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Peng J, Stowe HB, Samson PP, Robinson CG, Yang C, Hu W, Zhang Z, Kim T, Hugo GD, Mazur TR, Cai B. Inter-fractional portability of deep learning models for lung target tracking on cine imaging acquired in MRI-guided radiotherapy. Phys Eng Sci Med 2024; 47:769-777. [PMID: 38198064 DOI: 10.1007/s13246-023-01371-z] [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: 05/24/2023] [Accepted: 12/11/2023] [Indexed: 01/11/2024]
Abstract
MRI-guided radiotherapy systems enable beam gating by tracking the target on planar, two-dimensional cine images acquired during treatment. This study aims to evaluate how deep-learning (DL) models for target tracking that are trained on data from one fraction can be translated to subsequent fractions. Cine images were acquired for six patients treated on an MRI-guided radiotherapy platform (MRIdian, Viewray Inc.) with an onboard 0.35 T MRI scanner. Three DL models (U-net, attention U-net and nested U-net) for target tracking were trained using two training strategies: (1) uniform training using data obtained only from the first fraction with testing performed on data from subsequent fractions and (2) adaptive training in which training was updated each fraction by adding 20 samples from the current fraction with testing performed on the remaining images from that fraction. Tracking performance was compared between algorithms, models and training strategies by evaluating the Dice similarity coefficient (DSC) and 95% Hausdorff Distance (HD95) between automatically generated and manually specified contours. The mean DSC for all six patients in comparing manual contours and contours generated by the onboard algorithm (OBT) were 0.68 ± 0.16. Compared to OBT, the DSC values improved 17.0 - 19.3% for the three DL models with uniform training, and 24.7 - 25.7% for the models based on adaptive training. The HD95 values improved 50.6 - 54.5% for the models based on adaptive training. DL-based techniques achieved better tracking performance than the onboard, registration-based tracking approach. DL-based tracking performance improved when implementing an adaptive strategy that augments training data fraction-by-fraction.
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Affiliation(s)
- Jiayuan Peng
- Academy for Engineering and Technology, Fudan University, Shanghai, China
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Hayley B Stowe
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA
| | - Pamela P Samson
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA
| | - Clifford G Robinson
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA
| | - Cui Yang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Weigang Hu
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Zhen Zhang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Taeho Kim
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA
| | - Geoffrey D Hugo
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA
| | - Thomas R Mazur
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA.
| | - Bin Cai
- Department of Radiation Oncology, Washington University, 63110, St. Louis, MO, USA.
- Department of Radiation Oncology's Division of Medical Physics & Engineering, University of Texas Southwestern Medical Center, 75390, Dallas, TX, USA.
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Finnegan RN, Quinn A, Booth J, Belous G, Hardcastle N, Stewart M, Griffiths B, Carroll S, Thwaites DI. Cardiac substructure delineation in radiation therapy - A state-of-the-art review. J Med Imaging Radiat Oncol 2024. [PMID: 38757728 DOI: 10.1111/1754-9485.13668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/29/2024] [Indexed: 05/18/2024]
Abstract
Delineation of cardiac substructures is crucial for a better understanding of radiation-related cardiotoxicities and to facilitate accurate and precise cardiac dose calculation for developing and applying risk models. This review examines recent advancements in cardiac substructure delineation in the radiation therapy (RT) context, aiming to provide a comprehensive overview of the current level of knowledge, challenges and future directions in this evolving field. Imaging used for RT planning presents challenges in reliably visualising cardiac anatomy. Although cardiac atlases and contouring guidelines aid in standardisation and reduction of variability, significant uncertainties remain in defining cardiac anatomy. Coupled with the inherent complexity of the heart, this necessitates auto-contouring for consistent large-scale data analysis and improved efficiency in prospective applications. Auto-contouring models, developed primarily for breast and lung cancer RT, have demonstrated performance comparable to manual contouring, marking a significant milestone in the evolution of cardiac delineation practices. Nevertheless, several key concerns require further investigation. There is an unmet need for expanding cardiac auto-contouring models to encompass a broader range of cancer sites. A shift in focus is needed from ensuring accuracy to enhancing the robustness and accessibility of auto-contouring models. Addressing these challenges is paramount for the integration of cardiac substructure delineation and associated risk models into routine clinical practice, thereby improving the safety of RT for future cancer patients.
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Affiliation(s)
- Robert N Finnegan
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales, Australia
| | - Alexandra Quinn
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia
| | - Jeremy Booth
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales, Australia
| | - Gregg Belous
- Australian e-Health Research Centre, Commonwealth Scientific and Industrial Research Organisation, Brisbane, Queensland, Australia
| | - Nicholas Hardcastle
- Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
| | - Maegan Stewart
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia
- School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Brooke Griffiths
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia
| | - Susan Carroll
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales, Australia
- School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - David I Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, New South Wales, Australia
- Radiotherapy Research Group, Leeds Institute of Medical Research, St James's Hospital and University of Leeds, Leeds, UK
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3
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Qubala A, Shafee J, Tessonnier T, Horn J, Winter M, Naumann J, Jäkel O. Characteristics of breathing-adapted gating using surface guidance for use in particle therapy: A phantom-based end-to-end test from CT simulation to dose delivery. J Appl Clin Med Phys 2024; 25:e14249. [PMID: 38128056 PMCID: PMC10795430 DOI: 10.1002/acm2.14249] [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: 10/10/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
To account for intra-fractional tumor motion during dose delivery in radiotherapy, various treatment strategies are clinically implemented such as breathing-adapted gating and irradiating the tumor during specific breathing phases. In this work, we present a comprehensive phantom-based end-to-end test of breathing-adapted gating utilizing surface guidance for use in particle therapy. A commercial dynamic thorax phantom was used to reproduce regular and irregular breathing patterns recorded by the GateRT respiratory monitoring system. The amplitudes and periods of recorded breathing patterns were analysed and compared to planned patterns (ground-truth). In addition, the mean absolute deviations (MAD) and Pearson correlation coefficients (PCC) between the measurements and ground-truth were assessed. Measurements of gated and non-gated irradiations were also analysed with respect to dosimetry and geometry, and compared to treatment planning system (TPS). Further, the latency time of beam on/off was evaluated. Compared to the ground-truth, measurements performed with GateRT showed amplitude differences between 0.03 ± 0.02 mm and 0.26 ± 0.03 mm for regular and irregular breathing patterns, whilst periods of both breathing patterns ranged with a standard deviation between 10 and 190 ms. Furthermore, the GateRT software precisely acquired breathing patterns with a maximum MAD of 0.30 ± 0.23 mm. The PCC constantly ranged between 0.998 and 1.000. Comparisons between TPS and measured dose profiles indicated absolute mean dose deviations within institutional tolerances of ±5%. Geometrical beam characteristics also varied within our institutional tolerances of 1.5 mm. The overall time delays were <60 ms and thus within both recommended tolerances published by ESTRO and AAPM of 200 and 100 ms, respectively. In this study, a non-invasive optical surface-guided workflow including image acquisition, treatment planning, patient positioning and gated irradiation at an ion-beam gantry was investigated, and shown to be clinically viable. Based on phantom measurements, our results show a clinically-appropriate spatial, temporal, and dosimetric accuracy when using surface guidance in the clinical setting, and the results comply with international and institutional guidelines and tolerances.
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Affiliation(s)
- Abdallah Qubala
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- Faculty of MedicineUniversity of HeidelbergHeidelbergGermany
- National Center for Radiation Research in Oncology (NCRO)Heidelberg Institute of Radiation Oncology (HIRO)HeidelbergGermany
| | - Jehad Shafee
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- Saarland University of Applied SciencesSaarbrueckenGermany
| | - Thomas Tessonnier
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- National Center for Radiation Research in Oncology (NCRO)Heidelberg Institute of Radiation Oncology (HIRO)HeidelbergGermany
| | - Julian Horn
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- National Center for Radiation Research in Oncology (NCRO)Heidelberg Institute of Radiation Oncology (HIRO)HeidelbergGermany
| | - Marcus Winter
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- National Center for Radiation Research in Oncology (NCRO)Heidelberg Institute of Radiation Oncology (HIRO)HeidelbergGermany
| | - Jakob Naumann
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- National Center for Radiation Research in Oncology (NCRO)Heidelberg Institute of Radiation Oncology (HIRO)HeidelbergGermany
| | - Oliver Jäkel
- Heidelberg Ion Beam Therapy Center (HIT)HeidelbergGermany
- National Center for Radiation Research in Oncology (NCRO)Heidelberg Institute of Radiation Oncology (HIRO)HeidelbergGermany
- Department of Medical Physics in Radiation OncologyGerman Cancer Research Center (DKFZ)HeidelbergGermany
- National Center for Tumor Diseases (NCT)HeidelbergGermany
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Nakayama H, Okamoto H, Nakamura S, Iijima K, Chiba T, Takemori M, Nakaichi T, Mikasa S, Fujii K, Sakasai T, Kuwahara J, Miura Y, Fujiyama D, Tsunoda Y, Hanzawa T, Igaki H, Chang W. Film measurement and analytical approach for assessing treatment accuracy and latency in a magnetic resonance-guided radiotherapy system. J Appl Clin Med Phys 2023; 24:e13915. [PMID: 36934441 PMCID: PMC10161048 DOI: 10.1002/acm2.13915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 11/25/2022] [Accepted: 01/12/2023] [Indexed: 03/20/2023] Open
Abstract
PURPOSE We measure the dose distribution of gated delivery for different target motions and estimate the gating latency in a magnetic resonance-guided radiotherapy (MRgRT) system. METHOD The dose distribution accuracy of the gated MRgRT system (MRIdian, Viewray) was investigated using an in-house-developed phantom that was compatible with the magnetic field and gating method. This phantom contains a simulated tumor and a radiochromic film (EBT3, Ashland, Inc.). To investigate the effect of the number of beam switching and target velocity on the dose distribution, two types of target motions were applied. One is that the target was periodically moved at a constant velocity of 5 mm/s with different pause times (0, 1, 3, 10, and 20 s) between the motions. During different pause times, different numbers of beams were switched on/off. The other one is that the target was moved at velocities of 3, 5, 8, and 10 mm/s without any pause (i.e., continuous motion). The gated method was applied to these motions at MRIdian, and the dose distributions in each condition were measured using films. To investigate the relation between target motion and dose distribution in the gating method, we compared the results of the gamma analysis of the calculated and measured dose distributions. Moreover, we analytically estimated the gating latencies from the dose distributions measured using films and the gamma analysis results. RESULTS The gamma pass rate linearly decreased with increasing beam switching and target velocity. The overall gating latencies of beam-hold and beam-on were 0.51 ± 0.17 and 0.35 ± 0.05 s, respectively. CONCLUSIONS Film measurements highlighted the factors affecting the treatment accuracy of the gated MRgRT system. Our analytical approach, employing gamma analysis on films, can be used to estimate the overall latency of the gated MRgRT system.
