Hostname: page-component-7c8c6479df-94d59 Total loading time: 0 Render date: 2024-03-28T10:23:34.377Z Has data issue: false hasContentIssue false

Image-guided radiation therapy using computed tomography in radiotherapy

Published online by Cambridge University Press:  12 November 2010

Winky Wing Ki Fung*
Affiliation:
Department of Radiotherapy, Hong Kong Sanatorium and Hospital, Hong Kong
Vincent Wing Cheung Wu
Affiliation:
Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
*
Correspondence to: Winky Wing Ki Fung, Department of Radiotherapy, G/F, Li Shu Pui Block, 2 Village Road, Happy Valley, Hong Kong. E-mail: winky.fung@gmail.com

Abstract

The sharp dose gradients in intensity-modulated radiation therapy increase the treatment sensitivity to various inter- and intra-fractional uncertainties, in which a slight anatomical change may greatly alter the actual dose delivered. Image-guided radiotherapy refers to the use of advanced imaging techniques to precisely track and correct these patient-specific variations in routine treatment. It can also monitor organ changes during a radiotherapy course. Currently, image-guided radiotherapy using computed tomography has gained much popularity in radiotherapy verification as it provides volumetric images with soft-tissue contrast for on-line tracking of tumour. This article reviews four types of computed tomography-based image guidance systems and their working principles. The system characteristics and clinical applications of the helical, megavoltage, computed tomography, and kilovoltage, cone-beam, computed tomography systems are discussed, given that they are currently the most commonly used systems for radiotherapy verification. This article also focuses on the recent techniques of soft-tissue contrast enhancement, digital tomosynthesis, four-dimensional fluoroscopic image guidance, and kilovoltage/megavoltage, in-line cone-beam imaging. These evolving systems are expected to take over the conventional two-dimensional verification system in the near future and provide the basis for implementing adaptive radiotherapy.

Type
Literature Review
Copyright
Copyright © Cambridge University Press 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

O'Daniel, JC, Garden, AS, Schwartz, DL, Wang, H, Ang, KK, Ahamad, A, Rosenthal, DI, Morrison, WH, Asper, JA, Zhang, L, Tung, SM, Mohan, R, Dong, L. Parotid gland dose in intensity-modulated radiotherapy for head and neck cancer: is what you plan what you get?. Int J Radiat Oncol Biol Phys 2007; 69:12901296.CrossRefGoogle Scholar
Barker, JL Jr, Garden, AS, Ang, KK, O'Daniel, JC, Wang, H, Court, LE, Morrison, WH, Rosenthal, DI, Chao, KS, Tucker, SL, Mohan, R, Dong, L. Quantification of volumetric and geometric changes occurring during fractionated radiotherapy for head-and-neck cancer using an integrated CT/linear accelerator system. Int J Radiat Oncol Biol Phys 2004; 59:960970.CrossRefGoogle ScholarPubMed
