Radiation injury of the lung after three-dimensional conformal radiation therapy.
OBJECTIVE
The objective of this study is to describe the CT patterns of radiation injury in the lungs of patients who have undergone three-dimensional (3D) conformal radiation therapy (CRT).


METHODS
Over a 36-month period, the chest CT scans of 19 patients with non-small cell lung cancer who were treated with 3D CRT were reviewed. CT scans were evaluated for findings of radiation injury (ground-glass opacities, consolidation, bronchiectasis, and volume loss). The presence, extent, and distribution of these findings were reached by consensus.


RESULTS
Radiation pneumonitis limited to a small area immediately around the tumor was present in all patients who were imaged within 3 months after completion of the treatment (n = 7). Radiation-induced fibrosis occurred in all patients (n = 19). Three distinct patterns of fibrosis were consistently present, and these were classified as modified conventional, masslike, and scarlike. Modified conventional fibrosis (consolidation, volume loss, and bronchiectasis similar to, but less extensive than, conventional radiation fibrosis) was seen in five patients. Masslike fibrosis (focal consolidation with traction bronchiectasis limited to the site of the original tumor) was seen in eight patients. Scarlike fibrosis (linear opacity in the region of the original tumor associated with moderate to severe volume loss) was seen in six patients.


CONCLUSIONS
Three-dimensional conformal radiation therapy results in three patterns of radiation fibrosis that differ from the conventional radiation-induced lung injury. Knowledge of the full spectrum of these manifestations is useful in the correct interpretation of CT scans after 3D CRT.
Koenig
Titus R
TR
Department of Radiology, Division of Diagnostic Imaging, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
Munden
Reginald F
RF
Erasmus
Jeremy J
JJ
Sabloff
Bradley S
BS
Gladish
Gregory W
GW
Komaki
Ritsuko
R
Stevens
Craig W
CW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D055370:Lung Injury; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000209:etiology*; D020266:Radiotherapy, Conformal / Q000009:adverse effects* / Q000379:methods*