title: Utility of an initial adaptive bladder volume control with ultrasonography for proton-beam irradiation for prostate cancer.
abstract: OBJECTIVE
  Our purpose was to evaluate the utility of time-fixed bladder volume control and adaptive bladder volume control with ultrasonography (US).
  
  
  METHODS
  Seventy-five patients with prostate cancer treated with proton-beam therapy were enrolled. Treatment plans were created using computed tomography (CT) images obtained 60 min after urination with usual water intake. Just before each irradiation, bladder volume was measured with US at the directed urine collection time. Bladder volume was calculated according to orthogonal diameters. A bladder volume of <50 ml was considered to reflect a collapsed bladder. The percentage of collapsed bladders was examined in total and from the first to fifth irradiations.
  
  
  RESULTS
  In total, 1,439 US confirmations (51 %) in 2,821 fractions were obtained and analyzed. A collapsed bladder was observed 152 of 1,439 times (11 %) in total, and the percentages of collapsed bladders from the first to fifth irradiations were 32 %, 18 %, 16 %, 12 %, and 7 %, respectively.
  
  
  CONCLUSIONS
  Time-fixed bladder control is associated with a risk of bladder volume insufficiency. Adaptive bladder volume control with initial US feedback could decrease the risk of bladder volume insufficiency.
authors.affiliation: Department of Radiotherapy, Graduate School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 920-8640, Japan, shigerad@staff.kanazawa-u.ac.jp.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Takamatsu
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Mariko
authors.initials: M
authors.lastname: Kawamura
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Sato
authors.forename: Satoko
authors.initials: S
authors.lastname: Asahi
authors.forename: Tamaki
authors.initials: T
authors.lastname: Kondou
authors.forename: Yuuji
authors.initials: Y
authors.lastname: Tameshige
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Maeda
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Kumano
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Gabata
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011467:Prostate / Q000000981:diagnostic imaging; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography; D001743:Urinary Bladder / Q000033:anatomy & histology / Q000000981:diagnostic imaging*