Erridge, SC, Seppenwoolde, Y, Muller, SH, van Herk, M, De Jaeger, K, Belderbos, JS, Boersma, LJ, Lebesque, JV. Portal imaging to assess set-up errors, tumor motion and tumor shrinkage during conformal radiotherapy of non-small cell lung cancer. Radiother Oncol 2003; 66:7585.CrossRefGoogle ScholarPubMed
Buchali, A, Koswig, S, Dinges, S, Rosenthal, P, Salk, J, Lackner, G, Böhmer, D, Schlenger, L, Budach, V. Impact of the filling status of the bladder and rectum on their integral dose distribution and the movement of the uterus in the treatment planning of gynaecological cancer. Radiother Oncol 1999; 52:2934.CrossRefGoogle ScholarPubMed
Roeske, JC, Forman, JD, Mesina, CF, He, T, Pelizzari, CA, Fontenla, E, Vijayakumar, S, Chen, GT. Evaluation of changes in the size and location of the prostate, seminal vesicles, bladder, and rectum during a course of external beam radiation therapy. Int J Radiat Oncol Biol Phys 1995; 33:13211329.CrossRefGoogle ScholarPubMed
Zhao, KL, Liao, Z, Bucci, MK, Komaki, R, Cox, JD, Yu, ZH, Zhang, L, Mohan, R, Dong, L. Evaluation of respiratory-induced target motion for esophageal tumors at the gastroesophageal junction. Radiother Oncol 2007; 84:283289.CrossRefGoogle ScholarPubMed
Mackie, TR, Kapatoes, J, Ruchala, K, Lu, W, Wu, C, Olivera, G, Forrest, L, Tome, W, Welsh, J, Jeraj, R, Harari, P, Reckwerdt, P, Paliwal, B, Ritter, M, Keller, H, Fowler, J, Mehta, M. Image guidance for precise conformal radiotherapy. Int J Radiat Oncol Biol Phys 2003; 56:89105.CrossRefGoogle ScholarPubMed
Fung, AY, Ayyangar, KM, Djajaputra, D, Nehru, RM, Enke, CA. Ultrasound-based guidance of intensity-modulated radiation therapy. Med Dosim 2006; 31:2029.CrossRefGoogle ScholarPubMed
Verellen, D, Soete, G, Linthout, N, van Acker, S, De Roover, P, Vinh-Hung, V, Van De Steene, J, Storme, G. Quality assurance of a system for improved target localization and patient set-up that combines real-time infrared tracking and stereoscopic X-ray imaging. Radiother Oncol 2003; 67:129141.CrossRefGoogle ScholarPubMed
Kupelian, P, Willoughby, T, Mahadevan, A, Djemil, T, Weinstein, G, Jani, S, Enke, C, Solberg, T, Flores, N, Liu, D, Beyer, D, Levine, L. Multi-institutional clinical experience with the Calypso System in localization and continuous, real-time monitoring of the prostate gland during external radiotherapy. Int J Radiat Oncol Biol Phys 2007; 67:10881098.CrossRefGoogle ScholarPubMed
Yang, C, Liu, T, Lehmann, J et al. IGRT using a video-based 3-D surface imaging system in combination with CBCT. Int J Radiat Oncol Biol Phys 2007; 69:S637S638.CrossRefGoogle Scholar
Ma, CM, Paskalev, K. In-room CT techniques for image-guided radiation therapy. Med Dosim 2006; 31:3039.CrossRefGoogle ScholarPubMed
Fung, AY, Wong, JR, Cheng, CW, Lisa Grimm, S, Uematsu, M. A comparison of two image fusion techniques in ct-on-rails localization of radiation delivery. Phys Med 2005; 21:113119.CrossRefGoogle ScholarPubMed
Mota, HC, Ferreira, ML, Ove, R et al. Clinical Comparison of Two IGRT Techniques: CT-on-rails and Megavoltage CT. Int J Radiat Oncol Biol Phys 2008; 72:S663.CrossRefGoogle Scholar
Feldkamp, LA, Davis, LC, Kress, JW. Practical cone-beam algorithm. J Opt Soc Am 1984; A6:612619.CrossRefGoogle Scholar
