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Title: Kilovoltage Imaging of Implanted Fiducials to Monitor Intrafraction Motion With Abdominal Compression During Stereotactic Body Radiation Therapy for Gastrointestinal Tumors

Abstract

Purpose: To assess intrafraction respiratory motion using a commercial kilovoltage imaging system for abdominal tumor patients with implanted fiducials and breathing constrained by pneumatic compression during stereotactic body radiation therapy (SBRT). Methods and Materials: A pneumatic compression belt limited respiratory motion in 19 patients with radiopaque fiducials in or near their tumor during SBRT for abdominal tumors. Kilovoltage images were acquired at 5- to 6-second intervals during treatment using a commercial system. Intrafractional fiducial displacements were measured using in-house software. The dosimetric effect of the observed displacements was calculated for 3 sessions for each patient. Results: Intrafraction displacement patterns varied between patients and between individual treatment sessions. Averaged over 19 patients, 73 sessions, 7.6% of craniocaudal displacements exceeded 0.5 cm, and 1.2% exceeded 0.75 cm. The calculated single-session dose to 95% of gross tumor volume differed from planned by an average of −1.2% (range, −11.1% to 4.8%) but only for 4 patients was the total 3-session calculated dose to 95% of gross tumor volume more than 3% different from planned. Conclusions: Our pneumatic compression limited intrafractional abdominal target motion, maintained target position established at setup, and was moderately effective in preserving coverage. Commercially available intrafractional imaging is useful for surveillance but can bemore » made more effective and reliable.« less

Authors:
 [1];  [2];  [3]; ; ; ; ;  [1];  [4]
  1. Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States)
  2. Department of Radiation Oncology, China-Japan Friendship Hospital, Beijing (China)
  3. Department of Radiotherapy, Henan Provincial People's Hospital, Zhengzhou (China)
  4. Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York (United States)
Publication Date:
OSTI Identifier:
22648718
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 95; Journal Issue: 3; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; BIOMEDICAL RADIOGRAPHY; COMPRESSION; COMPUTER CODES; IMAGES; NEOPLASMS; PATIENTS; PNEUMATICS; RADIOTHERAPY

