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The impact of cine EPID image acquisition frame rate on markerless soft-tissue tracking
1. Y. Nagata, K. Takayama, Y. Matsuo, Y. Norihisa, T. Mizowaki, T. Sakamoto, M. Sakamoto, M. Mitsumori, K. Shibuya, N. Araki, S. Yano, and M. Hiraoka, “Clinical outcomes of a phase I/II study of 48 Gy of stereotactic body radiotherapy in 4 fractions for primary lung cancer using a stereotactic body frame,” Int. J. Radiat. Oncol., Biol., Phys. 63, 1427–1431 (2005).
2. H. Onishi, H. Shirato, Y. Nagata, M. Hiraoka, M. Fujino, K. Gomi, K. Karasawa, K. Hayakawa, Y. Niibe, Y. Takai, T. Kimura, A. Takeda, A. Ouchi, M. Hareyama, M. Kokubo, T. Kozuka, T. Arimoto, R. Hara, J. Itami, and T. Araki, “Stereotactic body radiotherapy (SBRT) for operable stage I non-small-cell lung cancer: Can SBRT be comparable to surgery?,” Int. J. Radiat. Oncol., Biol., Phys. 81, 1352–1358 (2011).
3. A. J. Fakiris, R. C. McGarry, C. T. Yiannoutsos, L. Papiez, M. Williams, M. A. Henderson, and R. Timmerman, “Stereotactic body radiation therapy for early-stage non-small-cell lung carcinoma: Four-year results of a prospective phase II study,” Int. J. Radiat. Oncol., Biol., Phys. 75, 677–682 (2009).
4. P. J. Keall, G. S. Mageras, J. M. Balter, R. S. Emery, K. M. Forster, S. B. Jiang, J. M. Kapatoes, D. A. Low, M. J. Murphy, B. R. Murray, C. R. Ramsey, M. B. Van Herk, S. S. Vedam, J. W. Wong, and E. Yorke, “The management of respiratory motion in radiation oncology report of AAPM Task Group 76,” Med. Phys. 33, 3874–3900 (2006).
5. L. Ekberg, O. Holmberg, L. Wittgren, G. Bjelkengren, and T. Landberg, “What margins should be added to the clinical target volume in radiotherapy treatment planning for lung cancer?,” Radiother. Oncol. 48, 71–77 (1998).
6. L. A. Dawson, K. K. Brock, S. Kazanjian, D. Fitch, C. J. McGinn, T. S. Lawrence, R. K. Ten Haken, and J. Balter, “The reproducibility of organ position using active breathing control (ABC) during liver radiotherapy,” Int. J. Radiat. Oncol., Biol., Phys. 51, 1410–1421 (2001).
8. R. I. Berbeco, F. Hacker, D. Ionascu, and H. J. Mamon, “Clinical feasibility of using an EPID in cine mode for image-guided verification of stereotactic body radiotherapy,” Int. J. Radiat. Oncol., Biol., Phys. 69, 258–266 (2007).
9. S.-J. Park, D. Ionascu, F. Hacker, H. Mamon, and R. Berbeco, “Automatic marker detection and 3D position reconstruction using cine EPID images for SBRT verification,” Med. Phys. 36, 4536–4546 (2009).
10. N. Kothary, J. J. Heit, J. D. Louie, W. T. Kuo, B. W. Loo, A. Koong, D. T. Chang, D. Hovsepian, D. Y. Sze, and L. V. Hofmann, “Safety and efficacy of percutaneous fiducial marker implantation for image-guided radiation therapy,” J. Vasc. Interv. Radiol. 20, 235–239 (2009).
11. N. A. Christie, A. Pennathur, S. A. Burton, and J. D. Luketich, “Stereotactic radiosurgery for early stage non-small cell lung cancer: Rationale, patient selection, results, and complications,” Semin. Thoracic Cardiovasc. Surg. 20, 290–297 (2008).
12. H. Arimura, Y. Egashira, Y. Shioyama, K. Nakamura, S. Yoshidome, S. Anai, S. Nomoto, H. Honda, F. Toyofuku, Y. Higashida, Y. Onizuka, and H. Terashima, “Computerized method for estimation of the location of a lung tumor on EPID cine images without implanted markers in stereotactic body radiotherapy,” Phys. Med. Biol. 54, 665–677 (2009).
13. A. Richter, J. Wilbert, K. Baier, M. Flentje, and M. Guckenberger, “Feasibility study for markerless tracking of lung tumors in stereotactic body radiotherapy,” Int. J. Radiat. Oncol., Biol., Phys. 78, 618–627 (2010).