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Affiliation(s)
- Hiroki Nakayama
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.,Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Higashioku, Arakawa-ku, Tokyo, Japan
| | - Hiroyuki Okamoto
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Satoshi Nakamura
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Kotaro Iijima
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Takahito Chiba
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.,Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Higashioku, Arakawa-ku, Tokyo, Japan
| | - Mihiro Takemori
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.,Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Higashioku, Arakawa-ku, Tokyo, Japan
| | - Tetsu Nakaichi
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Shohei Mikasa
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Kyohei Fujii
- Department of Radiation Sciences, Komazawa University, Setagaya-ku, Tokyo, Japan
| | - Tatsuya Sakasai
- Department of Radiological Technology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Junichi Kuwahara
- Radiation Safety and Quality Assurance Division, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan.,Department of Radiological Technology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Yuki Miura
- Department of Radiological Technology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan
| | - Daisuke Fujiyama
- Department of Radiological Technology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Yuki Tsunoda
- Department of Radiological Technology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Takuma Hanzawa
- Department of Radiological Technology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Hiroshi Igaki
- Department of Radiation Oncology, National Cancer Center Hospital, Chuo-ku, Tokyo, Japan
| | - Weishan Chang
- Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Higashioku, Arakawa-ku, Tokyo, Japan
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5
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Kim C, Kim H, Kim SW, Goh Y, Park MJ, Kim H, Jeong C, Cho B, Choi EK, Lee SW, Yoon SM, Kim SS, Park JH, Jung J, Song SY, Kwak J. A study of quantitative indicators for slice sorting in cine-mode 4DCT. PLoS One 2022; 17:e0272639. [PMID: 36026490 PMCID: PMC9417040 DOI: 10.1371/journal.pone.0272639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/22/2022] [Indexed: 11/28/2022] Open
Abstract
The uncertainties of four-dimensional computed tomography (4DCT), also called as residual motion artefacts (RMA), induced from irregular respiratory patterns can degrade the quality of overall radiotherapy. This study aims to quantify and reduce those uncertainties. A comparative study on quantitative indicators for RMA was performed, and based on this, we proposed a new 4DCT sorting method that is applicable without disrupting the current clinical workflow. In addition to the default phase sorting strategy, both additional amplitude information from external surrogates and the quantitative metric for RMA, investigated in this study, were introduced. The comparison of quantitative indicators and the performance of the proposed sorting method were evaluated via 10 cases of breath-hold (BH) CT and 30 cases of 4DCT. It was confirmed that N-RMSD (normalised root-mean-square-deviation) was best matched to the visual standards of our institute’s regime, manual sorting method, and could accurately represent RMA. The performance of the proposed method to reduce 4DCT uncertainties was improved by about 18.8% in the averaged value of N-RMSD compared to the default phase sorting method. To the best of our knowledge, this is the first study that evaluates RMA indicators using both BHCT and 4DCT with visual-criteria-based manual sorting and proposes an improved 4DCT sorting strategy based on them.
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Affiliation(s)
- Changhwan Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Hojae Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Seoul, Republic of Korea
| | - Sung-woo Kim
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Youngmoon Goh
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Min-jae Park
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Hojin Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Chiyoung Jeong
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
| | - Byungchul Cho
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Eun Kyung Choi
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang-wook Lee
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Sang Min Yoon
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Su Ssan Kim
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jin-hong Park
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jinhong Jung
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Si Yeol Song
- Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jungwon Kwak
- Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea
- * E-mail:
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6
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Puangragsa U, Setakornnukul J, Dankulchai P, Phasukkit P. 3D Kinect Camera Scheme with Time-Series Deep-Learning Algorithms for Classification and Prediction of Lung Tumor Motility. SENSORS (BASEL, SWITZERLAND) 2022; 22:s22082918. [PMID: 35458903 PMCID: PMC9024525 DOI: 10.3390/s22082918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/04/2022] [Accepted: 04/09/2022] [Indexed: 05/27/2023]
Abstract
This paper proposes a time-series deep-learning 3D Kinect camera scheme to classify the respiratory phases with a lung tumor and predict the lung tumor displacement. Specifically, the proposed scheme is driven by two time-series deep-learning algorithmic models: the respiratory-phase classification model and the regression-based prediction model. To assess the performance of the proposed scheme, the classification and prediction models were tested with four categories of datasets: patient-based datasets with regular and irregular breathing patterns; and pseudopatient-based datasets with regular and irregular breathing patterns. In this study, 'pseudopatients' refer to a dynamic thorax phantom with a lung tumor programmed with varying breathing patterns and breaths per minute. The total accuracy of the respiratory-phase classification model was 100%, 100%, 100%, and 92.44% for the four dataset categories, with a corresponding mean squared error (MSE), mean absolute error (MAE), and coefficient of determination (R2) of 1.2-1.6%, 0.65-0.8%, and 0.97-0.98, respectively. The results demonstrate that the time-series deep-learning classification and regression-based prediction models can classify the respiratory phases and predict the lung tumor displacement with high accuracy. Essentially, the novelty of this research lies in the use of a low-cost 3D Kinect camera with time-series deep-learning algorithms in the medical field to efficiently classify the respiratory phase and predict the lung tumor displacement.
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Affiliation(s)
- Utumporn Puangragsa
- Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (U.P.); (J.S.); (P.D.)
| | - Jiraporn Setakornnukul
- Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (U.P.); (J.S.); (P.D.)
| | - Pittaya Dankulchai
- Division of Radiation Oncology, Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand; (U.P.); (J.S.); (P.D.)
| | - Pattarapong Phasukkit
- School of Engineering, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand
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Suzuki K, Usui K, Sasai K. Improving the accuracy of motion quantification using area detector computed tomography for real-time tumor-tracking irradiation in stereotactic ablative radiotherapy. Med Dosim 2022; 47:166-172. [PMID: 35277317 DOI: 10.1016/j.meddos.2022.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 01/27/2022] [Accepted: 02/03/2022] [Indexed: 10/18/2022]
Abstract
CyberKnife radiotherapy enables tumor-tracking irradiation using positional information regarding the tumor and a fiducial marker in a patient's body. This positional information acts as a surrogate of tumor motion. Therefore, deviations in these movements should be quantitatively estimated and included as an internal margin for radiation treatment planning. This study aimed to investigate variations between the positions of fiducial markers and tumor regions using 320-row area detector computed tomography and to analyze the effectiveness of our proposed method in contouring tumor regions based on the fiducial marker position. To determine the moving tumor volume, a typical single-phase image was selected, and pixel values in other phase images were accumulated. Moreover, a maximum-intensity projection image was created to clarify motion deviations in the tumor volume. To evaluate the delineation accuracy, the dice similarity coefficient and mean distance to agreement were calculated in phase-selected and breath-holding computed tomography. Moving chest phantom images were acquired using helical scanning 4-dimensional computed tomography (H-4DCT) and volumetric scanning 4-dimensional computed tomography (V-4DCT), and the delineation accuracies were compared for each scanning type. The average dice similarity coefficient and mean distance to agreement were degraded in limited-phase images, which cannot represent the hysteretic motion of a tumor. Moreover, deviations in tumor volume with unstable motion reached 71.6% in H-4DCT but only 1.6% in V-4DCT. Our proposed method with V-4DCT using area detector computed tomography can achieve accurate moving tumor delineation and can clarify positional associations between the fiducial marker and tumor under respiratory motion.
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Affiliation(s)
- Kentaro Suzuki
- Department of Radiation Oncology, Graduate School of Medicine, Juntendo University, Tokyo 113-8421, Japan.
| | - Keisuke Usui
- Department of Radiological Technology, Faculty of Health Science, Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, 113-8421, Japan
| | - Keisuke Sasai
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University, Tokyo, 113-8421, Japan
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8
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Gut P, Krieger M, Lomax T, Weber DC, Hrbacek J. Combining rescanning and gating for a time-efficient treatment of mobile tumors using pencil beam scanning proton therapy. Radiother Oncol 2021; 160:82-89. [PMID: 33839206 DOI: 10.1016/j.radonc.2021.03.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/04/2021] [Accepted: 03/31/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND PURPOSE Respiratory motion during proton therapy can severely degrade dose distributions, particularly due to interplay effects when using pencil beam scanning. Combined rescanning and gating treatments for moving tumors mitigates dose degradation, but at the cost of increased treatment delivery time. The objective of this study was to identify the time efficiency of these dose degradation-motion mitigation strategies for different range of motions. MATERIALS AND METHODS Seventeen patients with thoracic or abdominal tumors were studied. Tumor motion amplitudes ranged from 2-30 mm. Deliveries using different combinations of rescanning and gating were simulated with a dense dose spot grid (4 × 4 × 2.5 mm3) for all patients and a sparse dose spot grid (8 × 8 × 5 mm3) for six patients with larger tumor movements (>8 mm). The resulting plans were evaluated in terms of CTV coverage and time efficiency. RESULTS Based on the studied patient cohort, it has been shown that for amplitudes up to 5 mm, no motion mitigation is required with a dense spot grid. For amplitudes between 5 and 10 mm, volumetric rescanning should be applied while maintaining a 100% duty cycle when using a dense spot grid. Although gating could be envisaged to reduce the target volume for intermediate motion, it has been shown that the dose to normal tissues would only be reduced marginally. Moreover, the treatment time would increase. Finally, for larger motion amplitudes, both volumetric rescanning and respiratory gating should be applied with both spot grids. In addition, it has been shown that a dense spot grid delivers better CTV dose coverage than a sparse dose grid. CONCLUSION Volumetric rescanning and/or respiratory gating can be used in order to effectively and efficiently mitigate dose degradation due to tumor movement.
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Affiliation(s)
- Pauline Gut
- Department of Physics, ETH Zurich, Zurich, Switzerland; Center for Proton Therapy, Paul Scherrer Institute (PSI), Villigen PSI, Switzerland
| | - Miriam Krieger
- Department of Physics, ETH Zurich, Zurich, Switzerland; Center for Proton Therapy, Paul Scherrer Institute (PSI), Villigen PSI, Switzerland
| | - Tony Lomax
- Department of Physics, ETH Zurich, Zurich, Switzerland; Center for Proton Therapy, Paul Scherrer Institute (PSI), Villigen PSI, Switzerland
| | - Damien C Weber
- Center for Proton Therapy, Paul Scherrer Institute (PSI), Villigen PSI, Switzerland; Department of Radiation Oncology, University Hospital of Zurich, Zurich, Switzerland; Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Jan Hrbacek
- Center for Proton Therapy, Paul Scherrer Institute (PSI), Villigen PSI, Switzerland.