Citation Formats

Yorke, Ellen, E-mail: yorke@mskcc.org, Xiong, Ying, Han, Qian, Zhang, Pengpeng, Mageras, Gikas, Lovelock, Michael, Pham, Hai, Xiong, Jian-Ping, and Goodman, Karyn A. Kilovoltage Imaging of Implanted Fiducials to Monitor Intrafraction Motion With Abdominal Compression During Stereotactic Body Radiation Therapy for Gastrointestinal Tumors. United States: N. p., 2016. Web. doi:10.1016/J.IJROBP.2015.11.018.
Yorke, Ellen, E-mail: yorke@mskcc.org, Xiong, Ying, Han, Qian, Zhang, Pengpeng, Mageras, Gikas, Lovelock, Michael, Pham, Hai, Xiong, Jian-Ping, & Goodman, Karyn A. Kilovoltage Imaging of Implanted Fiducials to Monitor Intrafraction Motion With Abdominal Compression During Stereotactic Body Radiation Therapy for Gastrointestinal Tumors. United States. doi:10.1016/J.IJROBP.2015.11.018.
Yorke, Ellen, E-mail: yorke@mskcc.org, Xiong, Ying, Han, Qian, Zhang, Pengpeng, Mageras, Gikas, Lovelock, Michael, Pham, Hai, Xiong, Jian-Ping, and Goodman, Karyn A. Fri . "Kilovoltage Imaging of Implanted Fiducials to Monitor Intrafraction Motion With Abdominal Compression During Stereotactic Body Radiation Therapy for Gastrointestinal Tumors". United States. doi:10.1016/J.IJROBP.2015.11.018.
@article{osti_22648718,
title = {Kilovoltage Imaging of Implanted Fiducials to Monitor Intrafraction Motion With Abdominal Compression During Stereotactic Body Radiation Therapy for Gastrointestinal Tumors},
author = {Yorke, Ellen, E-mail: yorke@mskcc.org and Xiong, Ying and Han, Qian and Zhang, Pengpeng and Mageras, Gikas and Lovelock, Michael and Pham, Hai and Xiong, Jian-Ping and Goodman, Karyn A.},
abstractNote = {Purpose: To assess intrafraction respiratory motion using a commercial kilovoltage imaging system for abdominal tumor patients with implanted fiducials and breathing constrained by pneumatic compression during stereotactic body radiation therapy (SBRT). Methods and Materials: A pneumatic compression belt limited respiratory motion in 19 patients with radiopaque fiducials in or near their tumor during SBRT for abdominal tumors. Kilovoltage images were acquired at 5- to 6-second intervals during treatment using a commercial system. Intrafractional fiducial displacements were measured using in-house software. The dosimetric effect of the observed displacements was calculated for 3 sessions for each patient. Results: Intrafraction displacement patterns varied between patients and between individual treatment sessions. Averaged over 19 patients, 73 sessions, 7.6% of craniocaudal displacements exceeded 0.5 cm, and 1.2% exceeded 0.75 cm. The calculated single-session dose to 95% of gross tumor volume differed from planned by an average of −1.2% (range, −11.1% to 4.8%) but only for 4 patients was the total 3-session calculated dose to 95% of gross tumor volume more than 3% different from planned. Conclusions: Our pneumatic compression limited intrafractional abdominal target motion, maintained target position established at setup, and was moderately effective in preserving coverage. Commercially available intrafractional imaging is useful for surveillance but can be made more effective and reliable.},
doi = {10.1016/J.IJROBP.2015.11.018},
journal = {International Journal of Radiation Oncology, Biology and Physics},
number = 3,
volume = 95,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 2016},
month = {Fri Jul 01 00:00:00 EDT 2016}
}
  • Purpose: AAPM TG-76 report advises lung patients experiencing tumor motion >5mm to use some form of motion management with even smaller limit for complex/special procedures like SBRT. Generally, either respiratory gating or abdominal compression is used for motion management. In this retrospective study, we are using an innovative index, Volumetric Indices (VI) = (GTVnn AND GTV{sub 50+}Xmm)/(GTVnn) to quantify how much of the tumor remains within 1, 2, and 3mm margins throughout the breathing cycle using GTV{sub 50+}Xmm margin on GTV{sub 50}[nn=0,10,20,…90]. Using appropriate limits, VI can provide tumor motion information and to check if RPM gates could have beenmore » used in conjunction with abdominal compression to better manage tumor motion. Methods: 64 SBRT patients with a total of 67 lung tumors were studied. 4DCT scans were taken, fully capturing tumor motion throughout the 10 phases of the breathing cycle. For each phase, Gross Tumor Volume (GTV) was segmented and appropriates structures were defined to determine VI values. For the 2mm margin, VI values less than 0.95 for peripheral lesions and 0.97 for central lesions indicate tumor movement greater than 4mm. VI values for 1mm and 3mm margins were also analyzed signifying tumor motion of 2mm & 6mm, respectively. Results: Of the 64 patients, 35 (55%) had motion greater than 4mm & could have benefited from respiratory gating. For 5/8 (63%) middle lobe lesions, 21/27 (78%) lower lobe lesions, and 10/32 (31%) upper lobe lesions, gating could have resulted in smaller ITV. 32/55 (58%) peripheral lesions and 4/12 (33%) central lesions could have had gating. Average ITV decreased by 1.25cc (11.43%) and average VI increased by 0.11. Conclusion: Out of 64 patients, 55% exhibited motion greater than 4mm even with abdominal compression. Even with abdominalcompression, lung tumors can move >4mm as the degree of pressure which a patient can tolerate, is patient specific.« less
  • Purpose: Stereotactic body radiation therapy (SBRT) for early-stage inoperable non-small cell lung cancer (NSCLC) patients delivers high doses that require high-precision treatment. Typically, image guidance is used to minimize day-to-day target displacement, but intrafraction position variability is often not corrected. Currently, volumetric modulated arc therapy (VMAT) is replacing intensity modulated radiation therapy (IMRT) in many departments because of its shorter delivery time. This study aimed to evaluate whether intrafraction variation in VMAT patients is reduced in comparison with patients treated with IMRT. Methods and Materials: NSCLC patients (197 IMRT and 112 VMAT) treated with a frameless SBRT technique to amore » prescribed dose of 3 × 18 Gy were evaluated. Image guidance for both techniques was identical: pretreatment cone beam computed tomography (CBCT) (CBCT{sub precorr}) for setup correction followed immediately before treatment by postcorrection CBCT (CBCT{sub postcorr}) for verification. Then, after either a noncoplanar IMRT technique or a VMAT technique, a posttreatment (CBCT{sub postRT}) scan was acquired. The CBCT{sub postRT} and CBCT{sub postcorr} scans were then used to evaluate intrafraction motion. Treatment delivery times, systematic (Σ) and random (σ) intrafraction variations, and associated planning target volume (PTV) margins were calculated. Results: The median treatment delivery time was significantly reduced by 20 minutes (range, 32-12 minutes) using VMAT compared with noncoplanar IMRT. Intrafraction tumor motion was significantly larger for IMRT in all directions up to 0.5 mm systematic (Σ) and 0.7 mm random (σ). The required PTV margins for IMRT and VMAT differed by less than 0.3 mm. Conclusion: VMAT-based SBRT for NSCLC was associated with significantly shorter delivery times and correspondingly smaller intrafraction motion compared with noncoplanar IMRT. However, the impact on the required PTV margin was small.« less
