title: Evaluation of mass-like consolidation after stereotactic body radiation therapy for lung tumors.
abstract: BACKGROUND
  The purpose of this study was to evaluate the characteristics of mass-like consolidation of the lung on computed tomography (CT) after stereotactic body radiation therapy (SBRT) retrospectively.
  
  
  METHODS
  Forty lung tumors in 37 patients who underwent SBRT were evaluated. Mass-like consolidation was defined as a dense consolidation that newly appeared over or around the original tumor, which included radiation-induced lung injury (RILI) and local recurrence. Time of appearance, initial CT findings (ectatic bronchi and conformity to dose distribution) and serial changes in the size of the mass-like consolidation were evaluated.
  
  
  RESULTS
  Mass-like consolidation appeared in 27 (68%) of 40 tumors at a median of 5 months after SBRT. Follow-up examination revealed that 24 (89%) of the 27 mass-like consolidations were RILI and 3 (11%) were local recurrence. There were no significant differences in the initial CT findings between RILI and local recurrence. The size of the mass-like consolidation varied in the 12 months after SBRT. After 12 months or more, however, the size did not increase in any of the RILI cases, but it did increase in all recurrence cases.
  
  
  CONCLUSIONS
  Mass-like consolidations were observed in 68% of cases at a median of 5 months after SBRT. Although most of the mass-like consolidations were RILI, local recurrence was observed in a few cases. Early detection of local recurrence after SBRT was difficult.
authors.affiliation: Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nagata
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizowaki
authors.forename: Kenji
authors.initials: K
authors.lastname: Takayama
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Masato
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Norihisa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D003937:Diagnosis, Differential; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014916:Whole-Body Irradiation