title: The superiority of hybrid-volumetric arc therapy (VMAT) technique over double arcs VMAT and 3D-conformal technique in the treatment of locally advanced non-small cell lung cancer--a planning study.
abstract: OBJECTIVE
  To compare the dosimetric performance of three different treatment techniques - conformal radiotherapy (CRT), double arcs volumetric modulated arc therapy (RapidArc, RA) and Hybrid-RapidArc (H-RA) for locally-advanced non-small cell lung cancer (NSCLC).
  
  
  METHODS
  CRT, RA and H-RA plans were optimized for 24 stage III NSCLC patients. The target prescription dose was 60Gy. CRT consisted of 5-7 coplanar fields, while RA comprised of two 204(o) arcs. H-RA referred to two 204(o) arcs plus 2 static fields, which accounted for approximately half of the total dose. The plans were optimized to fulfill the departmental plan acceptance criteria.
  
  
  RESULTS
  RA and H-RA yielded a 20% better conformity compared with CRT. Lung volume receiving >20Gy (V20) and mean lung dose (MLD) were the lowest in H-RA (V20 1.7% and 2.1% lower, MLD 0.59Gy and 0.41Gy lower than CRT & RA respectively) without jeopardizing the low-dose lung volume (V5). H-RA plans gave the lowest mean maximum spinal cord dose (34.4Gy, 3.9Gy<CRT and 2.2Gy<RA plans) and NTCP of lung. Higher average MU per fraction (addition 52.4MU) was observed with a reduced treatment time compared with CRT plans.
  
  
  CONCLUSIONS
  The H-RA technique was superior in dosimetric outcomes for treating locally-advanced NSCLC compared to CRT and RA.
authors: Department of Clinical Oncology, Pamela Youde Nethersole Eastern Hospital, 3 Lok Man Road, Chai Wan, Hong Kong. chansh2@ha.org.hk
authors: Oscar S H
authors: OS
authors: Chan
authors: Michael C H
authors: MC
authors: Lee
authors: Albert W M
authors: AW
authors: Hung
authors: Amy T Y
authors: AT
authors: Chang
authors: Rebecca M W
authors: RM
authors: Yeung
authors: Anne W M
authors: AW
authors: Lee
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods; D016896:Treatment Outcome