Abstract:
: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.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Kyriakou E,McKenzie DRdoi
10.1088/0031-9155/57/4/919subject
Has Abstractpub_date
2012-02-21 00:00:00pages
919-35issue
4eissn
0031-9155issn
1361-6560journal_volume
57pub_type
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