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9
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Keiper TD, Tai A, Chen X, Paulson E, Lathuilière F, Bériault S, Hébert F, Cooper DT, Lachaine M, Li XA. Feasibility of real‐time motion tracking using cine MRI during MR‐guided radiation therapy for abdominal targets. Med Phys 2020; 47:3554-3566. [DOI: 10.1002/mp.14230] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/31/2020] [Accepted: 04/30/2020] [Indexed: 12/25/2022] Open
Affiliation(s)
- Timothy D. Keiper
- Department of Radiation Oncology Medical College of Wisconsin 8701 Watertown Plank Rd Milwaukee WI 53226 USA
| | - An Tai
- Department of Radiation Oncology Medical College of Wisconsin 8701 Watertown Plank Rd Milwaukee WI 53226 USA
| | - Xinfeng Chen
- Department of Radiation Oncology Medical College of Wisconsin 8701 Watertown Plank Rd Milwaukee WI 53226 USA
| | - Eric Paulson
- Department of Radiation Oncology Medical College of Wisconsin 8701 Watertown Plank Rd Milwaukee WI 53226 USA
| | | | | | - François Hébert
- Elekta 2050 Rue de Bleury Suite 200 Montréal QC H3A 2J5 Canada
| | - David T. Cooper
- Elekta 2050 Rue de Bleury Suite 200 Montréal QC H3A 2J5 Canada
| | - Martin Lachaine
- Elekta 2050 Rue de Bleury Suite 200 Montréal QC H3A 2J5 Canada
| | - X. Allen Li
- Department of Radiation Oncology Medical College of Wisconsin 8701 Watertown Plank Rd Milwaukee WI 53226 USA
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Ali Mirzapour S, Mazur T, Sharp G, Salari E. Intra-fraction motion prediction in MRI-guided radiation therapy using Markov processes. ACTA ACUST UNITED AC 2019; 64:195006. [DOI: 10.1088/1361-6560/ab37a9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Chaudhary RK, Kumar R, Sharma SD, Bera S, Mittal V, Deshpande S. Performance Validation of In-House Developed Four-dimensional Dynamic Phantom. J Med Phys 2019; 44:99-105. [PMID: 31359927 PMCID: PMC6580812 DOI: 10.4103/jmp.jmp_114_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Objective: The objective of this study was to validate the performance characteristics of in-house developed four-dimensional (4D) dynamic phantom (FDDP). Materials and Methods: There are three target inserts of 1.0, 1.5 and 2.0 cm diameter. The targets were driven in sinusoidal pattern in the longitudinal direction, using the combinations of amplitudes of 0.5, 1.0, and 1.5 cm with frequencies of 0.2 and 0.25 Hz. The amplitude and frequency of motion were measured manually, and by using Real-Time Position Management (RPM) system also. The static, free-breathing, and 4D computed tomography (CT) scans of the phantom were acquired with 1.0 mm slice thickness. The 4DCT scans were sorted into 0%–90% phase, and the maximum intensity projection (MIP) images were also generated. The static, free-breathing, and 4DCT data sets and MIP images were contoured to get VStatic, VFB, V00......V90, and internal target volume ITV MIP, respectively. The individual phase volumes were summed to obtain V4D. The length of the target in the motion was measured using MIP image and compared with theoretical length (TL). The variation of 3D displacement vector of individual phase volume with respect to V00 with the phase of motion was studied at amplitude and frequency of 1.0 cm and 0.25 Hz, respectively. The degree of similarity between VFB and V4D and VFB and ITVMIP was also studied for all the target sizes at amplitude and frequency of 1.0 cm and 0.2 Hz and 1.0 cm and 0.25 Hz, respectively. Results: The amplitude and frequency of motion agreed within the limits of uncertainty with the manually and RPM measured values. The length of target in the motion matched within 1.0 mm with TL. The 3D displacement of individual phase volume showed no target size dependence, and the degree of similarity between VFB and V4D and VFB and ITVMIP decreases with increase in the displacement between the two volumes. Conclusions: The mechanical and imaging performances of FDDP were found within the acceptable limits. Therefore, this phantom can be used for quality assurance of 4D imaging process in radiotherapy.
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Affiliation(s)
- Rahul Kumar Chaudhary
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - Rajesh Kumar
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
| | - S D Sharma
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India.,Homi Bhabha National Institute, Anushakti Nagar, Mumbai, Maharashtra, India
| | - Soumen Bera
- P. D. Hinduja National Hospital and Medical Research Centre, Mumbai, Maharashtra, India
| | - Vikram Mittal
- P. D. Hinduja National Hospital and Medical Research Centre, Mumbai, Maharashtra, India
| | - Sudesh Deshpande
- P. D. Hinduja National Hospital and Medical Research Centre, Mumbai, Maharashtra, India
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Prunaretty J, Boisselier P, Aillères N, Riou O, Simeon S, Bedos L, Azria D, Fenoglietto P. Tracking, gating, free-breathing, which technique to use for lung stereotactic treatments? A dosimetric comparison. Rep Pract Oncol Radiother 2019; 24:97-104. [PMID: 30532657 PMCID: PMC6261085 DOI: 10.1016/j.rpor.2018.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 09/04/2018] [Accepted: 11/10/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The management of breath-induced tumor motion is a major challenge for lung stereotactic body radiation therapy (SBRT). Three techniques are currently available for these treatments: tracking (T), gating (G) and free-breathing (FB). AIM To evaluate the dosimetric differences between these three treatment techniques for lung SBRT. MATERIALS AND METHODS Pretreatment 4DCT data were acquired for 10 patients and sorted into 10 phases of a breathing cycle, such as 0% and 50% phases defined respectively as the inhalation and exhalation maximum. GTVph, PTVph (=GTVph + 3 mm) and the ipsilateral lung were contoured on each phase.For the tracking technique, 9 fixed fields were adjusted to each PTVph for the 10 phases. The gating technique was studied with 3 exhalation phases (40%, 50% and 60%). For the free-breathing technique, ITVFB was created from a sum of all GTVph and a 3 mm margin was added to define a PTVFB. Fields were adjusted to PTVFB and dose distributions were calculated on the average intensity projection (AIP) CT. Then, the beam arrangement with the same monitor units was planned on each CT phase.The 3 modalities were evaluated using DVHs of each GTVph, the homogeneity index and the volume of the ipsilateral lung receiving 20 Gy (V 20Gy). RESULTS The FB system improved the target coverage by increasing D mean (75.87(T)-76.08(G)-77.49(FB)Gy). Target coverage was slightly more homogeneous, too (HI: 0.17(T and G)-0.15(FB)). But the lung was better protected with the tracking system (V 20Gy: 3.82(T)-4.96(G)-6.34(FB)%). CONCLUSIONS Every technique provides plans with a good target coverage and lung protection. While irradiation with free-breathing increases doses to GTV, irradiation with the tracking technique spares better the lung but can dramatically increase the treatment complexity.
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Jöhl A, Bogowicz M, Ehrbar S, Guckenberger M, Klöck S, Meboldt M, Riesterer O, Zeilinger M, Schmid Daners M, Tanadini-Lang S. Body motion during dynamic couch tracking with healthy volunteers. Phys Med Biol 2018; 64:015001. [PMID: 30523943 DOI: 10.1088/1361-6560/aaf361] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In precision radiotherapy, the intrafractional motion can cause a considerable uncertainty of the location of the tumor to be treated. An established approach is the expansion of the target volume to account for the motion. An alternative approach is couch-tracking, in which the patient is continually moved to compensate the intrafractional motion. However, couch-tracking itself might induce uncertainty of the patient's body position, because the body is non-rigid. One hundred healthy volunteers were positioned supine on a robotic couch. Optical markers were placed on the torso of the volunteers as well as on the couch, and their positions were tracked with an optical surface measurement system. Using these markers, the uncertainty of the body position relative to the couch position was estimated while the couch was static or moving. Over the included 83 healthy volunteers, the median of the uncertainty increased by 0.8 mm (SI), 0.4 mm (LR) and 0.4 mm (AP) when the couch moved. Couch motion was found to increase the uncertainty of the body position relative to the couch. However, this uncertainty is one order of magnitude smaller than the intrafractional tumor motion amplitudes to be compensated. Therefore, even with body motion present, the couch-tracking approach is a viable option. The study was registered at ClinicalTrials.gov (NCT02820532) and the Swiss national clinical trials portal (SNCTP000001878).
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Affiliation(s)
- Alexander Jöhl
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Zurich 8092, Switzerland. Department of Radiation Oncology, University Hospital Zurich, Zurich 8091, Switzerland
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Valenti M, Campanelli A, Parisotto M, Maggi S. Cine 4DCT imaging artifacts: Quantification and correlations with scanning parameters and target kinetics. Phys Med 2018; 52:133-142. [DOI: 10.1016/j.ejmp.2018.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 12/25/2022] Open
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Zhou D, Quan H, Yan D, Chen S, Qin A, Stanhope C, Lachaine M, Liang J. A feasibility study of intrafractional tumor motion estimation based on 4D-CBCT using diaphragm as surrogate. J Appl Clin Med Phys 2018; 19:525-531. [PMID: 29971918 PMCID: PMC6123140 DOI: 10.1002/acm2.12410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 03/14/2018] [Accepted: 06/12/2018] [Indexed: 12/25/2022] Open
Abstract
Purpose To investigate the intrafractional stability of the motion relationship between the diaphragm and tumor, as well as the feasibility of using diaphragm motion to estimate lung tumor motion. Methods Eighty‐five paired (pre and posttreatment) daily 4D‐CBCT images were obtained from 20 lung cancer patients who underwent SBRT. Bony registration was performed between the pre‐ and post‐CBCT images to exclude patient body movement. The end‐exhalation phase image of the pre‐CBCT image was selected as the reference image. Tumor positions were obtained for each phase image using contour‐based translational alignments. Diaphragm positions were obtained by translational alignment of its apex position. A linear intrafraction model was constructed using regression analysis performed between the diaphragm and tumor positions manifested on the pretreatment 4D‐CBCT images. By applying this model to posttreatment 4D‐CBCT images, the tumor positions were estimated from posttreatment 4D‐CBCT diaphragm positions and compared with measured values. A receiver operating characteristic (ROC) test was performed to determine a suitable indicator for predicting the estimate accuracy of the linear model. Results Using the linear model, per‐phase position, mean position, and excursion estimation errors were 1.12 ± 0.99 mm, 0.97 ± 0.88 mm, and 0.79 ± 0.67 mm, respectively. Intrafractional per‐phase tumor position estimation error, mean position error, and excursion error were within 3 mm 95%, 96%, and 99% of the time, respectively. The residual sum of squares (RSS) determined from pretreatment images achieved the largest prediction power for the tumor position estimation error (discrepancy < 3 mm) with an Area Under ROC Curve (AUC) of 0.92 (P < 0.05). Conclusion Utilizing the relationship between diaphragm and tumor positions on the pretreatment 4D‐CBCT image, intrafractional tumor positions were estimated from intrafractional diaphragm positions. The estimation accuracy can be predicted using the RSS obtained from the pretreatment 4D‐CBCT image.
