title: Computed tomography appearance of early radiation injury to the lung: correlation with clinical and dosimetric factors.
abstract: OBJECTIVE
  To systematically assess the spectrum of radiologic changes in the lung after radiation therapy for non-small-cell lung cancer.
  
  
  METHODS
  We reviewed the cases of 146 patients treated with radical radiotherapy at our institution. All patients had computed tomography (CT) scans performed 3 months after completion of therapy. Radiographic appearances were categorized using a standard grading system. The association of these abnormalities with pretreatment factors and clinical radiation pneumonitis (RP) was investigated.
  
  
  RESULTS
  New intrapulmonary abnormalities were seen in 92 patients (63%). These were ground-glass opacity in 16 (11%), patchy consolidation in 19 (13%), and diffuse consolidation in 57 (39%). Twenty-five patients (17%) developed clinical symptoms of RP. Although 80% of the patients with RP had areas of consolidation seen on the posttreatment CT scan, the majority (74%) of patients with such radiographic changes were asymptomatic. For patients with lung infiltrates, the minimum isodose encompassing the volume of radiologic abnormality was usually ≥27 Gy. Traditional dose-volume metrics, pulmonary function tests, and the coadministration of angiotensin converting enzyme inhibitors (ACE-I) were all strongly correlated with the presence of radiologic injury on univariate analysis (p≤0.002). There was also an inverse correlation between prior smoking history and CT scan changes (p=0.02). On multivariate analysis, dosimetric parameters and the use of ACE-I retained significance (p=0.005).
  
  
  CONCLUSIONS
  Our findings suggest that there is substantial interindividual variation in lung radiosensitivity. ACE-I prevented the radiologic changes seen after high-dose radiation therapy, and their role as radioprotectants warrants further investigation.
authors.affiliation: Gloucestershire Oncology Centre, Cheltenham General Hospital, Cheltenham, UK. peter.jenkins@glos.nhs.uk
authors.forename: Peter
authors.initials: P
authors.lastname: Jenkins
authors.forename: Anne
authors.initials: A
authors.lastname: Welsh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control; D011836:Radiation Tolerance / Q000187:drug effects; D011879:Radiotherapy Dosage; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors