title: IMRT treatment plans and functional planning with functional lung imaging from 4D-CT for thoracic cancer patients.
abstract: OBJECTIVE
  Currently, the inhomogeneity of the pulmonary function is not considered when treatment plans are generated in thoracic cancer radiotherapy. This study evaluates the dose of treatment plans on highly-functional volumes and performs functional treatment planning by incorporation of ventilation data from 4D-CT.
  
  
  METHODS
  Eleven patients were included in this retrospective study. Ventilation was calculated using 4D-CT. Two treatment plans were generated for each case, the first one without the incorporation of the ventilation and the second with it. The dose of the first plans was overlapped with the ventilation and analyzed. Highly-functional regions were avoided in the second treatment plans.
  
  
  RESULTS
  For small targets in the first plans (PTV < 400 cc, 6 cases), all V5, V20 and the mean lung dose values for the highly-functional regions were lower than that of the total lung. For large targets, two out of five cases had higher V5 and V20 values for the highly-functional regions. All the second plans were within constraints.
  
  
  CONCLUSIONS
  Radiation treatments affect functional lung more seriously in large tumor cases. With compromise of dose to other critical organs, functional treatment planning to reduce dose in highly-functional lung volumes can be achieved.
authors.affiliation: Department of Biomedical Imaging and Radiological Science, China Medical University, 91, Hsueh-Shih Road, Taichung City, Taiwan. tzungchi.huang@mail.cmu.edu.tw
authors.forename: Tzung-Chi
authors.initials: TC
authors.lastname: Huang
authors.forename: Chien-Yi
authors.initials: CY
authors.lastname: Hsiao
authors.forename: Chun-Ru
authors.initials: CR
authors.lastname: Chien
authors.forename: Ji-An
authors.initials: JA
authors.lastname: Liang
authors.forename: Tzu-Ching
authors.initials: TC
authors.lastname: Shih
authors.forename: Geoffrey G
authors.initials: GG
authors.lastname: Zhang
mesh_terms: D000368:Aged; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011874:Radiometry / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012189:Retrospective Studies; D013899:Thoracic Neoplasms / Q000532:radiotherapy*