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Affiliation(s)
- Dingyi Zhou
- Key Laboratory of Artificial Micro- & Nano- structures of Ministry of Education and Center for Electronic Microscopy; School of Physics and Technology; Wuhan University; Wuhan China
- Department of Radiation Oncology; Beaumont Health System; Royal Oak MI USA
| | - Hong Quan
- Key Laboratory of Artificial Micro- & Nano- structures of Ministry of Education and Center for Electronic Microscopy; School of Physics and Technology; Wuhan University; Wuhan China
| | - Di Yan
- Department of Radiation Oncology; Beaumont Health System; Royal Oak MI USA
| | - Shupeng Chen
- Department of Radiation Oncology; Beaumont Health System; Royal Oak MI USA
| | - An Qin
- Department of Radiation Oncology; Beaumont Health System; Royal Oak MI USA
| | - Carl Stanhope
- Department of Radiation Oncology; Beaumont Health System; Royal Oak MI USA
| | | | - Jian Liang
- Department of Radiation Oncology; Beaumont Health System; Royal Oak MI USA
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Li H, Chang JY. Accounting for, Mitigating, and Choice of Margins for Moving Tumors. Semin Radiat Oncol 2018; 28:194-200. [DOI: 10.1016/j.semradonc.2018.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Kesner A, Pan T, Zaidi H. Data-driven motion correction will replace motion-tracking devices in molecular imaging-guided radiation therapy treatment planning. Med Phys 2018; 45:3477-3480. [PMID: 29679489 DOI: 10.1002/mp.12928] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 04/14/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
- Adam Kesner
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Tinsu Pan
- Department of Imaging Physics, The University of Texas, M D Anderson Cancer Center, 1515 Holcombe Blvd., Unit 1352, Houston, TX, 77030-4009, USA
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Performance assessment of a programmable five degrees-of-freedom motion platform for quality assurance of motion management techniques in radiotherapy. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:643-649. [DOI: 10.1007/s13246-017-0572-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/09/2017] [Indexed: 10/19/2022]
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Ehrbar S, Jöhl A, Tartas A, Stark LS, Riesterer O, Klöck S, Guckenberger M, Tanadini-Lang S. ITV, mid-ventilation, gating or couch tracking - A comparison of respiratory motion-management techniques based on 4D dose calculations. Radiother Oncol 2017; 124:80-88. [PMID: 28587761 DOI: 10.1016/j.radonc.2017.05.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 04/19/2017] [Accepted: 05/20/2017] [Indexed: 12/17/2022]
Abstract
PURPOSE Respiratory motion-management techniques (MMT) aim to ensure tumor dose coverage while sparing lung tissue. Dynamic treatment-couch tracking of the moving tumor is a promising new MMT and was compared to the internal-target-volume (ITV) concept, the mid-ventilation (MidV) principle and the gating approach in a planning study based on 4D dose calculations. METHODS For twenty patients with lung lesions, planning target volumes (PTV) were adapted to the MMT and stereotactic body radiotherapy treatments were prepared with the 65%-isodose enclosing the PTV. For tracking, three concepts for target volume definition were considered: Including the gross tumor volume of one phase (single-phase tracking), including deformations between phases (multi-phase tracking) and additionally including tracking latencies of a couch tracking system (reliable couch tracking). The accumulated tumor and lung doses were estimated with 4D dose calculations based on 4D-CT datasets and deformable image registration. RESULTS Single-phase tracking showed the lowest ipsilateral lung Dmean (median: 3.3Gy), followed by multi-phase tracking, gating, reliable couch tracking, MidV and ITV concepts (3.6, 3.8, 4.1, 4.3 and 4.8Gy). The 4D dose calculations showed the MidV and single-phase tracking overestimated the target mean dose (-2.3% and -1.3%), while it was slightly underestimated by the other MMT (<+1%). CONCLUSION The ITV concept ensures tumor coverage, but exposes the lung tissue to a higher dose. The MidV, gating and tracking concepts were shown to reduce the lung dose. Neglecting non-translational changes of the tumor in the target volume definition for tracking results in a slightly reduced target coverage. The slightly inferior dose coverage for MidV should be considered when applying this technique clinically.
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Affiliation(s)
- Stefanie Ehrbar
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland.
| | - Alexander Jöhl
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Switzerland
| | - Adrianna Tartas
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Warsaw, Faculty of Physics, Poland
| | - Luisa Sabrina Stark
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Oliver Riesterer
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Stephan Klöck
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Matthias Guckenberger
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Stephanie Tanadini-Lang
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
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Ahmed N, Venkataraman S, Johnson K, Sutherland K, Loewen SK. Does Motion Assessment With 4-Dimensional Computed Tomographic Imaging for Non-Small Cell Lung Cancer Radiotherapy Improve Target Volume Coverage? CLINICAL MEDICINE INSIGHTS-ONCOLOGY 2017; 11:1179554917698461. [PMID: 28469512 PMCID: PMC5395259 DOI: 10.1177/1179554917698461] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 02/12/2017] [Indexed: 12/25/2022]
Abstract
Introduction: Modern radiotherapy with 4-dimensional computed tomographic (4D-CT) image acquisition for non–small cell lung cancer (NSCLC) captures respiratory-mediated tumor motion to provide more accurate target delineation. This study compares conventional 3-dimensional (3D) conformal radiotherapy (3DCRT) plans generated with standard helical free-breathing CT (FBCT) with plans generated on 4D-CT contoured volumes to determine whether target volume coverage is affected. Materials and methods: Fifteen patients with stage I to IV NSCLC were enrolled in the study. Free-breathing CT and 4D-CT data sets were acquired at the same simulation session and with the same immobilization. Gross tumor volume (GTV) for primary and/or nodal disease was contoured on FBCT (GTV_3D). The 3DCRT plans were obtained, and the patients were treated according to our institution’s standard protocol using FBCT imaging. Gross tumor volume was contoured on 4D-CT for primary and/or nodal disease on all 10 respiratory phases and merged to create internal gross tumor volume (IGTV)_4D. Clinical target volume margin was 5 mm in both plans, whereas planning tumor volume (PTV) expansion was 1 cm axially and 1.5 cm superior/inferior for FBCT-based plans to incorporate setup errors and an estimate of respiratory-mediated tumor motion vs 8 mm isotropic margin for setup error only in all 4D-CT plans. The 3DCRT plans generated from the FBCT scan were copied on the 4D-CT data set with the same beam parameters. GTV_3D, IGTV_4D, PTV, and dose volume histogram from both data sets were analyzed and compared. Dice coefficient evaluated PTV similarity between FBCT and 4D-CT data sets. Results: In total, 14 of the 15 patients were analyzed. One patient was excluded as there was no measurable GTV. Mean GTV_3D was 115.3 cm3 and mean IGTV_4D was 152.5 cm3 (P = .001). Mean PTV_3D was 530.0 cm3 and PTV_4D was 499.8 cm3 (P = .40). Both gross primary and nodal disease analyzed separately were larger on 4D compared with FBCT. D95 (95% isodose line) covered 98% of PTV_3D and 88% of PTV_4D (P = .003). Mean dice coefficient of PTV_3D and PTV_4D was 84%. Mean lung V20 was 24.0% for the 3D-based plans and 22.7% for the 4D-based plans (P = .057). Mean heart V40 was 12.1% for the 3D-based plans and 12.7% for the 4D-based plans (P = .53). Mean spinal cord Dmax was 2517 and 2435 cGy for 3D-based and 4D-based plans, respectively (P = .019). Mean esophageal dose was 1580 and 1435 cGy for 3D and 4D plans, respectively (P = .13). Conclusions: IGTV_4D was significantly larger than GTV_3D for both primary and nodal disease combined or separately. Mean PTV_3D was larger than PTV_4D, but the difference was not statistically significant. The PTV_4D coverage with 95% isodose line was inferior, indicating the importance of incorporating the true size and shape of the target volume. Relatively less dose was delivered to spinal cord and esophagus with plans based on 4D data set. Dice coefficient analysis for degree of similarity revealed that 16% of PTVs from both data sets did not overlap, indicating different anatomical positions of the PTV due to tumor/nodal motion during a respiratory cycle. All patients with lung cancer planned for radical radiotherapy should have 4D-CT simulation to ensure accurate coverage of the target volumes.
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Affiliation(s)
- Naseer Ahmed
- Department of Radiation Oncology, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
| | - Sankar Venkataraman
- Department of Radiation Oncology, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
| | - Kate Johnson
- Department of Radiation Oncology, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
| | - Keith Sutherland
- Department of Radiation Oncology, CancerCare Manitoba, Winnipeg, MB, Canada
| | - Shaun K Loewen
- Division of Radiation Oncology, Department of Radiation Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary, AB, Canada
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Agrawal S, Kumar S, Maurya AK. Potential for adaptive dose escalation in radiotherapy for patients with locally advanced non-small-cell lung cancer in a low mid income setting. Br J Radiol 2017; 90:20140234. [PMID: 27897060 DOI: 10.1259/bjr.20140234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To evaluate the effect of tumour volume regression on adaptive treatment planning, reduction in doses to organs at risk (OARs) and dose escalation. METHODS 20 patients undergoing radical chemoradiotherapy were imaged in the fifth week of radiotherapy (CT_45) to evaluate differences in tumour volume regression between concurrent and sequential chemoradiotherapy. Replanning was carried out in the CT_45 in those with >20% regression (n = 10) and evaluated for change in target coverage indices (the coverage index and external volume index) and doses to the OAR [mean lung dose, V20 and V5 of whole and ipsilateral lung (MLDWL, V20WL, V5WL, MLDIL, V20IL, V5IL); mean oesophagus dose, V50oesophagus; and maximum spinal cord doses]. The feasibility of maximum dose escalation was explored keeping the limit of the OAR below their tolerance limits. RESULTS Tumour regression was higher with concurrent chemoradiotherapy as compared with sequential chemoradiotherapy (p = 0.02). With the adaptive plan, the mean coverage index improved from 0.96 (±0.14) to 1.29 (±0.36), the mean external volume index changed from 1.39(±0.60) to 1.41(±0.56) and the reduction in doses to the OARs were MLDWL 10.6%, V20WL 1.3%, V5WL 1.2%, MLDIL 6.6%, V20IL 1.5%, V5IL 2.3%, mean oesophagus dose 7%, V50oesophagus 31% and maximum cord dose 0.35%. Dose escalation was possible in four patients in CT_45. CONCLUSION There is 35% reduction in tumour volume with chemoradiotherapy at 45 Gy which allows improvement in conformality, reduction in doses to the OARs and dose escalation in 40% of patients. Advances in knowledge: This article emphasizes that adaptive planning with a single diagnostic scan at 45 Gy has the potential for improvement of radiotherapy planning indices, dose escalation while respecting the dose to the OAR. This simple strategy can be helpful in radiotherapy planning upto 60 Gy in 40% of the patients of locally advanced non-small-cell lung cancer in countries with limited resources.
