title: 4DCT-based measurement of changes in pulmonary function following a course of radiation therapy.
abstract: OBJECTIVE
  Radiation therapy (RT) for lung cancer is commonly limited to subtherapeutic doses due to unintended toxicity to normal lung tissue. Reducing the frequency of occurrence and magnitude of normal lung function loss may benefit from treatment plans that incorporate the regional lung and radiation dose information. In this article, the authors propose a method that quantitatively measures the regional changes in lung tissue function following a course of radiation therapy by using 4DCT and image registration techniques.
  
  
  METHODS
  4DCT data sets before and after RT from two subjects are used in this study. Nonlinear 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration to estimate the pulmonary function. The Jacobian of the image registration transformation, indicating local lung expansion or contraction, serves as an index of regional pulmonary function. Approximately 120 annotated vascular bifurcation points are used as landmarks to evaluate registration accuracy. The authors compare regional pulmonary function before and after RT to the planned radiation dose at different locations of the lung.
  
  
  RESULTS
  In all registration pairs, the average landmark distances after registration are on the order of 1 mm. The pulmonary function change as indicated by the Jacobian change ranges from -0.15 to 0.1 in the contralateral lung and -0.22 to 0.23 in the ipsilateral lung for subject A, and ranges from -0.4 to 0.39 in the contralateral lung and -0.25 to 0.5 in the ipsilateral lung for subject B. Both of the subjects show larger range of the increase in the pulmonary function in the ipsilateral lung than the contralateral lung. For lung tissue regions receiving a radiation dose larger than 24 Gy, a decrease in pulmonary function was observed. For regions receiving a radiation dose smaller than 24 Gy, either an increase or a decrease in pulmonary function was observed. The relationship between the pulmonary function change and the radiation dose varies at different locations.
  
  
  CONCLUSIONS
  With the use of 4DCT and image registration techniques, the pulmonary function prior to and following a course of radiation therapy can be measured. In the preliminary application of this approach for two subjects, changes in pulmonary function were observed with a weak correlation between the dose and pulmonary function change. In certain sections of the lung, detected locally compromised pulmonary function may have resulted from radiation injury.
authors.affiliation: Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Ding
authors.forename: John E
authors.initials: JE
authors.lastname: Bayouth
authors.forename: John M
authors.initials: JM
authors.lastname: Buatti
authors.forename: Gary E
authors.initials: GE
authors.lastname: Christensen
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Reinhardt
mesh_terms: D000465:Algorithms; D016477:Artifacts; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011881:Radiotherapy, Computer-Assisted / Q000379:methods; D020266:Radiotherapy, Conformal / Q000379:methods; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
references.citation: Int J Radiat Oncol Biol Phys. 1999 Sep 1;45(2):323-9
references.pmid: 10487552
references.citation: Int J Radiat Oncol Biol Phys. 2008 Jul 1;71(3):838-47
references.pmid: 18439765
references.citation: Int J Radiat Oncol Biol Phys. 2006 Dec 1;66(5):1281-93
references.pmid: 17126203
references.citation: Int J Radiat Oncol Biol Phys. 2005 Jul 1;62(3):630-4
references.pmid: 15936537
references.citation: Int J Radiat Oncol Biol Phys. 2001 Nov 1;51(3):650-9
references.pmid: 11597805
references.citation: Respir Physiol Neurobiol. 2005 Aug 25;148(1-2):65-83
references.pmid: 16061426
references.citation: Int J Radiat Oncol Biol Phys. 2003 Mar 1;55(3):724-35
references.pmid: 12573760
references.citation: IEEE Trans Med Imaging. 2009 Feb;28(2):202-14
references.pmid: 19188109
references.citation: Oncology (Williston Park). 2008 Jan;22(1):37-47; discussion 52-3
references.pmid: 18251282
references.citation: IEEE Trans Med Imaging. 2001 Jun;20(6):490-8
references.pmid: 11437109
references.citation: Int J Radiat Oncol Biol Phys. 2009 Jan 1;73(1):112-8
references.pmid: 18786780
references.citation: Acad Radiol. 2006 Aug;13(8):929-31
references.pmid: 16843844
references.citation: Int J Radiat Oncol Biol Phys. 2008 Feb 1;70(2):374-81
references.pmid: 18029106
references.citation: Int J Radiat Oncol Biol Phys. 2006 May 1;65(1):255-65
references.pmid: 16618580
references.citation: Med Phys. 2007 Jun;34(6):2155-63
references.pmid: 17654918
references.citation: Int J Radiat Oncol Biol Phys. 2006 Dec 1;66(5):1543-52
references.pmid: 17126212
references.citation: Int J Radiat Oncol Biol Phys. 2005 Oct 1;63(2):324-33
references.pmid: 16168827
references.citation: Acad Radiol. 2003 Oct;10(10):1147-52
references.pmid: 14587632
references.citation: Int J Radiat Oncol Biol Phys. 2007 Jun 1;68(2):562-71
references.pmid: 17398028
references.citation: IEEE Trans Med Imaging. 2001 Jul;20(7):568-82
references.pmid: 11465464
references.citation: Med Image Anal. 2008 Dec;12(6):752-63
references.pmid: 18501665
references.citation: Int J Radiat Oncol Biol Phys. 2006 Sep 1;66(1):117-25
references.pmid: 16765528
references.citation: Magn Reson Med. 2002 Jun;47(6):1029-51
references.pmid: 12111949
references.citation: J Appl Physiol (1985). 2001 Feb;90(2):421-30
references.pmid: 11160037
references.citation: Int J Radiat Oncol Biol Phys. 1998 Aug 1;42(1):1-9
references.pmid: 9747813
references.citation: Int J Radiat Oncol Biol Phys. 2008 Nov 15;72(4):967-71
references.pmid: 18954709
references.citation: J Magn Reson Imaging. 2004 Oct;20(4):540-54
references.pmid: 15390146
references.citation: Int J Radiat Oncol Biol Phys. 2007 Apr 1;67(5):1510-8
references.pmid: 17394947
references.citation: Ann Nucl Med. 2002 Jul;16(5):303-10
references.pmid: 12230089
references.citation: Med Phys. 2007 Nov;34(11):4098-108
references.pmid: 18072476
references.citation: Int J Radiat Oncol Biol Phys. 2007 Oct 1;69(2):552-9
references.pmid: 17869668
references.citation: Int J Radiat Oncol Biol Phys. 2002 Oct 1;54(2):329-39
references.pmid: 12243805
references.citation: Int J Radiat Oncol Biol Phys. 2007 Feb 1;67(2):417-24
references.pmid: 17236965
references.citation: Med Image Comput Comput Assist Interv. 2008;11(Pt 2):1006-13
references.pmid: 18982703
references.citation: Nature. 2005 Apr 7;434(7034):777-82
references.pmid: 15772676
references.citation: J Appl Physiol (1985). 2007 Jan;102(1):448-58
references.pmid: 17038490
references.citation: Int J Radiat Oncol Biol Phys. 2005 Sep 1;63(1):5-24
references.pmid: 15963660
references.citation: J Appl Physiol (1985). 2008 Apr;104(4):1177-84
references.pmid: 18258804
references.citation: Int J Radiat Oncol Biol Phys. 2006 Apr 1;64(5):1495-502
references.pmid: 16580500
references.citation: Med Phys. 2009 Sep;36(9):4213-22
references.pmid: 19810495