14. J. Rottmann, M. Aristophanous, A. Chen, L. Court, and R. Berbeco, “A multi-region algorithm for markerless beam's-eye view lung tumor tracking,” Phys. Med. Biol. 55, 5585–5598 (2010).
15. J. Rottmann, P. Keall, and R. Berbeco, “Real-time soft tissue motion estimation for lung tumors during radiotherapy delivery,” Med. Phys. 40, 091713 (7pp.) (2013).
16. P. B. Greer and C. C. Popescu, “Dosimetric properties of an amorphous silicon electronic portal imaging device for verification of dynamic intensity modulated radiation therapy,” Med. Phys. 30, 1618–1627 (2003).
17. P. Winkler, A. Hefner, and D. Georg, “Dose-response characteristics of an amorphous silicon EPID,” Med. Phys. 32, 3095–3105 (2005).
18. M. Bakhtiari, L. Kumaraswamy, D. W. Bailey, S. de Boer, H. K. Malhotra, and M. B. Podgorsak, “Using an EPID for patient-specific VMAT quality assurance,” Med. Phys. 38, 1366–1373 (2011).
19. L. N. McDermott, S. M. J. J. G. Nijsten, J.-J. Sonke, M. Partridge, M. van Herk, and B. J. Mijnheer, “Comparison of ghosting effects for three commercial a-Si EPIDs,” Med. Phys. 33, 2448–2451 (2006).
20. R. M. Haralick, “Statistical and structural approaches to texture,” Proc. IEEE 67, 786–804 (1979).
21. K. Zhang, L. Zhang, H. Song, and W. Zhou, “Active contours with selective local or global segmentation: A new formulation and level set method,” Image Vis. Comput. 28, 668–676 (2010).
22. N. C. Silver and W. P. Dunlap, Averaging correlation coefficients: Should Fisher's z transformation be used? (American Psychological Association, United States, 1987), Vol. 72, pp. 146–148.
23. H. Hotelling, “New light on the correlation coefficient and its transforms,” J. R. Stat. Soc. Ser. B (Methodological) 15, 193–232 (1953).
24. W. Mao, A. Hsu, N. Riaz, L. Lee, R. Wiersma, G. Luxton, C. King, L. Xing, and T. Solberg, “Image-guided radiotherapy in near real time with intensity-modulated radiotherapy megavoltage treatment beam imaging,” Int. J. Radiat. Oncol., Biol., Phys. 75, 603–610 (2009).
25. C. K. McGarry, M. W. D. Grattan, and V. P. Cosgrove, “Optimization of image quality and dose for Varian aS500 electronic portal imaging devices (EPIDs),” Physics in Medicine and Biology 52, 6865–6877 (2007).
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Although reduction of the cine electronic portal imaging device (EPID) acquisition frame rate through multiple frame averaging may reduce hardware memory burden and decrease image noise, it can hinder the continuity of soft-tissue motion leading to poor autotracking results. The impact of motion blurring and image noise on the tracking performance was investigated.
Phantom and patient images were acquired at a frame rate of 12.87 Hz with an amorphous silicon portal imager (AS1000, Varian Medical Systems, Palo Alto, CA). The maximum frame rate of 12.87 Hz is imposed by the EPID. Low frame rate images were obtained by continuous frame averaging. A previously validated tracking algorithm was employed for autotracking. The difference between the programmed and autotracked positions of a Las Vegas phantom moving in the superior-inferior direction defined the tracking error (δ). Motion blurring was assessed by measuring the area change of the circle with the greatest depth. Additionally, lung tumors on 1747 frames acquired at 11 field angles from four radiotherapy patients are manually and automatically tracked with varying frame averaging. δ was defined by the position difference of the two tracking methods. Image noise was defined as the standard deviation of the background intensity. Motion blurring and image noise are correlated with δ using Pearson correlation coefficient (R).
For both phantom and patient studies, the autotracking errors increased at frame rates lower than 4.29 Hz. Above 4.29 Hz, changes in errors were negligible withδ < 1.60 mm. Motion blurring and image noise were observed to increase and decrease with frame averaging, respectively. Motion blurring and tracking errors were significantly correlated for the phantom (R = 0.94) and patient studies (R = 0.72). Moderate to poor correlation was found between image noise and tracking error with R −0.58 and −0.19 for both studies, respectively.
Cine EPID image acquisition at the frame rate of at least 4.29 Hz is recommended. Motion blurring in the images with frame rates below 4.29 Hz can significantly reduce the accuracy of autotracking.
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