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Affiliation(s)
- Sushma Agrawal
- Department of Radiotherapy, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Sunil Kumar
- Department of Radiotherapy, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
| | - Anil K Maurya
- Department of Radiotherapy, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
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Ehrbar S, Perrin R, Peroni M, Bernatowicz K, Parkel T, Pytko I, Klöck S, Guckenberger M, Tanadini-Lang S, Weber DC, Lomax A. Respiratory motion-management in stereotactic body radiation therapy for lung cancer - A dosimetric comparison in an anthropomorphic lung phantom (LuCa). Radiother Oncol 2016; 121:328-334. [PMID: 27817945 DOI: 10.1016/j.radonc.2016.10.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 09/19/2016] [Accepted: 10/06/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND PURPOSE The objective of this study was to compare the latest respiratory motion-management strategies, namely the internal-target-volume (ITV) concept, the mid-ventilation (MidV) principle, respiratory gating and dynamic couch tracking. MATERIALS AND METHODS An anthropomorphic, deformable and dynamic lung phantom was used for the dosimetric validation of these techniques. Stereotactic treatments were adapted to match the techniques and five distinct respiration patterns, and delivered to the phantom while radiographic film measurements were taken inside the tumor. To report on tumor coverage, these dose distributions were used to calculate mean doses (Dmean), changes in homogeneity indices (ΔH2-98), gamma agreement, and areas covered by the planned minimum dose (A>Dmin). RESULTS All techniques achieved good tumor coverage (A>Dmin>99.0%) and minor changes in Dmean (±3.2%). Gating and tracking strategies showed superior results in gamma agreement and ΔH2-98 compared to ITV and MidV concepts, which seem to be more influenced by the interplay and the gradient effect. For lung, heart and spinal cord, significant dose differences between the four techniques were found (p<0.05), with lowest doses for gating and tracking strategies. CONCLUSION Active motion-management techniques, such as gating or tracking, showed superior tumor dose coverage and better organ dose sparing than the passive techniques based on tumor margins.
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Affiliation(s)
- Stefanie Ehrbar
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland.
| | - Rosalind Perrin
- Center for Proton Therapy, Paul Scherrer Institute (PSI), Switzerland
| | - Marta Peroni
- Center for Proton Therapy, Paul Scherrer Institute (PSI), Switzerland
| | - Kinga Bernatowicz
- Center for Proton Therapy, Paul Scherrer Institute (PSI), Switzerland
| | - Thomas Parkel
- Innovative Design, Centre Suisse d'Electronique et de Microtechnique (CSEM) S. A., Switzerland
| | - Izabela Pytko
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Stephan Klöck
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Matthias Guckenberger
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Stephanie Tanadini-Lang
- Department of Radiation Oncology, University Hospital Zurich (USZ), Switzerland; University of Zurich, Switzerland
| | - Damien Charles Weber
- University of Zurich, Switzerland; Center for Proton Therapy, Paul Scherrer Institute (PSI), Switzerland
| | - Antony Lomax
- Center for Proton Therapy, Paul Scherrer Institute (PSI), Switzerland; Swiss Federal Institute of Technology in Zurich (ETHZ), Switzerland
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Web of Science, Scopus, and Google Scholar citation rates: a case study of medical physics and biomedical engineering: what gets cited and what doesn't? AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2016; 39:817-823. [PMID: 27578318 DOI: 10.1007/s13246-016-0478-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
Abstract
There are often differences in a publication's citation count, depending on the database accessed. Here, aspects of citation counts for medical physics and biomedical engineering papers are studied using papers published in the journal Australasian physical and engineering sciences in medicine. Comparison is made between the Web of Science, Scopus, and Google Scholar. Papers are categorised into subject matter, and citation trends are examined. It is shown that review papers as a group tend to receive more citations on average; however the highest cited individual papers are more likely to be research papers.
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Tatinati S, Nazarpour K, Tech Ang W, Veluvolu KC. Ensemble framework based real-time respiratory motion prediction for adaptive radiotherapy applications. Med Eng Phys 2016; 38:749-57. [PMID: 27238760 DOI: 10.1016/j.medengphy.2016.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 03/25/2016] [Accepted: 04/24/2016] [Indexed: 10/21/2022]
Abstract
Successful treatment of tumors with motion-adaptive radiotherapy requires accurate prediction of respiratory motion, ideally with a prediction horizon larger than the latency in radiotherapy system. Accurate prediction of respiratory motion is however a non-trivial task due to the presence of irregularities and intra-trace variabilities, such as baseline drift and temporal changes in fundamental frequency pattern. In this paper, to enhance the accuracy of the respiratory motion prediction, we propose a stacked regression ensemble framework that integrates heterogeneous respiratory motion prediction algorithms. We further address two crucial issues for developing a successful ensemble framework: (1) selection of appropriate prediction methods to ensemble (level-0 methods) among the best existing prediction methods; and (2) finding a suitable generalization approach that can successfully exploit the relative advantages of the chosen level-0 methods. The efficacy of the developed ensemble framework is assessed with real respiratory motion traces acquired from 31 patients undergoing treatment. Results show that the developed ensemble framework improves the prediction performance significantly compared to the best existing methods.
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Affiliation(s)
- Sivanagaraja Tatinati
- School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu, South Korea
| | - Kianoush Nazarpour
- School of Electrical and Electronic Engineering, Newcastle University, Newcastle-upon-Tyne NE1-7RU, UK; Institute of Neuroscience, Newcastle University, Newcastle-upon-Tyne NE2 4HH, UK
| | - Wei Tech Ang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - Kalyana C Veluvolu
- School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu, South Korea; School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.
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Ahunbay E, Li XA. Investigation of the reliability, accuracy, and efficiency of gated IMRT delivery with a commercial linear accelerator. Med Phys 2016; 34:2928-38. [PMID: 17822001 DOI: 10.1118/1.2740009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
This work reports an investigation on the reliability, accuracy, and efficiency of gated intensity modulated radiation therapy (IMRT) delivery with a commercial linear accelerator. The dosimetry measurements of segmented multileaf collimated IMRT (SMLC-IMRT) were performed by using radiographic films and a two-dimensional diode array. Testing involved a series of IMRT fields from actual patients combined with some manually generated fields. To examine the delivery time, dosimetry plans of standard beamlet IMRT, direct-aperture-optimized (DAO) IMRT, compensator IMRT, and three-dimensional conformal radiotherapy with wedges were delivered with and without gating. The results demonstrated that the gated SMLC-IMRT can be reliably and accurately delivered on this type of accelerators, as long as extremely high interruption frequencies and very low number of monitor units per segment are avoided. Beam flatness exceeded 5% and monitor linearity deviated more than 3% for the gated operation with 2.5 s breathing cycle and 20% duty cycle with segment sizes less than 10 MU. Gating does not change multi leaf collimator (MLC) positioning accuracy. The DAO IMRT is preferred for gated delivery because of its short delivery time.
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Affiliation(s)
- Ergun Ahunbay
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Thiyagarajan R, Sinha SN, Ravichandran R, Samuvel K, Yadav G, Sigamani AK, Subramani V, Raj NAN. Respiratory gated radiotherapy-pretreatment patient specific quality assurance. J Med Phys 2016; 41:65-70. [PMID: 27051173 PMCID: PMC4795420 DOI: 10.4103/0971-6203.177279] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Organ motions during inter-fraction and intra-fraction radiotherapy introduce errors in dose delivery, irradiating excess of normal tissue, and missing target volume. Lung and heart involuntary motions cause above inaccuracies and gated dose delivery try to overcome above effects. Present work attempts a novel method to verify dynamic dose delivery using a four-dimensional (4D) phantom. Three patients with mobile target are coached to maintain regular and reproducible breathing pattern. Appropriate intensity projection image set generated from 4D-computed tomography (4D-CT) is used for target delineation. Intensity modulated radiotherapy plans were generated on selected phase using CT simulator (Siemens AG, Germany) in conjunction with “Real-time position management” (Varian, USA) to acquire 4D-CT images. Verification plans were generated for both ion chamber and Gafchromic (EBT) film image sets. Gated verification plans were delivered on the phantom moving with patient respiratory pattern. We developed a MATLAB-based software to generate maximum intensity projection, minimum intensity projections, and average intensity projections, also a program to convert patient breathing pattern to phantom compatible format. Dynamic thorax quality assurance (QA) phantom (Computerized Imaging Reference Systems type) is used to perform the patient specific QA, which holds an ion chamber and film to measure delivered radiation intensity. Exposed EBT films are analyzed and compared with treatment planning system calculated dose. The ion chamber measured dose shows good agreement with planned dose within ± 0.5% (0.203 ± 0.57%). Gamma value evaluated from EBT film shows passing rates 92–99% (96.63 ± 3.84%) for 3% dose and 3 mm distance criteria. Respiratory gated treatment delivery accuracy is found to be within clinically acceptable level.
