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Title: SU-G-JeP1-06: Correlation of Lung Tumor Motion with Tumor Location Using Electromagnetic Tracking

Abstract

Purpose: It is well known that lung tumors move with respiration. However, most measurements of lung tumor motion have studied long treatment times with intermittent imaging; those populations may not necessarily represent conventional LINAC patients. We summarized the correlation between tumor motion and location in a multi-institutional trial with electromagnetic tracking, and identified the patient cohort that would most benefit from respiratory gating. Methods: Continuous electromagnetic transponder data (Varian Medical, Seattle, WA) of lung tumor motion was collected from 14 patients (214 total fractions) across 3 institutions during external beam radiation therapy in a prospective clinical trial (NCT01396551). External intervention from the clinician, such as couch shifts, instructed breath-holds, and acquisition pauses, were manually removed from the 10 Hz tracking data according to recorded notes. The average three-dimensional displacement from the breathing cycle’s end-expiratory to end-inhalation phases (peak-to-peak distance) of the transponders’ isocenter was calculated for each patient’s treatment. A weighted average of each isocenter was used to assess the effects of location on motion. A total of 14 patients were included in this analysis, grouped by their transponders’ location in the lung: upper, medial, and lower. Results: 8 patients had transponders in the upper lung, and 3 patients eachmore » in the medial lobe and lower lung. The weighted average ± standard deviation of all peak-to-peak distances for each group was: 1.04 ± 0.39 cm in the lower lung, 0.56 ± 0.14 cm in the medial lung, and 0.30 ± 0.06 cm in the upper lung. Conclusion: Tumors in the lower lung are most susceptible to excessive motion and daily variation, and would benefit most from continuous motion tracking and gating. Those in the medial lobe might be at moderate risk. The upper lobes have limited motion. These results can guide different motion management strategies between lung tumor locations. This is part of an NIH-funded prospective clinical trial (NCT01396551), using an electromagnetic transponder tracking system and additional funding from Varian Medical (Seattle, WA).« less

Authors:
; ;  [1]; ;  [2]
  1. Washington University School of Medicine, Saint Louis, MO (United States)
  2. Lindbergh High School, St. Louis, MO (United States)
Publication Date:
OSTI Identifier:
22649331
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; 61 RADIATION PROTECTION AND DOSIMETRY; BIOMEDICAL RADIOGRAPHY; CLINICAL TRIALS; CORRELATIONS; DAILY VARIATIONS; EXTERNAL BEAM RADIATION THERAPY; LINEAR ACCELERATORS; LUNGS; NEOPLASMS; PATIENTS

