Analysis of patient repositioning accuracy in precision radiation therapy using automated image fusion

This work describes a rapid and objective method of determining repositioning error during the course of precision radiation therapy using off‐line CT imaging and automated mutual‐information image fusion. The technique eliminates the variability associated with manual identification of anatomical landmarks by observers. A phantom study was conducted to quantify the accuracy of the image co‐registration‐based analysis itself. For CT voxel dimensions of 0.65×0.65×1.0mm3, the method is shown to detect translations with an accuracy of 0.5 mm in the anterior‐posterior and lateral dimensions and 0.8 mm in the superior‐inferior dimension. Phantom rotation in the coronal plane was detected to within 0.5° of expected values. The analysis has been applied to eight radiotherapy patients at two independent clinics, each immobilized by the same system for cranial stereotactic radiotherapy and CT‐imaged once per week over the five‐ to six‐week course of treatment. Among all patients, the ranges of translation in the anterior‐posterior, lateral, and superior‐inferior dimensions were −0.91mmto0.77mm,−0.66mm to1.02mm, and −2.24mm to3.47mm, respectively. Considering all patients and CT scans, the standard deviations of translation were 0.42 mm, 0.47 mm, and 1.36 mm in the anterior‐posterior, lateral, and superior‐inferior dimensions, respectively. The ranges of patient rotation about the superior‐inferior, left‐right, and anterior‐posterior axes were −2.84to2.62°,−1.74°to1.96°, and −1.78°to1.42°, respectively. PACS numbers: 87.53.‐j, 87.53.Kn, 87.53.Ly, 87.53.Xd

[1]  Michael Vogele,et al.  A Simple and Non-Invasive Vacuum Mouthpiece-Based Head Fixation System for High Precision Radiotherapy , 2001, Strahlentherapie und Onkologie.

[2]  Patient position reproducibility in fractionated stereotactic radiotherapy: an update after changing dental impression material. , 1999, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[3]  Stanley J. Rosenthal,et al.  A precision cranial immobilization system for conformal stereotactic fractionated radiation therapy. , 1995, International journal of radiation oncology, biology, physics.

[4]  M. Phillips,et al.  Stereotactic frame for neuroradiology and charged particle Bragg peak radiosurgery of intracranial disorders. , 1989, International journal of radiation oncology, biology, physics.

[5]  R Bale,et al.  Repositioning accuracy: comparison of a noninvasive head holder with thermoplastic mask for fractionated radiotherapy and a case report. , 1998, International journal of radiation oncology, biology, physics.

[6]  M. Mills,et al.  MO‐E‐230A‐03: Journal of Applied Clinical Medical Physics , 2006 .

[7]  O A Mendiondo,et al.  A precision repeat localization head frame for fractionated stereotactic radiotherapy. , 1997, Medical dosimetry : official journal of the American Association of Medical Dosimetrists.

[8]  F. Lohr,et al.  Noninvasive patient fixation for extracranial stereotactic radiotherapy. , 1999, International journal of radiation oncology, biology, physics.

[9]  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.

[10]  B. Salter,et al.  The TALON removable head frame system for stereotactic radiosurgery/radiotherapy: measurement of the repositioning accuracy. , 2001, International journal of radiation oncology, biology, physics.

[11]  K. Bratengeier,et al.  CT simulation in stereotactic brain radiotherapy--analysis of isocenter reproducibility with mask fixation. , 1997, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[12]  A. Warrington,et al.  A non-invasive, relocatable stereotactic frame for fractionated radiotherapy and multiple imaging. , 1991, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[13]  H. Alheit,et al.  Patient Position Reproducibility in Fractionated Stereotactically Guided Conformal Radiotherapy Using the BrainLab® Mask System , 2001, Strahlentherapie und Onkologie.

[14]  J I Fabrikant,et al.  Heavy charged-particle stereotactic radiosurgery: cerebral angiography and CT in the treatment of intracranial vascular malformations. , 1989, International journal of radiation oncology, biology, physics.

[15]  Michael Unser,et al.  A pyramid approach to sub-pixel image fusion based on mutual information , 1996, Proceedings of 3rd IEEE International Conference on Image Processing.

[16]  Colin Studholme,et al.  Automated 3-D registration of MR and CT images of the head , 1996, Medical Image Anal..

[17]  R. Wurm,et al.  [Improved patient repositioning accuracy by integrating an additional jaw fixation into a high precision face mask system in stereotactic radiotherapy of the head]. , 2003, Strahlentherapie und Onkologie : Organ der Deutschen Rontgengesellschaft ... [et al].

[18]  S. Tung,et al.  CT verification of isocentre relocatability using stereotactic mask fixation system. , 2003, Clinical oncology (Royal College of Radiologists (Great Britain)).

[19]  T. Tomita,et al.  Repositioning accuracy with the Laitinen frame for fractionated stereotactic radiation therapy in adult and pediatric brain tumors: preliminary report. , 2001, Radiology.

[20]  B. Clark,et al.  Commissioning a System for Stereotactic Radiosurgery/Radiotherapy of the Head and Neck , 2002 .

[21]  C A Pelizzari,et al.  Repositioning accuracy of a noninvasive head fixation system for stereotactic radiotherapy. , 1996, Medical physics.