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Affiliation(s)
- Rajesh Thiyagarajan
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta - The Medicity, Gurgaon, Haryana, India
| | - Sujit Nath Sinha
- Department of Radiation Oncology, Nayati Healthcare and Research, Mathura, India
| | | | - Kothandaraman Samuvel
- Division of Medical Physics, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India
| | - Girigesh Yadav
- Division of Medical Physics, Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, India
| | | | - Vikraman Subramani
- Division of Radiation Oncology, Medanta Cancer Institute, Medanta - The Medicity, Gurgaon, Haryana, India
| | - N Arunai Nambi Raj
- Department of Physics, School of Advanced Sciences, VIT University, Vellore, Tamil Nadu, India
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Tanaka R, Sanada S, Sakuta K, Kawashima H. Improved accuracy of markerless motion tracking on bone suppression images: preliminary study for image-guided radiation therapy (IGRT). Phys Med Biol 2015; 60:N209-18. [DOI: 10.1088/0031-9155/60/10/n209] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Serpa M, Baier K, Cremers F, Guckenberger M, Meyer J. Suitability of markerless EPID tracking for tumor position verification in gated radiotherapy. Med Phys 2014; 41:031702. [PMID: 24593706 DOI: 10.1118/1.4863597] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To maximize the benefits of respiratory gated radiotherapy (RGRT) of lung tumors real-time verification of the tumor position is required. This work investigates the feasibility of markerless tracking of lung tumors during beam-on time in electronic portal imaging device (EPID) images of the MV therapeutic beam. METHODS EPID movies were acquired at ∼2 fps for seven lung cancer patients with tumor peak-to-peak motion ranges between 7.8 and 17.9 mm (mean: 13.7 mm) undergoing stereotactic body radiotherapy. The external breathing motion of the abdomen was synchronously measured. Both datasets were retrospectively analyzed in PortalTrack, an in-house developed tracking software. The authors define a three-step procedure to run the simulations: (1) gating window definition, (2) gated-beam delivery simulation, and (3) tumor tracking. First, an amplitude threshold level was set on the external signal, defining the onset of beam-on/-off signals. This information was then mapped onto a sequence of EPID images to generate stamps of beam-on/-hold periods throughout the EPID movies in PortalTrack, by obscuring the frames corresponding to beam-off times. Last, tumor motion in the superior-inferior direction was determined on portal images by the tracking algorithm during beam-on time. The residual motion inside the gating window as well as target coverage (TC) and the marginal target displacement (MTD) were used as measures to quantify tumor position variability. RESULTS Tumor position monitoring and estimation from beam's-eye-view images during RGRT was possible in 67% of the analyzed beams. For a reference gating window of 5 mm, deviations ranging from 2% to 86% (35% on average) were recorded between the reference and measured residual motion. TC (range: 62%-93%; mean: 77%) losses were correlated with false positives incidence rates resulting mostly from intra-/inter-beam baseline drifts, as well as sudden cycle-to-cycle fluctuations in exhale positions. Both phenomena can lead to considerable deviations (with MTD values up to a maximum of 7.8 mm) from the intended tumor position, and in turn may result in a marginal miss. The difference between tumor traces determined within the gating window against ground truth trajectory maps was 1.1 ± 0.7 mm on average (range: 0.4-2.3 mm). CONCLUSIONS In this retrospective analysis of motion data, it is demonstrated that the system is capable of determining tumor positions in the plane perpendicular to the beam direction without the aid of fiducial markers, and may hence be suitable as an online verification tool in RGRT. It may be possible to use the tracking information to enable on-the-fly corrections to intra-/inter-beam variations by adapting the gating window by means of a robotic couch.
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Affiliation(s)
- Marco Serpa
- Institute for Research and Development on Advanced Radiation Technologies (radART), Paracelsus Medical University, 5020 Salzburg, Austria; University Clinic for Radiotherapy and Radio-Oncology, Landeskrankenhaus Salzburg, Paracelsus Medical University Clinics, 5020 Salzburg, Austria; and Department of Physics and Astronomy, University of Canterbury, Christchurch 8140, New Zealand
| | - Kurt Baier
- Department of Radiation Oncology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Florian Cremers
- Department of Radiation Oncology, University Medical Center Hamburg Eppendorf, D-20246 Hamburg, Germany
| | - Matthias Guckenberger
- Department of Radiation Oncology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Juergen Meyer
- Department of Radiation Oncology, University of Washington, Seattle, Washington 98195, USA
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Cole A, Hanna G, Jain S, O'Sullivan J. Motion Management for Radical Radiotherapy in Non-small Cell Lung Cancer. Clin Oncol (R Coll Radiol) 2014; 26:67-80. [DOI: 10.1016/j.clon.2013.11.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 09/23/2013] [Accepted: 09/24/2013] [Indexed: 11/28/2022]
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Belderbos J, Sonke JJ. State-of-the-art lung cancer radiation therapy. Expert Rev Anticancer Ther 2014; 9:1353-63. [DOI: 10.1586/era.09.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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White BM, Zhao T, Lamb J, Bradley JD, Low DA. Quantification of the thorax-to-abdomen breathing ratio for breathing motion modeling. Med Phys 2014; 40:063502. [PMID: 23718613 DOI: 10.1118/1.4805099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The purpose of this study was to develop a methodology to quantitatively measure the thorax-to-abdomen breathing ratio from a 4DCT dataset for breathing motion modeling and breathing motion studies. METHODS The thorax-to-abdomen breathing ratio was quantified by measuring the rate of cross-sectional volume increase throughout the thorax and abdomen as a function of tidal volume. Twenty-six 16-slice 4DCT patient datasets were acquired during quiet respiration using a protocol that acquired 25 ciné scans at each couch position. Fifteen datasets included data from the neck through the pelvis. Tidal volume, measured using a spirometer and abdominal pneumatic bellows, was used as breathing-cycle surrogates. The cross-sectional volume encompassed by the skin contour when compared for each CT slice against the tidal volume exhibited a nearly linear relationship. A robust iteratively reweighted least squares regression analysis was used to determine η(i), defined as the amount of cross-sectional volume expansion at each slice i per unit tidal volume. The sum Ση(i) throughout all slices was predicted to be the ratio of the geometric expansion of the lung and the tidal volume; 1.11. The Xiphoid process was selected as the boundary between the thorax and abdomen. The Xiphoid process slice was identified in a scan acquired at mid-inhalation. The imaging protocol had not originally been designed for purposes of measuring the thorax-to-abdomen breathing ratio so the scans did not extend to the anatomy with η(i) = 0. Extrapolation of η(i)-η(i) = 0 was used to include the entire breathing volume. The thorax and abdomen regions were individually analyzed to determine the thorax-to-abdomen breathing ratios. There were 11 image datasets that had been scanned only through the thorax. For these cases, the abdomen breathing component was equal to 1.11 - Ση(i) where the sum was taken throughout the thorax. RESULTS The average Ση(i) for thorax and abdomen image datasets was found to be 1.20 ± 0.17, close to the expected value of 1.11. The thorax-to-abdomen breathing ratio was 0.32 ± 0.24. The average Ση(i) was 0.26 ± 0.14 in the thorax and 0.93 ± 0.22 in the abdomen. In the scan datasets that encompassed only the thorax, the average Ση(i) was 0.21 ± 0.11. CONCLUSIONS A method to quantify the relationship between abdomen and thoracic breathing was developed and characterized.
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Affiliation(s)
- Benjamin M White
- Department of Radiation Oncology, University of California Los Angeles, Westwood, California 90095, USA.
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Pollock S, Lee D, Keall P, Kim T. Audiovisual biofeedback improves motion prediction accuracy. Med Phys 2013; 40:041705. [PMID: 23556875 DOI: 10.1118/1.4794497] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The accuracy of motion prediction, utilized to overcome the system latency of motion management radiotherapy systems, is hampered by irregularities present in the patients' respiratory pattern. Audiovisual (AV) biofeedback has been shown to reduce respiratory irregularities. The aim of this study was to test the hypothesis that AV biofeedback improves the accuracy of motion prediction. METHODS An AV biofeedback system combined with real-time respiratory data acquisition and MR images were implemented in this project. One-dimensional respiratory data from (1) the abdominal wall (30 Hz) and (2) the thoracic diaphragm (5 Hz) were obtained from 15 healthy human subjects across 30 studies. The subjects were required to breathe with and without the guidance of AV biofeedback during each study. The obtained respiratory signals were then implemented in a kernel density estimation prediction algorithm. For each of the 30 studies, five different prediction times ranging from 50 to 1400 ms were tested (150 predictions performed). Prediction error was quantified as the root mean square error (RMSE); the RMSE was calculated from the difference between the real and predicted respiratory data. The statistical significance of the prediction results was determined by the Student's t-test. RESULTS Prediction accuracy was considerably improved by the implementation of AV biofeedback. Of the 150 respiratory predictions performed, prediction accuracy was improved 69% (103/150) of the time for abdominal wall data, and 78% (117/150) of the time for diaphragm data. The average reduction in RMSE due to AV biofeedback over unguided respiration was 26% (p < 0.001) and 29% (p < 0.001) for abdominal wall and diaphragm respiratory motion, respectively. CONCLUSIONS This study was the first to demonstrate that the reduction of respiratory irregularities due to the implementation of AV biofeedback improves prediction accuracy. This would result in increased efficiency of motion management techniques affected by system latencies used in radiotherapy.
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Affiliation(s)
- Sean Pollock
- Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia
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Clinical practice patterns of lung stereotactic body radiation therapy in the United States: a secondary analysis. Am J Clin Oncol 2013; 36:269-72. [PMID: 22495454 DOI: 10.1097/coc.0b013e3182467db3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES Stereotactic body radiation therapy (SBRT) is a technique used to deliver high, ablative doses of radiation in a limited number of fractions to ≥1 extracranial target(s). Although recent studies have shown that SBRT provides effective local tumor control in medically inoperable early-stage lung cancer patients, its implementation in clinical practice is unknown. METHODS A random sample of 1600 American radiation oncologists was surveyed regarding lung SBRT usage, including year adopted, most common prescription, respiratory motion management, and target localization. A biological equivalent dose (BED) was calculated using the linear quadratic model with α/β=10. Spearman rank correlation coefficients (r(s)) were calculated to identify factors associated with BED. RESULTS Of 1373 contactable physicians, 551 responses (40%) were received. Of 510 evaluable responses, 275 physicians (54%) reported using lung SBRT, over half of whom adopted it in 2008 or later. The most commonly reported prescriptions were 20 Gy×3 (22%), 18 Gy×3 (21%), and 12 Gy×4 (17%). Three fraction regimens were most common (48%), with nearly all (89%) prescribing ≥18 Gy/fraction. The median BED was 132 Gy, with 95% of reported prescriptions having BED≥100 Gy. Factors associated with increased BED included use of fiducial markers (r(s)=0.26, P<0.001), use of planar imaging (r(s)=0.18, P<0.01), and years of experience with lung SBRT (r(s)=0.13, P=0.04). CONCLUSIONS Lung SBRT has rapidly become a widely adopted treatment approach in the United States with a range of varying implementations. Further research and additional prospective trials are necessary to optimize this novel approach.