Pouliot, J, Bani-Hashemi, A, Chen, J, Svatos, M, Ghelmansarai, F, Mitschke, M, Aubin, M, Xia, P, Morin, O, Bucci, K, Roach, M 3rd, Hernandez, P, Zheng, Z, Hristov, D, Verhey, L. Low-dose megavoltage cone-beam CT for radiation therapy. Int J Radiat Oncol Biol Phys 2005; 61:552560.CrossRefGoogle ScholarPubMed
Meyer, JL. IMRT, IGRT, SBRT: advances in the treatment planning and delivery of radiotherapy. Basel:Karger, 2007.Google Scholar
Morin, O, Gillis, A, Chen, J, Aubin, M, Bucci, MK, Roach, M 3rd, Pouliot, J. Megavoltage cone-beam CT: system description and clinical applications. Med Dosim 2006; 31:5161.CrossRefGoogle ScholarPubMed
McBain, CA, Henry, AM, Sykes, J, Amer, A, Marchant, T, Moore, CM, Davies, J, Stratford, J, McCarthy, C, Porritt, B, Williams, P, Khoo, VS, Price, P. X-ray volumetric imaging in image-guided radiotherapy: the new standard in on-treatment imaging. Int J Radiat Oncol Biol Phys 2006; 64:625634.CrossRefGoogle ScholarPubMed
Islam, MK, Purdie, TG, Norrlinger, BD, Alasti, H, Moseley, DJ, Sharpe, MB, Siewerdsen, JH, Jaffray, DA. Patient dose from kilovoltage cone beam computed tomography imaging in radiation therapy. Med Phys 2006; 33:15731582.CrossRefGoogle ScholarPubMed
Forrest, LJ, Mackie, TR, Ruchala, K, Turek, M, Kapatoes, J, Jaradat, H, Hui, S, Balog, J, Vail, DM, Mehta, MP. The utility of megavoltage computed tomography images from a helical tomotherapy system for setup verification purposes. Int J Radiat Oncol Biol Phys 2004; 60:16391644.CrossRefGoogle ScholarPubMed
Jeraj, R, Mackie, TR, Balog, J, Olivera, G, Pearson, D, Kapatoes, J, Ruchala, K, Reckwerdt, P. Radiation characteristics of helical tomotherapy. Med Phys 2004; 31:396404.CrossRefGoogle ScholarPubMed
Sharpe, MB, Moseley, DJ, Purdie, TG, Islam, M, Siewerdsen, JH, Jaffray, DA. The stability of mechanical calibration for a kV cone beam computed tomography system integrated with linear accelerator. Med Phys 2006; 33:136144.CrossRefGoogle ScholarPubMed
Schubert, LK, Westerly, DC, Tomé, WA, Mehta, MP, Soisson, ET, Mackie, TR, Ritter, MA, Khuntia, D, Harari, PM, Paliwal, BR. A comprehensive assessment by tumor site of patient setup using daily MVCT imaging from more than 3,800 helical tomotherapy treatments. Int J Radiat Oncol Biol Phys 2009; 73:12601269.CrossRefGoogle ScholarPubMed
Boswell, SA, Jeraj, R, Ruchala, KJ, Olivera, GH, Jaradat, HA, James, JA, Gutierrez, A, Pearson, D, Frank, G, Mackie, TR. A novel method to correct for pitch and yaw patient setup errors in helical tomotherapy. Med Phys 2005; 32:16301639.CrossRefGoogle ScholarPubMed
Meyer, J, Wilbert, J, Baier, K, Guckenberger, M, Richter, A, Sauer, O, Flentje, M. Positioning accuracy of cone-beam computed tomography in combination with a HexaPOD robot treatment table. Int J Radiat Oncol Biol Phys 2007; 67:12201228.CrossRefGoogle ScholarPubMed
Borst, GR, Sonke, JJ, Betgen, A, Remeijer, P, van Herk, M, Lebesque, JV. Kilo-voltage cone-beam computed tomography setup measurements for lung cancer patients; first clinical results and comparison with electronic portal-imaging device. Int J Radiat Oncol Biol Phys 2007; 68:555561.CrossRefGoogle ScholarPubMed
