Positioning accuracy of cone-beam computed tomography in combination with a HexaPOD robot treatment table.

PURPOSE To scrutinize the positioning accuracy and reproducibility of a commercial hexapod robot treatment table (HRTT) in combination with a commercial cone-beam computed tomography system for image-guided radiotherapy (IGRT). METHODS AND MATERIALS The mechanical stability of the X-ray volume imaging (XVI) system was tested in terms of reproducibility and with a focus on the moveable parts, i.e., the influence of kV panel and the source arm on the reproducibility and accuracy of both bone and gray value registration using a head-and-neck phantom. In consecutive measurements the accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated. The operational range of the HRTT was also determined and analyzed. RESULTS The system performance of the XVI system alone was very stable with mean translational and rotational errors of below 0.2 mm and below 0.2 degrees , respectively. The mean positioning accuracy of the HRTT in combination with the XVI system summarized over all measurements was below 0.3 mm and below 0.3 degrees for translational and rotational corrections, respectively. The gray value match was more accurate than the bone match. CONCLUSION The XVI image acquisition and registration procedure were highly reproducible. Both translational and rotational positioning errors can be corrected very precisely with the HRTT. The HRTT is therefore well suited to complement cone-beam computed tomography to take full advantage of position correction in six degrees of freedom for IGRT. The combination of XVI and the HRTT has the potential to improve the accuracy of high-precision treatments.

[1]  C C Ling,et al.  Cone-beam CT with megavoltage beams and an amorphous silicon electronic portal imaging device: potential for verification of radiotherapy of lung cancer. , 2002, Medical physics.

[2]  Kamil M Yenice,et al.  CT image-guided intensity-modulated therapy for paraspinal tumors using stereotactic immobilization. , 2003, International journal of radiation oncology, biology, physics.

[3]  Matthias Guckenberger,et al.  Magnitude and clinical relevance of translational and rotational patient setup errors: a cone-beam CT study. , 2006, International journal of radiation oncology, biology, physics.

[4]  Mark Oldham,et al.  Cone-beam-CT guided radiation therapy: A model for on-line application. , 2005, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[5]  Kajetan Berlinger,et al.  Target motion measurement without implanted markers and its validation by comparison with manually obtained data. , 2005, Medical physics.

[6]  T. Bortfeld,et al.  How much margin reduction is possible through gating or breath hold? , 2005, Physics in medicine and biology.

[7]  M Engelsman,et al.  The effect of breathing and set-up errors on the cumulative dose to a lung tumor. , 2001, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[8]  Frank Van den Heuvel,et al.  Independent verification of ultrasound based image-guided radiation treatment, using electronic portal imaging and implanted gold markers. , 2003, Medical physics.

[9]  Hazim Jaradat,et al.  The utility of megavoltage computed tomography images from a helical tomotherapy system for setup verification purposes. , 2004, International journal of radiation oncology, biology, physics.

[10]  M. Oldham,et al.  Cone-beam-CT guided radiation therapy: technical implementation. , 2005, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[11]  Brenda G. Clark,et al.  Analysis of patient repositioning accuracy in precision radiation therapy using automated image fusion , 2005, Journal of applied clinical medical physics.

[12]  Jan-Jakob Sonke,et al.  Automatic prostate localization on cone-beam CT scans for high precision image-guided radiotherapy. , 2005, International journal of radiation oncology, biology, physics.

[13]  J. Wong,et al.  Flat-panel cone-beam computed tomography for image-guided radiation therapy. , 2002, International journal of radiation oncology, biology, physics.

[14]  J. Pouliot,et al.  Evaluation of ultrasound-based prostate localization for image-guided radiotherapy. , 2003, International journal of radiation oncology, biology, physics.

[15]  Ping Xia,et al.  Low-dose megavoltage cone-beam CT for radiation therapy. , 2005, International journal of radiation oncology, biology, physics.

[16]  Ravinder Nath,et al.  A method to implement full six-degree target shift corrections for rigid body in image-guided radiotherapy. , 2005, Medical physics.

[17]  David A Jaffray,et al.  The stability of mechanical calibration for a kV cone beam computed tomography system integrated with linear accelerator. , 2005, Medical physics.

[18]  W A Beckham,et al.  Evaluation of the validity of a convolution method for incorporating tumour movement and set-up variations into the radiotherapy treatment planning system. , 2000, Physics in medicine and biology.

[19]  P. Munro,et al.  Portal Imaging Technology: Past, Present, and Future. , 1995, Seminars in radiation oncology.

[20]  Icru.  Prescribing, recording, and reporting photon beam therapy , 1993 .

[21]  Steve Webb,et al.  Intensity-Modulated Radiation Therapy , 1996, International journal of radiation oncology, biology, physics.

[22]  H. Kooy,et al.  Automatic three-dimensional correlation of CT-CT, CT-MRI, and CT-SPECT using chamfer matching. , 1994, Medical physics.

[23]  D A Jaffray,et al.  Managing geometric uncertainty in conformal intensity-modulated radiation therapy. , 1999, Seminars in radiation oncology.

[24]  A G Glendinning,et al.  Dosimetric characteristics of the Elekta Beam Modulator™ , 2005, Physics in medicine and biology.

[25]  C. Ma,et al.  In-room CT techniques for image-guided radiation therapy. , 2006, Medical dosimetry : official journal of the American Association of Medical Dosimetrists.

[26]  B. Rhein,et al.  Stereotactic intensity modulated radiation therapy and inverse treatment planning for tumors of the head and neck region: clinical implementation of the step and shoot approach and first clinical results. , 2003, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[27]  S Webb,et al.  A cone-beam megavoltage CT scanner for treatment verification in conformal radiotherapy. , 1998, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[28]  T. Rockwell Mackie,et al.  Helical Tomotherapy: An Innovative Technology and Approach to Radiation Therapy , 2002, Technology in cancer research & treatment.