title: Comparison of Two RapidArc Delivery Strategies in Stereotactic Body Radiotherapy of Peripheral Lung Cancer with Flattening Filter Free Beams.
abstract: OBJECTIVE
  To investigate the performance of using partial arc (PA) and full arc with avoidance sectors (FAAS) in stereotactic body radiotherapy (SBRT) of peripheral lung cancer with flattening filter free (FFF) beams.
  
  
  METHODS
  Eighteen patients with primary (T1 or T2) non-small-cell lung cancer (NSCLC) or lung metastatic were selected for this study. Nine patients with a gross tumor volume (GTV) <= 10 cc were designated as the small tumor group. The other nine patients with a GTV between 10 cc and 44 cc were assigned to the large tumor group. The treatment plans were generated in eighteen patients using PA and FAAS techniques, respectively, and delivered with a Varian TrueBeam Linac. Dosimetry of the target and organs at risk (OARs), monitor unit (MU), out-of-field dose, and delivery time were statistically analyzed. Delta4 and portal dosimetry were employed to evaluate the delivery accuracy.
  
  
  RESULTS
  For the small tumor group, compared with the PA plans, the FAAS plans significantly achieved a lower MU/fraction, out-of-field dose and a shorter treatment time (p<0.05), but the target dose was slightly higher than that delivered by PA plans (p<0.05). For the large tumor group, the PA plans significantly attained a shorter treatment time (p<0.05), whereas MU/fraction, out-of-field dose and dose to OARs were comparable between the two plans (p>0.05). Furthermore, all plans generated from the eighteen patients achieved a high pass rate in patient-specific quality assurance, with all the gamma indices greater than 97% at the Γ3mm, 3% threshold.
  
  
  CONCLUSIONS
  This study suggests that the FAAS technique is more beneficial for the small tumor patients undergoing lung SBRT with FFF beams because of its higher treatment efficiency and MU reduction. However, for the large tumor patients, the PA technique is recommended due to its higher treatment efficiency.
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Bao-Tian
authors.initials: BT
authors.lastname: Huang
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Jia-Yang
authors.initials: JY
authors.lastname: Lu
authors.affiliation: Department of Nosocomial Infection Management, the Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Pei-Xian
authors.initials: PX
authors.lastname: Lin
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Jian-Zhou
authors.initials: JZ
authors.lastname: Chen
authors.affiliation: Medical Physics Program, University of Nevada Las Vegas, Las Vegas, NV, 89154, Unites States of America.
authors.forename: Yu
authors.initials: Y
authors.lastname: Kuang
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China.
authors.forename: Chuang-Zhen
authors.initials: CZ
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011874:Radiometry; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D016896:Treatment Outcome