Meeks, SL, Harmon, JF Jr, Langen, KM, Willoughby, TR, Wagner, TH, Kupelian, PA. Performance characterization of megavoltage computed tomography imaging on a helical tomotherapy unit. Med Phys 2005; 32:26732681.CrossRefGoogle ScholarPubMed
Perks, JR, Lehmann, J, Chen, AM, Yang, CC, Stern, RL, Purdy, JA. Comparison of peripheral dose from image-guided radiation therapy (IGRT) using kV cone beam CT to intensity-modulated radiation therapy (IMRT). Radiother Oncol 2008; 89:304310.CrossRefGoogle ScholarPubMed
Lee, C, Langen, KM, Lu, W, Haimerl, J, Schnarr, E, Ruchala, KJ, Olivera, GH, Meeks, SL, Kupelian, PA, Shellenberger, TD, Mañon, RR. Evaluation of geometric changes of parotid glands during head and neck cancer radiotherapy using daily MVCT and automatic deformable registration. Radiother Oncol 2008; 89:8188.CrossRefGoogle ScholarPubMed
Han, C, Chen, YJ, Liu, A, Schultheiss, TE, Wong, JY. Actual dose variation of parotid glands and spinal cord for nasopharyngeal cancer patients during radiotherapy. Int J Radiat Oncol Biol Phys 2008; 70:12561262.CrossRefGoogle ScholarPubMed
Lee, C, Langen, KM, Lu, W, Haimerl, J, Schnarr, E, Ruchala, KJ, Olivera, GH, Meeks, SL, Kupelian, PA, Shellenberger, TD, Mañon, RR. Assessment of parotid gland dose changes during head and neck cancer radiotherapy using daily megavoltage computed tomography and deformable image registration. Int J Radiat Oncol Biol Phys 2008; 71:15631571.CrossRefGoogle ScholarPubMed
Wang, C, Chong, F, Wu, J, Lai, M, Cheng, J. Body weight loss associates with set-up error in nasopharyngeal cancer patients undergoing image guided radiotherapy. Int J Radiat Oncol Biol Phys 2007; 69:S203.CrossRefGoogle Scholar
Ding, GX, Duggan, DM, Coffey, CW, Deeley, M, Hallahan, DE, Cmelak, A, Malcolm, A. A study on adaptive IMRT treatment planning using kV cone-beam CT. Radiother Oncol 2007; 85:116125.CrossRefGoogle Scholar
Yan, D, Lockman, D, Martinez, A, Wong, J, Brabbins, D, Vicini, F, Liang, J, Kestin, L. Computed tomography guided management of interfractional patient variation. Semin Radiat Oncol 2005; 15:168179.CrossRefGoogle ScholarPubMed
Guckenberger, M, Meyer, J, Wilbert, J, Richter, A, Baier, K, Mueller, G, Flentje, M. Intra-fractional uncertainties in cone-beam CT based image-guided radiotherapy (IGRT) of pulmonary tumors. Radiother Oncol 2007; 83:5764.CrossRefGoogle ScholarPubMed
Guckenberger, M, Meyer, J, Wilbert, J, Baier, K, Mueller, G, Wulf, J, Flentje, M. Cone-beam CT based image-guidance for extracranial stereotactic radiotherapy of intrapulmonary tumors. Acta Oncol 2006; 45:897906.CrossRefGoogle ScholarPubMed
Lin, L, Shi, C, Swanson, G, Papanikolaou, N. Quantification of inter-fractional organ motion and deformation using megavoltage computed tomography images from helical tomotherapy. Int J Radiat Oncol Biol Phys 2007; 69:S527S528.CrossRefGoogle Scholar
Chen, YJ, Han, C, Liu, A, Schultheiss, TE, Kernstine, KH, Shibata, S, Vora, NL, Pezner, RD, Wong, JY. Setup variations in radiotherapy of esophageal cancer: evaluation by daily megavoltage computed tomographic localization. Int J Radiat Oncol Biol Phys 2007; 68:15371545.CrossRefGoogle ScholarPubMed
