title: Dosimetric evaluation of compensator intensity modulation-based stereotactic body radiotherapy for Stage I non-small-cell lung cancer.
abstract: OBJECTIVE
  To evaluate the dosimetry of compensator intensity modulation-based stereotactic body radiotherapy (SBRT) [non-coplanar intensity-modulated radiotherapy (ncIMRT)], its use was compared with that of three-dimensional conformation-based SBRT, for patients with Stage I non-small-cell lung cancer (NSCLC).
  
  
  METHODS
  21 consecutive patients with Stage I NSCLC were treated with ncIMRT or SBRT at Tokyo Medical University. To compare the two techniques, ncIMRT and SBRT plans for each patient were generated, where the planning target volume (PTV) coverages were adjusted to be equivalent to each other. The prescribed dose was set as 75 Gy in 30 fractions. PTV coverage, conformity index, conformation number (CN) and homogeneity index (HI) were used to compare the two strategies.
  
  
  RESULTS
  There was no statistically significant difference between PTV coverage for the 100%, 95% and 90% dose levels in the SBRT plan and those in the ncIMRT plan. The CN values were 0.53 ± 0.13 in the SBRT plan and 0.72 ± 0.10 in the ncIMRT plan. These values were significantly better than those of the SBRT plan (p < 0.001). The HI in the ncIMRT plan was 1.04 ± 0.03%, which was also significantly better than that of SBRT.
  
  
  CONCLUSIONS
  The ncIMRT plan provided superior conformity and reduced the doses to the lung for patients with Stage I NSCLC.
  
  
  CONCLUSIONS
  The delivery technique with compensator intensity modulation-based SBRT was evaluated. Concerning target motion, this is thought to be more robust and safer than SBRT for early-stage NSCLC.
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tajima
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakayama
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Itonaga
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shiraishi
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okubo
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Mikami
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sugahara
authors.affiliation: Department of Radiology, Tokyo Medical University, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tokuuye
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000601:surgery*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D008297:Male; D011874:Radiometry; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D016896:Treatment Outcome