title: Two-dimensional in vivo rectal dosimetry using an endorectal balloon with unfoldable radiochromic film during prostate cancer radiotherapy.
abstract: The present study aims to investigate the feasibility of two-dimensional (2D) in vivo rectal dosimetry using an endorectal balloon for the radiotherapy of prostate cancer.
  
  
  
  The endorectal balloon was equipped with an unfoldable radiochromic film. The film was unrolled as the balloon was inflated, and rolled as it was deflated. Its mechanical and imaging properties were tested, and the dosimetric effectiveness was evaluated in clinical photon and proton beams.
  
  
  
  The size of the endorectal balloon including the film was linearly proportional to the volume of water filled in the balloon, and its position could be identified by X-ray radiography. The loss of dose information due to film cutting was within ±1mm from the cutting line. Applying linear interpolation on cut film, the gamma passing rate was more than 95% for 2%/2mm criteria. The measured dose profiles agreed with the plan within 3% and 4% for the photon and proton beams, respectively. A dose-volume histogram of the anterior rectal wall could be obtained from the measured dose distribution in the balloon, which also agreed well with the plan.
  
  
  
  2D in vivo rectal dosimetry is feasible using the endorectal balloon with a radiochromic film in the radiotherapy of prostate cancer.
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Jeang
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Soonki
authors.initials: S
authors.lastname: Min
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Kwan Ho
authors.initials: KH
authors.lastname: Cho
authors.affiliation: Department of Radiation Oncology, National Medical Center, Seoul, Republic of Korea.
authors.forename: Ui-Jung
authors.initials: UJ
authors.lastname: Hwang
authors.affiliation: Department of Radiation Oncology, Korea Cancer Center Hospital, Seoul, Republic of Korea.
authors.forename: Sang Hyoun
authors.initials: SH
authors.lastname: Choi
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Jungwon
authors.initials: J
authors.lastname: Kwak
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Jong Hwi
authors.initials: JH
authors.lastname: Jeong
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Haksoo
authors.initials: H
authors.lastname: Kim
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Se Byeong
authors.initials: SB
authors.lastname: Lee
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Dongho
authors.initials: D
authors.lastname: Shin
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Jeonghoon
authors.initials: J
authors.lastname: Park
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Joo-Young
authors.initials: JY
authors.lastname: Kim
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Dae Yong
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea. Electronic address: yklim@ncc.re.kr.
authors.forename: Young Kyung
authors.initials: YK
authors.lastname: Lim
mesh_terms: D005373:Film Dosimetry; D006801:Humans; D000072231:In Vivo Dosimetry / Q000379:methods*; D008297:Male; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012007:Rectum / Q000000981:diagnostic imaging* / Q000473:pathology / Q000528:radiation effects*
keywords: Endorectal balloon; In vivo rectal dosimetry; Prostate cancer; Radiochromic film; Radiotherapy