Kupelian, PA, Ramsey, C, Meeks, SL, Willoughby, TR, Forbes, A, Wagner, TH, Langen, KM. Serial megavoltage CT imaging during external beam radiotherapy for non-small-cell lung cancer: observations on tumor regression during treatment. Int J Radiat Oncol Biol Phys 2005; 63:10241028.CrossRefGoogle ScholarPubMed
Mehta, VK, Ye, J, Cao, D, Shepard, D, Wong, T. Evaluation of a motion-encompassing treatment strategy for treating non-small cell lung cancer. Int J Radiat Oncol Biol Phys 2007; 69:S503S504.CrossRefGoogle Scholar
Santanam, L, Esthappan, J, Mutic, S, Klein, EE, Goddu, SM, Chaudhari, S, Wahab, S, El Naqa, IM, Low, DA, Grigsby, PW. Estimation of setup uncertainty using planar and MVCT imaging for gynecologic malignancies. Int J Radiat Oncol Biol Phys 2008; 71:15111517.CrossRefGoogle ScholarPubMed
Schubert, L, Rasmussen, K, Westerly, D et al. Effect of body weight on patient setup for prostate helical tomotherapy treatments. Med Phys 2008; 35:2697.CrossRefGoogle Scholar
Kupelian, PA, Langen, KM, Zeidan, OA, Meeks, SL, Willoughby, TR, Wagner, TH, Jeswani, S, Ruchala, KJ, Haimerl, J, Olivera, GH. Daily variations in delivered doses in patients treated with radiotherapy for localized prostate cancer. Int J Radiat Oncol Biol Phys 2006; 66:876882.CrossRefGoogle ScholarPubMed
Langen, KM, Zhang, Y, Andrews, RD, Hurley, ME, Meeks, SL, Poole, DO, Willoughby, TR, Kupelian, PA. Initial experience with megavoltage (MV) CT guidance for daily prostate alignments. Int J Radiat Oncol Biol Phys 2005; 62:15171524.CrossRefGoogle ScholarPubMed
Fiorino, C, Di Muzio, N, Broggi, S, Cozzarini, C, Maggiulli, E, Alongi, F, Valdagni, R, Fazio, F, Calandrino, R. Evidence of limited motion of the prostate by carefully emptying the rectum as assessed by daily MVCT image guidance with helical tomotherapy. Int J Radiat Oncol Biol Phys 2008; 71:611617.CrossRefGoogle ScholarPubMed
Moseley, DJ, White, EA, Wiltshire, KL, Rosewall, T, Sharpe, MB, Siewerdsen, JH, Bissonnette, JP, Gospodarowicz, M, Warde, P, Catton, CN, Jaffray, DA. Comparison of localization performance with implanted fiducial markers and cone-beam computed tomography for on-line image-guided radiotherapy of the prostate. Int J Radiat Oncol Biol Phys 2007; 67:942953.CrossRefGoogle ScholarPubMed
Ashish, K, Bansal, V, Patel, V et al. Marker based IGRT in prostate radiotherapy—merits and pitfalls. Int J Radiat Oncol Biol Phys 2008; 72:S353.CrossRefGoogle Scholar
Salamon, M, Burtzlaff, S, Voland, V, Sukowski, F, Uhlmann, N. Upcoming challenges in high-resolution CT below 1 μm. Nucl Instr Meth Phys Res Sec A 2009; 607:176178.CrossRefGoogle Scholar
Majurin, ML, Valavaara, R, Varpula, M, Kurki, T, Kulmala, J. Low-dose and conventional-dose high resolution CT of pulmonary changes in breast cancer patients treated by tangential field radiotherapy. Eur J Radiol 1995; 20:114119.CrossRefGoogle ScholarPubMed