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Pan T, Riegel AC, Ahmad MU, Sun X, Chang JY, Luo D. New weighted maximum-intensity-projection images from cine CT for delineation of the lung tumor plus motion. Med Phys 2013; 40:061901. [DOI: 10.1118/1.4803534] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Introduction to 4D Motion Modeling and 4D Radiotherapy. 4D MODELING AND ESTIMATION OF RESPIRATORY MOTION FOR RADIATION THERAPY 2013. [DOI: 10.1007/978-3-642-36441-9_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Dunn L, Kron T, Taylor ML, Callahan J, Franich RD. A phantom for testing of 4D-CT for radiotherapy of small lesions. Med Phys 2012; 39:5372-83. [PMID: 22957605 DOI: 10.1118/1.4742053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE The use of time-resolved four-dimensional computed tomography (4D-CT) in radiotherapy requires strict quality assurance to ensure the accuracy of motion management protocols. The aim of this work was to design and test a phantom capable of large amplitude motion for use in 4D-CT, with particular interest in small lesions typical for stereotactic body radiotherapy. METHODS The phantom of "see-saw" design is light weight, capable of including various sample materials and compatible with several surrogate marker signal acquisition systems. It is constructed of polymethylmethacrylate (Perspex) and its movement is controlled via a dc motor and drive wheel. It was tested using two CT scanners with different 4D acquisition methods: the Philips Brilliance Big Bore CT (helical scan, pressure belt) and a General Electric Discovery STE PET∕CT (axial scan, infrared marker). Amplitudes ranging from 1.5 to 6.0 cm and frequencies of up to 40 cycles per minute were used to study the effect of motion on image quality. Maximum intensity projections (MIPs), as well as average intensity projections (AIPs) of moving objects were investigated and their quality dependence on the number of phase reconstruction bins assessed. RESULTS CT number discrepancies between moving and stationary objects were found to have no systematic dependence on amplitude, frequency, or specific interphase variability. MIP-delineated amplitudes of motion were found to match physical phantom amplitudes to within 2 mm for all motion scenarios tested. Objects undergoing large amplitude motions (>3.0 cm) were shown to cause artefacts in MIP and AIP projections when ten phase bins were assigned. This problem can be mitigated by increasing the number of phase bins in a 4D-CT scan. CONCLUSIONS The phantom was found to be a suitable tool for evaluating the image quality of 4D-CT motion management technology, as well as providing a quality assurance tool for intercenter∕intervendor testing of commercial 4D-CT systems. When imaging objects with large amplitudes, the completeness criterion described here indicates the number of phase bins required to prevent missing data in MIPs and AIPs. This is most relevant for small lesions undergoing large motions.
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Affiliation(s)
- L Dunn
- School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, Australia
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Ding K, Cao K, Fuld MK, Du K, Christensen GE, Hoffman EA, Reinhardt JM. Comparison of image registration based measures of regional lung ventilation from dynamic spiral CT with Xe-CT. Med Phys 2012; 39:5084-98. [PMID: 22894434 DOI: 10.1118/1.4736808] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this paper, the authors propose a new regional measure of lung mechanics-the specific air volume change by corrected Jacobian. The authors compare this new measure, along with two existing registration based measures of lung ventilation, to a regional ventilation measurement derived from xenon-CT (Xe-CT) imaging. METHODS 4DCT and Xe-CT datasets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). The authors show that the commonly used SAI measure can be derived from the direct SAJ measure by using the air-tissue mixture model and assuming there is no tissue volume change between the end inspiration and end expiration datasets. All three ventilation measures are evaluated by comparing to Xe-CT estimates of regional ventilation. RESULTS After registration, the mean registration error is on the order of 1 mm. For cubical regions of interest (ROIs) in cubes with size 20 mm × 20 mm × 20 mm, the SAJ and SACJ measures show significantly higher correlation (linear regression, average r(2) = 0.75 and r(2) = 0.82) with the Xe-CT based measure of specific ventilation (sV) than the SAI measure. For ROIs in slabs along the ventral-dorsal vertical direction with size of 150 mm × 8 mm × 40 mm, the SAJ, SACJ, and SAI all show high correlation (linear regression, average r(2) = 0.88, r(2) = 0.92, and r(2) = 0.87) with the Xe-CT based sV without significant differences when comparing between the three methods. The authors demonstrate a linear relationship between the difference of specific air volume change and difference of tissue volume in all four animals (linear regression, average r(2) = 0.86). CONCLUSIONS Given a deformation field by an image registration algorithm, significant differences between the SAJ, SACJ, and SAI measures were found at a regional level compared to the Xe-CT sV in four sheep that were studied. The SACJ introduced here, provides better correlations with Xe-CT based sV than the SAJ and SAI measures, thus providing an improved surrogate for regional ventilation.
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Affiliation(s)
- Kai Ding
- Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa 52242, USA
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Bowen SR, Nyflot MJ, Gensheimer M, Hendrickson KRG, Kinahan PE, Sandison GA, Patel SA. Challenges and opportunities in patient-specific, motion-managed and PET/CT-guided radiation therapy of lung cancer: review and perspective. Clin Transl Med 2012; 1:18. [PMID: 23369522 PMCID: PMC3560984 DOI: 10.1186/2001-1326-1-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 07/25/2012] [Indexed: 12/25/2022] Open
Abstract
The increasing interest in combined positron emission tomography (PET) and computed tomography (CT) to guide lung cancer radiation therapy planning has been well documented. Motion management strategies during treatment simulation PET/CT imaging and treatment delivery have been proposed to improve the precision and accuracy of radiotherapy. In light of these research advances, why has translation of motion-managed PET/CT to clinical radiotherapy been slow and infrequent? Solutions to this problem are as complex as they are numerous, driven by large inter-patient variability in tumor motion trajectories across a highly heterogeneous population. Such variation dictates a comprehensive and patient-specific incorporation of motion management strategies into PET/CT-guided radiotherapy rather than a one-size-fits-all tactic. This review summarizes challenges and opportunities for clinical translation of advances in PET/CT-guided radiotherapy, as well as in respiratory motion-managed radiotherapy of lung cancer. These two concepts are then integrated into proposed patient-specific workflows that span classification schemes, PET/CT image formation, treatment planning, and adaptive image-guided radiotherapy delivery techniques.
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Affiliation(s)
- Stephen R Bowen
- University of Washington Medical Center, Department of Radiation Oncology, 1959 NE Pacific St, Box 356043, Seattle, WA 98195, USA.
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Interfractional Positional Variability of Fiducial Markers and Primary Tumors in Locally Advanced Non-Small-Cell Lung Cancer During Audiovisual Biofeedback Radiotherapy. Int J Radiat Oncol Biol Phys 2012; 83:1566-72. [DOI: 10.1016/j.ijrobp.2011.10.051] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 10/18/2011] [Accepted: 10/25/2011] [Indexed: 12/20/2022]
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Moorees J, Bezak E. Four dimensional CT imaging: a review of current technologies and modalities. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2012; 35:9-23. [PMID: 22302463 DOI: 10.1007/s13246-012-0124-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Accepted: 01/16/2012] [Indexed: 12/25/2022]
Abstract
Organ motion is a substantial concern in the treatment of thoracic tumours using radiotherapy. A number of technologies have evolved in order to address this both during computed tomography (CT) imaging and radiation delivery. This review paper investigates the various technologies which have been developed in the field of CT scanning as well as their accuracy, cost and the implications of their clinical implementation. The scanning modalities covered include: slow CT, breath hold CT, gated CT and retrospectively correlated CT (4DCT). It was found that there are advantages and drawbacks to each of the mentioned techniques relating to patient dose, scan time, extra equipment and workload. Also some scanning techniques are only compatible with certain treatment modalities which would further influence the decision as to which technologies to implement.
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Affiliation(s)
- J Moorees
- Medical Physics Department, Royal Adelaide Hospital, Adelaide, SA, USA
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Yan C, Hugo G, Salguero FJ, Saleh-Sayah N, Weiss E, Sleeman WC, Siebers JV. A method to evaluate dose errors introduced by dose mapping processes for mass conserving deformations. Med Phys 2012; 39:2119-28. [PMID: 22482633 PMCID: PMC3326071 DOI: 10.1118/1.3684951] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To present a method to evaluate the dose mapping error introduced by the dose mapping process. In addition, apply the method to evaluate the dose mapping error introduced by the 4D dose calculation process implemented in a research version of commercial treatment planning system for a patient case. METHODS The average dose accumulated in a finite volume should be unchanged when the dose delivered to one anatomic instance of that volume is mapped to a different anatomic instance-provided that the tissue deformation between the anatomic instances is mass conserving. The average dose to a finite volume on image S is defined as d(S)=e(s)/m(S), where e(S) is the energy deposited in the mass m(S) contained in the volume. Since mass and energy should be conserved, when d(S) is mapped to an image R(d(S→R)=d(R)), the mean dose mapping error is defined as Δd(m)=|d(R)-d(S)|=|e(R)/m(R)-e(S)/m(S)|, where the e(R) and e(S) are integral doses (energy deposited), and m(R) and m(S) are the masses within the region of interest (ROI) on image R and the corresponding ROI on image S, where R and S are the two anatomic instances from the same patient. Alternatively, application of simple differential propagation yields the differential dose mapping error, Δd(d)=|∂d∂e*Δe+∂d∂m*Δm|=|(e(S)-e(R))m(R)-(m(S)-m(R))m(R) (2)*e(R)|=α|d(R)-d(S)| with α=m(S)/m(R). A 4D treatment plan on a ten-phase 4D-CT lung patient is used to demonstrate the dose mapping error evaluations for a patient case, in which the accumulated dose, D(R)=∑(S=0) (9)d(S→R), and associated error values (ΔD(m) and ΔD(d)) are calculated for a uniformly spaced set of ROIs. RESULTS For the single sample patient dose distribution, the average accumulated differential dose mapping error is 4.3%, the average absolute differential dose mapping error is 10.8%, and the average accumulated mean dose mapping error is 5.0%. Accumulated differential dose mapping errors within the gross tumor volume (GTV) and planning target volume (PTV) are lower, 0.73% and 2.33%, respectively. CONCLUSIONS A method has been presented to evaluate the dose mapping error introduced by the dose mapping process. This method has been applied to evaluate the 4D dose calculation process implemented in a commercial treatment planning system. The method could potentially be developed as a fully-automatic QA method in image guided adaptive radiation therapy (IGART).