  • Purpose: To investigate in a three-dimensional framework the effectiveness and reproducibility of reducing the respiratory motion of liver tumors using abdominal compression in a stereotactic body frame. Methods and Materials: A total of 12 patients with liver tumors, who were treated with stereotactic body radiotherapy, were included in this study. These patients had three gold fiducial markers implanted in the healthy liver tissue surrounding the tumor. Fluoroscopic videos were acquired on the planning day and before each treatment fraction to visualize the motion of the fiducial markers during free breathing and varying levels of abdominal compression. Software was developed tomore » track the fiducial markers and measure their excursions. Results: Abdominal compression reduced the patient group median excursion by 62% in the craniocaudal and 38% in the anteroposterior direction with respect to the median free-breathing excursions. In the left-right direction, the median excursion increased 15% (maximal increase 1.6 mm). The median residual excursion was 4.1 mm in the craniocaudal, 2.4 mm in the anteroposterior, and 1.8 mm in the left-right direction. The mean excursions were reduced by compression to <5 mm in all patients and all directions, with two exceptions (craniocaudal excursion reduction of 20.5 mm to 7.4 mm and of 21.1 mm to 5.9 mm). The residual excursions reproduced well during the treatment course, and the craniocaudal excursions measured on the treatment days were never significantly ({alpha} = 0.05) greater than on the planning days. Fine tuning the compression did not considerably change the excursion on the treatment days. Conclusions: Abdominal compression effectively reduced liver tumor motion, yielding small and reproducible excursions in three dimensions. The compression level established at planning could have been safely used on the treatment days.« less
  • Purpose: Lung SABR patients are treated using Volumetrically Modulated Arc Therapy (VMAT), utilizing 2 arcs with Conebeam CT (CBCT) image-guidance prior to each arc. Intra-fraction imaging can prolong treatment time (up to 20%), and the aim of this study is to determine if it is necessary. Methods: We utilize an in-house abdominal compression device to minimize respiratory motion, 4DCT to define the ITV, a 5 mm PTV margin and a 2–3 mm PRV margin. We treated 23 patients with VMAT, fifteen were treated to 48 Gy in 4 fractions, while eight were treated with up to 60 Gy in 8more » fractions. Intrafraction motion was assessed by the translational errors recorded for the second CBCT. Results: There was no significant difference (t-test, p=0.93) in the intra-fraction motion between the patients treated with 4 and 8 fractions, or between the absolute translations in each direction (ANOVA, p=0.17). All 124 intra-fraction CBCT images were analysed and 95% remained localized within the 5 mm PTV margin The mean magnitude of the vector displacement was 1.8 mm. Conclusions: For patients localized with an abdominal compression device, the intrafraction CBCT image may not be necessary, if it is only the tumor coverage that is of concern, as the patients are typically well within the 5 mm PTV margin. On the other hand, if there is a structure with a smaller PRV margin, an intrafraction CBCT is recommended to ensure that the dose limit for the organ at risk is not exceeded.« less
  • Purpose: To quantify rigid and nonrigid motion of liver tumors using reconstructed 3-dimensional (3D) fiducials from stereo imaging during CyberKnife-based stereotactic body radiation therapy (SBRT). Methods and Materials: Twenty-three liver patients treated with 3 fractions of SBRT were used in this study. After 2 orthogonal kilovoltage images were taken during treatment, the 3D locations of the fiducials were generated by the CyberKnife system and validated using geometric derivations. A total of 4824 pairs of kilovoltage images from start to end of treatment were analyzed. For rigid motion, the rotational angles and translational shifts were reported by aligning 3D fiducial groupsmore » from different image pairs, using least-squares fitting. For nonrigid motion, we quantified interfractional tumor volume variations by using the proportional volume derived from the fiducials, which correlates to the sum of interfiducial distances. The individual fiducial displacements were also reported (1) after rigid corrections and (2) without angle corrections. Results: The proportional volume derived by the fiducials demonstrated a volume-increasing trend in the second (101.9% ± 3.6%) and third (101.0 ± 5.9%) fractions among most patients, possibly due to radiation-induced edema. For all patients, the translational shifts in left-right, anteroposterior, and superoinferior directions were 2.1 ± 2.3 mm, 2.9 ± 2.8 mm, and 6.4 ± 5.5 mm, respectively. The greatest translational shifts occurred in the superoinferior direction, likely due to respiratory motion from the diaphragm. The rotational angles in roll, pitch, and yaw were 1.2° ± 1.8°, 1.8° ± 2.4°, and 1.7° ± 2.1°, respectively. The 3D individual fiducial displacements with rigid corrections were 0.2 ± 0.2 mm and increased to 0.5 ± 0.4 mm without rotational corrections. Conclusions: Accurate 3D locations of internal fiducials can be reconstructed from stereo imaging during treatment. As an effective surrogate to tumor motion, fiducials provide a close estimation of both rigid and nonrigid motion of liver tumors. The reported displacements could be further utilized for tumor margin definition and motion management in conventional linear accelerator–based liver SBRT.« less