Citation Formats

Muccigrosso, D, Maughan, N, Parikh, P, Schultejans, H, and Bera, R. SU-G-JeP1-06: Correlation of Lung Tumor Motion with Tumor Location Using Electromagnetic Tracking. United States: N. p., 2016. Web. doi:10.1118/1.4956981.
Muccigrosso, D, Maughan, N, Parikh, P, Schultejans, H, & Bera, R. SU-G-JeP1-06: Correlation of Lung Tumor Motion with Tumor Location Using Electromagnetic Tracking. United States. doi:10.1118/1.4956981.
Muccigrosso, D, Maughan, N, Parikh, P, Schultejans, H, and Bera, R. Wed . "SU-G-JeP1-06: Correlation of Lung Tumor Motion with Tumor Location Using Electromagnetic Tracking". United States. doi:10.1118/1.4956981.
@article{osti_22649331,
title = {SU-G-JeP1-06: Correlation of Lung Tumor Motion with Tumor Location Using Electromagnetic Tracking},
author = {Muccigrosso, D and Maughan, N and Parikh, P and Schultejans, H and Bera, R},
abstractNote = {Purpose: It is well known that lung tumors move with respiration. However, most measurements of lung tumor motion have studied long treatment times with intermittent imaging; those populations may not necessarily represent conventional LINAC patients. We summarized the correlation between tumor motion and location in a multi-institutional trial with electromagnetic tracking, and identified the patient cohort that would most benefit from respiratory gating. Methods: Continuous electromagnetic transponder data (Varian Medical, Seattle, WA) of lung tumor motion was collected from 14 patients (214 total fractions) across 3 institutions during external beam radiation therapy in a prospective clinical trial (NCT01396551). External intervention from the clinician, such as couch shifts, instructed breath-holds, and acquisition pauses, were manually removed from the 10 Hz tracking data according to recorded notes. The average three-dimensional displacement from the breathing cycle’s end-expiratory to end-inhalation phases (peak-to-peak distance) of the transponders’ isocenter was calculated for each patient’s treatment. A weighted average of each isocenter was used to assess the effects of location on motion. A total of 14 patients were included in this analysis, grouped by their transponders’ location in the lung: upper, medial, and lower. Results: 8 patients had transponders in the upper lung, and 3 patients each in the medial lobe and lower lung. The weighted average ± standard deviation of all peak-to-peak distances for each group was: 1.04 ± 0.39 cm in the lower lung, 0.56 ± 0.14 cm in the medial lung, and 0.30 ± 0.06 cm in the upper lung. Conclusion: Tumors in the lower lung are most susceptible to excessive motion and daily variation, and would benefit most from continuous motion tracking and gating. Those in the medial lobe might be at moderate risk. The upper lobes have limited motion. These results can guide different motion management strategies between lung tumor locations. This is part of an NIH-funded prospective clinical trial (NCT01396551), using an electromagnetic transponder tracking system and additional funding from Varian Medical (Seattle, WA).},
doi = {10.1118/1.4956981},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}
  • Purpose: Prior Data Assisted Compressed Sensing (PDACS) is a partial k-space acquisition and reconstruction method for mobile tumour (i.e. lung) tracking using on-line MRI in radiotherapy. PDACS partially relies on prior data acquired at the beginning of dynamic scans, and is therefore susceptible to artifacts in longer duration scan due to slow drifts in MR signal. A novel sliding window strategy is presented to mitigate this effect. Methods: MRI acceleration is simulated by retrospective removal of data from the fully sampled sets. Six lung cancer patients were scanned (clinical 3T MRI) using a balanced steady state free precession (bSSFP) sequencemore » for 3 minutes at approximately 4 frames per second, for a total of 650 dynamics. PDACS acceleration is achieved by undersampling of k-space in a single pseudo-random pattern. Reconstruction iteratively minimizes the total variations while constraining the images to satisfy both the currently acquired data and the prior data in missing k-space. Our novel sliding window technique (SW-PDACS), uses a series of distinct pseudo-random under-sampling patterns of partial k-space – with the prior data drawn from a sliding window of the most recent data available. Under-sampled data, simulating 2 – 5x acceleration are reconstructed using PDACS and SW-PDACS. Three quantitative metrics: artifact power, centroid error and Dice’s coefficient are computed for comparison. Results: Quantitively metric values from all 6 patients are averaged in 3 bins, each containing approximately one minute of dynamic data. For the first minute bin, PDACS and SW-PDACS give comparable results. Progressive decline in image quality metrics in bins 2 and 3 are observed for PDACS. No decline in image quality is observed for SW-PDACS. Conclusion: The novel approach presented (SW-PDACS) is a more robust for accelerating longer duration (>1 minute) dynamic MRI scans for tracking lung tumour motion using on-line MRI in radiotherapy. B.G. Fallone is a co-founder and CEO of MagnetTx Oncology Solutions (under discussions to license Alberta bi-planar linac MR for commercialization).« less
  • Purpose: The new real-time tumor-tracking radiotherapy (RTRT) system was installed in our institution. This system consists of two x-ray tubes and color image intensifiers (I.I.s). The fiducial marker which was implanted near the tumor was tracked using color fluoroscopic images. However, the implantation of the fiducial marker is very invasive. Color fluoroscopic images enable to increase the recognition of the tumor. However, these images were not suitable to track the tumor without fiducial marker. The purpose of this study was to investigate the feasibility of markerless tracking using dual energy colored fluoroscopic images for real-time tumor-tracking radiotherapy system. Methods: Themore » colored fluoroscopic images of static and moving phantom that had the simulated tumor (30 mm diameter sphere) were experimentally acquired using the RTRT system. The programmable respiratory motion phantom was driven using the sinusoidal pattern in cranio-caudal direction (Amplitude: 20 mm, Time: 4 s). The x-ray condition was set to 55 kV, 50 mA and 105 kV, 50 mA for low energy and high energy, respectively. Dual energy images were calculated based on the weighted logarithmic subtraction of high and low energy images of RGB images. The usefulness of dual energy imaging for real-time tracking with an automated template image matching algorithm was investigated. Results: Our proposed dual energy subtraction improve the contrast between tumor and background to suppress the bone structure. For static phantom, our results showed that high tracking accuracy using dual energy subtraction images. For moving phantom, our results showed that good tracking accuracy using dual energy subtraction images. However, tracking accuracy was dependent on tumor position, tumor size and x-ray conditions. Conclusion: We indicated that feasibility of markerless tracking using dual energy fluoroscopic images for real-time tumor-tracking radiotherapy system. Furthermore, it is needed to investigate the tracking accuracy using proposed dual energy subtraction images for clinical cases.« less