Zhang, Y, Zhang, L, Zhu, XR, Lee, AK, Chambers, M, Dong, L. Reducing metal artifacts in cone-beam CT images by preprocessing projection data. Int J Radiat Oncol Biol Phys 2007; 67:924932.CrossRefGoogle ScholarPubMed
Jaffray, DA, Siewerdsen, JH, Wong, JW, Martinez, AA. Flat-panel cone-beam computed tomography for image-guided radiation therapy. Int J Radiat Oncol Biol Phys 2002; 53:13371349.CrossRefGoogle ScholarPubMed
Siewerdsen, JH, Moseley, DJ, Bakhtiar, B, Richard, S, Jaffray, DA. The influence of antiscatter grids on soft-tissue detectability in cone-beam computed tomography with flat-panel detectors. Med Phys 2004; 31:35063520.CrossRefGoogle ScholarPubMed
Zhu, L, Wang, J, Xing, L. Noise suppression in scatter correction for cone-beam CT. Med Phys 2009; 36:741752.CrossRefGoogle ScholarPubMed
Mail, N, Moseley, DJ, Siewerdsen, JH, Jaffray, DA. The influence of bowtie filtration on cone-beam CT image quality. Med Phys 2009; 36:2232.CrossRefGoogle ScholarPubMed
Graham, SA, Moseley, DJ, Siewerdsen, JH, Jaffray, DA. Compensators for dose and scatter management in cone-beam computed tomography. Med Phys 2007; 34:26912703.CrossRefGoogle ScholarPubMed
Toth, T, Ge, Z, Daly, MP. The influence of patient centering on CT dose and image noise. Med Phys 2007; 34:30933101.CrossRefGoogle Scholar
Ghelmansarai, F, Bani-Hashemi, A, Pouliot, J et al. Soft tissue visualization using a highly efficient megavoltage cone beam CT Imaging system. 45th Annual AAPM Meeting. Med Phys 2005; 32:2131.Google Scholar
Mei, X, Pang, G. Development of high quantum efficiency, flat panel, thick detectors for megavoltage x-ray imaging: an experimental study of a single-pixel prototype. Med Phys 2005; 32:33793388.CrossRefGoogle ScholarPubMed
Seppi, EJ, Munro, P, Johnsen, SW, Shapiro, EG, Tognina, C, Jones, D, Pavkovich, JM, Webb, C, Mollov, I, Partain, LD, Colbeth, RE. Megavoltage cone-beam computed tomography using a high-efficiency image receptor. Int J Radiat Oncol Biol Phys 2003; 55:793803.CrossRefGoogle ScholarPubMed
Wu, V, Faddegon, BA, Bani-Hashemi, A, Gangadharan, B, Morin, O, Pouliot, J. Improved image quality and beam stability for a high contrast imaging beam line used for megavoltage cone-beam CT. Int J Radiat Oncol Biol Phys 2007; 69:S633.CrossRefGoogle Scholar
Lu, M, Sawkey, D, Morin, O, Aubin, M, Faddegon, BA. Improved beam stability and increased dose rate for low dose, high contrast megavoltage cone beam CT. Int J Radiat Oncol Biol Phys 2009; 75:S599.CrossRefGoogle Scholar
Tse, RV, Moseley, DJ, Siewerdsen, J et al. Intrahepatic tumor and vessel identification in intravenous contrast enhanced liver kV cone beam CT. Int J Radiat Oncol Biol Phys 2007; 69:S666S667.CrossRefGoogle Scholar
Monroe, JI, Exner, A, Sohn, JW. Developing contrast enhanced biodegradable markers to enhance image guided radiation therapy. Med Phys 2008; 35:2694.CrossRefGoogle Scholar
Kriminski, S, Lovelock, D, Mageras, G et al. Evaluation of respiration-correlated digital tomosynthesis for soft tissue visualization. Med Phys 2006; 33:19881989.CrossRefGoogle Scholar
Godfrey, DJ, Yin, FF, Oldham, M, Yoo, S, Willett, C. Digital tomosynthesis with an on-board kilovoltage imaging device. Int J Radiat Oncol Biol Phys 2006; 65:815.CrossRefGoogle ScholarPubMed
