title: Radiation dose-effect relations and local recovery in perfusion for patients with non-small-cell lung cancer.
abstract: OBJECTIVE
  To determine local dose-effect relations for lung perfusion and density changes due to irradiation for patients with non-small-cell lung cancer (NSCLC) and to quantify the effect of reperfusion.
  
  
  METHODS
  For 25 NSCLC patients and a reference group of 81 patients with healthy lungs, registered single photon emission computed tomography (SPECT) lung perfusion and CT scans were made, before and after radiotherapy. Average dose-effect relations for perfusion and CT-density changes were calculated and compared with the dose-effect relation of the reference group. On the basis of these dose-effect relations, the post-RT perfusion was predicted for each patient and compared to the measured post-RT perfusion.
  
  
  RESULTS
  Well-perfused lung regions of the NSCLC patients showed the same dose-effect relation as the reference patients. By comparing predicted and measured post-treatment perfusion scans, regions of reperfusion could be determined for 18 of 25 NSCLC patients but for none of the reference patients.
  
  
  CONCLUSIONS
  Well-perfused lung tissue of patients with NSCLC behaves like healthy lung tissue with respect to radiation. The dose-effect relation for perfusion and CT density was extended for doses up to 80 Gy. Radiation damage in poorly perfused lung regions was less than predicted as a consequence of local reperfusion.
authors.affiliation: Department of Radiotherapy, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Huis, Amsterdam, The Netherlands.
authors.forename: Y
authors.initials: Y
authors.lastname: Seppenwoolde
authors.forename: S H
authors.initials: SH
authors.lastname: Muller
authors.forename: J C
authors.initials: JC
authors.lastname: Theuws
authors.forename: P
authors.initials: P
authors.lastname: Baas
authors.forename: J S
authors.initials: JS
authors.lastname: Belderbos
authors.forename: L J
authors.initials: LJ
authors.lastname: Boersma
authors.forename: J V
authors.initials: JV
authors.lastname: Lebesque
mesh_terms: D000465:Algorithms; D001943:Breast Neoplasms / Q000503:physiopathology / Q000532:radiotherapy; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000528:radiation effects*; D008171:Lung Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000532:radiotherapy*; D008223:Lymphoma / Q000503:physiopathology / Q000532:radiotherapy; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012119:Respiration; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed