Tracking errors in a prototype real-time tumour tracking system.

In motion-compensated radiation therapy, radio-opaque markers can be implanted in or near a tumour and tracked in real-time using fluoroscopic imaging. Tracking these implanted markers gives highly accurate position information, except when tracking fails due to poor or ambiguous imaging conditions. This study investigates methods for automatic detection of tracking errors, and assesses the frequency and impact of tracking errors on treatments using the prototype real-time tumour tracking system. We investigated four indicators for automatic detection of tracking errors, and found that the distance between corresponding rays was most effective. We also found that tracking errors cause a loss of gating efficiency of between 7.6 and 10.2%. The incidence of treatment beam delivery during tracking errors was estimated at between 0.8% and 1.25%.

[1]  R Mohan,et al.  Determining parameters for respiration-gated radiotherapy. , 2001, Medical physics.

[2]  David G. Stork,et al.  Pattern Classification , 1973 .

[3]  Shinichi Shimizu,et al.  Real-time tumour-tracking radiotherapy , 1999, The Lancet.

[4]  Koichi Yamazaki,et al.  Feasibility of insertion/implantation of 2.0-mm-diameter gold internal fiducial markers for precise setup and real-time tumor tracking in radiotherapy. , 2003, International journal of radiation oncology, biology, physics.

[5]  E. Yorke,et al.  Deep inspiration breath hold and respiratory gating strategies for reducing organ motion in radiation treatment. , 2004, Seminars in radiation oncology.

[6]  C. Ramsey,et al.  Clinical efficacy of respiratory gated conformal radiation therapy. , 1999, Medical dosimetry : official journal of the American Association of Medical Dosimetrists.

[7]  Gregory C Sharp,et al.  Integrated radiotherapy imaging system (IRIS): design considerations of tumour tracking with linac gantry-mounted diagnostic x-ray systems with flat-panel detectors , 2004, Physics in medicine and biology.

[8]  C. Ramsey,et al.  A comparison of beam characteristics for gated and nongated clinical x-ray beams. , 1999, Medical physics.

[9]  Jean-Claude Latombe,et al.  Image-Guided Robotic Radiosurgery , 1994, Modelling and Planning for Sensor Based Intelligent Robot Systems.

[10]  H. Mostafavi,et al.  Breathing-synchronized radiotherapy program at the University of California Davis Cancer Center. , 2000, Medical physics.

[11]  J. Adler,et al.  Robotic Motion Compensation for Respiratory Movement during Radiosurgery , 2000, Computer aided surgery : official journal of the International Society for Computer Aided Surgery.

[12]  R. Mohan,et al.  Motion adaptive x-ray therapy: a feasibility study , 2001, Physics in medicine and biology.

[13]  H Shirato,et al.  Use of an implanted marker and real-time tracking of the marker for the positioning of prostate and bladder cancers. , 2000, International journal of radiation oncology, biology, physics.

[14]  R. K. Münch,et al.  A novel tracking technique for the continuous precise measurement of tumour positions in conformal radiotherapy. , 2000, Physics in medicine and biology.

[15]  Koichi Yamazaki,et al.  Real‐time tumor‐tracking radiation therapy for lung carcinoma by the aid of insertion of a gold marker using bronchofiberscopy , 2002, Cancer.

[16]  Martin J Murphy,et al.  Fiducial-based targeting accuracy for external-beam radiotherapy. , 2002, Medical physics.

[17]  H. Shirato,et al.  Four-dimensional treatment planning and fluoroscopic real-time tumor tracking radiotherapy for moving tumor. , 2000, International journal of radiation oncology, biology, physics.

[18]  Martin J Murphy,et al.  Tracking moving organs in real time. , 2004, Seminars in radiation oncology.

[19]  Wolfgang Birkfellner,et al.  Evaluation of a miniature electromagnetic position tracker. , 2002, Medical physics.

[20]  H. Kubo,et al.  Respiration gated radiotherapy treatment: a technical study. , 1996, Physics in medicine and biology.

[21]  K. Ohara,et al.  Irradiation synchronized with respiration gate. , 1989, International journal of radiation oncology, biology, physics.

[22]  H Shirato,et al.  Detection of lung tumor movement in real-time tumor-tracking radiotherapy. , 2001, International journal of radiation oncology, biology, physics.

[23]  S Minohara,et al.  Respiratory gated irradiation system for heavy-ion radiotherapy. , 2000, International journal of radiation oncology, biology, physics.

[24]  Steve B Jiang,et al.  Synchronized moving aperture radiation therapy (SMART): average tumour trajectory for lung patients. , 2003, Physics in medicine and biology.

[25]  Y Suh,et al.  Aperture maneuver with compelled breath (AMC) for moving tumors: a feasibility study with a moving phantom. , 2004, Medical physics.

[26]  Quynh-Thu Le,et al.  Patterns of patient movement during frameless image-guided radiosurgery. , 2003, International journal of radiation oncology, biology, physics.

[27]  Christopher M. Bishop,et al.  Neural networks for pattern recognition , 1995 .

[28]  M. V. van Herk,et al.  Physical aspects of a real-time tumor-tracking system for gated radiotherapy. , 2000, International journal of radiation oncology, biology, physics.