided intensity-modulated radiotherapy. Strahlenther Onkol 2012; 188:120-6. [DOI: 10.1007/s00066-011-0021-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 09/15/2011] [Indexed: 10/14/2022]
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79
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Krauss A, Nill S, Oelfke U. The comparative performance of four respiratory motion predictors for real-time tumour tracking. Phys Med Biol 2011; 56:5303-17. [DOI: 10.1088/0031-9155/56/16/015] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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80
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Hofmann K, Krauss A, Nill S, Oelfke U. TU-G-BRC-09: A Comparison of Step-And-Shoot and DMLC IMRT-Delivery for Real-Time Tumor Tracking. Med Phys 2011. [DOI: 10.1118/1.3613238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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81
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Krauss A, Fast M, Nill S, Oelfke U. TU-G-BRC-07: Multileaf Collimator Tracking of Respiratory Motion Using a Novel X-Ray Monitoring System. Med Phys 2011. [DOI: 10.1118/1.3613236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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82
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Koenig T, Zuber M, Zwerger A, Fauler A, Nill S, Fiederle M, Oelfke U. SU-C-211-03: X-Ray Imaging Properties of Two Highly Granular Spectroscopic Pixel Detectors Intended for Small Animal Imaging. Med Phys 2011. [DOI: 10.1118/1.3611493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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83
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Fast M, Krauss A, Nill S, Oelfke U. TU-C-214-08: Position Detection Accuracy of a Novel Linac-Mounted Intra-Fractional X-Ray Imaging System. Med Phys 2011. [DOI: 10.1118/1.3613140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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84
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Schulze J, Koenig T, Zuber M, Zwerger A, Fauler A, Nill S, Fiederle M, Oelfke U. TU-G-110-06: Detection of Contrast Agents with a CdTe Semiconductor Detector Intended for Small Animal Imaging. Med Phys 2011. [DOI: 10.1118/1.3613247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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85
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Stoll A, Nill S, Oelfke U. SU-E-T-881: Simulation of a Multileaf Collimator vs. Iris Variable Aperture Collimation for Prostate Robotic Radiosurgery and IMRT. Med Phys 2011. [DOI: 10.1118/1.3612845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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86
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Krauss A, Nill S, Oelfke U. 454 poster COMPARATIVE PERFORMANCE OF RESPIRATORY MOTION PREDICTORS FOR REAL-TIME TUMOR TRACKING. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)70576-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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87
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Schwahofer A, Nill S, Oelfke U, Rhein B, Bois AZD. 1221 poster INCORPORATING IMAGING DOSE TO THE TREATMENT DOSE IN IGRT – A COMPARISON OF 200°AND 360°MV-CBCT SCANS. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)71343-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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88
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Krauss A, Nill S, Oelfke U. 209 speaker MANAGEMENT OF BREATHING MOTION THROUGH MULTILEAF COLLIMATOR TRACKING. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)70331-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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89
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Stoll A, Nill S, Oelfke U. 418 poster MU REDUCTION FOR IMRT PLANNING WITH DIFFERENT FLUENCE MEDIAN FILTER STRATEGIES. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)70540-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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90
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Schubert K, Maric T, Nill S, Sroka-Perez G, Herfarth K, Oelfke U, Debus J. 1568 poster TOMOTHERAPY MVCT IN 3D-CONFORMAL TREATMENT PLANNING. Radiother Oncol 2011. [DOI: 10.1016/s0167-8140(11)71690-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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91
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Jensen AD, Nill S, Rochet N, Bendl R, Harms W, Huber PE, Debus J, Münter MW. Whole-abdominal IMRT for advanced ovarian carcinoma: planning issues and feasibility. Phys Med 2011; 27:194-202. [PMID: 21215671 DOI: 10.1016/j.ejmp.2010.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/09/2010] [Accepted: 12/09/2010] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION Despite enormous efforts to improve therapeutic strategies for patients with advanced ovarian carcinoma, outcome remains poor even with the advent cisplatinum-based chemotherapy regimen or taxanes with over 70% of patients developing local failure. Several trials were able to establish the potential benefit of adjuvant whole abdominal RT (WAI) though at the cost of sometimes marked side-effects. New technologies like IMRT have the potential of sparing normal tissues thus also potentially limiting treatment-related toxicity, hence a phase I trial was initiated to evaluate potential clinical benefit of WAI with IMRT. We intended to demonstrate that whole-abdominal IMRT is feasible and can be used in a routine clinical setting. METHODS A water-equivalent phantom containing OARs was created simulating organ shape of the upper abdomen to investigate the necessary number of beams for the upper abdominal target irrespective of the number of segments and hence treatment times. We prescribed a total dose of 30 Gy in 1.5 Gy fractions to the median of the target. IMRT treatment plans for three patients with advanced ovarian cancer were created using 2 isocentres and between 12 and 14 beams while restricting the number of segments so as to restrict treatment times to less than 45 min. Dose to OARs such as kidneys and liver was strictly limited even below established maxima. RESULTS In the phantom plans, no clear indication as to the optimum number of beams could be shown though there seems to be a slight trend toward a higher number of beams yielding better results. Examples demonstrating clinically inacceptable dose distributions for plans using only 9 beams. Acceptable treatment plans for real patients could be achieved using 12-14 beams and 2 isocentres. Treatment plans consisted of 264-286 segments resulting in an overall treatment time of approximately 37-45 min. Mean doses to the kidneys could be limited to 29.3% [23.1-33.2%] (right), and 26.8% [21-30.4%] (left). 50% of the liver received less than 72.4% [61-83%]. CONCLUSION IMRT for whole abdominal irradiation in patients with advanced ovarian carcinoma is applicable and feasible though treatment planning is complex and time-consuming. There is a significant reduction of dose to critical organs by using IMRT while maintaining target volume coverage.
