Changes in lung tumor shape during respiration

Evidence that some lung tumors change shape during respiration is derived from respiratory gated CT data by statistical shape modeling and image manipulation. Some tumors behave as rigid objects while others show systematic shape changes. Two views of lung motion are presented to allow analysis of the results. In the first, lung motion is viewed as a wave motion in which inertial effects arising from mass are present and in the second it is a quasistatic motion in which the mass of the lung tissues is neglected. In the first scenario, the extremes of tumor compression and expansion are expected to correlate with maximum upward and downward velocity of the tumor, respectively. In the second, they should occur at end exhale and end inhale, respectively. An observed correlation between tumor strain and tumor velocity provides more support for the first view of lung motion and may explain why previous attempts at observing tumor shape changes during respiration have largely failed. The implications for the optimum gating of radiation therapy are discussed.

[1]  C. Meyer,et al.  Automated generation of a four-dimensional model of the liver using warping and mutual information. , 2003, Medical physics.

[2]  Timothy F. Cootes,et al.  Statistical models of appearance for medical image analysis and computer vision , 2001, SPIE Medical Imaging.

[3]  G. Christensen,et al.  A method for the reconstruction of four-dimensional synchronized CT scans acquired during free breathing. , 2003, Medical physics.

[4]  M. Kris,et al.  Promising survival with three-dimensional conformal radiation therapy for non-small cell lung cancer. , 1997, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[5]  J. Wong,et al.  The use of active breathing control (ABC) to reduce margin for breathing motion. , 1999, International journal of radiation oncology, biology, physics.

[6]  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.

[7]  L. Xing,et al.  Tissue feature-based and segmented deformable image registration for improved modeling of shear movement of lungs. , 2009, International journal of radiation oncology, biology, physics.

[8]  James M Balter,et al.  Evaluation of the influence of breathing on the movement and modeling of lung tumors. , 2002, International journal of radiation oncology, biology, physics.

[9]  M. V. van Herk,et al.  Precise and real-time measurement of 3D tumor motion in lung due to breathing and heartbeat, measured during radiotherapy. , 2002, International journal of radiation oncology, biology, physics.

[10]  J. Lebesque,et al.  Dose escalation in NSCLC using three dimensional conformal radiotherapy (3 DCRT) , 2000 .

[11]  D R McKenzie,et al.  Dynamic modeling of lung tumor motion during respiration , 2011, Physics in medicine and biology.

[12]  T. Pan,et al.  4D-CT imaging of a volume influenced by respiratory motion on multi-slice CT. , 2004, Medical physics.

[13]  Suresh Senan,et al.  4D imaging for target definition in stereotactic radiotherapy for lung cancer , 2006, Acta oncologica.

[14]  R Mohan,et al.  Predicting respiratory motion for four-dimensional radiotherapy. , 2004, Medical physics.

[15]  Gregory C Sharp,et al.  Evaluation of deformable registration of patient lung 4DCT with subanatomical region segmentations. , 2008, Medical physics.

[16]  Raj Shekhar,et al.  Do tumors in the lung deform during normal respiration? An image registration investigation. , 2009, International journal of radiation oncology, biology, physics.

[17]  Martin J Murphy,et al.  Issues in respiratory motion compensation during external-beam radiotherapy. , 2002, International journal of radiation oncology, biology, physics.

[18]  Geoffrey D. Hugo,et al.  Anatomic and pathologic variability during radiotherapy for a hybrid active breath-hold gating technique. , 2010, International journal of radiation oncology, biology, physics.

[19]  P. Keall.  4-dimensional computed tomography imaging and treatment planning. , 2004, Seminars in radiation oncology.

[20]  Eric C Ford,et al.  Measurement of lung tumor motion using respiration-correlated CT. , 2004, International journal of radiation oncology, biology, physics.