  • Purpose: The respirato ry gating system combined the TrueBeam and a new real-time tumor-tracking radiotherapy system (RTRT) was installed. The RTRT system consists of two x-ray tubes and color image intensifiers. Using fluoroscopic images, the fiducial marker which was implanted near the tumor was tracked and was used as the internal surrogate for respiratory gating. The purposes of this study was to develop the verification technique of the respiratory gating with the new RTRT using cine electronic portal image device images (EPIDs) of TrueBeam and log files of the RTRT. Methods: A patient who underwent respiratory gated SBRT of themore » lung using the RTRT were enrolled in this study. For a patient, the log files of three-dimensional coordinate of fiducial marker used as an internal surrogate were acquired using the RTRT. Simultaneously, the cine EPIDs were acquired during respiratory gated radiotherapy. The data acquisition was performed for one field at five sessions during the course of SBRT. The residual motion errors were calculated using the log files (E{sub log}). The fiducial marker used as an internal surrogate into the cine EPIDs was automatically extracted by in-house software based on the template-matching algorithm. The differences between the the marker positions of cine EPIDs and digitally reconstructed radiograph were calculated (E{sub EPID}). Results: Marker detection on EPID using in-house software was influenced by low image contrast. For one field during the course of SBRT, the respiratory gating using the RTRT showed the mean ± S.D. of 95{sup th} percentile E{sub EPID} were 1.3 ± 0.3 mm,1.1 ± 0.5 mm,and those of E{sub log} were 1.5 ± 0.2 mm, 1.1 ± 0.2 mm in LR and SI directions, respectively. Conclusion: We have developed the verification method of respiratory gating combined TrueBeam and new real-time tumor-tracking radiotherapy system using EPIDs and log files.« less
  • Purpose: Investigate capability and accuracy of Kinect v2 camera for tracking respiratory motion to use as a tool during 4DCT or in combination with motion management during radiotherapy treatments. Methods: Utilizing the depth sensor on the Kinect as well as code written in C#, the respiratory motion of a patient was tracked by recording the depth (distance) values obtained at several points on the patient. Respiratory traces were also obtained using Varian’s RPM system, which traces the movement of a propriety marker placed on the patient’s abdomen, as well as an Anzai belt, which utilizes a pressure sensor to trackmore » respiratory motion. With the Kinect mounted 60 cm above the patient and pointing straight down, 11 breathing cycles were recorded with each system simultaneously. Relative displacement values during this time period were saved to file. While RPM and the Kinect give displacement values in distance units, the Anzai system has arbitrary units. As such, displacement for all three are displayed relative to the maximum value for the time interval from that system. Additional analysis was performed between RPM and Kinect for absolute displacement values. Results: Analysis of the data from all three systems indicates the relative motion obtained from the Kinect is both accurate and in sync with the data from RPM and Anzai. The absolute displacement data from RPM and Kinect show similar displacement values throughout the acquisition except for the depth obtained from the Kinect during maximum exhalation (largest distance from Kinect). Conclusion: By simply utilizing the depth data of specific points on a patient obtained from the Kinect, respiratory motion can be tracked and visualized with accuracy comparable to that of the Varian RPM and Anzai belt.« less
  • Purpose: To develop a novel strategy to extract the lung tumor motion from cone beam CT (CBCT) projections by an active contour model with interpolated respiration learned from diaphragm motion. Methods: Tumor tracking on CBCT projections was accomplished with the templates derived from planning CT (pCT). There are three major steps in the proposed algorithm: 1) The pCT was modified to form two CT sets: a tumor removed pCT and a tumor only pCT, the respective digitally reconstructed radiographs DRRtr and DRRto following the same geometry of the CBCT projections were generated correspondingly. 2) The DRRtr was rigidly registered withmore » the CBCT projections on the frame-by-frame basis. Difference images between CBCT projections and the registered DRRtr were generated where the tumor visibility was appreciably enhanced. 3) An active contour method was applied to track the tumor motion on the tumor enhanced projections with DRRto as templates to initialize the tumor tracking while the respiratory motion was compensated for by interpolating the diaphragm motion estimated by our novel constrained linear regression approach. CBCT and pCT from five patients undergoing stereotactic body radiotherapy were included in addition to scans from a Quasar phantom programmed with known motion. Manual tumor tracking was performed on CBCT projections and was compared to the automatic tracking to evaluate the algorithm accuracy. Results: The phantom study showed that the error between the automatic tracking and the ground truth was within 0.2mm. For the patients the discrepancy between the calculation and the manual tracking was between 1.4 and 2.2 mm depending on the location and shape of the lung tumor. Similar patterns were observed in the frequency domain. Conclusion: The new algorithm demonstrated the feasibility to track the lung tumor from noisy CBCT projections, providing a potential solution to better motion management for lung radiation therapy.« less