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92
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Schmitt D, Nill S, Herfarth K, Münter M, Pfitzenmaier J, Zabel-du Bois A, Röder F, Huber P, Oelfke U. Intrafraction Organ Motion during Prostate Radiotherapy: Quantitative Correlation of Treatment Time and Margin Size. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.1741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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93
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Krauss A, Nill S, Oelfke U. SU-GG-J-09: Effective Tracking of Intrafractional Organ Motion Due to Breathing Using a Siemens 160 MLC. Med Phys 2010. [DOI: 10.1118/1.3468232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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94
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Krauss A, Rau A, Tacke M, Nill S, Oelfke U. Real-time Tumor Position Monitoring and Dynamic Dose Adaptation: Geometric and Dosimetric Accuracy of an Integrated Tracking System. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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95
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Oelfke U, Tacke M, Kraus A, Nill S. Sci-Wed PM: Delivery-06: Management of Intra-Fraction Organ Motion: First Performance Evaluation of an Experimental Dynamic Tumor Tracking System. Med Phys 2009. [DOI: 10.1118/1.3244098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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96
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Ulrich S, Nill S, Oelfke U. DYNAMIC ROTATIONAL ARC THERAPY WITH A NON FLATTENED BEAM. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(12)73093-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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97
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Nill S, Tücking T, Schwarz M, Bendl R, Oelfke U. RESPIRATION GATED CONE BEAM IMAGING AND FLUOROSCOPY AT A LINEAR ACCELERATOR. Radiother Oncol 2009. [DOI: 10.1016/s0167-8140(12)72730-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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98
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Haering P, Nill S, Rhein B. SU-FF-T-210: Method for and Results From a EPID Based IMRT QA for the Siemens Artiste. Med Phys 2009. [DOI: 10.1118/1.3181685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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99
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Rau AW, Nill S, Eidens RS, Oelfke U. Synchronized tumour tracking with electromagnetic transponders and kV x-ray imaging: evaluation based on a thorax phantom. Phys Med Biol 2008; 53:3789-805. [PMID: 18574313 DOI: 10.1088/0031-9155/53/14/006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Intrafractional organ motion remains a source of error in conformal radiotherapy of dynamic targets such as tumours of the lung or of the prostate. The purpose of this work was to devise a method for the continuous and routine measurement of intrafractional organ motion. The method consists of a combination of an electromagnetic (EM), internal marker-based tracking system with the on-board kilovoltage x-ray imaging system of a modern treatment machine. The EM system continuously tracks the target, while x-ray images can be acquired simultaneously if demand arises. An image processing algorithm has been developed to automatically localize and track the EM markers in the x-ray images. We have demonstrated simultaneous target tracking using the EM system and x-ray imaging of a mobile target inside a programmable thorax phantom. The target motion was very well reproduced by both systems. The comparability of the target locations reported by both systems was established (better than 0.25 mm up to target velocities of 3 cm s(-1)). One immediate use of the synchronized system was shown: the generation of a 4D cone beam computed tomography data set using the EM system for the measurement of motion. In conclusion, we have developed a system for the routine measurement of intrafractional motion that continuously provides the 3D position of the target with the ability to acquire images of the treatment field only when needed, thereby eliminating avoidable imaging dose to the patient.
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100
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Tacke M, Nill S, Oelfke U. SU-EE-A1-05: A Real-Time Feedback Control Algorithm to Compensate 2D Target Motion with a Dynamic Multileaf Collimator. Med Phys 2008. [DOI: 10.1118/1.2961378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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