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Affiliation(s)
- C Yan
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Yi BSK, Perks J, Houston R, Stern R, Purdy JA, Chen AM. Changes in position and volume of lung cancer target volumes during stereotactic body radiotherapy (SBRT): is image guidance necessary? Technol Cancer Res Treat 2012; 10:495-504. [PMID: 21895034 DOI: 10.7785/tcrt.2012.500226] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The purpose of this study was to analyze inter- and intra-fractional changes in tumor volume with respect to both spatial and volumetric parameters among patients treated by SBRT for lung cancer. Twelve patients (13 tumors) were treated by SBRT with abdominal compression in 3-5 fractions over a 2 week period to a median dose of 60 Gy (range, 48 to 60 Gy). Kilovoltage cone-beam CT (CBCT) was obtained prior to the delivery of each fraction as well as intra-fractionally yielding a total of 55 CBCT scans. All CBCT scans were registered with the planning CT for target alignment and shifts were recorded and analyzed. Retrospectively, gross tumor volume (GTV) was contoured on all CBCT images and compared to initial planning volumes; positional differences were evaluated utilizing directional and vector analysis. Shifts greater than 5 mm were applied inter-fractionally in 6.8% (lateral), 29.5% (longitudinal), and 6.8% (vertical) of all delivered treatments. Using a 10 mm threshold, the corresponding percentages were 2.3%, 13.6%, and 2.3%, respectively. Across all fractions, the calculated inter-fractional shift vectors ranged from 0 to 31.2 mm, with 40.9%, 15.9%, and 11.4% of all fractions having shift vectors≥5 mm, ≥10 mm, and ≥20 mm, respectively. Intra-fractional shifts were also evaluated and found negligible in a small portion of patients evaluated. The mean overall reduction in GTV was 21.1% during SBRT. Significant changes in both position and volume occur during SBRT for lung cancer. Shifts (particularly in the superior-inferior axis) may exceed applied margins and compromise target coverage. Due to the extreme hypofractionation associated with SBRT, inter-fractional image guidance is necessary.
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Affiliation(s)
- B S K Yi
- Department of Radiation Oncology, University of California, Davis Cancer Center 4501 "X" St, G-140 Sacramento, CA 95817, USA
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Ahmad M, Balter P, Pan T. Four-dimensional volume-of-interest reconstruction for cone-beam computed tomography-guided radiation therapy. Med Phys 2011; 38:5646-56. [PMID: 21992381 DOI: 10.1118/1.3634058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Data sufficiency are a major problem in four-dimensional cone-beam computed tomography (4D-CBCT) on linear accelerator-integrated scanners for image-guided radiotherapy. Scan times must be in the range of 4-6 min to avoid undersampling artifacts. Various image reconstruction algorithms have been proposed to accommodate undersampled data acquisitions, but these algorithms are computationally expensive, may require long reconstruction times, and may require algorithm parameters to be optimized. The authors present a novel reconstruction method, 4D volume-of-interest (4D-VOI) reconstruction which suppresses undersampling artifacts and resolves lung tumor motion for undersampled 1-min scans. The 4D-VOI reconstruction is much less computationally expensive than other 4D-CBCT algorithms. METHODS The 4D-VOI method uses respiration-correlated projection data to reconstruct a four-dimensional (4D) image inside a VOI containing the moving tumor, and uncorrelated projection data to reconstruct a three-dimensional (3D) image outside the VOI. Anatomical motion is resolved inside the VOI and blurred outside the VOI. The authors acquired a 1-min. scan of an anthropomorphic chest phantom containing a moving water-filled sphere. The authors also used previously acquired 1-min scans for two lung cancer patients who had received CBCT-guided radiation therapy. The same raw data were used to test and compare the 4D-VOI reconstruction with the standard 4D reconstruction and the McKinnon-Bates (MB) reconstruction algorithms. RESULTS Both the 4D-VOI and the MB reconstructions suppress nearly all the streak artifacts compared with the standard 4D reconstruction, but the 4D-VOI has 3-8 times greater contrast-to-noise ratio than the MB reconstruction. In the dynamic chest phantom study, the 4D-VOI and the standard 4D reconstructions both resolved a moving sphere with an 18 mm displacement. The 4D-VOI reconstruction shows a motion blur of only 3 mm, whereas the MB reconstruction shows a motion blur of 13 mm. With graphics processing unit hardware used to accelerate computations, the 4D-VOI reconstruction required a 40-s reconstruction time. CONCLUSIONS 4D-VOI reconstruction effectively reduces undersampling artifacts and resolves lung tumor motion in 4D-CBCT. The 4D-VOI reconstruction is computationally inexpensive compared with more sophisticated iterative algorithms. Compared with these algorithms, our 4D-VOI reconstruction is an attractive alternative in 4D-CBCT for reconstructing target motion without generating numerous streak artifacts.
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Affiliation(s)
- Moiz Ahmad
- Department of Imaging Physics, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA
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A programmable motion phantom for quality assurance of motion management in radiotherapy. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2011; 35:93-100. [DOI: 10.1007/s13246-011-0114-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 11/15/2011] [Indexed: 12/25/2022]
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McQuaid D, Bortfeld T. 4D planning over the full course of fractionation: assessment of the benefit of tumor trailing. Phys Med Biol 2011; 56:6935-49. [PMID: 22008696 DOI: 10.1088/0031-9155/56/21/011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Quantifying variability in radiation dose due to respiratory-induced tumor motion. Med Image Anal 2011; 15:640-9. [DOI: 10.1016/j.media.2010.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Revised: 05/01/2010] [Accepted: 07/06/2010] [Indexed: 12/25/2022]
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Kron T, Eyles D, Schreiner LJ, Battista J. Magnetic resonance imaging for adaptive cobalt tomotherapy: A proposal. J Med Phys 2011; 31:242-54. [PMID: 21206640 PMCID: PMC3004099 DOI: 10.4103/0971-6203.29194] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 08/01/2006] [Indexed: 11/04/2022] Open
Abstract
Magnetic resonance imaging (MRI) provides excellent soft tissue contrast for oncology applications. We propose to combine a MRI scanner with a helical tomotherapy (HT) system to enable daily target imaging for improved conformal radiation dose delivery to a patient. HT uses an intensity-modulated fan-beam that revolves around a patient, while the patient slowly advances through the plane of rotation, yielding a helical beam trajectory. Since the use of a linear accelerator to produce radiation may be incompatible with the pulsed radiofrequency and the high and pulsed magnetic fields required for MRI, it is proposed that a radioactive Cobalt-60 ((60)Co) source be used instead to provide the radiation. An open low field (0.25 T) MRI system is proposed where the tomotherapy ring gantry is located between two sets of Helmholtz coils that can generate a sufficiently homogenous main magnetic field.It is shown that the two major challenges with the design, namely acceptable radiation dose rate (and therefore treatment duration) and moving parts in strong magnetic field, can be addressed. The high dose rate desired for helical tomotherapy delivery can be achieved using two radiation sources of 220TBq (6000Ci) each on a ring gantry with a source to axis-of-rotation distance of 75 cm. In addition to this, a dual row multi-leaf collimator (MLC) system with 15 mm leaf width at isocentre and relatively large fan beam widths between 15 and 30 mm per row shall be employed. In this configuration, the unit would be well-suited for most pelvic radiotherapy applications where the soft tissue contrast of MRI will be particularly beneficial. Non-magnetic MRI compatible materials must be used for the rotating gantry. Tungsten, which is non-magnetic, can be used for primary collimation of the fan-beam as well as for the MLC, which allows intensity modulated radiation delivery. We propose to employ a low magnetic Cobalt compound, sycoporite (CoS) for the Cobalt source material itself.Rotational delivery is less susceptible to problems related to the use of a low energy megavoltage photon source while the helical delivery reduces the negative impact of the relatively large penumbra inherent in the use of Cobalt sources for radiotherapy. On the other hand, the use of a (60)Co source ensures constant dose rate with gantry rotation and makes dose calculation in a magnetic field as easy as the range of secondary electrons is limited.The MR-integrated Cobalt tomotherapy unit, dubbed 'MiCoTo,' uses two independent physical principles for image acquisition and treatment delivery. It would offer excellent target definition and will allow following target motion during treatment using fast imaging techniques thus providing the best possible input for adaptive radiotherapy. As an additional bonus, quality assurance of the radiation delivery can be performed in situ using radiation sensitive gels imaged by MRI.
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Affiliation(s)
- Tomas Kron
- Peter MacCallum Cancer Centre, Melbourne, Australia
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Pan H, Simpson DR, Mell LK, Mundt AJ, Lawson JD. A survey of stereotactic body radiotherapy use in the United States. Cancer 2011; 117:4566-72. [PMID: 21412761 DOI: 10.1002/cncr.26067] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND Stereotactic body radiotherapy (SBRT) is a technique used to deliver high, ablative doses of radiation in a limited number of fractions to ≥ 1 extracranial target(s). To the authors' knowledge, the prevalence of SBRT use among radiation oncologists in the United States is unknown. METHODS A random sample of 1600 American radiation oncologists was surveyed via e-mail and facsimile (fax) regarding SBRT usage, including year of adoption, motivations, disease sites treated, and common prescriptions used. RESULTS Of 1373 contactable physicians, 551 responses (40.1%) were received. The percentage of physicians using SBRT was 63.9% (95% confidence interval, 60%-68%), of whom nearly half adopted it in 2008 or later. The most commonly cited reasons for adopting SBRT were to allow the delivery of higher than conventional radiation doses (90.3%) and to allow retreatment (73.9%) in select patients. Academic physicians were more likely to report research as a motivation for SBRT adoption, whereas physicians in private practice were more likely to list competitive reasons. Among SBRT users, the most common disease sites treated were lung (89.3%), spine (67.5%), and liver (54.5%) tumors. Overall, 76.0% of current SBRT users planned to increase their use, whereas 66.5% of nonusers planned to adopt the technology in the future. CONCLUSIONS SBRT has rapidly become a widely adopted treatment approach among American radiation oncologists. Further research and prospective trials are necessary to assess the benefits and risks of this novel technology.
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Affiliation(s)
- Hubert Pan
- Department of Radiation Oncology, Center for Advanced Radiotherapy Technologies, University of California at San Diego, La Jolla, California, USA
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Hong SM, Jung BH, Ruan D. Real-time prediction of respiratory motion based on a local dynamic model in an augmented space. Phys Med Biol 2011; 56:1775-89. [DOI: 10.1088/0031-9155/56/6/016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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