Wu, QJ, Godfrey, DJ, Wang, Z, Zhang, J, Zhou, S, Yoo, S, Brizel, DM, Yin, FF. On-board patient positioning for head-and-neck IMRT: comparing digital tomosynthesis to kilovoltage radiography and cone-beam computed tomography. Int J Radiat Oncol Biol Phys 2007; 69:598606.CrossRefGoogle ScholarPubMed
Zhang, J, Wu, QJ, Godfrey, DJ, Fatunase, T, Marks, LB, Yin, FF. Comparing digital tomosynthesis to cone-beam CT for position verification in patients undergoing partial breast irradiation. Int J Radiat Oncol Biol Phys 2009; 73:952957.CrossRefGoogle ScholarPubMed
Sonke, JJ, Zijp, L, Remeijer, P, van Herk, M. Respiratory correlated cone beam CT. Med Phys 2005; 32:11761186.CrossRefGoogle ScholarPubMed
Dietrich, L, Jetter, S, Tücking, T, Nill, S, Oelfke, U. Linac-integrated 4D cone beam CT: first experimental results. Phys Med Biol 2006; 51:29392952.CrossRefGoogle ScholarPubMed
Li, T, Xing, L. Optimizing 4D cone-beam CT acquisition protocol for external beam radiotherapy. Int J Radiat Oncol Biol Phys 2007; 67:12111219.CrossRefGoogle ScholarPubMed
Thompson, BP, Hugo, GD. Quality and accuracy of cone beam computed tomography gated by active breathing control. Med Phys 2008; 35:55955608.CrossRefGoogle ScholarPubMed
Zhang, T, Jeraj, R, Keller, H, Lu, W, Olivera, GH, McNutt, TR, Mackie, TR, Paliwal, B. Treatment plan optimization incorporating respiratory motion. Med Phys 2004; 31:15761586.CrossRefGoogle ScholarPubMed
Green, A, Ramsey, C, Usynin, A. Correcting for missing data in 4D-MVCT. Med Phys 2008; 35:2693.CrossRefGoogle Scholar
Ramsey, C, Mahan, S. Four-dimensional megavoltage CT imaging with a helical tomotherapy system. Int J Radiat Oncol Biol Phys 2005; 63:S519S520.Google Scholar
Sorcini, B, Tilikidis, A. Clinical application of image-guided radiotherapy, IGRT (on the Varian OBI platform). Cancer Radiother 2006; 10:252257.CrossRefGoogle ScholarPubMed
Mao, W, Riaz, N, Lee, L, Wiersma, R, Xing, L. A fiducial detection algorithm for real-time image guided IMRT based on simultaneous MV and kV imaging. Med Phys 2008; 35:35543564.CrossRefGoogle ScholarPubMed
Luo, W, Yoo, S, Wu, J, Wang, Z, Song, H, Yin, F. Effect of MV scatter on kV image quality during simultaneous kV-MV imaging. Int J Radiat Oncol Biol Phys 2007; 69:S671.CrossRefGoogle Scholar
Eccles, C, Brock, KK, Bissonnette, JP, Hawkins, M, Dawson, LA. Reproducibility of liver position using active breathing coordinator for liver cancer radiotherapy. Int J Radiat Oncol Biol Phys 2006; 64:751759.CrossRefGoogle ScholarPubMed
Ruchala, KJ, Olivera, GH, Kapatoes, JM, Schloesser, EA, Reckwerdt, PJ, Mackie, TR. Megavoltage CT image reconstruction during tomotherapy treatments. Phys Med Biol 2000; 45:35453562.CrossRefGoogle ScholarPubMed
Thilmann, C, Nill, S, Tücking, T, Höss, A, Hesse, B, Dietrich, L, Bendl, R, Rhein, B, Häring, P, Thieke, C, Oelfke, U, Debus, J, Huber, P. Correction of patient positioning errors based on in-line cone beam CTs: clinical implementation and first experiences. Radiat Oncol 2006; 1:16.CrossRefGoogle ScholarPubMed